Θ
BOOK VIII


Lectio 1
Opinions on the beginning and end of motion
Chapter 1
1 Πότερον γέγονέ ποτε κίνησις οὐκ οὖσα πρότερον, καὶ φθείρεται πάλιν οὕτως ὥστε κινεῖσθαι μηδέν, ἢ οὔτ' ἐγένετο οὔτε φθείρεται, ἀλλ' ἀεὶ ἦν καὶ ἀεὶ ἔσται, καὶ τοῦτ' ἀθάνατον καὶ ἄπαυστον ὑπάρχει τοῖς οὖσιν, οἷον ζωή τις οὖσα τοῖς φύσει συνεστῶσι πᾶσιν; It remains to consider the following question. Was there ever a becoming of motion before which it had no being, and is it perishing again so as to leave nothing in motion? Or are we to say that it never had any becoming and is not perishing, but always was and always will be? Is it in fact an immortal never-failing property of things that are, a sort of life as it were to all naturally constituted things?
εἶναι μὲν οὖν κίνησιν πάντες φασὶν οἱ περὶ φύσεώς τι λέγοντες διὰ τὸ κοσμοποιεῖν καὶ περὶ γενέσεως καὶ φθορᾶς εἶναι τὴν θεωρίαν πᾶσαν αὐτοῖς, ἣν ἀδύνατον ὑπάρχειν μὴ κινήσεως οὔσης· Now the existence of motion is asserted by all who have anything to say about nature, because they all concern themselves with the construction of the world and study the question of becoming and perishing, which processes could not come about without the existence of motion.
ἀλλ' ὅσοι μὲν ἀπείρους τε κόσμους εἶναί φασιν, καὶ τοὺς μὲν γίγνεσθαι τοὺς δὲ φθείρεσθαι τῶν κόσμων, ἀεί φασιν εἶναι κίνησιν (ἀναγκαῖον γὰρ τὰς γενέσεις καὶ τὰς φθορὰς εἶναι μετὰ κινήσεως αὐτῶν)· But those who say that there is an infinite number of worlds, some of which are in process of becoming while others are in process of perishing, assert that there is always motion (for these processes of becoming and perishing of the worlds necessarily involve motion),
ὅσοι δ' ἕνα <ἢ ἀεὶ> ἢ μὴ ἀεί, καὶ περὶ τῆς κινήσεως ὑποτίθενται κατὰ λόγον. εἰ δὴ ἐνδέχεταί ποτε μηδὲν κινεῖσθαι, διχῶς ἀνάγκη τοῦτο συμβαίνειν· ἢ γὰρ ὡς Ἀναξαγόρας λέγει (φησὶν γὰρ ἐκεῖνος, ὁμοῦ πάντων ὄντων καὶ ἠρεμούντων τὸν ἄπειρον χρόνον, κίνησιν ἐμποιῆσαι τὸν νοῦν καὶ διακρῖναι), ἢ ὡς Ἐμπεδοκλῆς ἐν μέρει κινεῖσθαι καὶ πάλιν ἠρεμεῖν, κινεῖσθαι μὲν ὅταν ἡ φιλία ἐκ πολλῶν ποιῇ τὸ ἓν ἢ τὸ νεῖκος πολλὰ ἐξ ἑνός, ἠρεμεῖν δ' ἐν τοῖς μεταξὺ χρόνοις, whereas those who hold that there is only one world, whether everlasting or not, make corresponding assumptions in regard to motion. If then it is possible that at any time nothing should be in motion, this must come about in one of two ways: either in the manner described by Anaxagoras, who says that all things were together and at rest for an infinite period of time, and that then Mind introduced motion and separated them; or in the manner described by Empedocles, according to whom the universe is alternately in motion and at rest—in motion, when Love is making the one out of many, or Strife is making many out of one, and at rest in the intermediate periods of time—his account being as follows:
λέγων οὕτως ᾗ μὲν ἓν ἐκ πλεόνων μεμάθηκε φύεσθαι, ἠδὲ πάλιν διαφύντος ἑνὸς πλέον' ἐκτελέθουσιν, (251a.) τῇ μὲν γίγνονταί τε καὶ οὔ σφισιν ἔμπεδος αἰών· ᾗ δὲ τάδ' ἀλλάσσοντα διαμπερὲς οὐδαμὰ λήγει, ταύτῃ δ' αἰὲν ἔασιν ἀκίνητοι κατὰ κύκλον. 'Since One hath learned to spring from Manifold, And One disjoined makes manifold arise, Thus they Become, nor stable is their life: But since their motion must alternate be, Thus have they ever Rest upon their round':
τὸ γὰρ "ᾗ δὲ τάδ' ἀλλάσσοντα" ἐνθένδε ἐκεῖσε λέγειν αὐτὸν ὑποληπτέον. for we must suppose that he means by this that they alternate from the one motion to the other.
σκεπτέον δὴ περὶ τούτων πῶς ἔχει· We must consider, then, how this matter stands, for the discovery of the truth about it is of importance, not only for the study of nature, but also for the investigation of the First Principle.
Postquam philosophus in praecedenti libro ostendit quod necesse est ponere primum mobile, et primum motum, et primum motorem; in hoc libro intendit inquirere qualis sit primus motor, et primus motus, et primum mobile. Et dividitur in partes duas: in prima praemittit quoddam quod est necessarium ad sequentem investigationem, scilicet motum esse sempiternum; in secunda procedit ad investigationem propositi, ibi: principium autem considerationis et cetera. 965. After showing in the preceding book that it is necessary to posit a first mobile, and a first motion, and a first mover, the Philosopher intends in this present book to inquire after a description of the first mover, and first motion, and first mobile, The book is divided into two parts: In the first he premises something necessary to the following investigation, namely, that motion is sempiternal; In the second he proceeds to investigate what is proposed, (L. 5).
Circa primum tria facit: primo movet dubitationem; secundo ostendit veritatem secundum suam opinionem, ibi: incipiemus autem primum etc.; tertio solvit ea quae in contrarium obiici possunt, ibi: contraria autem his et cetera. About the first he does three things: First he raises a problem; Secondly, he states the truth according to his own opinion, (L. 2); Thirdly, he answers possible objections to the contrary, (L. 4)#
Circa primum tria facit: primo proponit dubitationem; secundo ponit opiniones ad utramque partem, ibi: sed quanti quidem etc.; tertio ostendit utilitatem huius considerationis, ibi: considerandum igitur de hoc et cetera. In regard to the first he does three things: First he proposes his problem; Secondly, he gives opinions for both sides, at 968; Thirdly, he shows the usefulness of this consideration, at 970.
Circa primum duo facit: primo proponit dubitationem de qua investigare intendit; secundo respondet tacitae quaestioni, ibi: esse quidem igitur et cetera. About the first he does two things: First he proposes the problem he intends to investigate; Secondly, he responds to a tacit question, at 967.
Circa primum sciendum est, quod Averroes dicit quod Aristoteles in hoc capitulo non intendit inquirere in universali utrum motus sit sempiternus, sed de primo motu. 966. In regard to the first it should be known that Averroes says that Aristotle in this book does not intend to inquire whether motion is sempiternal universally, but limits his question to the first motion.
Sed si quis consideret et verba et processum philosophi, hoc est omnino falsum. Verba enim philosophi universaliter de motu loquuntur, quia dicit: utrum factus sit aliquando motus, cum non esset prius, et corrumpitur iterum sic quod moveri nihil sit. Ex quo manifeste apparet quod non de aliquo motu determinato quaerit, sed universaliter: utrum aliquando nihil fuerit motus. But if one considers both the words and procedure of the Philosopher, this is entirely false. For the words of the Philosopher speak of motion in a universal sense. He says in effect: “Was there ever a becoming of motion before which it had no being and is it perishing again so as to leave nothing in motion?” From this it is clear that he is not inquiring about one definite motion but about motion universally, asking whether at any time there was no motion.
Ex ipso etiam Aristotelis processu apparet hoc esse falsum. Primo quidem quia consuetudo sua est, semper ad propositum ex propriis argumentari; si quis autem sequentes rationes consideret quas inducit, in nulla earum sumitur aliquid pro medio, quod proprie ad primum motum pertineat, sed ad motum in communi. Unde ex hoc satis apparet quod intendit hic inquirere de sempiternitate motus in communi. The falseness of Averroes’ statement appears also from the very procedure of Aristotle. First, it is Aristotle’s custom always to argue to his proposition from proper causes. Now, if anyone will consider the arguments he adduces, he will see that in none of them does Aristotle argue from a middle term that refers properly to the first motion, but he argues rather from a middle proper to motion in general. Hence this alone shows that he intends to inquire here about the sempiternity of motion in general.
Secundo quia, si iam probatum esset quod est aliquis motus unus vel plures sempiterni, frustra inquireret inferius, utrum aliqua moveantur semper; cum hoc iam esset probatum. Ridiculum est etiam dicere quod Aristoteles inferius reiteret suam considerationem a principio, quasi aliquid omisisset, ut Commentator fingit. Erat enim copia Aristoteli corrigendi librum suum, et supplendi in loco debito quod fuerat omissum, ut non inordinate procederet. Si enim hoc capitulum exponatur secundum praedicti Commentatoris intentionem, omnia sequentia confusa et inordinata apparebunt. Nec est mirum: quia uno inconvenienti posito, alia sequuntur. Secondly, if he had already proved that there is one or a number of sempiternal motions, he would have been foolish to ask below whether anything is eternally in motion, for that question would have been already answered. It also is ridiculous to say that Aristotle would repeat from the start his consideration of a problem he had already settled, and act as though he had omitted something, as the Commentator pretends. For Aristotle had the opportunity to correct his book and fill in at the proper place any section he had omitted, so as not to proceed in a disorderly way. For if this chapter had been treated in the way charged by the Commentator, everything that follows would be confused and disorderly. This is not strange, for, having supposed an initial impossibility, others then follow.
Adhuc autem manifestius hoc apparet per hoc, quod Aristoteles inferius inquirere intendens de sempiternitate primi motus, utitur eo quod hic demonstratur, quasi principio: quod nullo modo faceret, si hic probasset primum motum esse aeternum. Furthermore, the correctness of our view is shown by the fact that Aristotle later on uses what he proves here, as a principle to prove the eternity of the first motion. He would never have done this, had he already proved that the first motion is eternal.
Ratio autem ex qua Averroes motus fuit, omnino frivola est. Dicit enim quod si dicatur quod Aristoteles hic intendit inquirere de sempiternitate motus in communi, sequetur quod consideratio Aristotelis hic sit diminuta; quia non apparet per id quod hic determinatur, quomodo motus semper possint continuari ad invicem. The reason which moved Averroes is wholly frivolous. For he says that if Aristotle is here intending to inquire into the eternity of motion in common, it will follow that the consideration of Aristotle has been diminished, because it is not evident from what he proves in this place, how motions could be always continued one to the other.
Sed hoc nihil est: quia Aristoteli sufficit in hoc capitulo probare in communi quod motus semper fuerit; qualiter autem sempiternitas motus continuetur, utrum per hoc quod omnia semper moveantur, vel per hoc quod omnia quandoque moveantur et quandoque quiescant, vel per hoc quod quaedam semper moventur, quaedam vero quandoque moventur et quandoque quiescunt, statim immediate inquiret. But this has no weight, because it is enough for Aristotle to prove in this chapter in a general way that motion has always been. But how the eternity of motion is continued—whether it is because all things are always in motion, or because all things are sometimes in motion and sometimes at rest, or because some things are always in motion and others sometimes in motion and sometimes at rest—is a question he raises immediately after the present one.
Sic igitur secundum hanc intentionem exponendum est praesens capitulum, quod intendit hic inquirere de motu in communi. Quaerit ergo secundum hoc, utrum motus in communi aliquando esse inceperit, ita quod prius nihil unquam motum fuerit; et quandoque sic deficiat quod nihil postmodum moveatur: aut e contrario, neque unquam inceperit, neque unquam deficiet; sed semper erat, et semper erit. Thus the present chapter must be explained according to this intention, namely, that he intends to inquire about motion in common. According to this, therefore, he asks: “Did motion in common begin to be at some time, so that previously there had never been any motion, and so that at some time it will perish so as to leave nothing in motion, or, on the other hand, did it never begin and will it never cease, so that it always was and always will be?
Et ponit exemplum in animalibus, propter hoc quod quidam dixerunt mundum esse quoddam animal magnum. Videmus enim quod animalia vivunt, quamdiu apparet in eis aliquis motus: cessante autem omni motu, dicuntur animalia mori. Sic igitur et in tota universitate naturalium corporum motus consideratur ut vita quaedam. Si ergo motus semper fuit et semper erit, ista quasi vita naturalium corporum erit immortalis et sine cessatione. And he gives an example taken from animals, for some philosophers have said that the world is a certain large animal. For we see animals as alive so long as motion is apparent in them, but when all motion ceases in them they are said to be dead. Accordingly, motion in the whole universe of natural bodies is taken as a kind of life. If, therefore, motion always was and always will be, then this sort of life of natural bodies will be immortal and never-failing.
Deinde cum dicit: esse quidem igitur etc., respondet tacitae quaestioni. In praecedentibus enim libris Aristoteles locutus fuerat de motu in communi, non applicando ad res: nunc autem inquirens an motus semper fuerit, applicat communem considerationem motus ad esse quod habet in rebus. Posset ergo aliquis dicere, quod in hac consideratione prius erat quaerendum de motu, an habeat esse in rebus, quam quaeratur an sit sempiternus: et praecipue, cum quidam negaverint esse motum. 967. Then at (749) he answers a tacit question. For in the preceding books Aristotle had discussed motion in common, without applying it to things; but now, inquiring whether motion has always existed, he applies his general doctrine about motion to the existence it has in things. Therefore, someone could say that in this consideration the first question should have been about whether motion has existence in things rather than whether it is eternal, especially since there are some who have denied that motion exists.
Ad hoc respondet, dicens quod omnes qui locuti sunt de natura rerum, affirmant quod motus sit. Et hoc patet per hoc, quod dicunt mundum esse factum; et quod omnes considerant de generatione et corruptione rerum, quae non potest esse sine motu. Est igitur communis suppositio in scientia naturali, quod motus habeat esse in rebus. Unde de hoc non est quaerendum in scientia naturali: sicut nec in aliqua scientia movetur quaestio de suppositionibus illius scientiae. To this he responds that all who have spoken about the nature of things admit that motion exists. This is evident from their statements that the world was made, and from their consideration of the generation and ceasing-to-be of things, which cannot occur without motion. It is therefore a common supposition in natural science that motion has existence in things. Hence there is no need to raise this question in natural science any more than in other sciences are raised questions about the suppositions of the science.
Deinde cum dicit: sed quanti quidem etc., ponit opiniones ad utramque partem quaestionis motae. Et primo ponit opiniones dicentium motum semper esse; secundo opiniones ponentium motum non semper esse, ibi: quicumque autem et cetera. 968. Then at (750) he presents opinions for both sides of the question he proposed. First he gives the opinions which declare that motion is eternal; Secondly, those who declare that motion is not eternal, at 969.
Ad evidentiam ergo primae partis sciendum est, quod Democritus posuit prima rerum principia corpora indivisibilia per se et semper mobilia, ex quorum aggregatione dicebat mundum casualiter factum: et non solum istum in quo nos sumus, sed infinitos alios, secundum quod accidit in diversis partibus infiniti vacui, praedicta corpora congregata mundos fecisse. Nec tamen hos mundos ponebat in perpetuum duraturos; sed quosdam eorum fieri per aggregationem atomorum, quosdam vero corrumpi per eorum segregationem. Quotcumque igitur philosophi hoc ponunt cum Democrito, dicunt semper esse motum; quia semper dicunt esse generationes et corruptiones aliquorum mundorum, quas necessarium est esse cum motu. In explanation of the first part (750), therefore, it should be known that Democritus supposed that the first principles of things are bodies that are per se indivisible and always mobile and that the world came to be by the chance aggregation of these bodies—not only the world in which we exist but an infinitude of other worlds, since these bodies congregated to form worlds in diverse parts of infinite void. Still he did not posit these worlds as fated to endure forever; rather, some came into existence as a result of atoms combining, and others passed out of existence as a result of the same atoms scattering. Therefore all the philosophers who agree with Democritus assert the eternity of motion, because they say that the generation and ceasing-to-be of certain worlds is always going on-and that necessarily involves motion.
Deinde cum dicit: quicumque autem etc., ponit opiniones ad partem contrariam. Et dicit quod quicumque ponunt unum solum mundum, et non esse eum sempiternum, etiam de motu ponunt quod consequitur secundum rationem, ut scilicet non semper sit. 969. Then at (751) he gives the opinions of the other side. And he says that whoever declare that there is just one world which is not eternal, also declare what reasonably follows with respect to motion, namely, that it is not eternal.
Si ergo ponatur quod sit aliquod tempus in quo nihil movebatur, oportet quod hoc accidat duobus modis, sicut etiam duobus modis potest poni hic mundus non semper fuisse: uno modo quod mundus iste sic inceperit quod nunquam antea fuerit, sicut posuit Anaxagoras; alio modo quod mundus sic inceperit quod aliquo tempore non fuerit, sed ante illud tempus iterum fuerit, ut posuit Empedocles. parte temporis est aliquid moveri, et iterum in alia parte temporis est omnia quiescere. Therefore, if there be supposed a time in which nothing was in motion, this could happen in two ways, just as it is in two ways that this world could be supposed not always to have been: in one way, that this world began in such a way that previously it never existed at all, as Anaxagoras held; in another way, that the world so began to be that it did not exist for some time previously, but that it again had existed before that time, as Empedocles held.
Et similiter circa motum Anaxagoras dixit quod quondam omnia simul erant unum cum alio commixtum, et nihil erat ab alio segregatum: in qua quidem rerum mixtura necesse fuit ponere quod omnia quiescerent: motus enim non est absque disgregatione; omne enim quod movetur, ab aliquo recedit, ut in aliud tendat. Hanc ergo rerum mixturam et quietem posuit praeextitisse in tempore infinito, ita quod nunquam antea fuerat aliquis motus; et quod intellectus, qui solus non erat permixtus, incepit de novo facere motum, et disgregare res ab invicem. Empedocles vero dixit quod in aliqua In like manner with respect to motion, Anaxagoras said that at one time all things were a mixture of one thing with another and nothing was segregated from anything else—in which mixture it was necessary to posit that all things were at rest, for motion does not occur without separation, since whatever is in motion separates from one terminus in order to tend to another. Therefore Anaxagoras posited the pre-existence of this mixture and rest in infinite time, in such a way that at no time before (the present world) had there been any motion at all, and that it was Mind, which alone was unmixed, that caused motion in the first instance and began to separate things one from another.
Ponebat enim Empedocles quod amicitia et discordia sunt prima rerum moventia: amicitiae autem proprium est quod ex multis faciat unum, discordiae vero quod ex uno faciat multa. Quia vero ad esse corporis mixti requiritur quod elementa sint in unum commixta, ad esse vero mundi requiritur quod elementa sint in locis suis per ordinem distributa: ponebat quod amicitia est causa generationis corporum mixtorum, discordia vero causa corruptionis; sed e contrario in toto mundo amicitia causa corruptionis, et discordia generationis. Empedocles, on the other hand, said that in one period of time some things are in motion, and again in another period all things are at rest. For he posited Friendship and Discord as the first movers of things: Friendship’s property was to make a unity of all things, and Discord’s to make many things from the one. But because the existence of a mixed body requires a mingling of the elements so as to form one thing, whereas the existence of a world required that the elements be dispersed in orderly fashion, each to its respective place, he posited that Friendship is the cause of the coming-to-be of mixed bodies, and Discord the cause of their ceasing-to-be; but that, contrariwise, in the whole world Friendship was the cause of its ceasing-to-be and Discord the cause of its coming-to-be.
Sic ergo ponebat moveri totum mundum, cum vel amicitia ex multis facit unum, vel discordia multa facit ex uno: sed quietem ponebat esse in mediis temporibus, non quidem ita quod nihil moveretur, sed quantum ad generalem mundi mutationem. Accordingly, he posited that the whole world is being moved, when either Friendship makes one from the many or when Discord makes many of the one; but during the intermediate times, he supposed there was rest—not in the sense that there was no motion at all, but none with respect to the general change of the world.
Et quia posuit sententiam Empedoclis, ponit etiam eius verba, quae difficultatem habent, quia metrice scripsit. Because Aristotle had mentioned the opinion of Empedocles, he also gave the very words, which are difficult to interpret because they are in metre.
Sic ergo suam sententiam expressit Empedocles his verbis, quae sic construenda sunt: didicit nasci, idest sic consuetum est aliquid generari, inquantum ex pluribus fit unum; et iterum, idest alio modo, ex uno geminato, idest composito, perficiuntur plurima, idest fiunt multa per disgregationem: quaedam enim sunt quae generantur per compositionem, quaedam vero per disgregationem. Thus, therefore, did Empedocles express his opinion in this arrangement of words: “It has learned to be born,” i.e., it is customary for something to be generated, “the one from the manifold”; “and again,” i.e., in another way, “from the one commingled,” i.e., composed of a mixture, “the manifold arises,” i.e., the many come to be through separation—for some things are generated by combining with others, and others by separating.
Et sicut hoc videmus in particularibus generationibus, sic fiunt res, idest sic est intelligendum in universali rerum generatione quantum ad totum mundum. Et nullo modo est ipsius saeculum unum, idest non est unus status durationis rerum; sed quandoque generatur mundus, quandoque corrumpitur, quandoque medio modo se habet: saeculum enim dicitur mensura durationis alicuius rei. And according to what we observe in regard to particular instances of coming-to-be, so “thus do things come to be,” i.e., the same must be understood in the universal coming-t-o-be of things with respect to the whole world. “Nor is their era one,” i.e., there is not just one period of duration of things; but at one time a world is generated, at another it is destroyed, and in between there is rest: for “era” is taken to mean the measure of the duration of a thing..
Distinctionem autem horum saeculorum exprimit subdens, sic autem permutantur; quasi dicat: unum saeculum est in quo res permutantur per congregationem vel segregationem. Et ne aliquis opinaretur quod ad generationem mundi non requiritur saeculum, idest tempus aliquod, sed mundus fit in instanti, ad hoc excludendum subiungit: neque simul perficiuntur, sed per multam moram temporis. He expresses the distinction of these eras when he adds, “Thus are they changed,” i.e., as though stating that the time in which things pass through the cycle of combining or separating is called one era. And lest anyone suppose that the generation of a world does not require an era, i.e., a period of time, but that the universe comes to be in an instant, Empedocles adds, “nor are they made perfect all at once,” but after a long interval of time.
Deinde de alio saeculo subdens dicit: sic autem semper sunt immobiles; quia scilicet in medio tempore generationis et corruptionis posuit res quiescere. Then speaking of the other era he adds, “thus are they always immobile,” i.e., in the time between the generation and corruption cycle, he supposed that things are at rest.
Et ne aliquis crederet quod semper antea fuerit permutatio, et postea semper futura sit quies, ad hoc excludendum dicit, secundum circulum; quasi dicat: circulariter hoc contingit, quod permutantur res et postea quiescunt, et iterum permutantur, et sic in infinitum. And lest anyone believe that before there was always change, and that later there will be continual rest, he excludes this by saying “alternately,” i.e., as though saying that this happens in cycles, namely, that things change and then rest, and then change again, and so on ad infinitum.
Deinde subduntur verba Aristotelis exponentis praedicta verba Empedoclis, maxime quantum ad hoc quod dixit, sic autem permutantur. Dicit ergo quod opinandum est in hoc quod dixit, sic permutantur, intellexisse ab hinc inde, idest a quodam principio usque nunc; non quod semper fuerit motus, vel quod postquam incepit, sit interruptus. Then the words of Aristotle are added to explain the foregoing words of Empedocles, especially the expression, “thus they change.” He says therefore that following the words, “thus they change,” must be understood the addition, “from then hence,”, i.e., from a definite beginning up to the present—not in the sense that motion always was, or that after it began it had been interrupted.
Deinde cum dicit: considerandum igitur etc., ostendit utilitatem huius considerationis. Et dicit quod considerandum est quomodo se habeat veritas circa hanc quaestionem: quia scire veritatem huius quaestionis est praeopere, idest pernecessarium, non solum ad considerationem scientiae naturalis, sed etiam ad scientiam de primo principio: quia et hic in octavo et in Metaphys., ad probandum primum principium, utitur aeternitate motus. 970, Then at (752) he shows the usefulness of considering the question he has proposed. And he says that we must consider just what is the truth about this question, for to know the truth about it is most necessary not only for natural science but the science of the first principle as well, since both here and in the Metaphysics he uses the eternity of motion to prove the first principle.
Haec enim via probandi primum principium esse, est efficacissima, cui resisti non potest. Si enim mundo et motu existente sempiterno, necesse est ponere unum primum principium; multo magis sempiternitate eorum sublata; quia manifestum est quod omne novum indiget aliquo principio innovante. Hoc ergo solo modo poterat videri quod non est necessarium ponere primum principium, si res sunt ab aeterno. Unde si etiam hoc posito sequitur primum principium esse, ostenditur omnino necessarium primum principium esse. This method of proving the existence of a first principle is most efficacious and irresistible. For if on the supposition that both motion and the world existed forever, it is necessary to posit one first principle, then, if the eternity thereof should be rejected, it is all the more necessary, for it is clear that every new thing requires a principle bringing it into being. Now the only reason why it could seem that no first principle would be necessary, would be if things were ab aeterno. But if the existence of a first principle follows even on that supposition, i.e., that the world existed ab aeterno, it is clear that the existence of a first principle is absolutely necessary.

Lectio 2
Arguments for the eternity of motion
Chapter 1 cont.
πρὸ ἔργου γὰρ οὐ μόνον πρὸς τὴν περὶ φύσεως θεωρίαν ἰδεῖν τὴν ἀλήθειαν, ἀλλὰ καὶ πρὸς τὴν μέθοδον τὴν περὶ τῆς ἀρχῆς τῆς πρώτης. ἀρξώμεθα δὲ πρῶτον ἐκ τῶν διωρισμένων ἡμῖν ἐν τοῖς φυσικοῖς πρότερον. φαμὲν δὴ τὴν κίνησιν εἶναι ἐνέργειαν τοῦ κινητοῦ ᾗ κινητόν. ἀναγκαῖον ἄρα ὑπάρχειν τὰ πράγματα τὰ δυνάμενα κινεῖσθαι καθ' ἑκάστην κίνησιν. καὶ χωρὶς δὲ τοῦ τῆς κινήσεως ὁρισμοῦ, πᾶς ἂν ὁμολογήσειεν ἀναγκαῖον εἶναι κινεῖσθαι τὸ δυνατὸν κινεῖσθαι καθ' ἑκάστην κίνησιν, οἷον ἀλλοιοῦσθαι μὲν τὸ ἀλλοιωτόν, φέρεσθαι δὲ τὸ κατὰ τόπον μεταβλητόν, ὥστε δεῖ πρότερον καυστὸν εἶναι πρὶν κάεσθαι καὶ καυστικὸν πρὶν κάειν. Let us take our start from what we have already laid down in our course on Physics. Motion, we say, is the fulfilment of the movable in so far as it is movable. Each kind of motion, therefore, necessarily involves the presence of the things that are capable of that motion. In fact, even apart from the definition of motion, every one would admit that in each kind of motion it is that which is capable of that motion that is in motion: thus it is that which is capable of alteration that is altered, and that which is capable of local change that is in locomotion: and so there must be something capable of being burned before there can be a process of being burned, and something capable of burning before there can be a process of burning.
οὐκοῦν καὶ ταῦτα ἀναγκαῖον ἢ γενέσθαι ποτὲ οὐκ ὄντα ἢ ἀΐδια εἶναι. εἰ μὲν τοίνυν ἐγένετο τῶν κινητῶν ἕκαστον, ἀναγκαῖον πρότερον τῆς ληφθείσης ἄλλην γενέσθαι μεταβολὴν καὶ κίνησιν, καθ' ἣν ἐγένετο τὸ δυνατὸν κινηθῆναι ἢ κινῆσαι· εἰ δ' ὄντα προϋπῆρχεν ἀεὶ κινήσεως μὴ οὔσης, ἄλογον μὲν φαίνεται καὶ αὐτόθεν ἐπιστήσασιν, οὐ μὴν ἀλλὰ μᾶλλον ἔτι προάγουσι τοῦτο συμβαίνειν ἀναγκαῖον. εἰ γὰρ τῶν μὲν κινητῶν ὄντων τῶν δὲ κινητικῶν ὁτὲ μὲν ἔσται τι πρῶτον κινοῦν, τὸ δὲ κινούμενον, ὁτὲ δ' οὐθέν, ἀλλ' ἠρεμεῖ, ἀναγκαῖον τοῦτο μεταβάλλειν πρότερον· ἦν γάρ τι αἴτιον τῆς ἠρεμίας· ἡ γὰρ ἠρέμησις στέρησις κινήσεως. ὥστε πρὸ τῆς πρώτης μεταβολῆς ἔσται μεταβολὴ προτέρα. Moreover, these things also must either have a beginning before which they had no being, or they must be eternal. Now if there was a becoming of every movable thing, it follows that before the motion in question another change or motion must have taken place in which that which was capable of being moved or of causing motion had its becoming. To suppose, on the other hand, that these things were in being throughout all previous time without there being any motion appears unreasonable on a moment's thought, and still more unreasonable, we shall find, on further consideration. For if we are to say that, while there are on the one hand things that are movable, and on the other hand things that are motive, there is a time when there is a first movent and a first moved, and another time when there is no such thing but only something that is at rest, then this thing that is at rest must previously have been in process of change: for there must have been some cause of its rest, rest being the privation of motion. Therefore, before this first change there will be a previous change.
τὰ μὲν γὰρ κινεῖ μοναχῶς, τὰ δὲ καὶ τὰς ἐναντίας κινήσεις, οἷον τὸ μὲν πῦρ θερμαίνει, ψύχει δ' οὔ, ἡ δ' ἐπιστήμη δοκεῖ τῶν ἐναντίων εἶναι μία. φαίνεται μὲν οὖν κἀκεῖ τι εἶναι ὁμοιότροπον· τὸ γὰρ ψυχρὸν θερμαίνει στραφέν πως καὶ ἀπελθόν, ὥσπερ καὶ ἁμαρτάνει ἑκὼν ὁ ἐπιστήμων, ὅταν ἀνάπαλιν χρήσηται τῇ ἐπι(251b.) στήμῃ. ἀλλ' οὖν ὅσα γε δυνατὰ ποιεῖν καὶ πάσχειν ἢ κινεῖν, τὰ δὲ κινεῖσθαι, οὐ πάντως δυνατά ἐστιν, ἀλλ' ὡδὶ ἔχοντα καὶ πλησιάζοντα ἀλλήλοις. ὥσθ' ὅταν πλησιάσῃ, κινεῖ, τὸ δὲ κινεῖται, καὶ ὅταν ὑπάρξῃ ὡς ἦν τὸ μὲν κινητικὸν τὸ δὲ κινητόν. εἰ τοίνυν μὴ ἀεὶ ἐκινεῖτο, δῆλον ὡς οὐχ οὕτως εἶχον ὡς ἦν δυνάμενα τὸ μὲν κινεῖσθαι τὸ δὲ κινεῖν, ἀλλ' ἔδει μεταβάλλειν θάτερον αὐτῶν· ἀνάγκη γὰρ ἐν τοῖς πρός τι τοῦτο συμβαίνειν, οἷον εἰ μὴ ὂν διπλάσιον νῦν διπλάσιον, μεταβάλλειν, εἰ μὴ ἀμφότερα, θάτερον. ἔσται ἄρα τις προτέρα μεταβολὴ τῆς πρώτης. For some things cause motion in only one way, while others can produce either of two contrary motions: thus fire causes heating but not cooling, whereas it would seem that knowledge may be directed to two contrary ends while remaining one and the same. Even in the former class, however, there seems to be something similar, for a cold thing in a sense causes heating by turning away and retiring, just as one possessed of knowledge voluntarily makes an error when he uses his knowledge in the reverse way. But at any rate all things that are capable respectively of affecting and being affected, or of causing motion and being moved, are capable of it not under all conditions, but only when they are in a particular condition and approach one another: so it is on the approach of one thing to another that the one causes motion and the other is moved, and when they are present under such conditions as rendered the one motive and the other movable. So if the motion was not always in process, it is clear that they must have been in a condition not such as to render them capable respectively of being moved and of causing motion, and one or other of them must have been in process of change: for in what is relative this is a necessary consequence: e.g. if one thing is double another when before it was not so, one or other of them, if not both, must have been in process of change. It follows then, that there will be a process of change previous to the first.
πρὸς δὲ τούτοις τὸ πρότερον καὶ ὕστερον πῶς ἔσται χρόνου μὴ ὄντος; ἢ χρόνος μὴ οὔσης κινήσεως; (Further, how can there be any 'before' and 'after' without the existence of time? Or how can there be any time without the existence of motion?
εἰ δή ἐστιν ὁ χρόνος κινήσεως ἀριθμὸς ἢ κίνησίς τις, εἴπερ ἀεὶ χρόνος ἔστιν, ἀνάγκη καὶ κίνησιν ἀΐδιον εἶναι. If, then, time is the number of motion or itself a kind of motion, it follows that, if there is always time, motion must also be eternal.
ἀλλὰ μὴν περί γε χρόνου ἔξω ἑνὸς ὁμονοητικῶς ἔχοντες φαίνονται πάντες· ἀγένητον γὰρ εἶναι λέγουσιν. καὶ διὰ τούτου Δημόκριτός γε δείκνυσιν ὡς ἀδύνατον ἅπαντα γεγονέναι· τὸν γὰρ χρόνον ἀγένητον εἶναι. Πλάτων δὲ γεννᾷ μόνος· ἅμα μὲν γὰρ αὐτὸν τῷ οὐρανῷ [γεγονέναι], τὸν δ' οὐρανὸν γεγονέναι φησίν. But so far as time is concerned we see that all with one exception are in agreement in saying that it is uncreated: in fact, it is just this that enables Democritus to show that all things cannot have had a becoming: for time, he says, is uncreated. Plato alone asserts the creation of time, saying that it had a becoming together with the universe, the universe according to him having had a becoming.
εἰ οὖν ἀδύνατόν ἐστιν καὶ εἶναι καὶ νοῆσαι χρόνον ἄνευ τοῦ νῦν, τὸ δὲ νῦν ἐστι μεσότης τις, καὶ ἀρχὴν καὶ τελευτὴν ἔχον ἅμα, ἀρχὴν μὲν τοῦ ἐσομένου χρόνου, τελευτὴν δὲ τοῦ παρελθόντος, ἀνάγκη ἀεὶ εἶναι χρόνον. τὸ γὰρ ἔσχατον τοῦ τελευταίου ληφθέντος χρόνου ἔν τινι τῶν νῦν ἔσται (οὐδὲν γὰρ ἔστι λαβεῖν ἐν τῷ χρόνῳ παρὰ τὸ νῦν), ὥστ' ἐπεί ἐστιν ἀρχή τε καὶ τελευτὴ τὸ νῦν, ἀνάγκη αὐτοῦ ἐπ' ἀμφότερα εἶναι ἀεὶ χρόνον. ἀλλὰ μὴν εἴ γε χρόνον, φανερὸν ὅτι ἀνάγκη εἶναι καὶ κίνησιν, εἴπερ ὁ χρόνος πάθος τι κινήσεως. Now since time cannot exist and is unthinkable apart from the moment, and the moment a kind of middle-point, uniting as it does in itself both a beginning and an end, a beginning of future time and an end of past time, it follows that there must always be time: for the extremity of the last period of time that we take must be found in some moment, since time contains no point of contact for us except the moment. Therefore, since the moment is both a beginning and an end, there must always be time on both sides of it. But if this is true of time, it is evident that it must also be true of motion, time being a kind of affection of motion.)
ὁ δ' αὐτὸς λόγος καὶ περὶ τοῦ ἄφθαρτον εἶναι τὴν κίνησιν· καθάπερ γὰρ ἐπὶ τοῦ γενέσθαι κίνησιν συνέβαινεν προτέραν εἶναί τινα μεταβολὴν τῆς πρώ της, οὕτως ἐνταῦθα ὑστέραν τῆς τελευταίας· οὐ γὰρ ἅμα παύεται κινούμενον καὶ κινητὸν ὄν, οἷον καιόμενον καὶ καυστὸν ὄν (ἐνδέχεται γὰρ καυστὸν εἶναι μὴ καιόμενον), οὐδὲ (252a.) κινητικὸν καὶ κινοῦν. καὶ τὸ φθαρτικὸν δὴ δεήσει φθαρῆναι ὅταν φθείρῃ· καὶ τὸ τούτου φθαρτικὸν πάλιν ὕστερον· καὶ γὰρ ἡ φθορὰ μεταβολή τίς ἐστιν. εἰ δὴ ταῦτ' ἀδύνατα, δῆλον ὡς ἔστιν ἀΐδιος κίνησις, The same reasoning will also serve to show the imperishability of motion: just as a becoming of motion would involve, as we saw, the existence of a process of change previous to the first, in the same way a perishing of motion would involve the existence of a process of change subsequent to the last: for when a thing ceases to be moved, it does not therefore at the same time cease to be movable—e.g. the cessation of the process of being burned does not involve the cessation of the capacity of being burned, since a thing may be capable of being burned without being in process of being burned—nor, when a thing ceases to be movent, does it therefore at the same time cease to a be motive. Again, the destructive agent will have to be destroyed, after what it destroys has been destroyed, and then that which has the capacity of destroying it will have to be destroyed afterwards, (so that there will be a process of change subsequent to the last,) for being destroyed also is a kind of change. If, then, view which we are criticizing involves these impossible consequences, it is clear that motion is eternal
Postquam movit dubitationem de sempiternitate motus, hic intendit ostendere motum esse sempiternum. Et dividitur in partes duas: in prima ostendit propositum; in secunda solvit ea quae in contrarium obiici possent, ibi: contraria autem his et cetera. 971. After raising the problem of the eternity of motion, the Philosopher now intends to show that motion is eternal. His treatment is divided into two parts: In the first he explains his proposition; In the second he solves objections contrary to his proposition, (L.4).
Circa primum duo facit: primo ponit rationes ad ostendendum sempiternitatem motus; secundo ponit rationes contra opiniones philosophorum contrarium opinantium, ibi: sed non aliquando et cetera. About the first he does two things: First he presents arguments to show the eternity of motion; Secondly, he answers opinions to the contrary, (L. 3).
Circa primum duo facit: primo ostendit quod motus semper fuit; secundo quod semper erit, ibi: eadem autem ratio est et cetera. About the first he does two things: First he shows that motion always has been; Secondly, that it always will be, at 895.
Circa primum duo facit: primo ostendit propositum ratione accepta ex parte motus; secundo ratione accepta ex parte temporis, ibi: adhuc autem prius et posterius et cetera. About the first he does two things: First he explains his proposition with an argument from motion; Secondly, with an argument from time, at 979.
Circa primum tria facit: primo praemittit quoddam quod est necessarium ad probationem sequentem; secundo inducit probationem ad propositum ostendendum, ibi: ergo et hoc necessarium est etc., tertio ostendit necessitatem rationis inductae, ibi: alia quidem movent singulariter et cetera. About the first he does three things: First he premises something needed for his proposition; Secondly, he presents a proof that manifests his proposition, at 976; Thirdly, he shows that his argument proceeds necessarily, 977,
Dicit ergo primo, quod ad propositum ostendendum debemus incipere ab his quae primo determinata sunt in physicis, ut eis quasi principiis utamur. Per quod dat intelligere, quod praecedentes libri, in quibus de motu in communi determinavit, et propter hoc appellantur universaliter de naturalibus, habent quandam distinctionem ad hunc librum octavum, in quo iam incipit motum ad res applicare. Assumit ergo id quod dictum est in III physicorum, scilicet quod motus est actus mobilis inquantum huiusmodi. 972. He says first (753) therefore, that in order to demonstrate the proposition we must begin with things determined at the very beginning of the Physics and use them as principles. By this he gives us to understand that the preceding books, in which he determined about motion in general and which for this reason are given the general title “About Natural Things,” are set off from this Book VIII, in which he begins to apply motion to things.
Ex quo apparet quod ad hoc quod sit motus, necesse est existere res quae possint moveri quocumque motu: quia non potest esse actus sine eo cuius est actus. Sic ergo ex definitione motus apparet quod necesse est esse subiectum mobile, ad hoc quod sit motus. He assumes, therefore, what was said in Physics III, namely, that motion is the act of a mobile precisely as such. From this it appears that in order for motion to exist there must exist things which can be moved with some sort of motion, because an act cannot exist without the thing of which it is the act. Accordingly, from the definition of motion it is evident that there must be a subject of motion, if there is to be motion at all.
Sed etiam absque definitione motus per se manifestum est hoc, ut patet ex communi sententia omnium: quilibet enim confitetur hoc esse necessarium, quod non movetur nisi quod est possibile moveri: et hoc secundum unumquemque motum; sicut quod non contingit alterari nisi quod est alterabile, neque mutari secundum locum nisi quod est secundum locum mutabile. But even without the definition of motion that fact is per se evident from the general consent of all, for everyone admits as a necessary fact that nothing is moved except what can be moved—and this with reference to any and all motion; for example, nothing can be altered except what is alterable, or be moved with respect to place unless it be changeable with respect to place.
Et quia subiectum naturaliter prius est eo quod est in subiecto, possumus concludere in singulis mutationibus, et ex parte mobilis et ex parte moventis, quod prius est ipsum subiectum combustibile quam comburatur; et combustivum, idest subiectum potens comburere, quam comburat; prius inquam, non semper tempore, sed natura. And because the subject is by nature prior to what is in the subject, we can conclude that in individual changes—both from the viewpoint of the mobile and of the mover—the combustible subject is prior to its being set afire, and the subject capable of setting it afire is prior to its setting afire, prior, I say, not always in time but in nature.
Ex hac autem Aristotelis probatione, Averroes occasionem sumpsit loquendi contra id quod secundum fidem de creatione tenemus. Si enim fieri quoddam mutari est; omnis autem mutatio requirit subiectum, ut hic Aristoteles probat; necesse est quod omne quod fit, fiat ex aliquo subiecto: non ergo possibile est quod fiat aliquid ex nihilo. 973. From this argument of Aristotle, Averroes took occasion to speak against what is held by faith about creation. For if coming-to-be is a kind of change and every change requires a subject, as Aristotle here proves, it is necessary that whatever comes to be does so from a subject, therefore, it is not possible for something to come to be from nothing.
Adducit etiam ad hoc secundam rationem: quia cum dicitur nigrum fieri ex albo, hoc non dicitur per se, ita quod ipsum album convertatur in nigrum; sed hoc dicitur per accidens, quia scilicet recedente albo, succedit nigrum. Omne autem quod est per accidens, reducitur ad id quod est per se: hoc autem ex quo aliquid fit per se, est subiectum, quod intrat substantiam rei factae; omne ergo quod dicitur fieri ex opposito, fit quidem ex opposito per accidens, per se autem ex subiecto. Non ergo est possibile quod ens fiat ex non ente simpliciter. He confirms this with another argument: When it is said that the black comes to be from the white, this is not to speak per se, in the sense that the white itself is converted into the black, but it is to speak per accidens, in the sense that upon the departure of the white, the black succeeds it. Now whatever is per accidens is reduced to what is per se. But that from which something comes to be per se, is the subject, which enters into the substance of what comes to be. Therefore, whatever is said to come to be from its opposite comes to be from it per accidens, but per se it comes to be from the subject. Accordingly, it is not possible for being to come to be from non-being absolutely.
Adducit autem ad hoc tertio communem opinionem omnium antiquorum physicorum, ponentium nihil ex nihilo fieri. In further support of his position Averroes adduces the common opinion of the early philosophers that nothing comes to be from nothing.
Assignat autem duas causas, ex quibus reputat hanc positionem exortam, quod aliquid ex nihilo fiat. Quarum prima est, quod vulgus non reputat existentia, nisi ea quae sunt comprehensibilia visu: quia ergo vulgus videt aliquid factum visibile, quod prius visibile non erat, reputat possibile aliquid ex nihilo fieri. He also gives two reasons from which he considers that the position arose that something should come to be from nothing. The first is that ordinary people do not consider as existing anything but what is comprehensible by sight; therefore, because they see something visible come to be which previously was not visible, they think that it is possible for something to come to be from nothing.
Secunda causa est, quia apud vulgus reputatur esse ex diminutione virtutis agentis, quod indigeat materia ad agendum: quod tamen non est ex impotentia agentis, sed ex ipsa ratione motus. Quia ergo primum agens non habet potentiam aliquo modo defectivam, sequitur quod agat absque subiecto. The second reason is that among the common people it could be thought to be a weakening of the virtue of the agent that it should need matter in order to act, which condition, however, does not derive from the impotency of the agent, but from the very nature of motion. Therefore, because the first agent does not have a power which is in any way deficient, it follows that it should act without a subject.
Sed si quis recte consideret, ex simili causa ipse deceptus fuit, ex qua causa nos deceptos arbitratur, scilicet ex consideratione particularium entium. Manifestum est enim quod potentia activa particularis praesupponit materiam, quam agens universalius operatur; sicut artifex utitur materia quam natura facit. Ex hoc ergo quod omne particulare agens praesupponit materiam quam non agit, non oportet opinari quod primum agens universale, quod est activum totius entis, aliquid praesupponat, quasi non causatum ab ipso. 974. But if one considers rightly, he was deceived by a cause similar to the cause by which he claimed we are deceived, namely, by considering particular things. For it is clear that a particular active power presupposes the matter which a more universal agent produces, just as an artisan uses the matter which nature makes. From the fact therefore, that every particular agent presupposes matter which it does not produce, one should not suppose that the first universal agent—which is active with respect to all being—should presuppose something not caused by it.
Nec hoc etiam est secundum intentionem Aristotelis. Probat enim in II Metaphys., quod id quod est maxime verum et maxime ens, est causa essendi omnibus existentibus: unde hoc ipsum esse in potentia, quod habet materia prima, sequitur derivatum esse a primo essendi principio, quod est maxime ens. Non igitur necesse est praesupponi aliquid eius actioni, quod non sit ab eo productum. Nor, moreover, is this in keeping with the intention of Aristotle who in Metaphysics II proves that the supremely true and the supreme being is the cause of being for all existents. Hence the being which prime matter has—i.e., a being in potency—is derived from the first principle of being which is in a supreme way a being. Therefore, it is not necessary to presuppose for its action anything not produced by it.
Et quia omnis motus indiget subiecto, ut hic Aristoteles probat et rei veritas habet, sequitur quod productio universalis entis a Deo non sit motus nec mutatio, sed sit quaedam simplex emanatio. Et sic fieri et facere aequivoce dicuntur in hac universali rerum productione, et in aliis productionibus. And because every motion needs a subject—as Aristotle proves here, and as is the truth of the matter—it follows that the universal production of being by God is neither motion nor change, but a certain simple coming forth. Consequently, “to be made” and “to make” are used in an equivocal sense when applied to this universal production of being and to other productions.
Sicut ergo si intelligamus rerum productionem esse a Deo ab aeterno, sicut Aristoteles posuit, et plures Platonicorum, non est necessarium, immo impossibile, quod huic productioni universali aliquod subiectum non productum praeintelligatur: ita etiam, si ponamus secundum nostrae fidei sententiam, quod non ab aeterno produxerit res, sed produxerit eas postquam non fuerant, non est necessarium quod ponatur aliquod subiectum huic universali productioni. Patet ergo quod hoc quod Aristoteles hic probat, quod omnis motus indiget subiecto mobili, non est contra sententiam nostrae fidei: quia iam dictum est quod universalis rerum productio, sive ponatur ab aeterno, sive non ab aeterno, non est motus nec mutatio. Ad hoc enim quod sit motus vel mutatio, requiritur quod aliter se habeat nunc et prius: et sic aliquid esset prius existens; et per consequens haec non esset universalis rerum productio, de qua nunc loquimur. Therefore, just as, if we should understand the production of things to be from God ab aeterno—as Aristotle supposed, and a number of the Platonists—it is not necessary, indeed, it is impossible, that there have been a pre-existing but unproduced subject of this universal production, so also, in accord with the tenets of our faith, if we posit that he did not produce things ab aeterno but produced them after they had not existed, it is not necessary to posit a subject for this universal production. It is evident, therefore, that what Aristotle proves here, namely, that every motion requires a mobile subject, is not against a tenet of our faith—for it has already been said that the universal production of things, whether ab aeterno or not, is neither a motion nor a change. For in order that there be motion or change, it is required that something be other now than previously, and thus there would be something previously existing, and consequently this would not be the universal production of things about which we are now speaking.
Similiter quod dicit, quod aliquid dicitur fieri ex opposito per accidens, et ex subiecto per se, veritatem habet in particularibus factionibus, secundum quas fit hoc aut illud ens, ut homo aut canis: non autem habet veritatem in universali entis productione. 975. Similarly, Averroes’ statement that something is said to come to be from its opposite per accidens and from a subject per se is true in particular productions according to which this or that being comes to be, e.g., a man or a dog, but is not true in the universal production of being.
Quod patet ex hoc quod philosophus dixit in I physicorum. Dixit enim ibi, quod si fiat hoc animal, inquantum est hoc animal, non oportet quod fiat ex non animali, sed ex non hoc animali, puta si fiat homo ex non homine, aut equus ex non equo: si autem fiat animal inquantum est animal, oportet quod fiat ex non animali. Sic ergo si fiat aliquod particulare ens, non fit ex omnino non ente: sed si fit totum ens, quod est fieri ens inquantum est ens, oportet quod fiat ex penitus non ente: si tamen et hoc debeat dici fieri (aequivoce enim dicitur, ut dictum est). This is clear from what the Philosopher said in Physics I. For he said there that if this animal comes to be inasmuch as it is this animal, it ought not come to be from “non-animal” but from “non-this-animal”—for example, if a man comes to be from non-man or a horse from non-horse. But if animal is produced precisely as animal, it must come to be from non-animal. Accordingly, if some particular being comes to be, it does not come to be from absolute non-being; but if the whole being comes to be, i.e., if being precisely as being comes to be, it must be made from absolute non-being—if, indeed, this process should be called “being made,” for it is an equivocal way of speaking, as has been said.
Quod etiam introducit de antiquis philosophorum opinionibus, efficaciam non habet: quia antiqui naturales non potuerunt pervenire ad causam primam totius esse, sed considerabant causas particularium mutationum. What Averroes introduces about the early philosophers has no value, for they were unable to arrive at the first cause of all being but considered the causes of particular changes.
Quorum primi consideraverunt causas solarum mutationum accidentalium, ponentes omne fieri esse alterari: sequentes vero pervenerunt ad cognitionem mutationum substantialium: postremi vero, ut Plato et Aristoteles, pervenerunt ad cognoscendum principium totius esse. The first of these philosophers considered the causes solely of accidental changes, and posited all “being made” to be alteration. Those who succeeded them arrived at a knowledge of substantial changes, but those who came still later, such as Plato and Aristotle, arrived at a knowledge of the principle of all existence.
Sic igitur patet quod non movemur ad ponendum aliquid fieri ex nihilo, quia reputemus ea esse solum entia quae sunt visibilia: sed magis e contrario, quia non consideramus solas productiones particulares a causis particularibus, sed productionem universalem totius esse a primo essendi principio. Nec etiam ponimus quod indigere materia ad agendum sit potentiae diminutae, quasi deficientis a virtute naturali: sed dicimus hoc esse potentiae particularis, quae non potest super totum ens, sed facit aliquod ens. Consequently, it is clear that we are not moved to assert that something comes to be from nothing because we suppose only visible things to be beings; rather it is because we do not content ourselves with considering merely the particular productions of particular causes, but go on to consider the universal production of all being from the first principle of being. Nor do we assert that to need matter in order to act is due to a diminished power, in the sense of such a power’s lacking its natural energy, rather, what we say is that this is proper to a particular power, which does not extend to all being but makes a particular being.
Et potest sic dici esse potentiae diminutae facere aliquid ex aliquo, sicut si dicamus potentiam particularem esse minorem potentia universali. Hence one can say that it is characteristic of a “diminished power” to make something from something in the sense that we would say that a particular power is less than the universal power.
Deinde cum dicit: ergo et haec necessarium est etc., supposito quod ad hoc quod sit motus requiratur mobile et motivum, sic argumentatur. Si motus non semper fuit, necesse est dicere aut quod moventia et motiva sint aliquando facta, cum prius non essent; aut quod sint perpetua. Si ergo dicatur quod unumquodque mobile est factum, necesse est dicere quod ante mutationem quae accipitur ut prima, sit alia mutatio et motus, secundum quem factum est ipsum mobile, quod potest moveri et motum esse. Quae quidem illatio dependet ex praecedentibus. Si enim detur quod motus non semper fuerit, sed aliqua mutatio sit prima, ante quam nulla fuerit; sequetur quod illa prima mutatio habeat aliquod mobile, et quod illud mobile sit factum cum prius non fuerit; cum ponantur omnia mobilia esse facta. Omne autem quod fit cum prius non fuerit, fit per aliquem motum vel mutationem: motus autem vel mutatio per quam fit mobile, est prior quam mutatio qua mobile movebatur: ergo ante mutationem quae dicebatur esse prima, est alia mutatio; et sic in infinitum. 976. Then at (754), assuming that a mobile and a mover are required in order that there be motion, Aristotle argues in the following manner: If motion has not always existed, it is necessary to say either that mobiles and movers were at some time made, having previously not existed, or are eternal. If, therefore, it is held that each mobile has been made, it is necessary to say that previous to the change which is taken as the first, there was another change and motion according to which was made the very mobile which is able to be moved and to have been moved. This inference, indeed, depends on the preceding. For if it is granted that motion has not always been but that there is some first change before which there was none, it will follow that that first change involved a mobile, and that that mobile was made, for previously it did not exist—since it is being supposed that all mobiles have been made. Now, whatever comes to be after having previously not existed, comes to be through a motion or a change. But the motion or change through which a mobile comes to be, is prior to the change by which the mobile is moved. Therefore, prior to the change which was presumed to be first is another change and so on ad infinitum.
Si autem dicatur quod ea quae sunt mobilia semper praeexistebant, etiam motu nullo existente, hoc videtur irrationabile et dictum a nescientibus. Statim enim apparet quod si mobilia sunt, oportet esse motum: mobilia enim naturalia simul etiam sunt moventia, ut ex tertio patet. Moventibus autem et mobilibus naturalibus existentibus, necesse est esse motum. But if it is held that things which are mobile always pre-existed even when no motion existed, this seems to be unreasonable and a sign of ignorance. For it immediately appears that if mobiles exist, motion ought to exist, for natural mobiles are at once also movers, as is clear from Book III. But if natural mobiles and movers are existing, there must be motion.
Sed ut profundius ingrediamur ad veritatis inquisitionem, necessarium est hoc idem accidere, si ponantur mobilia et moventia praeexistentia semper ante motum, quod sequebatur si ponantur haec esse facta: scilicet quod ante mutationem quae ponitur prima, sit alia mutatio in infinitum. Quod sic patet. Quia si ponatur quod sint aliqua mobilia et aliqua motiva, et tamen aliquando primum movens incipiat movere, et aliquid moveri ab ipso, et ante hoc nihil moveatur sed quiescat; oportebit dicere quod sit alia mutatio prius facta in movente vel mobili, quam id quod ponebatur primo movens, incipiat movere: quod sic patet. But to enter more deeply into our search for the truth, it is necessary that this same thing happen—if mobiles and movers are assumed to be eternally existing prior to motion—that followed from the assumption that they were made, namely, that prior to the change supposed to be the first, there is other change ad infinitum. This is evident in the following way: If it be supposed that certain mobiles and certain movers exist, and yet the first mover begins at some time or other to cause motion and something is moved by it, and before this nothing is being moved but is at rest, it will be necessary to say that there was another change in the mover or mobile made prior to that which was assumed to be the first one produced by the mover beginning to cause motion, The truth of this is clear from the following:
Quies enim est privatio motus: privatio autem non inest susceptivo habitus et formae nisi propter aliquam causam: erat ergo aliqua causa vel ex parte motivi vel ex parte mobilis, quare quies erat: ergo ea durante, semper quies remanebat. Si ergo aliquando movens incipiat movere, oportet quod illa causa quietis removeatur. Sed non potest removeri nisi per aliquem motum vel mutationem: ergo sequitur quod ante illam mutationem, quae dicebatur esse prima, sit alia mutatio prior, qua removetur causa quietis. Rest is the privation of motion. Privation, however, is not present in a thing capable of habit and form except on account of some cause. Therefore there was a cause—either on the part of the mover or on the part of the mobile—why there was rest. Therefore, as long as that cause prevailed, there was always rest. If, then, a mover begins at some time to cause motion, the cause of rest must be removed. But it cannot be removed except by a motion or change. Therefore, it follows that before that change which was said to be first, there is a prior change by which the cause of rest is removed.
Deinde cum dicit: alia quidem enim etc., probat necessitatem praemissae rationis. Posset enim aliquis dicere quod contingit quandoque quiescere et quandoque moveri, absque hoc quod praeextiterit aliqua causa quietis, quae removeatur. Unde hoc vult excludere. Et circa hoc duo facit: primo praemittit quoddam quod est necessarium ad propositum; secundo inducit propositam probationem, ibi: sed igitur quaecumque possibilia sunt et cetera. 977. Then at (755) he proves the necessity of the foregoing argument. For someone could say that it happens that things are at rest at some time and in motion at some time, without any pre-existing cause of rest to be removed. Hence he wishes to refute this. And about this he does two things: First he premises something needed for his proof; Secondly, he presents the proposed proof, at 978.
Dicit ergo primo quod eorum quae movent, quaedam movent singulariter, idest uno modo tantum; quaedam vero movent secundum contrarios motus. Quae movent tantum uno modo, sunt naturalia; sicut ignis semper calefacit et nunquam frigefacit. Sed agentia per intellectum movent secundum contrarios motus, quia una scientia videtur esse contrariorum, sicut medicina est scientia sani et aegri: unde videtur quod medicus per suam scientiam possit movere secundum contrarios motus. He says therefore first that among movers, some move “singularly,” i.e., in just one way, while others move with respect to motions that are contrary. Things that cause motion in just one way are natural things, as fire always heats and never cools. But beings that act through intellect are causes of motions that are contrary, for one and the same knowledge seems to deal with things and their contraries, as medicine is the science of health and of sickness. Hence one sees that a doctor by means of his science can cause motions that are mutually contrary.
Posuit autem hanc distinctionem moventium, quia in iis quae agunt per intellectum, videtur non esse verum quod ipse dixerat, scilicet quod si aliquid movetur cum prius quieverit, oporteat prius removeri causam quietis. Agentia enim per intellectum, videntur se ad opposita habere absque aliqua sui mutatione: unde videtur quod possint movere et non movere, absque aliqua mutatione. Now Aristotle mentioned this distinction among movers, because in things that act through intellect it does not appear that what he had said is true, namely, that if something is moved when previously it had been at rest, the cause of the rest ought first be removed. For things that act according to intellect seem to be ready to move to opposites without any change of themselves being involved; hence it seems that they can cause motion and not cause it, without any change.
Ne ergo per hoc sua ratio impediatur, subiungit quod ratio sua similiter tenet in iis quae agunt per intellectum, et in iis quae agunt per naturam. Quia ea quae agunt per naturam, per se quidem semper movent ad unum, sed per accidens quandoque movent ad contrarium; et ad hoc quod illud accidens eveniat, necesse est esse aliquam mutationem; sicut frigidum per se semper frigefacit, sed per accidens calefacit. Therefore, lest his argument be forestalled by this objection, he adds that his reason holds both for things that act according to intellect and that act by nature. For things that act by nature do always per se move to one, but per accidens they sometimes move to the contrary, and in order that such an accident occur, some change is necessary; thus cold always per se causes coldness, but per accidens it produces warmth.
Sed quod per accidens calefaciat, hoc est per aliquam eius mutationem: vel inquantum vertitur ad alium situm, ut alio modo respiciat id quod nunc calefit ab eo, prius autem frigefiebat; vel inquantum totaliter abscedit. But that cold should per accidens cause warmth is due to some change affecting the cold object, either inasmuch as it is moved to another location, thus making it differently related to the object which is now made warm by it than it was when it was making it cold, or inasmuch as it completely departs.
Dicimus enim frigus esse causam caloris abscedendo, sicut gubernator per sui absentiam est causa submersionis navis: similiter etiam frigus per accidens fit causa caloris, vel per maiorem elongationem, vel etiam per maiorem appropinquationem; sicut in hyeme interiora animalium sunt calidiora, calore ad interius recurrente propter frigus circumstans. For we say that cold is the cause of warmth by departing in the way that a captain is by his absence the cause of the sinking of a ship; again, cold becomes per accidens the cause of warmth either by moving farther away or by approaching closer, as in the winter the interior of animals is warmer, because their heat retreats inward on account of the surrounding cold.
Sic etiam est in agente secundum intellectum. Scientia enim, licet sit una contrariorum, tamen non aequaliter utrorumque, sed unius principaliter; sicut medicina ad hoc est per se ordinata, quod faciat sanitatem. Si ergo contingat quod medicus utatur sua scientia in contrarium ad inducendum aegritudinem, hoc non erit ex scientia per se, sed per accidens, propter aliquid aliud. Et ad hoc quod illud aliud adveniat cum prius non esset, necesse est esse aliquam mutationem. The same applies to things that act by intellect, For knowledge, although it is one thing dealing with contraries, does not deal equally with them both but with one principally, as medicine is per se ordained to causing health. Therefore, if it happens that a doctor uses his knowledge for the contrary purpose of causing sickness, this will not be per se from this science but per accidens, on account of something else. And in order that that something else occur when previously it did not exist, some change is required.
Deinde cum dicit: sed igitur quaecumque etc., inducit probationem ad propositum ostendendum. Dicit ergo quod ex quo ita est, quod simili modo se habet in iis quae agunt secundum naturam et secundum intellectum, possumus universaliter de omnibus loquentes dicere, quod quaecumque sunt possibilia facere aut pati aut movere vel moveri, non penitus possibilia sunt, idest non possunt movere aut moveri in quacumque dispositione se habeant; sed prout se habent in aliqua determinata habitudine et propinquitate ad invicem. 978. Then at (756) he sets forth the proof which manifests his proposition. He says therefore that from the fact that things are such, i.e., that a similar situation prevails with respect to things that act by nature and things that act by intellect, then, speaking universally of all, we can say that whatever things are possible to make, or to be acted upon, or to cause motion, or to be moved, cannot cause motion or be moved in just any disposition in which they find themselves, but according as they are in some definite state and nearness with respect to each other.
Et hoc concludit ex praemissis: quia iam dictum est, quod tam in agentibus secundum naturam, quam in agentibus secundum voluntatem, non est aliquid causa diversorum, nisi in aliqua alia habitudine se habens. Et sic oportet quod quando appropinquant ad invicem movens et motum convenienti propinquitate, et similiter cum sunt in quacumque dispositione quae requiritur ad hoc quod unum moveat et aliud moveatur, necesse sit hoc moveri, et aliud movere. And this he concludes from the premises, because it has already been said that both in things that act according to nature and in things that act according to will, none is the cause of diverse things except as it is a different state. Accordingly, it is necessary that when the mover and the moved approach one another according to a suitable distance and likewise when they are in whatever disposition is required for one to cause motion and for the other to be moved, then the one must be moved and the other must cause motion.
Si ergo non semper erat motus, manifestum est quod non se habebant in ista habitudine ut tunc unum moveret et aliud moveretur; sed se habebant sicut non possibilia tunc movere et moveri; postmodum autem se habent in ista habitudine ut unum moveat et aliud moveatur. Ergo necesse est quod alterum eorum mutetur. If, therefore, there was not always motion, it is clear that existing things were not in that state that allowed for one to cause motion and another to be moved; rather, they were in the state of not being able to cause motion and of being moved at that time. But later they reached that state in which one moves and the other is moved. Therefore, one or the other of them changed.
Hoc enim videmus accidere in omnibus quae dicuntur ad aliquid, quod nunquam advenit nova habitudo, nisi per mutationem utriusque vel alterius; sicut si aliquid, cum prius non esset duplum, nunc factum est duplum, etsi non mutetur utrumque extremorum, saltem oportet quod alterum mutetur. Et sic si de novo adveniat habitudo per quam aliquid moveat et aliud moveatur, oportet vel utrumque vel alterum moveri prius. Et sic sequitur quod sit mutatio quaedam prior mutatione, quae dicebatur esse prima. For we see that in all things which are said to be “to something” it does not happen that a new relation arises except through a change affecting one or other or both, as, for example, if something which previously was not “double” has now become double, even though not both of the extremes were changed, yet at least one of them was. Accordingly, if there newly arises a relationship by which something causes motion and something is moved, then one or other or both had to be previously moved. Hence, it follows that there is a change prior to the one assumed to be the first.
Deinde cum dicit: adhuc autem prius et posterius etc., ostendit propositum, ratione sumpta ex parte temporis. 979. Then at (757) he explains his proposition with an argument from time.
Et primo praemittit duo quae sunt necessaria ad sequentem probationem. Quorum primum est, quod prius et posterius esse non possunt nisi tempus sit, cum tempus nihil sit aliud quam prius et posterius secundum quod sunt numerata. Secundum est, quod tempus non potest esse nisi sit motus; et hoc etiam patet ex definitione temporis, quam supra in quarto posuit, dicens quod tempus est numerus motus secundum prius et posterius. First he premises two things necessary for his proposition. The first of these is that “prior” and “subsequent” cannot occur unless there is time, since time is nothing else than prior and subsequent precisely as numbered. The second is that time cannot be, unless there is motion. This, too, is clear from the definition—given in Book IV—describing time as the number of motion with respect to prior and subsequent.
Secundo ibi: si igitur tempus etc., concludit quandam conditionalem ex iis quae in quarto dicta sunt. Posuit enim ibi secundum suam sententiam, quod tempus est numerus motus: secundum vero aliorum philosophorum sententiam, tempus est motus quidam, ut ibidem dixit. Quodcumque autem horum sit verum, sequitur hanc conditionalem esse veram: si tempus semper est, necesse est motum esse perpetuum. 980. Secondly, at (758) he concludes to a conditional proposition from statements made in Book IV, For there, according to his doctrine, he stated time to be the number of motion; according to the doctrine of the other philosophers time is a motion, as he there stated. But whichever of these is true, it follows that this conditional is true: If time always exists, it is necessary that motion be perpetual.
Tertio ibi: at vero de tempore etc., probat antecedens praedictae conditionalis dupliciter. Primo quidem per opiniones aliorum. Et dicit quod omnes philosophi praeter unum, scilicet Platonem, concorditer videntur sentire de tempore quod sit ingenitum, idest quod non inceperit esse postquam prius non fuit. Unde et Democritus probat impossibile esse quod omnia sint facta, quasi de novo inceperint, quia impossibile est sic tempus esse factum, quod de novo inceperit. 981. Thirdly, at (759) he proves in two ways the antecedent of this conditional. First, from the opinions of others. And he says that all the philosophers but one, namely, Plato, seem to be in accord with regard to the opinion that time is not begotten, i.e., that it did not begin to exist after previously not existing. Whence, Democritus also proved that it is impossible that all things should have been made in the sense of newly beginning to be, because it is impossible that time have been so made that it begin newly to be.
Sed solus Plato generat tempus, idest dicit tempus de novo factum. Dicit enim Plato quod tempus est simul factum cum caelo; ponebat autem caelum esse factum, idest habere durationis principium, ut hic Aristoteles ei imponit, secundum quod eius verba superficietenus sonare videntur; quamvis Platonici dicant Platonem sic dixisse caelum esse factum, inquantum habet principium activum sui esse, non autem ita quod habeat durationis principium. Sic igitur solus Plato intellexisse videtur quod tempus non potest esse sine motu; quia non posuit tempus esse ante motum caeli. Only Plato generates time, i.e., says that time was newly made. For he says that time was made at the same time as the heavens, and he supposed that the heavens were made, i.e., that they have a beginning of their duration, as Aristotle here claims, and as Plato’s words seem at first glance to indicate—although Platonists say that Plato asserted that the heavens were made in the sense that they have an active principle of their existence but not as having a principle of their duration. Thus, therefore, does Plato alone seem to have conceived that time cannot be without motion, for he did not suppose that time existed before the motion of the heavens.
Secundo ibi: si igitur impossibile etc., probat idem per rationem: quia impossibile est quod dicatur aut intelligatur esse tempus absque ipso nunc, sicut impossibile est quod sit linea sine puncto. Nunc autem est quoddam medium, habens de sui ratione quod sit simul et principium et finis, principium quidem futuri temporis, finis autem praeteriti. Ex quo apparet quod necesse est semper esse tempus. Quodcumque enim tempus accipiatur, eius extremum est aliquod nunc ex utraque parte. Et hoc patet per hoc, quod nihil est accipere in actu de tempore, nisi nunc: quia quod praeteritum est, iam abiit; quod autem futurum est, nondum est. Nunc autem quod accipitur in extremo temporis, est principium et finis, ut dictum est. Ergo necesse est quod ex utraque parte cuiuscumque temporis accepti, semper sit tempus: alioquin primum nunc non esset finis, et ultimum nunc non esset principium. 982. Secondly, at (760) he proves the same point by an argument, namely, from the fact that it is impossible to say or to understand time to exist without the “now,” just as it is impossible that there be a line without a point, The “now,” however, is something intermediate, having as part of its nature that it be at once a beginning and an end, i.e., the beginning of a future time, but the end of a past. From this it appears that it is necessary for time always to be. For whatever time is taken, its boundary is a “now” in both senses. And this is clear from the fact that nothing is actual in time but the “now,” because what is past has gone by, and what is future does not yet exist. But the “now” which is taken as the boundary of time, is both a beginning and an end, as has been said. Therefore it is necessary that from both aspects of whatever time is taken, time always be; otherwise the first “now” would not be an end, and the last not a beginning.
Ex hoc autem quod tempus est sempiternum, concludit quod necesse est motum sempiternum esse. Et rationem consequentiae assignat: quia tempus est quaedam proprietas motus; est enim numerus eius, ut dictum est. But from the fact that time is eternal, he concludes that motion too must be eternal; the reason for this conclusion being that time is a property of motion, for it is its number, as was said.
Videtur autem quod Aristotelis ratio non sit efficax. Sic enim se habet nunc ad tempus, sicut punctum ad lineam, ut in sexto habitum est: non est autem de ratione puncti quod sit medium; sed aliquod punctum est quod est tantum principium lineae, aliquod autem quod est tantum finis: accideret autem omne punctum esse principium et finem, inquantum est lineae infinitae. Non ergo posset probari quod linea sit infinita, ex hoc quod omne punctum sit principium et finis: sed potius e converso, ex hoc quod linea est infinita, probandum esset quod omne punctum esset principium et finis. Sic ergo videtur quod omne nunc esse principium et finem, non sic sit verum, nisi ex eo quod tempus ponitur sempiternum. Videtur ergo Aristoteles in assumptione huius medii supponere sempiternitatem temporis, quam debet probare. 983. But the argument of Aristotle does not appear efficacious. For the “now” is to time as the point is to the line, as was explained in Book VI. But it is not necessary that a point be an intermediate, for some points are merely the beginnings of lines and others the ends, although every point would be both a beginning and an end if the line were infinite. One could not, therefore, prove that a line is infinite from the fact that every point is a beginning and an end; rather it is the other way around: from the fact of a line’s being infinite, one would go on to prove that every point would be both a beginning and an end. Accordingly, it also appears that the claim that every “now” is a beginning and an end is not true, unless time is assumed to be eternal. Therefore in assuming this as a middle term, i.e., that every “now” is a beginning and an end, Aristotle seems to suppose the eternity of time—the very thing he ought to prove.
Averroes autem volens salvare Aristotelis rationem, dicit quod hoc quod nunc semper sit principium et finis, convenit ei inquantum tempus non est stans sicut linea, sed fluens. Quod manifestum est nihil ad propositum pertinere. Ex hoc enim quod tempus est fluens et non stans, sequitur quod unum nunc non possit bis sumi, sicut bis sumitur unum punctum: sed fluxus temporis nihil facit ad hoc quod nunc sit principium et finis simul. Eiusdem enim rationis est inceptio et terminatio in omnibus continuis, sive sint permanentia, sive fluentia, ut ex sexto patet. Now Averroes, in trying to save Aristotle’s argument, says that the attribute of always being both a beginning and an end belongs to the “now” inasmuch as time is not stationary like a line but flowing. But this does not pertain to the proposition. For from the fact that time is flowing and not stationary, it follows that one “now” cannot be taken twice in the way that one point is taken twice, but the flow of time has nothing to do with the “now” being at once a beginning and an end. For the notion of beginning and end is the same in all continua whether they be permanent or flowing, as is clear from Book VI.
Et ideo aliter dicendum est, secundum intentionem Aristotelis, quod hoc quod omne nunc sit principium et finis, vult accipere ex eo quod primo supposuit, scilicet quod prius et posterius non sit, tempore non existente: hoc enim principio supposito ad nihil aliud usus est; sed ex hoc concluditur quod omne nunc sit principium et finis. Detur enim quod aliquod nunc sit principium alicuius temporis: manifestum est autem ex definitione principii, quod principium temporis est ante quod nihil eius existit: est ergo accipere aliquid ante vel prius quam ipsum nunc, quod ponitur principium temporis. Prius autem non est sine tempore: ergo nunc quod ponitur principium temporis, est etiam temporis finis. Et eodem modo si ponatur nunc esse finis temporis, sequitur quod sit etiam principium: quia de ratione finis est quod post ipsum nihil sit eius: posterius autem non est sine tempore: sequitur ergo quod nunc quod ponitur finis, sit etiam principium temporis. 984. And therefore another explanation must be furnished in accord with the intention of Aristotle, which is that he wishes to derive the fact that every “now” is a beginning and an end from what he had first supposed, namely, that “prior” and “subsequent” would not be, if time did not exist. For he uses this principle which he supposes for no other purpose, but deduces from it that every “now” is a beginning and an end. For let us suppose that some “now” is the beginning of a time; but it is clear from the definition of a beginning, that the beginning of a time is that before which nothing of the time existed. Therefore, there must be taken something “before” or “prior” to the “now” which is assumed as the beginning of the time. “Prior,” however, does not exist without time. Therefore, the “now” which is taken as the beginning of a time is also the end of a time. In the same way, if a “now” be taken as the end of a time, it too will be a beginning, because an end is by definition that “after which” nothing of a thing exists; but “after” cannot be without time. Therefore, it follows that the “now” which is the end of a time is also a beginning.
Deinde cum dicit: eadem autem ratio est etc., ostendit quod motus semper sit futurus. Et ostendit hoc ex parte motus: quia ratio supra ex parte motus accepta, non concludebat nisi quod motus nunquam incipiat; ratio vero sumpta ex parte temporis, concludebat utrumque, et quod nunquam inceperit, et quod nunquam deficiat. Dicit ergo quod eadem ratione potest probari quod motus sit incorruptibilis, idest quod nunquam deficiat, per quam probatur quod motus nunquam incepit. Sicut enim ex hoc quod est motum incipere, sequitur quod sit quaedam mutatio prior mutatione quae ponitur prima; sic si ponatur quod motus quandoque deficiat, sequitur quod sit aliqua mutatio posterior ea quae ponitur postrema. 985. Then at (761) he shows that motion will always be. And he shows this on the part of motion, because the argument from motion given above concluded only that motion never began, whereas the argument from time concluded both, i.e., that it never began and that it never ceases. He says therefore that the very argument by which it was proved that motion never began can prove that motion is indestructible, i.e., that it will never end. For just as from the assumption that motion began it followed that there was a change prior to the change assumed to be first, so too, if it be supposed that motion at some time ceases, it follows that a change will occur after the one assumed to be the last,
Et quomodo hoc sequatur manifestat abbreviando quod supra diffusius dixerat circa inceptionem motus. Posuerat enim quod si motus incepit, aut mobilia et moventia inceperunt, aut semper fuerunt. Et similis divisio posset hic fieri; quia si motus deficiat, aut mobilia et moventia remanebunt, aut non: sed quia supra ostenderat quod idem sequitur secundum utrumque, ideo hic non utitur nisi altera via, scilicet quod ponatur sic motus deficere, quod mobilia et moventia deficiant. How this follows he explains by abbreviating the more diffuse explanation he gave with regard to the beginning of motion. For he had supposed that if motion began, the mobiles and movers either began or always were. The same alternatives can be taken here, namely, that if motion should cease, the mobiles and movers will remain or they will not. But because he had previously shown that the same conclusion follows from either alternative, here therefore he uses only the one alternative, i.e., the supposition that motion ceases in such a way that the mobiles and movers also pass away.
Hoc ergo supposito, dicit quod non simul quiescit, idest deficit, motus in actu et ipsum mobile: sed sicut prior est generatio mobilis quam motus eius, ita posterior est corruptio mobilis quam cessatio motus. Quod sic patet: quia contingit quod remaneat aliquid combustibile, postquam desinit comburi. Therefore, beginning with the assumption mentioned, he says that both the actual motion and the mobile do not pass away simultaneously, but just as the generation of a mobile is prior to its motion, so the ceasing-to-be of a mobile is subsequent to the passing away of its motion. This is so because something combustible can remain after combustion ceases.
Et sicut dictum est de mobili, ita dicendum est de motivo: quia non simul desinit esse movens in actu, et esse motivum in potentia. Sic igitur patet quod si etiam ipsum mobile corrumpitur post cessationem motus, necessarium erit esse quandam corruptionem ipsius mobilis. And what was said of the mobile must also be said of the mover, because a mover in act does not in ceasing to be cease at the same time to be a mover in potency. Accordingly, it is evident that if even the mobile cease to be after the destruction of its motion, then there has to be a process by which the mobile passes out of existence.
Et iterum quia ponitur quod omnia moventia et mota desinunt, necessarium erit posterius, quod etiam ipsum corruptivum corrumpatur. Cum ergo corruptio sit mutatio quaedam, sequetur quod post ultimam mutationem sint aliquae mutationes. Cum ergo hoc sit impossibile, sequitur quod motus in perpetuum duret. And again, because we are supposing that all mobiles and motions are ceasing to be, it will be necessary later that even the cause of their ceasing-to-be cease to be. But because ceasing-to-be is a type of motion, it will follow that after the final change, other changes occur. But since this is impossible, it follows that motion endures forever.
Hae igitur rationes sunt, ex quibus Aristoteles probare intendit motum semper fuisse et nunquam deficere. Quod quidem quantum ad unam partem fidei nostrae repugnat, scilicet quod ponatur motus semper fuisse. Nihil enim secundum fidem nostram ponitur semper fuisse, nisi solus Deus, qui est omnino immobilis: nisi forte quis ipsum divinum intelligere velit nominare motum; quod aequivoce intelligeretur: non enim de tali motu Aristoteles hic intelligit, sed de motu proprie dicto. 986. These, therefore, are the arguments by which Aristotle intends to prove that motion always has been and will never cease, The first part of which, i.e., that motion always existed, conflicts with our faith, For our faith admits nothing as eternally existing but God alone, Who is utterly immobile—unless, of course, you wish to refer to the act of the divine intellect as a motion, but that would be an equivocal sense, and Aristotle is not here speaking of motion in that sense but of motion properly so called.
Quantum vero ad aliam partem, non omnino est contrarium fidei: quia ut supra dictum est, non agit Aristoteles de motu caeli, sed universaliter de motu. Ponimus autem secundum fidem nostram, substantiam mundi sic quandoque incepisse, quod tamen nunquam desinat esse. Ponimus etiam quod aliqui motus semper erunt, praesertim in hominibus, qui semper remanebunt, incorruptibilem vitam agentes, vel miseram vel beatam. The other part of the conclusion is not entirely contrary to the faith, because, as was said above, Aristotle is not treating of the motion of the heavens in particular but of motion universally. Now we believe according to our faith that the substance of the world indeed began, yet so as never to cease. For we posit that some motions will always exist, especially in men who will always remain living an unceasing life either of happiness or misery.
Quidam vero frustra conantes Aristotelem ostendere non contra fidem locutum esse, dixerunt quod Aristoteles non intendit hic probare quasi verum, quod motus sit perpetuus; sed inducere rationem ad utramque partem, quasi ad rem dubiam: quod ex ipso modo procedendi frivolum apparet. Et praeterea, perpetuitate temporis et motus quasi principio utitur ad probandum primum principium esse, et hic in octavo et in XII Metaphys.; unde manifestum est, quod supponit hoc tanquam probatum. But some, vainly trying to show that Aristotle concluded nothing contrary to the faith, have said that Aristotle does not intend here to prove as a truth that motion is eternal but to allege reason for both sides of a question that is doubtful. Rut this is a foolish statement to anyone who investigates Aristotle’s procedure here. Moreover, he uses the eternity of time and of motion as a principle to prove the existence of a first principle both here in Physics VIII and in Metaphysics XII. That shows he considered it proved.
Sed si quis recte rationes hic positas consideret, huiusmodi rationibus veritas fidei efficaciter impugnari non potest. Sunt enim huiusmodi rationes efficaces ad probandum quod motus non inceperit per viam naturae, sicut ab aliquibus ponebatur: sed quod non inceperit quasi rebus de novo productis a primo rerum principio, ut fides nostra ponit, hoc iis rationibus probari non potest; quod patet singulas illationes hic positas consideranti. 987. But if one rightly considers the arguments here given, the truth of the faith is not assailed by them, For they prove that motion did not begin through the way of nature, as some taught it did, but that it did not begin by things being created by a first principle of things, as our faith holds, cannot be proved by these arguments. And that will be evident to anyone who considers each of the inferences here drawn by Aristotle.
Cum enim quaerit, si motus non semper fuit, utrum moventia et mobilia semper fuerunt vel non: respondendum est quod primum movens semper fuit; omnia vero alia, sive sint moventia sive mobilia, non semper fuerunt, sed inceperunt esse a causa universali totius esse. Ostensum est autem supra, quod productio totius esse a causa prima essendi, non est motus, sive ponatur quod haec rerum emanatio sit ab aeterno, sive non. Sic ergo non sequitur quod ante primam mutationem sit aliqua mutatio. Sequeretur autem si moventia et mobilia essent de novo producta in esse ab aliquo agente particulari, quod ageret aliquo subiecto praesupposito, quod transmutaretur de non esse in esse, sive de privatione ad formam: de hoc enim modo incipiendi procedit ratio Aristotelis. For when he asks whether, if motion did not always exist, the movers and mobiles always existed or not, the reply must be that the first mover always existed; other things—movers or mobiles—did not always exist, but began to exist from the universal cause of all existence. But it has been pointed out above that the production of all being by the first cause of being is not a motion, whether this coming-forth be taken to be ab aeterno or not. Accordingly, it does not follow that before the first change there was a previous change. But this would follow if the movers and mobiles were newly brought into existence by some particular agent acting upon some presupposed subject that would be changed from non-being to being, or from privation to form—and Aristotle’s argument concerns this way of coming into existence.
Sed quia ponimus saltem primum motorem semper fuisse, respondendum restat sequenti eius deductioni, qua concludit quod si, praeexistentibus moventibus et mobilibus, incipiat de novo esse motus, oportet quod moventia vel mobilia prius non essent in hac dispositione, in qua sunt dum est motus; et sic oportet quod primam mutationem praecedat aliqua mutatio. 988. But because we posit that at least a first mover always existed, we need to give an answer to his subsequent deduction that, if movers and mobiles pre-exist, and motion begins newly to be in them, then the movers or mobiles could not have been previously in that disposition in which they are while there is motion, and therefore, some change must have preceded the first change.
Et si quidem de ipso motu loquamur, facilis est responsio: non enim mobilia prius erant in hac dispositione in qua nunc sunt, quia prius non erant; unde moveri non poterant. Sed sicut dictum est, ipsum esse non acquisiverunt per mutationem vel motum, sed per emanationem a primo rerum principio: et sic non sequitur quod ante primam mutationem sit aliqua mutatio. Sed ulterius remanet quaestio de prima rerum productione. Si enim primum principium, quod est Deus, non aliter se habet nunc quam prius, non magis nunc res producit quam prius: si vero aliter se habet, saltem mutatio quae est ex parte eius, erit prior mutatione quae ponitur prima. Now, if we are speaking of the motion itself, the answer is easy: the mobiles were not previously in that disposition in which they now are, because previously they did not exist; hence they could not be moved. But, as it has been said, they received their existence not through a change or motion but through coming forth from the first principle of things; accordingly, it does not follow that before the first change there was a change. But there still remains the question about the first production of things. For if the first principle, which is God, is no different now than before, then neither does he produce things now any more than before; but if he is different, at least the change affecting him will be prior to the change which is supposed to be the first.
Et quidem si esset agens per naturam tantum, et non per voluntatem et intellectum, ex necessitate concluderet ratio: sed quia agit per voluntatem, potest per voluntatem aeternam producere effectum non aeternum, sicut intellectu aeterno potest intelligere rem non aeternam: res enim intellecta est quodammodo principium actionis in agentibus per voluntatem, sicut forma naturalis in agentibus per naturam. And indeed, if he were a cause that acts only through nature and not through intellect and will, this reason would conclude necessarily. But because he acts through will, he can through an eternal will produce an effect which is non-eternal, just as by his eternal intellect he can understand a thing that is non-eternal—the thing understood being in a certain way the principle of action in causes that act by intellect, as a natural form is in causes that act by nature.
Sed adhuc magis instat. Non enim videmus quod voluntas postponat facere quod vult, nisi propter hoc quod aliquid exspectatur in futurum, quod nondum est in praesenti; sicut si volo facere ignem non nunc, sed postea exspectatur in futurum frigus, cuius causa facio ignem; vel ad minus exspectatur praesentia temporis. Quod autem tempus succedat post tempus, hoc non est absque motu: non ergo potest esse quod voluntas, etiam si ponatur immutabilis, postponat facere id quod vult, nisi aliquo motu interveniente. Et sic non potest esse quod nova productio rerum proveniat a voluntate aeterna, nisi mediantibus motibus succedentibus sibi in infinitum. 989. But a further point must be pursued. For we do not say that a will postpones doing what it wants, unless something is expected in the future that does not yet exist in the present, as for example, when I will to make a fire not now but later, because in the future it is expected to be cold, on account of which I make the fire; or at least a presence of time is awaited. But that time succeeds time does not occur without motion. Therefore, it cannot be that a will, even if it be immutable, postpones doing what it wills, without some motion being involved, Accordingly, the new production of things cannot come forth from the eternal will except by means of motions succeeding one another ad infinitum.
Latet autem sic obiicientes, quod haec obiectio procedit de agente in tempore, quod scilicet agit tempore praesupposito: in huiusmodi enim actione quae fit in tempore, oportet considerare aliquam determinatam habitudinem ad hoc tempus, vel ad aliquid eorum quae sunt in hoc tempore, ut fiat magis in hoc tempore quam in alio. Sed haec ratio locum non habet in agente universali, quod et ipsum tempus simul cum ceteris producit. Now those who raise this objection fail to see that it assumes a thing acting in time, i.e., something that acts on the assumption that time exists; for in this kind of action which occurs in time, one must consider some determinate relationship to this time or to things that exist in this time to explain why it be performed in this time rather than in some other time. But this reasoning has no place in the universal agent, which produces time itself at the same time that it produces other things.
Cum enim dicimus res non semper fuisse a Deo productas, non intelligimus quod infinitum tempus praecesserit, in quo Deus ab agendo cessaverit, et postmodum tempore determinato agere ceperit: sed quod Deus tempus et res simul in esse produxerit postquam non fuerant. Et sic non restat in divina voluntate considerandum, quod voluerit facere res non tunc sed postea, quasi tempore iam existente: sed considerandum solum est hoc, quod voluit quod res et tempus durationis earum inceperint esse postquam non fuerant. For when we say that things have not always been produced by God, we do not understand that an infinite time preceded, in which God refrained from acting and that later, at a definite time, He began to act; rather, we understand that God produced at once both time and things after they did not exist. Accordingly, we must not consider in the divine will that it willed to make things not then but later, as though time were already existing; rather, we must solely consider the fact that he willed that things and the time of their duration should begin to be after they had no existed at all.
Si autem quaeratur quare hoc voluit, sine dubio dicendum est quod propter seipsum. Sicut enim propter seipsum res fecit, ut in eis suae bonitatis similitudo manifestaretur; ita voluit eas non semper esse, ut sua sufficientia manifestaretur, in hoc quod omnibus aliis non existentibus, ipse in seipso omnem sufficientiam beatitudinis habuit, et virtutis ad rerum productionem. If it be asked why he willed this, it must be said without a doubt that it was for his own sake. For just as he made things because of himself, in order that in them the likeness of his goodness be manifested, so he willed that they not always be, in order to show his self-sufficiency, from the fact that, although nothing else existed, he in himself had all sufficiency of happiness and of power to produce things.
Et hoc quidem dici potest quantum humana ratio capere potest de divinis: salvo tamen secreto divinae sapientiae, quod a nobis comprehendi non potest. And this can indeed be said as far as human reason can grasp divine things, saving, of course, the secret of divine wisdom which cannot be comprehended by us.
Quia igitur huius rationis solutio procedit supponendo quod tempus non fuerit semper, restat solvere rationem per quam ostendi videtur tempus semper fuisse: et ideo forte Aristoteles post rationem de motu posuit rationem de tempore, quia consideravit quod praemissa ratio de motu efficaciam non haberet, nisi poneretur tempus aeternum. Quod ergo dicit, quod quandocumque est tempus, necesse est ponere aliquod nunc esse, indubitanter concedendum est: omne autem nunc esse principium et finem temporis, concedi non oportet, nisi ponatur etiam motum semper esse; ut scilicet sic quodlibet indivisibile in motu acceptum, quod momentum dicitur, sit principium et finis motus: sic enim se habet nunc ad momentum, sicut tempus ad motum. Si ergo ponimus motum non semper fuisse, sed est accipere aliquod primum indivisibile in motu, ante quod nihil fuit motus; erit etiam accipere aliquod nunc in tempore, ante quod non fuit aliquod tempus. 990. Because the solution of this argument proceeded on the supposition that time did not always exist, there remains the problem of solving the argument which seems to prove that time always existed. And perhaps Aristotle, after the argument from motion, gave one from time, because he thought that the one from motion would be inefficacious, unless time was assumed to be eternal. His statement, therefore, that whenever there is time there must be a “now” existing, must be granted without demur. But the statement that every “now” is both a beginning and an end should not be conceded, unless it be also granted that motion always existed, so that every indivisible of motion (which is called a “moment”) should be both a beginning and an end of motion—for the “now” is to the moment as time is to motion. If, therefore, we suppose that motion has not always existed, but that we can take some first indivisible in motion before which nothing of motion existed, we can also take some “now” in time before which there was no time.
Iam autem ostendimus, exponendo litteram, quod id quod Averroes dicit ad hanc rationem confirmandam, efficaciam non habet. Sed nec illud quod Aristoteles ad hoc ponit, scilicet quod prius et posterius non sunt sine tempore, efficax esse potest. Now we have already shown, in explaining the text, that what Averroes says to bolster this argument is inefficacious. But neither is there any efficacy in what Aristotle cites to bolster his own position, namely, that “before” and “after” do not exist without time.
Cum enim dicimus quod principium temporis est ante quod nihil eius est, non propter hoc oportet quod ipsum nunc quod est principium temporis, praecedat tempus quod significatur cum dicitur ante: sicut si in magnitudine dicam quod principium magnitudinis est extra quod nihil est eius, non oportet quod extra illud principium significet aliquem locum in rerum natura existentem, sed imaginabilem tantum: alioquin esset ponere locum extra caelum, cuius est magnitudo finita, habens principium et finem. For when we say that a time’s beginning is “that before which nothing of the time existed,” we are not thereby compelled to say that the “now” which is the beginning of the time, is preceded by a time signified by the word “before,” any more than in magnitudes, if I say that the beginning of a magnitude is “that beyond which nothing exists of that magnitude,” it is necessary to say that the phrase, “beyond which beginning,” signifies some real place existing in nature—for it signifies an imaginary one only. Otherwise, it would be necessary to posit a place beyond the universe, whose magnitude is finite and has a beginning and an end.
Similiter etiam primum nunc quod est principium temporis, non praecedit tempus in rerum natura existens, sed secundum imaginationem nostram tantum. Et hoc tempus designatur, cum dicitur quod primum nunc est principium temporis, ante quod nihil est temporis. Similarly, the first “now” which is the beginning of time is not preceded by a time existing in reality but only in our imagination. And this is the time that is described when one says that the first “now” is the beginning of time, “before which” nothing of time exists.
Vel potest dici, quod cum dicitur principium temporis est ante quod nihil est temporis, ly ante non remanet affirmatum, sed negatur; et sic non oportet ponere tempus ante principium temporis. In iis enim quae sunt in tempore, accidit quod eorum principio tempus aliquod praeexistat: sicut cum dicitur quod principium iuventutis est ante quod nihil est de iuventute, potest intelligi ly ante etiam affirmative, quia iuventus tempore mensuratur. Tempus autem non mensuratur tempore; unde eius principio tempus non praeexistit: et sic ly ante, quod ponitur in definitione principii temporis, non oportet quod remaneat affirmatum, sed negatur. Or it may be said that in the expression, “the beginning of time is that before which nothing of time exists,” the word, “before,” is not affirmed but denied—and so it is not necessary to posit a time before the beginning of time. For in things which exist in time, it happens that some certain time precedes their beginning, as, when it is said that the beginning of youth is that before which there was nothing of youth, the word “before” can be taken in an affirmative sense, because youth is measured by time. But time is not measured by time; hence no time preceded its beginning; hence the word “before” in the definition of time is not taken affirmatively but negatively.
Est tamen ante tempus aliqua duratio, scilicet aeternitas Dei, quae non habet extensionem aut prius et posterius, sicut tempus, sed est tota simul; et non est eiusdem rationis cum tempore, sicut nec magnitudo divina cum magnitudine corporali. But before time there does exist a duration, namely, the eternity of God. But this eternity has no extension or any before or after as time does; rather, it is all at once—and is not of the same nature as time any more than the divine magnitude is of the same nature as a bodily magnitude.
Sicut ergo, cum dicimus extra mundum non esse nisi Deum, non ponimus aliquam dimensionem extra mundum; ita cum dicimus ante mundum nihil fuisse, non ponimus aliquam successivam durationem ante mundum. Therefore, just as when we say that “outside” the universe there is nothing but God, we are not positing some dimension outside the world, so too, when we say that “before” the universe nothing existed, we are not positing any sort of successive duration before the universe.

Lectio 3
Arguments against Anaxagoras and Empedocles
Chapter 1 cont.
ἀλλ' οὐχ ὁτὲ μὲν ἦν ὁτὲ δ' οὔ· καὶ γὰρ ἔοικε τὸ οὕτω λέγειν πλάσματι μᾶλλον. and cannot have existed at one time and not at another: in fact such a view can hardly be described as anythling else than fantastic.
ὁμοίως δὲ καὶ τὸ λέγειν ὅτι πέφυκεν οὕτως καὶ ταύτην δεῖ νομίζειν εἶναι ἀρχήν, ὅπερ ἔοικεν Ἐμπεδοκλῆς ἂν εἰπεῖν, ὡς τὸ κρατεῖν καὶ κινεῖν ἐν μέρει τὴν φιλίαν καὶ τὸ νεῖκος ὑπάρχει τοῖς πράγμασιν ἐξ ἀνάγκης, ἠρεμεῖν δὲ τὸν μεταξὺ χρόνον. τάχα δὲ καὶ οἱ μίαν ἀρχὴν ποιοῦντες, ὥσπερ Ἀναξαγόρας, οὕτως ἂν εἴποιεν. And much the same may be said of the view that such is the ordinance of nature and that this must be regarded as a principle, as would seem to be the view of Empedocles when he says that the constitution of the world is of necessity such that Love and Strife alternately predominate and cause motion, while in the intermediate period of time there is a state of rest. Probably also those who like like Anaxagoras, assert a single principle (of motion) would hold this view.
ἀλλὰ μὴν οὐδέν γε ἄτακτον τῶν φύσει καὶ κατὰ φύσιν· ἡ γὰρ φύσις αἰτία πᾶσιν τάξεως. τὸ δ' ἄπειρον πρὸς τὸ ἄπειρον οὐδένα λόγον ἔχει· τάξις δὲ πᾶσα λόγος. τὸ δ' ἄπειρον χρόνον ἠρεμεῖν, εἶτα κινηθῆναί ποτε, τούτου δὲ μηδεμίαν εἶναι διαφοράν, ὅτι νῦν μᾶλλον ἢ πρότερον, μηδ' αὖ τινὰ τάξιν ἔχειν, οὐκέτι φύσεως ἔργον. ἢ γὰρ ἁπλῶς ἔχει τὸ φύσει, καὶ οὐχ ὁτὲ μὲν οὕτως ὁτὲ δ' ἄλλως, οἷον τὸ πῦρ ἄνω φύσει φέρεται καὶ οὐχ ὁτὲ μὲν ὁτὲ δ' οὔ· ἢ λόγον ἔχει τὸ μὴ ἁπλοῦν. διόπερ βέλτιον ὡς Ἐμπεδοκλῆς, κἂν εἴ τις ἕτερος εἴρηκεν οὕτως ἔχειν, ἐν μέ ρει τὸ πᾶν ἠρεμεῖν καὶ κινεῖσθαι πάλιν· τάξιν γὰρ ἤδη τιν' ἔχει τὸ τοιοῦτον. But that which is produced or directed by nature can never be anything disorderly: for nature is everywhere the cause of order. Moreover, there is no ratio in the relation of the infinite to the infinite, whereas order always means ratio. But if we say that there is first a state of rest for an infinite time, and then motion is started at some moment, and that the fact that it is this rather than a previous moment is of no importance, and involves no order, then we can no longer say that it is nature's work: for if anything is of a certain character naturally, it either is so invariably and is not sometimes of this and sometimes of another character (e.g. fire, which travels upwards naturally, does not sometimes do so and sometimes not) or there is a ratio in the variation. It would be better, therefore, to say with Empedocles and any one else who may have maintained such a theory as his that the universe is alternately at rest and in motion: for in a system of this kind we have at once a certain order.
ἀλλὰ καὶ τοῦτο δεῖ τὸν λέγοντα μὴ φάναι μόνον, ἀλλὰ καὶ τὴν αἰτίαν αὐτοῦ λέγειν, καὶ μὴ τίθεσθαι μηδὲν μηδ' ἀξιοῦν ἀξίωμ' ἄλογον, ἀλλ' ἢ ἐπαγωγὴν ἢ ἀπόδειξιν φέρειν· αὐτὰ μὲν γὰρ οὐκ αἴτια τὰ ὑποτεθέντα, οὐδὲ τοῦτ' ἦν τὸ φιλότητι ἢ νείκει εἶναι, ἀλλὰ τῆς μὲν τὸ συνάγειν, τοῦ δὲ τὸ διακρίνειν. εἰ δὲ προσοριεῖται τὸ ἐν μέρει, λεκτέον ἐφ' ὧν οὕτως, ὥσπερ ὅτι ἔστιν τι ὃ συνάγει τοὺς ἀνθρώπους, ἡ φιλία, καὶ φεύγουσιν οἱ ἐχθροὶ ἀλλήλους· τοῦτο γὰρ ὑποτίθεται καὶ ἐν τῷ ὅλῳ εἶναι· φαίνεται γὰρ ἐπί τινων οὕτως. τὸ δὲ καὶ δι' ἴσων χρόνων δεῖται λόγου τινός. But even here the holder of the theory ought not only to assert the fact: he ought to explain the cause of it: i.e. he should not make any mere assumption or lay down any gratuitous axiom, but should employ either inductive or demonstrative reasoning. The Love and Strife postulated by Empedocles are not in themselves causes of the fact in question, nor is it of the essence of either that it should be so, the essential function of the former being to unite, of the latter to separate. If he is to go on to explain this alternate predominance, he should adduce cases where such a state of things exists, as he points to the fact that among mankind we have something that unites men, namely Love, while on the other hand enemies avoid one another: thus from the observed fact that this occurs in certain cases comes the assumption that it occurs also in the universe. Then, again, some argument is needed to explain why the predominance of each of the two forces lasts for an equal period of time.
ὅλως δὲ τὸ νομίζειν ἀρχὴν εἶναι ταύτην ἱκανήν, εἴ τι αἰεὶ ἢ ἔστιν οὕτως ἢ γίγνεται, οὐκ ὀρθῶς ἔχει ὑπολαβεῖν, ἐφ' ὃ Δημόκριτος ἀνάγει τὰς περὶ φύσεως αἰτίας, ὡς οὕτω καὶ τὸ πρότερον ἐγίγνετο· τοῦ δὲ ἀεὶ οὐκ (252b.) ἀξιοῖ ἀρχὴν ζητεῖν, λέγων ἐπί τινων ὀρθῶς, ὅτι δ' ἐπὶ πάντων, οὐκ ὀρθῶς. καὶ γὰρ τὸ τρίγωνον ἔχει δυσὶν ὀρθαῖς ἀεὶ τὰς γωνίας ἴσας, ἀλλ' ὅμως ἐστίν τι τῆς ἀϊδιότητος ταύτης ἕτερον αἴτιον· τῶν μέντοι ἀρχῶν οὐκ ἔστιν ἕτερον αἴτιον ἀϊδίων οὐσῶν. ὅτι μὲν οὖν οὐδεὶς ἦν χρόνος οὐδ' ἔσται ὅτε κίνη σις οὐκ ἦν ἢ οὐκ ἔσται, εἰρήσθω τοσαῦτα. But it is a wrong assumption to suppose universally that we have an adequate first principle in virtue of the fact that something always is so or always happens so. Thus Democritus reduces the causes that explain nature to the fact that things happened in the past in the same way as they happen now: but he does not think fit to seek for a first principle to explain this 'always': so, while his theory is right in so far as it is applied to certain individual cases, he is wrong in making it of universal application. Thus, a triangle always has its angles equal to two right angles, but there is nevertheless an ulterior cause of the eternity of this truth, whereas first principles are eternal and have no ulterior cause. Let this conclude what we have to say in support of our contention that there never was a time when there was not motion, and never will be a time when there will not be motion.
Postquam philosophus posuit rationes ad ostendendum motum semper esse, hic ponit rationes contra Anaxagoram et Empedoclem, qui contrarium ponebant. Et circa hoc duo facit: primo ponit rationem contra eorum positionem; secundo contra rationem quam supponebant, ibi: similiter autem et dicere et cetera. 991. After presenting the reasons showing that motion always existed, the Philosopher here gives arguments against Anaxagoras and Empedocles who posited the contrary. About this he does two things: First he gives an argument against their position; Secondly, against the argument they presupposed, at 992.
Dicit ergo primo, quod cum ostensum sit quod motus semper est, non erit dicendum quod aliquando sit motus et aliquando non, sicut dixerunt Empedocles et Anaxagoras: sic enim dicere sicut ipsi posuerunt, assimilatur cuidam figmento, quia scilicet absque ratione hoc ponebant; omne enim quod ponitur absque ratione vel auctoritate divina, fictitium esse videtur. Auctoritas autem divina praevalet etiam rationi humanae, multo magis quam auctoritas alicuius philosophi praevaleret alicui debili rationi, quam aliquis puer induceret. Non ergo assimilantur figmento quae per fidem tenentur, licet absque ratione credantur: credimus enim divinae auctoritati miraculis approbatae, idest illis operibus quae solus Deus facere potest. He says therefore first that since it has been shown that motion always exists, it is wrong to say, as Empedocles and Anaxagoras did, that at some time motion exists and at another time it does not; for to make such a claim is a figment, because it has no basis. Something stated without a reason or the support of divine authority seems, indeed, to be a fiction. However, divine authority has more value than human reason, much more indeed than the authority of a philosopher is more valuable than the weak argument some child might give. Therefore, what is held by faith, even though it be believed without an argument is not a figment of the mind, because we believe on the divine authority approved by miracles —works that God alone can produce.
Deinde cum dicit: similiter autem et dicere etc., obiicit contra rationem cui innitebantur. Et circa hoc tria facit: primo ponit istam rationem esse inconvenientem; secundo ostendit quod inconvenientior erat secundum positionem Anaxagorae, quam secundum positionem Empedoclis, ibi: at vero nihil inordinatum etc.; tertio ostendit quod nec secundum opinionem Empedoclis convenienter se habet, ibi: sed et oportet hoc dicentem et cetera. 992. Then at (763) he objects against the argument on which they rested. About this he does three things: First he suggests that their argument is unsuitable; Secondly, that it was more unsuitable to Anaxagoras’ position than to that of Empedocles, at 993; Thirdly, he shows that even according to Empedocles’ opinion it is unsuitable, at 994.
Dicit ergo primo, quod similiter etiam hoc videtur esse fictitium, quod aliquis ponens motum quandoque esse et quandoque non esse, dicat hoc pro ratione, quod hoc ideo est, quia natum est sic esse, et hoc oportet accipere tanquam principium; sicut Empedocles videtur dicere, quod hoc quod res in parte temporis teneant amicitiam et in parte temporis teneant discordiam et moveantur, et quod in medio tempore quiescant, inest rebus ex necessitate; sicut si aliquis diceret quare calidum calefacit, quia sic necesse est esse, et hoc accipiatur quasi principium, quod calidum calefaciat. Similiter accipiebat Empedocles quasi principium, quod necesse est sic esse, quandoque res moveri per amicitiam, quandoque per discordiam, et quandoque quiescere. He says therefore first (763) that it also seems a fiction that anyone, positing that motion at one time exists and at another time does not, should give as his reason that this is so because it is natural for it to be that way, and then adds that this statement must be accepted as a principle. Now that is what Empedocles seems to say, namely, that the situation whereby during one period of time things maintain friendship, and during another are ruled by discord that sets things in motion, but in the interim are at rest, is due to a sort of necessity in things. That is like saying that the reason why heat warms is that it has to be that way, and that heat warms should then be accepted as a principle. This is exactly what Empedocles does, when he takes as a principle that it is due to an ordinance of nature that things are at one time being moved by friendship, and at another time by discord, and at another time are at rest.
Et forte etiam eodem modo diceret Anaxagoras et alii ponentes unum principium activum, quod oportet hoc accipere quasi principium, quod motus inceperit postquam infinito tempore non fuit. Perhaps Anaxagoras, too, and others who posit one active principle would speak in a similar vein, namely, that we must accept as a principle that motion began to exist after not existing for an infinite period of time.
Deinde cum dicit: at vero nihil inordinatum etc., ostendit quod hac ratione inconvenientius utebatur Anaxagoras quam Empedocles. Manifestum est enim quod cum ponitur aliquid esse quasi principium, oportet accipere quod hoc sit secundum rei naturam; hoc est, ut natura rei sit talis quod hoc ei conveniat. Sic enim accipimus quasi principium, quod omne totum maius est sua parte, quia hoc est de ratione et natura totius, quod excedat partis quantitatem. Unde Empedocles dicebat, sic aptum natum esse; dans intelligere quod hoc esset accipiendum quasi principium. Et similiter Anaxagoras diceret, licet non exprimeret. 993. Then at (764) he shows that Anaxagoras used this argument in a more unsuitable way than did Empedocles. For it is clear that when something is laid down as a principle, it should be accepted as being according to the nature of a thing, i.e., that the nature of a thing is such that such a thing belongs to it. Thus we accept the principle that the whole is greater than its part, because it is the very reason and nature of a whole that it exceed the quantity of a part. Hence, when Empedocles says, “It is natural that it be that way,” he gives us to understand that it should be accepted as a principle. Anaxagoras would have said the same, although he did not express it.
Sed manifestum est quod nulla res naturalis, nec aliquid eorum quae naturaliter rebus conveniunt, potest esse absque ordine; quia natura est causa ordinationis. Videmus enim naturam in suis operibus ordinate de uno in aliud procedere: quod ergo non habet aliquem ordinem, non est secundum naturam, nec potest accipi ut principium. But it is clear that no natural thing nor anything that belongs to things naturally, can exist without order, because nature is a cause of order. For we see that nature in its works proceeds in an orderly fashion from one thing to another. Therefore, whatever does not possess order is not according to nature and cannot be called a principle.
Sed duo infinita non habent ordinem ad invicem, quia infiniti ad infinitum nulla est proportio; omnis autem ordo proportio quaedam est. Sic ergo patet quod quiescere res tempore infinito, et postea incipere moveri per infinitum tempus, sine hoc quod sit aliqua differentia inter hoc tempus et illud, quare nunc magis quam prius motus fiat; neque iterum assignare aliquam aliam ordinationem inter aliqua duo, quorum uno deficiente, alterum incipiat et fiat motus, ut Anaxagoras ponebat; hoc non est opus naturae. Quia quidquid est in natura, aut semper simpliciter, idest eodem modo, se habet, et non aliquando sic, aliquando autem aliter, sicut ignis semper sursum fertur; aut aliqua ratio est quare non semper est eodem modo, sicut non semper animalia crescunt, sed quandoque diminuuntur, et hoc habet aliquam rationem. But two infinites have no order, one to the other, because there is no ratio between one infinite and another, whereas every order is a kind of ratio. Accordingly, it is evidently not a work of nature that things rest for an infinite time and later begin to be moved for an infinite time without there being, between this time and that, any difference to explain why motion comes to be now rather than before; any more than it is a work of nature not to assign some other order between the two things, so that when one fails the other begins and motion comes to be, as Anaxagoras posited. These are not works of nature, because whatever is in nature either is always the same and not sometimes this way and then that way—as fire always moves upwards—or there is some reason why it is not always the same, as for example, animals do not always continue growing but reach a point when they start to decrease—and for this there is a reason.
Sic ergo non videtur secundum naturam procedere, quod infinito tempore res quieverint, et postmodum moveri inceperint, ut Anaxagoras posuit. Accordingly, it does not seem to be according to nature that for an infinite time things be at rest and later begin to be moved, as Anaxagoras assumed.
Unde melius est quod dicatur, sicut Empedocles dixit, vel quicumque alius similiter opinatus est, quod totum universum in quadam parte temporis quiescit, et iterum movetur in alia parte temporis; quia iam hoc potest habere aliquam ordinationem: finiti enim ad finitum potest esse proportio. Hence it is better to say, as Empedocles said—and those who believed as he—that the whole universe is at rest at one time and in motion at another, because at least in this case there would be order, for there can be a ratio between one finite and another.
Est autem considerandum quod sententia fidei nostrae non est similis positioni Anaxagorae. Non enim ponimus ante mundum infinita spatia temporis, cuius sit necesse accipere proportionem ad tempus sequens: sed antequam mundus inciperet, sola Dei simplex aeternitas fuit, sicut dictum est, quae est omnino extra genus temporis. It should, however, be considered that the tenet of our faith is not akin to Anaxagoras’ position, for we do not assume before the world any infinite reaches of time that have to be related to a later time; rather, before the world began, only the simple eternity of God existed, and that is outside the genus of time.
Deinde cum dicit: sed et oportet hoc dicentem etc., ostendit quod nec etiam Empedocli convenit praedicta ratio. Et primo ostendit propositum; secundo excludit quandam falsam existimationem, ibi: omnino enim existimare et cetera. 994. Then at (765) he shows that the above-mentioned argument is not appropriate in Empedocles’ situation either. First he explains the proposition; Secondly, he rejects a false interpretation, at 995.
Dicit ergo primo, quod etiam qui hoc dicit quod Empedocles dixit, non oportet quod solum affirmet quod dicit, sed etiam quod assignet causam sui dicti; et quod nihil ex se apponat ultra id quod causa assignata requirit; neque etiam aliquid velit accipere ut dignitatem, idest ut principium, absque ratione. Sed oportet quod adducat ad manifestationem eius quod accepit quasi principium, aut inductionem, sicut in principiis naturalibus quae ex sensibilium experimento accipiuntur; aut demonstrationem, sicut in principiis quae per priora principia demonstrantur. Sed hoc Empedocles non servat. Esto enim quod ipse ponat amicitiam et litem esse causas, tamen hoc non est de ratione amicitiae vel inimicitiae, quod unum eorum post alterum moveat. Non est enim de ratione amicitiae, quod in inimicitiam convertatur, nec e converso: sed de ratione amicitiae est quod congreget, de ratione vero inimicitiae est quod disgreget. He says therefore first (765) that even the holder of Empedocles’ theory ought not to assert the fact only but also should explain the cause of his statement and not go beyond what is required by the cause he assigns. Nor should he accept anything as an axiom, i.e., as a principle without reason; rather, whatever is accepted as a principle should be explained either by induction, as is done in the case of natural principles based on sense experience, or by demonstration, as in the case of those principles which are proved by prior principles. But Empedocles does not do that. Granted that he posits friendship and discord as causes, yet it is not the property of friendship or hostility that one should cause motion after the other. For it is not the nature of friendship to be changed into hostility, or vice versa; though it is of the nature of friendship to gather and of hostility to scatter.
Sed si ulterius determinetur quod in quadam parte temporis haec congreget, et iterum in quadam parte temporis illa disgreget; est ulterius manifestandum in aliquibus particularibus, in quibus hoc contingat. Sicut quod amicitia congreget, et inimicitia disgreget, manifestatur in hominibus, quia amicitia homines adunantur ad invicem, inimicitia vero fugiunt ab invicem; et ideo hoc ab Empedocle supponitur esse in toto universo, quia videtur sic esse in aliquibus. Sed quod secundum aequalia tempora moveant successive amicitia et inimicitia, hoc indiget aliqua ratione manifestante: non enim videtur hoc in hominibus contingere. But if it is further determined that at one time the one gathers and that at another time the other scatters, it must be further made clear by definite instances in which this occurs. For example, that friendship gathers and discord scatters is manifested among men, because by the former men are united but by the latter they fly from one another. So Empedocles supposed that this is what happens in the whole universe, because it seems to happen in certain cases. But that according to equal periods friendship should move at one time and discord at another, needs to be supported by argument, since that is not seen to happen among men.
Deinde cum dicit: omnino enim existimare etc., excludit quandam falsam existimationem. Posset enim aliquis credere, quod quidquid semper est, non habet causam, propter hoc quod videmus ea quae apud nos causantur, de novo incipere: et ideo videbatur aliquibus, quod quando reducebatur aliqua quaestio in aliquid quod est semper, non oporteret ulterius causam seu rationem quaerere. Sic ergo posset Empedocles dicere, quod amicitia et lis semper secundum aequalia tempora moverunt: et ideo non est quaerenda huius alia ratio. Hoc ergo Aristoteles removet, dicens quod non recte se habet opinari quod aliquid existimetur esse principium, propter hoc quod semper aut sic est, aut sic fit. Ad hoc enim Democritus reducebat omnes causas naturales, assignans principium iis quae de novo fiunt; sed eius quod est semper, nolebat aliquod principium quaerere. Quod quidem in aliquibus recte dicitur, sed non in omnibus. Manifestum est enim quod triangulus semper habet tres angulos aequales duobus rectis; sed tamen huius perpetuae passionis est altera causa. Sed aliqua perpetua sunt, sicut principia, quorum non est alia causa. 995. Then at (766) he rejects a false assumption. For someone could believe that whatever is eternal has no cause, since whatever we observe as being caused among us is something that begins newly to be. Consequently, it seemed to some that when a discussion reached something that always existed, there was no need to inquire any further for a cause or a reasons In this vein Empedocles could say that friendship and discord had always caused motion according to equal times and therefore no reason for it need be sought. But Aristotle disqualifies this by saying that it is a wrong assumption to suppose that we have an adequate first principle in virtue of the fact that something always is so or always happens so. In this way Democritus reduced all the causes that explain nature to something existing always: he assigned a principle for things that begin newly to be, but would not look for a principle of what has always been, Now this is true in some things and not in others. For it is clear that a triangle always has three angles equal to two right angles, but even of this eternal property there is a cause other than the fact. But some things are indeed eternal, such as principles, that do not have a cause.
Est autem valde notandum quod hic dicitur; quia ut in II Metaphys. habetur, eadem est dispositio rerum in esse et in veritate. Sicut igitur aliqua sunt semper vera et tamen habent causam suae veritatis, ita Aristoteles intellexit quod essent aliqua semper entia, scilicet corpora caelestia et substantiae separatae, et tamen haberent causam sui esse. 996. Very special attention should be paid to what is here said, because, as is mentioned in Metaphysics II, the arrangement of things in existence and in truth is the same. Therefore, just as some things are always true and yet have a cause of their truth, so Aristotle understood that there are some eternal beings, namely, the heavenly bodies and separated substances, which nevertheless have a cause of existence.
Ex quo patet quod quamvis Aristoteles poneret mundum aeternum, non tamen credidit quod Deus non sit causa essendi ipsi mundo, sed causa motus eius tantum, ut quidam dixerunt. Ultimo autem concludit principale propositum epilogando. Et dicit tanta dicta esse de hoc quod nullum tempus erit in futuro, neque erat in praeterito, in quo aliquis motus non sit. From this it is evident that although Aristotle posited a world that was eternal, he did not believe that God is not the world’s cause of existence but of its motion only, as some maintained. Finally, he concludes his main proposition with a summary. And he says: “Let this conclude what we have to say in support of our claim that there never was a time when there was not motion and there will never be a time when there will not be motion.”

Lectio 4
Solution of arguments concluding motion was not always
Chapter 2
Τὰ δὲ ἐναντία τούτοις οὐ χαλεπὸν λύειν. δόξειε δ' ἂν ἐκ τῶν τοιῶνδε σκοποῦσιν ἐνδέχεσθαι μάλιστα κίνησιν εἶναί ποτε μὴ οὖσαν ὅλως, πρῶτον μὲν ὅτι οὐδεμία ἀΐδιος μεταβολή· μεταβολὴ γὰρ ἅπασα πέφυκεν ἔκ τινος εἴς τι, ὥστε ἀνάγκη πάσης μεταβολῆς εἶναι πέρας τὰ ἐναντία ἐν οἷς γίγνεται, εἰς ἄπειρον δὲ κινεῖσθαι μηδέν. The arguments that may be advanced against this position are not difficult to dispose of. The chief considerations that might be thought to indicate that motion may exist though at one time it had not existed at all are the following: First, it may be said that no process of change is eternal: for the nature of all change is such that it proceeds from something to something, so that every process of change must be bounded by the contraries that mark its course, and no motion can go on to infinity.
ἔτι ὁρῶμεν ὅτι δυνατὸν κινηθῆναι μήτε κινούμενον μήτ' ἔχον ἐν ἑαυτῷ μηδεμίαν κίνησιν, οἷον ἐπὶ τῶν ἀψύχων, ὧν οὔτε μέρος οὐδὲν οὔτε τὸ ὅλον κινούμενον ἀλλ' ἠρεμοῦν κινεῖταί ποτε· προσῆκεν δὲ ἢ ἀεὶ κινεῖσθαι ἢ μηδέποτε, εἴπερ μὴ γίγνεται οὐκ οὖσα. Secondly, we see that a thing that neither is in motion nor contains any motion within itself can be set in motion; e.g. inanimate things that are (whether the whole or some part is in question) not in motion but at rest, are at some moment set in motion: whereas, if motion cannot have a becoming before which it had no being, these things ought to be either always or never in motion.
πολὺ δὲ μάλιστα τὸ τοιοῦτον ἐπὶ τῶν ἐμψύχων εἶναι φανερόν· οὐδεμιᾶς γὰρ ἐν ἡμῖν ἐνούσης κινήσεως ἐνίοτε, ἀλλ' ἡσυχάζοντες ὅμως κινούμεθά ποτε, καὶ ἐγγίγνεται ἐν ἡμῖν ἐξ ἡμῶν αὐτῶν ἀρχὴ κινήσεως, κἂν μηθὲν ἔξωθεν κινήσῃ. τοῦτο γὰρ ἐπὶ τῶν ἀψύχων οὐχ ὁρῶμεν ὁμοίως, ἀλλ' ἀεὶ κινεῖ τι αὐτὰ τῶν ἔξωθεν ἕτερον· τὸ δὲ ζῷον αὐτό φαμεν ἑαυτὸ κινεῖν. ὥστ' εἴπερ ἠρεμεῖ ποτὲ πάμπαν, ἐν ἀκινήτῳ κίνησις ἂν γίγνοιτο ἐξ αὑτοῦ καὶ οὐκ ἔξωθεν. εἰ δ' ἐν ζῴῳ τοῦτο δυνατὸν γενέσθαι, τί κωλύει τὸ αὐτὸ συμβῆναι καὶ κατὰ τὸ πᾶν; εἰ γὰρ ἐν μικρῷ κόσμῳ γίγνεται, καὶ ἐν μεγάλῳ· καὶ εἰ ἐν τῷ κόσμῳ, κἀν τῷ ἀπείρῳ, εἴπερ ἐνδέχεται κινεῖσθαι τὸ ἄπειρον καὶ ἠρεμεῖν ὅλον. Thirdly, the fact is evident above all in the case of animate beings: for it sometimes happens that there is no motion in us and we are quite still, and that nevertheless we are then at some moment set in motion, that is to say it sometimes happens that we produce a beginning of motion in ourselves spontaneously without anything having set us in motion from without. We see nothing like this in the case of inanimate things, which are always set in motion by something else from without: the animal, on the other hand, we say, moves itself: therefore, if an animal is ever in a state of absolute rest, we have a motionless thing in which motion can be produced from the thing itself, and not from without. Now if this can occur in an animal, why should not the same be true also of the universe as a whole? If it can occur in a small world it could also occur in a great one: and if it can occur in the world, it could also occur in the infinite; that is, if the infinite could as a whole possibly be in motion or at rest.
τούτων δὴ τὸ μὲν πρῶτον λεχθέν, τὸ μὴ τὴν αὐτὴν ἀεὶ καὶ μίαν τῷ ἀριθμῷ εἶναι τὴν κίνησιν τὴν εἰς τὰ ἀντικείμενα, ὀρθῶς λέγεται. τοῦτο μὲν γὰρ ἴσως ἀναγκαῖον, εἴπερ μὴ ἀεὶ μίαν καὶ τὴν αὐτὴν εἶναι δυνατὸν τὴν τοῦ αὐτοῦ καὶ ἑνὸς κίνησιν· λέγω δ' οἷον πότερον τῆς μιᾶς χορδῆς εἷς καὶ ὁ αὐτὸς φθόγγος, ἢ ἀεὶ ἕτερος, ὁμοίως ἐχούσης καὶ κινουμένης. ἀλλ' ὅμως ὁποτέρως ποτ' ἔχει, οὐδὲν κωλύει τὴν αὐ(253a.) τὴν εἶναί τινα τῷ συνεχῆ εἶναι καὶ ἀΐδιον· δῆλον δ' ἔσται μᾶλλον ἐκ τῶν ὕστερον. Of these objections, then, the first-mentioned motion to opposites is not always the same and numerically one a correct statement; in fact, this may be said to be a necessary conclusion, provided that it is possible for the motion of that which is one and the same to be not always one and the same. (I mean that e.g. we may question whether the note given by a single string is one and the same, or is different each time the string is struck, although the string is in the same condition and is moved in the same way.) But still, however this may be, there is nothing to prevent there being a motion that is the same in virtue of being continuous and eternal: we shall have something to say later that will make this point clearer.
τὸ δὲ κινεῖσθαι μὴ κινούμενον οὐδὲν ἄτοπον, ἂν ὁτὲ μὲν ᾖ τὸ κινῆσον ἔξωθεν, ὁτὲ δὲ μή. τοῦτο μέντοι πῶς ἂν εἴη, ζητητέον, λέγω δὲ ὥστε τὸ αὐτὸ ὑπὸ τοῦ αὐτοῦ κινητικοῦ ὄντος ὁτὲ μὲν κινεῖσθαι ὁτὲ δὲ μή· οὐδὲν γὰρ ἄλλ' ἀπορεῖ ὁ τοῦτο λέγων ἢ διὰ τί οὐκ ἀεὶ τὰ μὲν ἠρεμεῖ τῶν ὄντων τὰ δὲ κινεῖται. As regards the second objection, no absurdity is involved in the fact that something not in motion may be set in motion, that which caused the motion from without being at one time present, and at another absent. Nevertheless, how this can be so remains matter for inquiry; how it comes about, I mean, that the same motive force at one time causes a thing to be in motion, and at another does not do so: for the difficulty raised by our objector really amounts to this—why is it that some things are not always at rest, and the rest always in motion?
μάλιστα δ' ἂν δόξειεν τὸ τρίτον ἔχειν ἀπορίαν, ὡς ἐγγιγνομένης οὐκ ἐνούσης πρότερον κινήσεως, τὸ συμβαῖνον ἐπὶ τῶν ἐμψύχων· ἠρεμοῦν γὰρ πρότερον μετὰ ταῦτα βαδίζει, κινήσαντος τῶν ἔξωθεν οὐδενός, ὡς δοκεῖ. τοῦτο δ' ἐστὶ ψεῦδος. ὁρῶμεν γὰρ ἀεί τι κινούμενον ἐν τῷ ζῴῳ τῶν συμφύτων· τούτου δὲ τῆς κινήσεως οὐκ αὐτὸ τὸ ζῷον αἴτιον, ἀλλὰ τὸ περιέχον ἴσως. αὐτὸ δέ φαμεν αὑτὸ κινεῖν οὐ πᾶσαν κίνησιν, ἀλλὰ τὴν κατὰ τόπον. οὐδὲν οὖν κωλύει, μᾶλλον δ' ἴσως ἀναγκαῖον, ἐν μὲν τῷ σώματι πολλὰς ἐγγίγνεσθαι κινήσεις ὑπὸ τοῦ περιέχοντος, τούτων δ' ἐνίας τὴν διάνοιαν ἢ τὴν ὄρεξιν κινεῖν, ἐκείνην δὲ τὸ ὅλον ἤδη ζῷον κινεῖν, οἷον συμβαίνει περὶ τοὺς ὕπνους· αἰσθητικῆς μὲν γὰρ οὐδεμιᾶς ἐνούσης κινήσεως, ἐνούσης μέντοι τινός, ἐγείρεται τὰ ζῷα πάλιν. ἀλλὰ γὰρ φανερὸν ἔσται καὶ περὶ τούτων ἐκ τῶν ἑπομένων. The third objection may be thought to present more difficulty than the others, namely, that which alleges that motion arises in things in which it did not exist before, and adduces in proof the case of animate things: thus an animal is first at rest and afterwards walks, not having been set in motion apparently by anything from without. This, however, is false: for we observe that there is always some part of the animal's organism in motion, and the cause of the motion of this part is not the animal itself, but, it may be, its environment. Moreover, we say that the animal itself originates not all of its motions but its locomotion. So it may well be the case—or rather we may perhaps say that it must necessarily be the case—that many motions are produced in the body by its environment, and some of these set in motion the intellect or the appetite, and this again then sets the whole animal in motion: this is what happens when animals are asleep: though there is then no perceptive motion in them, there is some motion that causes them to wake up again. But we will leave this point also to be elucidated at a later stage in our discussion.
Postquam philosophus posuit rationes ad probandum motum semper esse, hic intendit solvere ea quae in contrarium obiici possunt. Et circa hoc duo facit: primo ponit rationes; secundo solvit eas, ibi: horum autem primum et cetera. 997. After giving arguments proving that motion always exists, the Philosopher now intends to answer objections to the contrary. About this he does two things: First he gives the arguments; Secondly, he answers them, at 1000.
Circa primum ponit tres rationes, praemittens suam intentionem: et dicit quod ea quae in contrarium obiici possunt, non est difficile solvere. Ex tribus enim rationibus videtur maxime sequi quod motus aliquando incipiat esse, cum prius omnino non fuerit: In regard to the first he gives three arguments, after first stating that it is not difficult to solve the objections contrary to his position. And he says that there are three main arguments from which it seems to follow that motion began to be at some time after previously not existing at all.
quarum prima est, qua supra probavit in sexto quod nulla mutatio est infinita; eadem enim ratione probari potest quod nulla mutatio sit perpetua. Nulla enim mutatio terminata est perpetua, sicut nec infinita; sed omnis mutatio est terminata. Omnis enim mutatio naturaliter est ex quodam in quiddam, et ista duo sunt contraria; unde necesse est quod terminus cuiuslibet mutationis sint ipsa contraria in quibus fit transmutatio. Sed quia non in omni motu locali manifesta est contrarietas terminorum, subiungit quod est commune omni motui, quod nihil movetur in infinitum; quia nihil movetur ad id ad quod pertingere non potest, ut in sexto dictum est. Sic ergo patet quod nulla mutatio est perpetua, sicut nec infinita. Si ergo nulla mutatio est perpetua, videtur etiam possibile dari tempus in quo nulla mutatio sit. Et haec prima ratio accepta est ex parte motus. The first of these is that whereby he proved in Book VI that no change is infinite, because by the same argument it can be proved that no change is eternal. For no terminated change is eternal any more than it is infinite. But every change is terminated. For every motion is naturally from something to something, and these two are contraries; hence, of necessity, the termini of any change are the contraries within the sphere of that change. But because contrariety of termini is not evident in all cases of local motion, Aristotle adds something common to every motion, namely, that nothing is moved to infinity, because nothing is moved to what it cannot reach, as has been said in Book VI, Accordingly, it is clear that no motion is perpetual, just as it is not infinite. If, therefore, no motion is perpetual, it also seems possible to posit a time in which there is no change. This first argument is taken from motion.
Secunda ratio accipitur ex parte mobilis, quam ponit ibi: amplius videmus etc.; quae talis est. Si motus non potest fieri de novo cum prius non esset, videtur esse conveniens dicere de unoquoque, quod vel semper movetur, vel nequaquam moveatur: quia si in uno mobili potest quandoque motus esse et quandoque non esse, pari ratione in toto universo. Sed videmus quod possibile est aliquid moveri, quod prius non movebatur secundum totum, neque aliquem motum in seipso habebat secundum aliquam sui partem: sicut apparet in rebus inanimatis, in quibus aliquod mobile quandoque moveri incipit, cum antea nulla pars eius moveretur, neque ipsum totum, sed omnino quiesceret. Relinquitur ergo quod in toto universo potest esse motus, cum prius non fuerit. 998. The second argument is based on the mobile, at (768). It is this: If motion cannot newly come to be when previously it was not, it seems fitting to say of anything that either it is always in motion or never in notion; because if motion can sometimes be and sometimes not be in one particular mobile, why not for the whole universe? But we see that it is possible for something to be moved that previously was not moved as a whole, and that had no motion in itself with respect to any of its parts, as is apparent in non-living things, among which some mobile begins at one time to be moved when previously no part had been moved, nor the whole itself, but it was completely at rest. It remains, therefore, that in the whole universe there can be motion where previously there was none.
Sed quia in rebus inanimatis, licet appareat motus in aliquo de novo incipere nullo motu praeexistente in illo eodem, apparet tamen motus praeexistens in aliquo exteriori a quo movetur: ideo tertiam rationem ponit ex parte animalium, quae non moventur ab extrinseco, sed a seipsis; et hoc ibi: multo autem magis et cetera. 999. But because in non-living things, even though motion is seen to begin anew in something when previously there was none at all, yet motion appears to have been pre-existing in something external by which it is moved, he accordingly gives a third argument from animals, which are moved not from without but by themselves. This argument is at (769).
Et dicit quod incipere motum cum prius non esset, multo magis est manifestum in rebus animatis quam inanimatis. Cum enim nos quieverimus aliquando, nullo motu in nobis existente, aliquando moveri incipimus, et est ex nobis ipsis principium nostri motus, etiam si nihil extrinsecum moveat: quod quidem in rebus inanimatis non contingit, sed semper aliquid extrinsecum movet ipsa, vel generans, vel removens prohibens, vel violentiam inferens. Ex quo sequitur quod si animal quandoque totaliter quiescat, quod in aliquo immobili incipiat esse motus cum prius non fuerit, non ex aliquo extrinseco movente, sed ab ipsomet quod movetur. Et si hoc potest esse in animali, nihil prohibere videtur quin idem accidat in universo: habet enim animal, et maxime homo, similitudinem quandam cum mundo: unde dicitur a quibusdam quod homo sit parvus mundus. Et sic si in parvo mundo incipit motus cum prius non fuerit, videtur quod etiam in magno mundo idem possit contingere. Et si hoc contingit in mundo, potest etiam contingere in toto infinito, quod quidam posuerunt extra mundum: si tamen sit aliquod infinitum quod possit quiescere et moveri. It says that it is more evident in animals than in the non-living that motion begins after previously having not existed. For when we have rested for a time so that ho motion exists in us, we begin at a certain time to be moved and the principle of our motion is from our very selves even if nothing external moves us. This, however, does not happen in non-living things, because they are moved always by something external, such as the cause that generates them, or a cause that removes an obstacle, or a cause that subjects them to force. From this it follows, if an animal is at one time entirely at rest, that motion begins to exist in an immobile being after previously not existing in it, which motion does not originate from an external mover but from the very thing that is moved. And if this can occur in an animal, there is nothing to prevent its occurring in the universe. For an animal and especially man possesses a likeness to the world; wherefore it is said that man is a small world. Accordingly, if in this small world, motion can begin after previously not existing in it, it seems that the same can happen in the large world. And if this happens in the world, it can happen in the infinite whole, which some assumed exists beyond the world—provided, of course, that there is something infinite that can rest and be moved.
Deinde cum dicit: horum autem primum etc., solvit per ordinem rationes praemissas. 1000. Then at (770) he answers these arguments in order.
In solutione ergo primae rationis dicit, quod istud recte dicitur, quod motus qui est inter contraria non potest semper durare unus et idem numero; quia forte hoc est necessarium, ut infra probabitur: et ideo ponit sub dubitatione, quia nondum erat probatum. Sed quia posset aliquis dicere quod etiam motus qui est inter contraria, potest esse semper unus numero propter identitatem mobilis, quod iterato de contrario in contrarium movetur; sicut si prius movebatur de albo in nigrum, postea moveatur de nigro in album, et sic semper: ideo subiungit quod non est possibile quod semper motus qui est unius et eiusdem mobilis, per reiterationem sit unus et idem. Et hoc manifestat per exemplum. Ponatur enim quod chorda citharae similiter se habeat; et movens qui percutit chordam, similiter se habeat in movendo: potest esse dubitatio, utrum unius chordae bis percussae sit unus et idem motus et sonus, aut semper alius et alius. In answer, therefore, to the first he says that it is correct to say that motion which occurs between contraries cannot always endure as one and the same numerical motion, because perhaps this is necessary, as will be proved later—and he leaves this in doubt, because it has not yet been proved. But because someone could say that even motion which is between contraries can be always numerically the same on account of maintaining the same mobile which is repeatedly moved from one contrary to another—for example, if it is first moved from white to black, and then from black to white, and so on throughout time—he then adds that it is not possible that a motion which is always in one and the same mobile be kept one and the same by repetition. And he explains this by an example: Let the same chord be continually struck on a lyre and let the striker be unvarying in his striking; one may ask whether the motion and sound of the one chord struck twice is one and the same or continually other and other.
Sed tamen quidquid sit de aliis mobilibus, nihil tamen prohibet quin aliquis motus qui non est inter contraria, sicut circularis motus, idem semper maneat continuus et perpetuus: quod magis ex sequentibus erit manifestum. Licet ergo omnis motus sit finitus secundum terminos, tamen per reiterationem aliquis motus potest esse continuus et perpetuus. Yet whatever be the case with other mobiles, there is nothing to prevent a motion which is not between contraries, such as a circular motion, from being the same continual and perpetual motion. This will be made clearer from later development. Therefore, although every motion is finite with respect to its termini, yet by repetition some motion can be continuous and perpetual.
Deinde cum dicit: moveri autem quod non movetur etc.; solvit secundam rationem. Et dicit quod nullum inconveniens est si aliquid inanimatum incipiat moveri cum prius non moveretur, si hoc accidat propter hoc, quod movens extrinsecus aliquando sit praesens, aliquando non. Manifestum enim est quod oportet praeexistere motum ex parte moventis, quod aliquando fit prope cum prius non esset. Sed istud videtur esse inquirendum quasi dubium, scilicet si, existente movente, idem ab eodem quandoque moveatur, et quandoque non: hoc enim supra dixit non posse accidere, nisi praecedente aliqua mutatione, vel ex parte mobilis vel ex parte moventis: et sic semper praeexistit motus, sive praeexistat movens, sive non. Ideo autem hoc videtur quaerendum, quia ille qui hanc rationem induxit, de nullo alio videtur dubitare, quam propter quid quiescentia non semper quiescunt, et mobilia non semper moventur. 1001. Then at (771) he answers the second argument. And he says that it is nothing unusual for a non-living thing to begin to be moved when previously it was not being moved, provided that this occurs because an external mover is present at one time and not at another. For it is clear that motion must pre-exist on the part of a mover which at some time becomes near but previously was not so. However, this seems to be a point to be looked into as a problem, namely, whether, if a mover exists, the same object can be at one time moved by this mover and at another not—for he had previously said that such a thing cannot happen unless there intervenes some change affecting either the mover or the mobile. Accordingly, motion always pre-exists, whether or not a mover pre-exists. Now this point seems to need investigation, because whoever proposed this argument seems to be certain about everything but one factor, namely, why it is that things at rest do not always rest, and mobiles are not always in motion.
Deinde cum dicit: maxime autem etc., solvit tertiam rationem. Et dicit quod id quod tertio obiectum est, maxime facit dubitare quod possit esse motus cum prius non fuerit, sicut videtur accidere in rebus animatis. Videtur enim quod animal quod prius quiescebat, postmodum moveatur processivo motu, nullo motu facto ab exteriori: et sic videtur quod illum motum animalis non praecedebat aliquis motus, neque in ipso animali neque in alio, sicut in rebus inanimatis dicebatur. 1002. Then at (772) he answers the third argument, And he says that the third objection causes the greatest problem about whether motion can exist after previously not existing, based on what is seen to happen in living things. For it seems that an animal which previously was at rest, later begins to move about without any external cause of motion; accordingly, it seems that that motion of the animal was not preceded by any motion, either in the animal or in anything else, as happens in non-living things.
Sed hoc est falsum, scilicet quod motus animalis non fiat ab aliquo exteriori. Videmus enim semper in animalibus aliquid naturaliter motum, quod scilicet non movetur per voluntatem. Et huius quod movetur naturaliter, causa non est ipsum animal per suum appetitum: sed forsitan causa huius naturalis mutationis est continens, idest aer, et ulterius corpus caeleste; sicut manifeste apparet cum alteratur corpus animalis per calorem vel frigus aeris. But it is false that the motion of the animal does not come to be from something external. For we always observe in animals something naturally moved, which, namely, is not moved through will. And the cause of its being moved naturally is not the animal through its appetite, but perhaps the cause of this natural change is its surroundings, i.e., the air, and beyond that the heavens, as is plainly the case when the body of an animal is altered by heat or coldness of air.
Et dicit forsitan, quia in animali etiam aliquid naturaliter movetur ab interiori principio, sicut patet in mutationibus quae sunt in anima vegetabili, ut apparet in digestione cibi, et in sequentibus transmutationibus; quae dicuntur naturales, quia non sequuntur apprehensionem et appetitum. Et quia hoc videtur esse contra id quod est proprium animalis, scilicet quod moveat seipsum; ideo subiungit, quod cum dicimus animal movere seipsum, non intelligimus hoc de quolibet motu, sed de motu locali, secundum quem animal movet seipsum per apprehensionem et appetitum. And he says, “perhaps,” because in an animal something is also moved naturally by an internal principle, as is evident in those changes which occur in the vegetal soul, such as are the digestion of food and the subsequent transmutations, which are called “natural” because they do not follow upon apprehension and appetite. And because this seems to be contrary to what is proper to an animal, which is to move itself, he adds that when we say that an animal “moves itself,” we do not understand this of any and every motion, but of local motion, according to which an animal moves itself through apprehension and appetite.
Sic igitur nihil prohibet, immo necessarium est, quod in corpore animalis fiant multae transmutationes a continente, scilicet aere et corpore caelesti; quarum quaedam movent intellectum aut appetitum, ex quo ulterius iam totum animal movetur. Accordingly, there is nothing to prevent—indeed, it is necessary—many changes from taking place in the body of au animal on account of its surroundings, i.e., the air and the heavens, some of which changes move the understanding or the appetite, by which in turn the whole animal is moved.
Est autem considerandum quod hic declarat modum quo corpora caelestia in nos agunt. Non enim agunt directe in animas nostras, sed in corpora: motis autem corporibus, per accidens fit motus in viribus animae quae sunt actus corporalium organorum; non autem ex necessitate in intellectu et in intellectivo appetitu, qui non utuntur organis corporeis. Aliquando tamen intellectus et voluntas sequuntur aliquas praedictarum mutationum; sicut cum aliquis per rationem eligit vel sequi vel repellere vel aliquid agere propter passionem, vel in corpore vel in parte sensitiva exortam. Et ideo non dicit quod omnes motus qui fiunt a continente moveant intellectum aut appetitum, sed quidam, ut omnino necessitatem ab intellectiva parte excludat. 1003. It should be noted that Aristotle here declares the way in which heavenly bodies act upon us. For they do not act directly on our souls but on our bodies; but when our bodies are moved, then per accidens a change occurs in the powers of the soul, which are acts of bodily organs, but not necessarily in the intellect and the intellective appetite, which do not use bodily organs. Yet the intellect and will sometimes follow upon some of these changes, as when a person through his reason chooses either to pursue or to reject or to do something on account of a passion which began in the body or in the sensitive part. And therefore Aristotle does not say that all motions caused by the surroundings move the intellect or appetite, but that some of them do. In this way he excludes necessity from the intellective powers.
Ponit autem exemplum eorum quae dixerat, in dormientibus, in quibus maxima quies esse videtur quantum ad animales motus. Cum tamen in eis nullus motus sit sensibilis, idest a sensibili apprehensione procedens, iterum surgunt animalia evigilata, propter aliquem motum interius existentem, vel ex opere animae nutritivae, sicut cum digesto cibo deficiunt evaporationes quae somnum causabant, et animal excitatur; sive cum alteratur corpus a continente per calorem aut frigus. Of the things he said he gives an example from sleeping things, in which there seems to be maximum rest with respect to animal motions. But even though during sleep there be no motion that is sensible, i.e., proceeding from sense apprehension, animals rise awakened by some motion existing within, due either to the work of the nutritive soul, as when, as a result of the food’s being digested, the vapors which caused sleep vanish and the animal is aroused, or when the body is altered by its surroundings, from heat or cold.
Et sic diligenter consideranti apparet, quod nunquam in nobis aliquis motus apparet de novo, nisi praecedente aliquo alio motu. Et hoc promittit se in sequentibus magis manifestaturum. Thus it is clear to anyone who considers the matter diligently that no motion ever newly appears in us unless some other motion preceded. And he promises to give a fuller explanation of this later.

Lectio 5
Five ways in which things may be disposed with respect to motion or rest. Two first excluded.
Chapter 3
3 Ἀρχὴ δὲ τῆς σκέψεως ἥπερ καὶ περὶ τῆς λεχθείσης ἀπορίας, διὰ τί ποτε ἔνια τῶν ὄντων ὁτὲ μὲν κινεῖται ὁτὲ δὲ ἠρεμεῖ πάλιν. ἀνάγκη δὴ ἤτοι πάντα ἠρεμεῖν ἀεί, ἢ πάντα ἀεὶ κινεῖσθαι, ἢ τὰ μὲν κινεῖσθαι τὰ δ' ἠρεμεῖν, καὶ πάλιν τούτων ἤτοι τὰ μὲν κινούμενα κινεῖσθαι ἀεὶ τὰ δ' ἠρεμοῦντα ἠρεμεῖν, ἢ πάντα πεφυκέναι ὁμοίως κινεῖσθαι καὶ ἠρεμεῖν, ἢ τὸ λοιπὸν ἔτι καὶ τρίτον. ἐνδέχεται γὰρ τὰ μὲν ἀεὶ τῶν ὄντων ἀκίνητα εἶναι, τὰ δ' ἀεὶ κινούμενα, τὰ δ' ἀμφοτέρων μεταλαμβάνειν· ὅπερ ἡμῖν λεκτέον ἐστίν· τοῦτο γὰρ ἔχει λύσιν τε πάντων τῶν ἀπορουμένων, καὶ τέλος ἡμῖν ταύτης τῆς πραγματείας ἐστίν. Our enquiry will resolve itself at the outset into a consideration of the above-mentioned problem—what can be the reason why some things in the world at one time are in motion and at another are at rest again? Now one of three things must be true: either all things are always at rest, or all things are always in motion, or some things are in motion and others at rest: and in this last case again either the things that are in motion are always in motion and the things that are at rest are always at rest, or they are all constituted so as to be capable alike of motion and of rest; or there is yet a third possibility remaining—it may be that some things in the world are always motionless, others always in motion, while others again admit of both conditions. This last is the account of the matter that we must give: for herein lies the solution of all the difficulties raised and the conclusion of the investigation upon which we are engaged.
τὸ μὲν οὖν πάντ' ἠρεμεῖν, καὶ τούτου ζητεῖν λόγον ἀφέντας τὴν αἴσθησιν, ἀρρωστία τίς ἐστιν διανοίας, καὶ περὶ ὅλου τινὸς ἀλλ' οὐ περὶ μέρους ἀμφισβήτησις· οὐδὲ μόνον πρὸς τὸν φυσικόν, ἀλλὰ πρὸς πάσας τὰς (253b.) ἐπιστήμας ὡς εἰπεῖν καὶ πάσας τὰς δόξας διὰ τὸ κινήσει χρῆσθαι πάσας. ἔτι δ' αἱ περὶ τῶν ἀρχῶν ἐνστάσεις, ὥσπερ ἐν τοῖς περὶ τὰ μαθήματα λόγοις οὐδέν εἰσιν πρὸς τὸν μαθηματικόν, ὁμοίως δὲ καὶ ἐπὶ τῶν ἄλλων, οὕτως οὐδὲ περὶ τοῦ νῦν ῥηθέντος πρὸς τὸν φυσικόν· ὑπόθεσις γὰρ ὅτι ἡ φύσις ἀρχὴ τῆς κινήσεως. To maintain that all things are at rest, and to disregard sense-perception in an attempt to show the theory to be reasonable, would be an instance of intellectual weakness: it would call in question a whole system, not a particular detail: moreover, it would be an attack not only on the physicist but on almost all sciences and all received opinions, since motion plays a part in all of them. Further, just as in arguments about mathematics objections that involve first principles do not affect the mathematician—and the other sciences are in similar case—so, too, objections involving the point that we have just raised do not affect the physicist: for it is a fundamental assumption with him that motion is ultimately referable to nature herself.
σχεδὸν δὲ καὶ τὸ φάναι κινεῖσθαι πάντα ψεῦδος μέν, ἧττον δὲ τούτου παρὰ τὴν μέθοδον· ἐτέθη μὲν γὰρ ἡ φύσις ἐν τοῖς φυσικοῖς ἀρχή, καθάπερ κινήσεως, καὶ ἠρεμίας, ὅμως δὲ φυσικὸν ἡ κίνησις· The assertion that all things are in motion we may fairly regard as equally false, though it is less subversive of physical science: for though in our course on physics it was laid down that rest no less than motion is ultimately referable to nature herself, nevertheless motion is the characteristic fact of nature:
καί φασί τινες κινεῖσθαι τῶν ὄντων οὐ τὰ μὲν τὰ δ' οὔ, ἀλλὰ πάντα καὶ ἀεί, ἀλλὰ λανθάνειν τοῦτο τὴν ἡμετέραν αἴσθησιν· πρὸς οὓς καίπερ οὐ διορίζοντας ποίαν κίνησιν λέγουσιν, ἢ πάσας, οὐ χαλεπὸν ἀπαντῆσαι. moreover, the view is actually held by some that not merely some things but all things in the world are in motion and always in motion, though we cannot apprehend the fact by sense-perception. Although the supporters of this theory do not state clearly what kind of motion they mean, or whether they mean all kinds, it is no hard matter to reply to them:
οὔτε γὰρ αὐξάνεσθαι οὔτε φθίνειν οἷόν τε συνεχῶς, ἀλλ' ἔστι καὶ τὸ μέσον. ἔστι δ' ὅμοιος ὁ λόγος τῷ περὶ τοῦ τὸν σταλαγμὸν κατατρίβειν καὶ τὰ ἐκφυόμενα τοὺς λίθους διαιρεῖν· οὐ γὰρ εἰ τοσόνδε ἐξέωσεν ἢ ἀφεῖλεν ὁ σταλαγμός, καὶ τὸ ἥμισυ ἐν ἡμίσει χρόνῳ πρότερον· ἀλλ' ὥσπερ ἡ νεωλκία, καὶ οἱ σταλαγμοὶ οἱ τοσοιδὶ τοσονδὶ κινοῦσιν, τὸ δὲ μέρος αὐτῶν ἐν οὐδενὶ χρόνῳ τοσοῦτον. διαιρεῖται μὲν οὖν τὸ ἀφαιρεθὲν εἰς πλείω, ἀλλ' οὐδὲν αὐτῶν ἐκινήθη χωρίς, ἀλλ' ἅμα. φανερὸν οὖν ὡς οὐκ ἀναγκαῖον ἀεί τι ἀπιέναι, ὅτι διαιρεῖται ἡ φθίσις εἰς ἄπειρα, ἀλλ' ὅλον ποτὲ ἀπιέναι. thus we may point out that there cannot be a continuous process either of increase or of decrease: that which comes between the two has to be included. The theory resembles that about the stone being worn away by the drop of water or split by plants growing out of it: if so much has been extruded or removed by the drop, it does not follow that half the amount has previously been extruded or removed in half the time: the case of the hauled ship is exactly comparable: here we have so many drops setting so much in motion, but a part of them will not set as much in motion in any period of time. The amount removed is, it is true, divisible into a number of parts, but no one of these was set in motion separately: they were all set in motion together. It is evident, then, that from the fact that the decrease is divisible into an infinite number of parts it does not follow that some part must always be passing away: it all passes away at a particular moment.
ὁμοίως δὲ καὶ ἐπ' ἀλλοιώσεως ὁποιασοῦν· οὐ γὰρ εἰ μεριστὸν εἰς ἄπειρα τὸ ἀλλοιούμενον, διὰ τοῦτο καὶ ἡ ἀλλοίωσις, ἀλλ' ἀθρόα γίγνεται πολλάκις, ὥσπερ ἡ πῆξις. Similarly, too, in the case of any alteration whatever if that which suffers alteration is infinitely divisible it does not follow from this that the same is true of the alteration itself, which often occurs all at once, as in freezing.
ἔτι ὅταν τι νοσήσῃ, ἀνάγκη χρόνον γενέσθαι ἐν ᾧ ὑγιασθήσεται, καὶ μὴ ἐν πέρατι χρόνου μεταβάλλειν· ἀνάγκη δὲ εἰς ὑγίειαν μεταβάλλειν καὶ μὴ εἰς ἄλλο μηθέν. ὥστε τὸ φάναι συνεχῶς ἀλλοιοῦσθαι λίαν ἐστὶ τοῖς φανεροῖς ἀμφισβητεῖν. εἰς τοὐναντίον γὰρ ἡ ἀλλοίωσις· Again, when any one has fallen ill, there must follow a period of time in which his restoration to health is in the future: the process of change cannot take place in an instant: yet the change cannot be a change to anything else but health. The assertion. therefore, that alteration is continuous is an extravagant calling into question of the obvious: for alteration is a change from one contrary to another.
ὁ δὲ λίθος οὔτε σκληρότερος γίγνεται οὔτε μαλακώτερος. Moreover, we notice that a stone becomes neither harder nor softer.
κατά τε τὸ φέρεσθαι θαυμαστὸν εἰ λέληθεν ὁ λίθος κάτω φερόμενος ἢ μένων ἐπὶ τῆς γῆς. Again, in the matter of locomotion, it would be a strange thing if a stone could be falling or resting on the ground without our being able to perceive the fact.
ἔτι δ' ἡ γῆ καὶ τῶν ἄλλων ἕκαστον ἐξ ἀνάγκης μένουσι μὲν ἐν τοῖς οἰκείοις τόποις, κινοῦνται δὲ βιαίως ἐκ τούτων· εἴπερ οὖν ἔνι' αὐτῶν ἐστιν ἐν τοῖς οἰκείοις τόποις, (254a.) ἀνάγκη μηδὲ κατὰ τόπον πάντα κινεῖσθαι. ὅτι μὲν οὖν ἀδύνατον ἢ ἀεὶ πάντα κινεῖσθαι ἢ ἀεὶ πάντα ἠρεμεῖν, ἐκ τούτων καὶ ἄλλων τοιούτων πιστεύσειεν ἄν τις. Further, it is a law of nature that earth and all other bodies should remain in their proper places and be moved from them only by violence: from the fact then that some of them are in their proper places it follows that in respect of place also all things cannot be in motion. These and other similar arguments, then, should convince us that it is impossible either that all things are always in motion or that all things are always at rest.
Postquam philosophus in septimo ostenderat quod in moventibus et in mobilibus non est procedere in infinitum, sed est devenire ad aliquod primum; et hic iam ostendit quod motus semper fuit et semper erit; ulterius procedit ad inquirendum conditionem primi motus et primi motoris. Et dividitur in partes duas: in prima ostendit quod primus motus est sempiternus, et quod primum movens est omnino immobile; secundo ex hoc procedit ad ostendendum qualis sit primus motus, et qualis sit primus motor, ibi: at vero aliud facientibus principium et cetera. 1004. Having shown in Book VII that there is not an infinite process in movers and in mobiles but that a first must be reached, and having now shown that motion has always been and always will be, the Philosopher goes on further to consider the condition of the first motion and of the first mover. And his treatment is divided into two parts. In the first he shows that the first motion is eternal and that the first mover is entirely immobile; Secondly, from this he proceeds to show the condition of the first motion and of the first mover, (L. 14).
Prima autem pars dividitur in partes tres: in prima ponit sub quaestione quandam divisionem quinquemembrem; in secunda excludit tres partes propositae divisionis, ibi: omnia igitur quiescere etc.; tertio inquirit de duobus residuis membris, quod eorum sit verius, quia ex hoc dependet veritas quam inquirere intendit, ibi: omnia autem velle aliquando quidem et cetera. The first is divided into three parts: In the first he gives a division having five members; In the second he excludes three members of this division, at 1006; Thirdly, he investigates the two remaining members to see which of them is truer, because the truth of what he intends to settle depends on it, (L. 6).
Dicit ergo primo quod principium sequentis considerationis, qua inquirere intendimus de primo motu et primo motore, est quod pertinet ad dubitationem praedictam (quam scilicet movit solvendo secundam rationem): unde contingit quod quaedam aliquando moventur, et aliquando quiescunt iterum, et non semper vel moventur vel quiescunt, ex quo ponitur motus sempiternus in communi? 1005. He says therefore first (773) that the reason for the following consideration, in which we intend to investigate about the first motion and the first mover, is that it pertains to a question he raised in answering the second argument (given in the preceding lecture), namely, that of whence it happens that certain things are at one time in motion and at another time at rest, and are not either always in motion or always at rest since motion in common is considered perpetual.
Et dicit quod necesse est dispositionem rerum, quantum ad motum vel quietem, tripliciter se habere. Quorum unus modus est, ut omnia semper quiescant, et nihil aliquando moveatur; secundus modus est, ut omnia semper moveantur, et nihil quiescat; tertius modus est, quod quaedam moveantur et quaedam quiescant. And he says that the ways in which things are disposed with respect to motion or rest are necessarily limited to three. The first of which is that all things be always at rest and nothing ever in motion; the second is that all things be always in motion and nothing at rest; the third way is that some things are in motion and others at rest.
Sed iste tertius modus iterum dividitur in tres modos. Quorum primus est, quod quaedam moveantur et quaedam quiescant, ita tamen quod ea quae moventur, semper moveantur, et ea quae quiescunt, semper quiescant, et nihil sit quod quandoque moveatur et quandoque quiescat. But the third way is again divided into three ways. The first of these is that some things are in motion and some at rest in the sense that the ones in motion are always in motion and those at rest always at rest, and nothing is at one time in motion and at another time at rest.
Secundus modus est e contrario, quod omnia sunt nata et moveri et quiescere, et nihil est quod semper moveatur vel semper quiescat. The second way is the converse, i.e., that all things are apt to be in motion and to rest and that nothing is either always in motion or always at rest.
Tertius modus huius secundae divisionis est, quod alia semper sint immobilia et nunquam moveantur; alia semper mobilia et nunquam quiescant; alia vero possint accipi cum utroque, scilicet cum motu et quiete, ita quod quandoque moveantur et quandoque quiescant. The third way is that certain things are always immobile and never in motion; others are always mobile and never at rest; still others may be taken with both, i.e., with motion and rest, so as to be in motion at one time and at rest at another.
Et istud ultimum membrum est nobis determinandum pro veritate, quia in hoc habentur solutiones omnium obiectorum. Et quando hoc ostenderimus, habebimus finem quem intendimus in isto opere, scilicet pervenire ad primum motum sempiternum, et ad primum movens immobile. This last member must be determined by us to be the truth, because in it are contained the solutions of all objections. And when we shall have shown this, we shall possess the end which we intend in this work, namely, to arrive at a first eternal motion and a first immobile mover.
Sic ergo tertium membrum primae divisionis dividitur in tria membra, et fiunt in universo quinque membra huius divisionis. Therefore, it is in the above manner that the third member of the first division is divided into three members, thus making a general division consisting of five members.
Est autem considerandum quod in tribus horum membrorum omnia entia ponuntur unius dispositionis; sicut patet in primo membro, quo dicitur omnia semper quiescere; et in secundo, quo dicitur omnia semper moveri; et in quarto, quo dicitur omnia quandoque quiescere et quandoque moveri. In uno autem membro, scilicet in tertio, dividuntur entia in duas dispositiones, scilicet quod quaedam semper moveantur, et quaedam semper quiescant. In uno etiam membro, scilicet in quinto, dividuntur entia in tres dispositiones, scilicet quod quaedam semper moveantur, quaedam nunquam moveantur, quaedam quandoque moveantur et quandoque non moveantur. Et considerandum est quod in hoc ultimo membro non facit mentionem de quiete, sed de immobilitate: quia primus motor, qui nunquam movetur, non potest dici proprie quiescere; quia, ut in quinto dictum est, illud proprie quiescit, quod natum est moveri et non movetur. Now, it should be noticed that in three of these members all things are respectively put in one definite disposition; for example, in the first member all things are taken to be always at rest; in the second all things are always in motion; and in the fourth all things alternate between motion and rest. But in one member, namely, the third, beings are divided according to two dispositions, so that some are always in motion and others always at rest. Finally, in one member, the fifth, beings are divided according to three dispositions; namely, some are never in motion, others are never at rest, while the others are sometimes in motion and sometimes not. Notice, too, in this last member that it is not rest but immobility that is posited; because the first mover, who is never moved, can not strictly be said to be at rest, for, as was said in Book V, only what is apt to be moved, and is not being moved, is properly said to be at rest.
Deinde cum dicit: omnia igitur quiescere etc., excludit tria membra praedictae divisionis. Et primo ponit quod non omnia quiescunt semper; secundo quod non omnia moventur semper, ibi: fere autem adhuc etc.; tertio excludit tertium membrum, quo dicebatur quod quae moventur, moventur semper, et quae quiescunt, quiescunt semper, ibi: at vero neque alia quidem et cetera. 1006, Then at (774) he excludes three members of the division. First he posits that not all things are always at rest; Secondly, that not all things are always in motion, at 1007; Thirdly, he excludes the third member, in which it was said that the things in motion are always in motion and those at rest are always at rest, (L. 6).
Circa primum tria ponit. Quorum primum est, quod ex quadam intellectus infirmitate procedit, quod aliqui dicant omnia quiescere, et quod inquirant ad hoc aliquam sophisticam rationem, dimisso sensu: procedit enim ex hoc quod intellectus non est sufficiens ad dissolvendum sophisticas rationes, quae repugnant iis quae sunt manifesta secundum sensum. Dictum est autem in I topicorum, quod non est curandum disputare contra quascumque positiones vel problemata, de quibus aliquis dubitat indigens sensu vel poena: unde contra istam positionem non oportet dubitare, propter stultitiam dicentis. In regard to the first he posits three statements. The first of these is that it is due to a weakness of understanding that some affirm rest of all things and in support of their stand search for a sophistic reason without referring to sense. For it proceeds on the fact that the intellect is not capable of destroying sophistical arguments which conflict with things evident to sense. But it has been said in Topics I that there is no need to dispute against positions or problems that are in a mind which needs sense or punishment. Hence it is not necessary to dispute this position, due to its stupidity.
Secundum quod dicit est, quod ista dubitatio non est de aliquo particulari ente, sed universaliter de toto ente. Neque etiam pertinet solum ad naturalem philosophum, sed quodammodo pertinet ad omnes scientias demonstrativas, et ad omnes opiniones, idest ad omnes artes quae utuntur quibusdam opinionibus, sicut rhetorica et dialectica: quia omnes artes et scientiae utuntur motu; practicae quidem, quasi dirigentes aliquos motus, naturalis autem philosophia, speculando naturam motus et mobilium. Mathematici etiam utuntur motu imaginato, dicentes quod punctus motus facit lineam. Metaphysicus autem considerat de primis principiis. Sic igitur patet, quod destruere motum repugnat omnibus scientiis. The second thing he says is that this problem does not concern a particular being but being in general. Nor does it affect natural science alone, but in a way all demonstrative sciences and all opinions, i.e., all the arts which use opinions, as do rhetoric and dialectics, for all the arts and sciences make use of motion. For the practical arts in a way direct certain motions, and natural philosophy speculates about the nature of motion and about mobile beings. Mathematicians, too, make use of motion, i.e., of an imagined one, saying that a point in motion makes a line. The metaphysician, however, considers first principles. Accordingly, it is plain that to destroy motion conflicts with all sciences.
Error autem qui pertinet ad omnia entia et ad omnes scientias, non est reprobandus a naturali, sed a metaphysico. Non ergo pertinet ad naturalem contra istum errorem disputare. Now an error that affects all beings and all sciences is not to be reproved by the philosopher of nature but by the metaphysician. Therefore, it is not the business of natural philosophy to dispute this error.
Tertium quod dicit est, quod irrationabiles et importunae dubitationes de principiis in doctrinis mathematicis, non pertinent ad mathematicum, ut eas removeat; et similiter est in aliis scientiis. Et similiter nec ad physicum pertinet destruere huiusmodi positionem, quae repugnat suis principiis. In qualibet enim scientia supponitur pro principio definitio subiecti: unde et in scientia quae est de natura, supponitur quasi principium, quod natura sit principium motus. Sic ergo per tria media apparet quod ad naturalem non pertinet contra hanc positionem disputare. The third thing he says is that unreasonable and inappropriate problems about the principles of mathematical sciences do not pertain to mathematics to be answered. The same is true in the other sciences. In like manner, it is not the business of the physicist to destroy an affirmation that is contrary to its principles. For in each science the definition of the subject is assumed as a principle; hence in the science which deals with nature, it is assumed as a principle that nature is a principle of motion. Accordingly, in the light of these three statements, it is apparent that it does not belong to natural philosophy to dispute this position.
Deinde cum dicit: fere autem etc., excludit secundum membrum, quo ponebatur ab Heraclito omnia semper moveri. Et primo comparat hanc opinionem praecedenti opinioni, quae ponebat omnia semper quiescere: et dicit quod dicere omnia moveri semper, ut Heraclitus dixit, est quidem falsum et contra principia scientiae naturalis; sed tamen minus repugnat arti haec positio quam prima. 1007. Then at (775) he excludes the second member, in which Heraclitus posited that all things are always being moved. And first he compares this opinion with the previous one which posited that all things are always at rest; and he says that to say that all things are always in motion, as Heraclitus said, is both false and contrary to the principles of natural science. Yet this position is not in as great conflict with the art as the first one is.
Et quod quidem repugnet arti manifestum est: quia tollit suppositionem scientiae naturalis, in qua ponitur quod natura non solum est principium motus, sed etiam quietis; et sic patet quod similiter naturale est quies, sicut et motus. Unde sicut prima opinio, quae destruebat motum, erat contra scientiam naturalem; ita et haec positio quae destruit quietem. But that it does conflict with the art is clear, because it takes away the assumption of natural science that nature is principle not only of motion but also of rest, which supposition makes it clear that rest is something natural just as motion is. Hence, just as the first opinions which destroyed motion, was against natural science, so too is this one that destroys rest.
Ideo autem dixit hanc opinionem esse minus praeter artem, quia quies nihil est aliud quam privatio motus: quod autem non sit privatio motus, magis potest latere quam quod non sit motus. Sunt enim quidam motus parvi et debiles, qui vix possunt sentiri: et sic potest videri quod aliquid quiescat, quod non quiescit. Sed motus magni et fortes latere non possunt: unde non potest dici quod decipiatur sensus in perceptione motus, sicut in perceptione quietis. The reason why he says that this opinion is less against art is that rest is nothing more than the privation of motion. But it is less evident that there is no motion than that there is no privation of motion. For there are some motions so weak and insignificant that they can be scarcely noticed; for that reason it is easy to suppose that something is at rest when it really is not. But great and strong motions cannot be concealed; hence it cannot be said that the senses are deceived in perceiving motion as they are in perceiving rest.
Et ideo secundo, ibi: et dicunt quidam etc., ostendit quomodo hanc secundam positionem aliqui posuerunt. Et dicit quod quidam, scilicet Heraclitus et eius sequaces, dixerunt quod omnia quae sunt, semper moventur, non solum quaedam, aut aliquando; sed motus latet sensum nostrum. Qui si loquerentur de aliquibus motibus, eorum dictum sustineri posset: sunt enim aliqui motus qui nos latent. Sed quia non determinant de quali motu loquantur, sed dicunt de omnibus motibus, ideo non est difficile contra illos obiicere; quia multi motus sunt, de quibus manifestum est quod non possunt semper esse. Therefore, secondly, at (776) he shows how some posited this second opinion. And he says that some, such as Heraclitus and his supporters, have said that all things which exist are always in motion, and not some things only or just at some time, but this motion eludes our senses. Now, if they say this of some motions, they are correct; for some motions do elude us. But because they do not qualify their statement but speak of all motions, it is not hard to find arguments against them, for there are many motions which evidently could not have existed always.
Tertio ibi: neque enim augeri etc., ponit rationes contra opinionem praedictam. Et primo quantum ad motum augmenti; secundo quantum ad motum alterationis, ibi: similiter autem et in alteratione et cetera. Tertio quantum ad motum localem, ibi: et secundum quod fertur. 1008. Thirdly, at (777) he forms the arguments against this position. First with respect to the motion of growth; Secondly, with respect to the motion of alteration, at 1009; Thirdly, with respect to local motion, at 1012.
Ideo autem ab augmento incipit, quia Heraclitus maxime inducebatur ad suam positionem ex consideratione augmenti. Videbat enim aliquem augeri secundum aliquam modicam quantitatem in uno anno; et supponens augmentum esse continuum, credebat quod in qualibet parte illius temporis secundum aliquid illius quantitatis augeretur, et tamen non sentitur istud augmentum, quia fit in modica temporis parte; et sic arbitrabatur esse in aliis quae videntur quiescere. The reason he begins with growth is that Heraclitus was led to his doctrine as a result of considering growth. For he observed that a person grows a small amount in one year and, supposing that growth is continuous, he believed that in each part of that year he was increased with respect to part of that quantity; and yet that increase is not sensed, because it comes in a small portion of time, He reasoned, therefore, that the same thing happens in other things which seem to be at rest.
Dicit ergo contra hoc Aristoteles, quod non est possibile continue aliquid augeri vel minui, ita scilicet quod quantitas aucta dividatur secundum tempus, ita quod in qualibet parte aliquid eius augeatur: sed interponitur medium tempus post augmentum unius partis, in quo nihil augetur, sed fit dispositio ad augmentum sequentis partis. Against this Aristotle says that it is not possible for a thing to be continually increased or diminished so that the increased quantity can be divided according to time in such a way that in each part of time there is a corresponding increase. Rather, there is, after the increase of one part, a time in which there is no increase but a disposition is produced for the increase of the next part.
Et hoc manifestat per similia. Quorum primum est, quia videmus quod gutta pluviae multiplicata conterit lapidem. Secundum exemplum est, quia videmus quod nascentia, idest plantae in lapidibus nascentes, lapides dividunt. Nec possumus dicere quod si gutta multiplicata tantum fodit vel removet de lapide in tanto tempore, quod medietas guttarum prius in medio tempore removerit medietatem illius quantitatis; sed ita contingit hic, sicut in trahentibus navem. Non enim si centum homines trahunt navem per tantum spatium in tanto tempore, sequitur quod media pars illorum moveat per medietatem spatii in eodem tempore, vel per idem spatium in duplo tempore, ut in septimo dictum est. Ita etiam non sequitur, si multae guttae effodiunt lapidem, quod aliqua pars illarum guttarum prius removerit medietatem in aliquo tempore. And this he explains with kindred examples. The first of these is that we see that the multiplication of drops of rain breaks a stone. The second example is that we see that things being born, i.e., that plants born in stones divide the stones. Now, we cannot say that, if the repeated drops dig out or remove a certain quantity of the stone in a given time, half of this number of drops in half the time would previously remove half of that quantity. But what happens here is what happens with regard to shiphaulers. For it does not follow, if 100 men pull a ship a certain distance in a given time, that fifty of them will move it half the distance in the same time or the full distance in twice the time—this was said in Book VII. So also it does not follow, if many drops cave in a stone, that some part of those drops had previously removed the half in some certain time.
Et huius ratio est, quia illud quod removetur a lapide per multas guttas, est quidem divisibile in plura; sed tamen non seorsum aliquid illorum plurium a lapide removetur, sed simul omnes partes, prout sunt in potentia in toto remoto. The reason for this is that what is removed from the stone by many drops is indeed divisible into many parts, but none of them is removed separately from the stone, for all the parts are removed at once, in the sense that they are in the totality removed in potency.
Et loquitur hic de primo quod removetur: nihil enim prohibet per longinquum tempus aliquam tam magnam quantitatem removeri a lapide per guttas, quod aliqua pars remota est prius per partem guttarum: est tamen devenire ad aliquod quantum remotum, quod totum simul removetur, et non pars post partem. In remotione ergo illius totius, nulla guttarum praecedentium aliquid removebat, sed disponebat tantum ad remotionem: ultima autem agit in virtute omnium, removendo id ad cuius remotionem ceterae disponebant. And he is speaking here of the first total quantity that is removed, for there is nothing to prevent that, over a long period of time, such a large quantity, be removed from the stone by these drops that a certain part may have been removed previously by a part of these drops. But we must come to a removed quantity which is removed all together and not part after part. Therefore, in the removing of that whole, none of the preceding drops removed anything, but merely disposed for its removal. However, the last acts in virtue of all and removes what the others had disposed to be removed.
Et similiter etiam est in motu diminutionis. Non est enim necessarium quod si aliquid decrescit tantum in tanto tempore, licet illa quantitas in infinitum dividatur, quod semper in qualibet parte temporis aliquid illius quantitatis subtractum abeat; sed totum simul aliquando abibit. Et similiter etiam est in augmento. Et sic non oportet quod continue aliquid augeatur vel minuatur. The same is true in the motion called decrease. For it is not necessary, if something decreases a certain amount in a given time (even though the quantity be divided ad infinitum), that in every part of that time a corresponding part of the removed quantity should depart; rather, at some time a given amount will depart all together. The same holds in increase. Consequently, it is not required that something be continuously increased or decreased.
Deinde cum dicit: similiter autem et in alteratione etc., contradicit praedictae positioni quantum ad alterationem; et hoc tribus rationibus. Primo enim dicit quod similiter dicendum est in qualibet alteratione, sicut dictum est in augmento. Quamvis enim corpus quod alteratur, sit partibile in infinitum, non tamen oportet quod propter hoc alteratio in infinitum dividatur, ita scilicet quod in qualibet parte temporis aliquid alterationis fiat; sed multoties fit velox alteratio, ita scilicet quod multae partes corporis alterati simul alterantur, sicut accidit in densatione sive congelatione aquae. Tota enim aliqua aqua simul congelatur, non pars post partem (si tamen accipiatur multum de aqua, nihil prohibet partem post partem congelari). 1009. Then at (778) he contradicts the above-mentioned position of continuous motion with respect to alteration, and this with three arguments. First, he says that what was said about increase, applies also to alteration. For although a body that is being altered is infinitely divisible, that is no reason for supposing that alteration is divided ad infinitum, so that for each period of time a part of the alteration should occur. Rather, alteration very often takes place swiftly, i.e., many parts of the altered body are altered all at once, as happens when water is condensed or congealed. For a whole mass of water is congealed all at once and not part after part (although if it be a large mass of water, there is nothing to prevent part congealing after part).
Est autem considerandum, quod hoc quod hic dicitur de alteratione et augmento, videtur contrariari iis quae dicta sunt in sexto, ubi ostensum est quod motus dividitur secundum divisionem temporis et mobilis et rei secundum quam est motus. It should be noticed that what Aristotle says here about alteration growth seems contrary to what was said in Book VI, where it was shown that motion is divided according to the division of the time, and of the mobile, and of the sphere of motion.
Sed sciendum est quod Aristoteles in sexto determinabat de motu in communi, non applicando ad aliqua mobilia; et ideo ea quae ibi de motu tractavit, accipienda sunt secundum exigentiam continuitatis motus: hic autem loquitur de motu, applicando ad determinata mobilia, in quibus contingit aliquem motum interrumpi et non continuari, qui secundum rationem communem motus posset esse continuus. But it should be recognized that in Book VI Aristotle was talking about motion in common, without application to definite mobiles. Therefore, what he discussed there must be taken according to the requirements of motion’s continuity; but at present he is speaking of motion with application to definite mobiles, in which a motion can be interrupted and not be continuous, which, when viewed under the common aspect, could be continuous.
Secundam rationem ponit ibi: amplius cum infirmetur aliquis et cetera. Et dicit quod si aliquis qui infirmatur, debeat sanari, necesse est quod sanetur in aliquo tempore, et non in termino temporis. Et necesse est ulterius quod ipsa mutatio sanationis tendat in determinatum terminum, scilicet in sanitatem, et in nihil aliud. Sic ergo omnis alteratio requirit determinatum tempus et determinatum terminum (quia omnis alteratio est in contrarium, ut in quinto dictum est): nulla autem talis mutatio est semper continua: dicere ergo quod aliquid semper et continue alteretur, est dubitare de manifestis. 1010. He gives the second argument at (779), and he says that if a sick person is to get well, he has to become healed in a period of time and not in a terminus (an instant?) of the time. And it is further necessary that the very change, which is healing, tend to a definite terminus, i.e., to health and not to anything else. Accordingly, every alteration requires a definite time and a definite terminus, because every alteration tends to a contrary, as was said in Book V. But no such change is always continuous. Therefore, to say that something is being always and continuously altered, is to speak against the facts.
Tertiam rationem ponit ibi: atque lapis et cetera. Et dicit quod lapis non fit neque durior neque mollior, etiam per temporis longinquitatem: et sic stultum est dicere quod omnia semper alterentur. 1011. The third argument he gives at (780) and he says that a stone does not become harder or softer, even after a very great period of time; thus it is foolish to say that all things are always being altered.
Deinde cum dicit: et secundum quod fertur etc., contradicit praedictae opinioni quantum ad motum localem, dupliciter. Primo quidem, quia aliqui motus locales et quietes ita sunt manifesti, quod latere non possunt: mirabile enim videtur si lateat quando lapis fertur deorsum, aut quando quiescit in terra. Et sic non potest dici quod propter latentiam motus localis ponantur omnia semper moveri localiter. 1012. Then at (781) he contradicts the opinion at issue with respect to local motion, on two counts. First, indeed, because some local motions and rests are so evident that they cannot be hidden. For it would be strange if it were hidden from us when a stone is carried downwards or when it is at rest on the earth. Consequently, it cannot be said that, because of the concealment of local motions, all things should be supposed to be always being moved locally.
Secundo ibi: amplius autem terra etc., ratiocinatur sic. Terra et quodlibet aliud corpus naturale, quando sunt in propriis locis, ex necessitate naturae quiescunt, et non removentur ex propriis locis, nisi per violentiam: sed manifestum est quaedam corporum naturalium esse in propriis locis: necesse est ergo dicere quod quaedam quiescant secundum locum, et quod non omnia localiter moveantur. 1013. Secondly, at (782) he argues thus: Earth and any other natural body, when they are in their due places, rest from a necessity of nature and are not removed except by force. But it is evident that certain natural bodies are in their due place. Therefore, it is necessary to say that some things are at rest with respect to place and that not all things are being moved locally.
Ultimo autem epilogando concludit, quod ex praemissis et aliis similibus potest aliquis scire, quod impossibile est aut semper omnia moveri, sicut dixit Heraclitus, aut semper omnia quiescere, sicut dixit Zeno et Parmenides et Melissus. Finally, he concludes in summary that, from the foregoing and other things similar to the foregoing, anyone can know that it is impossible for all things always to be in motion, as Heraclitus said, or for all things always to be at rest, as Zeno and Parmenides and Melissus said,

Lectio 6
A third member of the division is rejected
Chapter 3 cont.
ἀλλὰ μὴν οὐδὲ τὰ μὲν ἀεὶ ἐνδέχεται ἠρεμεῖν, τὰ δ' ἀεὶ κινεῖσθαι, ποτὲ δ' ἠρεμεῖν καὶ ποτὲ κινεῖσθαι μηδέν. λεκτέον δ' ὅτι ἀδύνατον, ὥσπερ ἐπὶ τῶν εἰρημένων πρότερον, καὶ ἐπὶ τούτων (ὁρῶμεν γὰρ ἐπὶ τῶν αὐτῶν γιγνομένας τὰς εἰρημένας μεταβολάς), Nor again can it be that some things are always at rest, others always in motion, and nothing sometimes at rest and sometimes in motion. This theory must be pronounced impossible on the same grounds as those previously mentioned: viz. that we see the above-mentioned changes occurring in the case of the same things.
καὶ πρὸς τούτοις ὅτι μάχεται τοῖς φανεροῖς ὁ ἀμφισβητῶν· οὔτε γὰρ αὔξησις οὔθ' ἡ βίαιος ἔσται κίνησις, εἰ μὴ κινήσεται παρὰ φύσιν ἠρεμοῦν πρότερον. γένεσιν οὖν ἀναιρεῖ καὶ φθορὰν οὗτος ὁ λόγος. σχεδὸν δὲ καὶ τὸ κινεῖσθαι γίγνεσθαί τι καὶ φθείρεσθαι δοκεῖ πᾶσιν· εἰς ὃ μὲν γὰρ μεταβάλλει, γίγνεται τοῦτο ἢ ἐν τούτῳ, ἐξ οὗ δὲ μεταβάλλει, φθείρεται τοῦτο ἢ ἐντεῦθεν. ὥστε δῆλον ὅτι τὰ μὲν κινεῖται, τὰ δ' ἠρεμεῖ ἐνίοτε. We may further point out that the defender of this position is fighting against the obvious, for on this theory there can be no such thing as increase: nor can there be any such thing as compulsory motion, if it is impossible that a thing can be at rest before being set in motion unnaturally. This theory, then, does away with becoming and perishing. Moreover, motion, it would seem, is generally thought to be a sort of becoming and perishing, for that to which a thing changes comes to be, or occupancy of it comes to be, and that from which a thing changes ceases to be, or there ceases to be occupancy of it. It is clear, therefore, that there are cases of occasional motion and occasional rest.
τὸ δὲ πάντα ἀξιοῦν ὁτὲ μὲν ἠρεμεῖν ὁτὲ δὲ κινεῖσθαι, τοῦτ' ἤδη συναπτέον πρὸς τοὺς πάλαι λόγους. We have now to take the assertion that all things are sometimes at rest and sometimes in motion and to confront it with the arguments previously advanced.
ἀρχὴν δὲ πάλιν ποιητέον ἀπὸ τῶν νῦν διορισθέντων, τὴν αὐτὴν ἥνπερ ἠρξάμεθα πρότερον. ἢ γάρ τοι πάντα ἠρεμεῖ, ἢ πάντα κινεῖται, ἢ τὰ μὲν ἠρεμεῖ τὰ δὲ κινεῖται τῶν ὄντων. καὶ εἰ τὰ μὲν ἠρεμεῖ τὰ δὲ κινεῖται, ἀνάγκη ἤτοι πάντα ὁτὲ μὲν ἠρεμεῖν ὁτὲ δὲ κινεῖσθαι, <ἢ τὰ μὲν ἀεὶ ἠρεμεῖν τὰ δὲ ἀεὶ κινεῖσθαι>, ἢ τὰ μὲν ἀεὶ ἠρεμεῖν τὰ δὲ ἀεὶ κινεῖσθαι αὐτῶν, τὰ δ' ὁτὲ μὲν ἠρεμεῖν ὁτὲ δὲ κινεῖσθαι. We must take our start as before from the possibilities that we distinguished just above. Either all things are at rest, or all things are in motion, or some things are at rest and others in motion. And if some things are at rest and others in motion, then it must be that either all things are sometimes at rest and sometimes in motion, or some things are always at rest and the remainder always in motion, or some of the things are always at rest and others always in motion while others again are sometimes at rest and sometimes in motion.
ὅτι μὲν τοίνυν οὐχ οἷόν τε πάντ' ἠρεμεῖν, εἴρηται μὲν καὶ πρότερον, εἴπωμεν δὲ καὶ νῦν. εἰ γὰρ καὶ κατ' ἀλήθειαν οὕτως ἔχει καθάπερ φασί τινες, εἶναι τὸ ὂν ἄπειρον καὶ ἀκίνητον, ἀλλ' οὔτι φαίνεταί γε κατὰ τὴν αἴσθησιν, ἀλλὰ κινεῖσθαι πολλὰ τῶν ὄντων. εἴπερ οὖν ἔστιν δόξα ψευδὴς ἢ ὅλως δόξα, καὶ κίνησις ἔστιν, κἂν εἰ φαντασία, κἂν εἰ ὁτὲ μὲν οὕτως δοκεῖ ὁτὲ δ' ἑτέρως· ἡ γὰρ φαντασία καὶ ἡ δόξα κινήσεις τινὲς εἶναι δοκοῦσιν. ἀλλὰ τὸ μὲν περὶ τούτου σκοπεῖν, καὶ ζητεῖν λόγον ὧν βέλτιον ἔχομεν ἢ λόγου δεῖσθαι, κακῶς κρίνειν ἐστὶν τὸ βέλτιον καὶ τὸ χεῖρον, καὶ τὸ πιστὸν καὶ τὸ μὴ πιστόν, καὶ ἀρχὴν καὶ μὴ ἀρχήν. Now we have said before that it is impossible that all things should be at rest: nevertheless we may now repeat that assertion. We may point out that, even if it is really the case, as certain persons assert, that the existent is infinite and motionless, it certainly does not appear to be so if we follow sense-perception: many things that exist appear to be in motion. Now if there is such a thing as false opinion or opinion at all, there is also motion; and similarly if there is such a thing as imagination, or if it is the case that anything seems to be different at different times: for imagination and opinion are thought to be motions of a kind. But to investigate this question at all—to seek a reasoned justification of a belief with regard to which we are too well off to require reasoned justification—implies bad judgement of what is better and what is worse, what commends itself to belief and what does not, what is ultimate and what is not.
ὁμοίως δὲ ἀδύνατον καὶ τὸ πάντα κινεῖσθαι, ἢ τὰ μὲν ἀεὶ κινεῖσθαι τὰ δ' ἀεὶ ἠρεμεῖν. πρὸς ἅπαντα γὰρ ταῦτα ἱκανὴ μία πίστις· (254b.) ὁρῶμεν γὰρ ἔνια ὁτὲ μὲν κινούμενα ὁτὲ δ' ἠρεμοῦντα. ὥστε φανερὸν ὅτι ἀδύνατον ὁμοίως τὸ πάντα ἠρεμεῖν καὶ τὸ πάντα κινεῖσθαι συνεχῶς τῷ τὰ μὲν ἀεὶ κινεῖσθαι τὰ δ' ἠρεμεῖν ἀεί. It is likewise impossible that all things should be in motion or that some things should be always in motion and the remainder always at rest. We have sufficient ground for rejecting all these theories in the single fact that we see some things that are sometimes in motion and sometimes at rest. It is evident, therefore, that it is no less impossible that some things should be always in motion and the remainder always at rest than that all things should be at rest or that all things should be in motion continuously.
λοιπὸν οὖν θεωρῆσαι πότερον πάντα τοιαῦτα οἷα κινεῖσθαι καὶ ἠρεμεῖν, ἢ ἔνια μὲν οὕτως, ἔνια δ' ἀεὶ ἠρεμεῖ, ἔνια δ' ἀεὶ κινεῖται· τοῦτο γὰρ δεικτέον ἡμῖν. It remains, then, to consider whether all things are so constituted as to be capable both of being in motion and of being at rest, or whether, while some things are so constituted, some are always at rest and some are always in motion: for it is this last view that we have to show to be true.
Reprobatis duobus membris praemissae divisionis, hic reprobat tertium, quod scilicet poni posset entia dividi in duas dispositiones tantum, ita quod quaedam semper quiescerent; alia semper moverentur; et non sit tertium genus entium, quae quandoque moveantur, quandoque quiescant. Hoc autem reprobat dupliciter. 1014. Having disposed of two members of the foregoing division, the Philosopher now rejects a third, in which it was posited that things are divided into two dispositions only, in such a way, namely, that some things are always at rest and others always in motion, and there is not a third class of things that are sometimes in motion and sometimes at rest. He rejects this in two ways.
Primo quidem, sicut et praedictas duas positiones, ex eo quod repugnat sensui. Non solum enim videmus ad sensum quod quaedam moventur, per quod destruitur prima positio ponentium omnia quiescere semper; et quod quaedam quiescunt, per quod destruitur secunda positio ponentium omnia moveri semper: sed etiam videmus quod in eisdem rebus fiunt praedictae mutationes seu variationes de motu in quietem, et de quiete in motum; per quod apparet quod aliqua sunt quae quandoque moventur et quandoque quiescunt. He does this first (783) in the same way that he rejected the two previous positions, namely, on the ground that they are contrary to sense observation. For we see by the senses not only that some things are in motion (which destroys the first position, namely, of those who posit all things to be always at rest), and that some are at rest (by which is destroyed the second position, of those who maintain that all things are always in motion); but we also see that the aforementioned changes or variations from motion to rest, and from rest to motion, occur in the same things. This shows that there are some things which are sometimes moved and sometimes at rest.
Secundo ibi: et adhuc quia oppugnat etc., reprobat idem per hoc quod qui hanc dubitationem induceret, repugnaret iis quae sunt manifesta in natura. Primo enim tolleretur motus augmenti: videmus enim motum augmenti esse in his quae non semper augebantur; alioquin, si semper augerentur, non esset augmentum ad determinatam quantitatem, sed in infinitum. 1015. In a second way at (784) he rejects the same opinion on the ground that the one who would engender this doubt would be contrary to what is evident in nature. In the first place it would deny the motion of growth, for we see that growth takes place in things that are not always growing, because, were they always growing, they would be tending not to a definite quantity but to the infinite.
Secundo tollitur motus localis violentus: non enim est motus violentus, nisi sit aliquid quod extra naturam moveatur, quod prius quieverit secundum naturam; cum motus violentus non sit nisi recessus a quiete naturali. Si ergo nullum quiescens potest moveri, sequetur quod id quod quiescit naturaliter, non possit postmodum per violentiam moveri. In the second place it would deny compulsory local motion, for a motion is not compulsory, unless something is moved not in keeping with its nature when previously it was naturally at rest; for a forced motion is nothing more than a departure from natural rest. If therefore nothing at rest can be moved, it will follow that what is naturally at rest cannot later be moved by compulsion.
Tertio excluditur generatio et corruptio per hanc positionem. Generatio enim est mutatio de non esse in esse, corruptio vero de esse in non esse. Ad hoc ergo quod aliquid corrumpatur, oportet quod prius fuerit ens per aliquod tempus; et ad hoc quod generetur, oportet quod prius fuerit non ens per aliquod tempus. Quod autem per aliquod tempus est ens vel non ens, quiescit (ut large de quiete loquamur): si igitur nullum quiescens potest moveri, sequitur quod nihil quod non est per aliquod tempus, possit generari, et nihil quod est in aliquo tempore, possit corrumpi. In the third place generation and ceasing-to-be would be excluded by this opinion. For the former is a change from non-being to being, and the latter from being to non-being. Therefore, in order that a thing cease to be, it ought previously to have been existing for a time, and in order that a thing be generated, it ought previously not to have been existing for a time. But whatever is a being or a non-being for some time is at rest (where rest is taken in a very general sense), If, therefore, nothing at rest can be moved, it follows that nothing which is for some time a non-existent can be generated, and that nothing which exists for a time can cease to be.
Quarto autem ulterius haec positio destruit universaliter omnem motum: quia in omni motu est quaedam generatio et corruptio, vel simpliciter vel secundum quid. Quod enim in aliquid movetur sicut in terminum, generatur hoc, quantum ad motum alterationis et augmenti; aut in hoc, quantum ad motum localem; sicut quod movetur de nigro in album, aut de parvo in magnum, fit album aut magnum; quod autem movetur ad aliquem locum, fit existens in loco illo. Sed ex quo aliquid mutatur sicut a termino a quo, corrumpitur hoc in motu alterationis et augmenti, ut nigrum aut parvum; aut ab hinc quantum ad motum localem. Quia ergo in omni motu est generatio et corruptio, dum praedicta positio tollit generationem et corruptionem, per consequens tollit omnem motum. In the fourth place this position destroys all motion universally, because every motion involves generation and ceasing-to-be either absolutely or in a qualified sense. For what is being moved toward something as toward a terminus is being made such-and-such, so far as alteration and growth are concerned, or being made to be in such-and-such, so far as local motion is concerned; for example, what is being changed from black to white, or from small to large, becomes white or large, but whatever is being moved to a place comes to exist in that place. But from the fact that something is changed from its terminus a quo, a “such and such” ceased to be, when it is a case of alteration and growth, and a “there” ceased to be, if it is a case of local motion. Therefore, because in every motion there is generation and ceasing-to-be, it consequently rejects all motion.
Quia ergo haec quae dicta sunt, sunt impossibilia, manifestum fit quod quaedam moventur non quidem semper, sed aliquando; et quaedam quiescunt non semper, sed aliquando. Because such things are impossible, it becomes clear that some things are being moved, but not always; and that some things are at rest, not always, but sometimes.
Deinde cum dicit: omnia autem velle etc., inquirit de aliis duobus membris praemissae divisionis. Et primo manifestat suam intentionem; secundo exequitur ipsam, ibi: moventium igitur et eorum quae moventur et cetera. 1016. Then at (785) he studies the other two members of his division. First he reveals his intention; Secondly, he pursues it, (L. 7).
Circa primum tria facit: primo ostendit ad quam positionem pertineat quartum membrum; secundo ea quae dicta sunt in isto capitulo recolligit, ibi: principium autem iterum faciendum etc.; tertio ostendit quid restat dicendum, ibi: reliquum ergo considerandum et cetera. About the first he does three things: First he shows to which opinion the fourth member pertains; Secondly, he summarizes what has been said in this chapter, at 1017; Thirdly, he states what remains to be said, at 1020.
Dicit ergo primo, quod ponere quod omnia quandoque quiescunt et quandoque moventur, hoc iam pertinet ad antiquas rationes, quas tetigimus disputantes de motus sempiternitate. Hoc enim posuisse videtur praecipue Empedocles, quod omnia quandoque moventur sub dominio amicitiae et litis, et quandoque quiescunt intermediis temporibus. He says therefore first (785) that to posit that all things are sometimes at rest and sometimes in motion pertains to the ancient arguments which we touched upon in discussing the eternity of motion. For Empedocles seems to be the chief protagonist of this opinion that all things are at some time moved by friendship and by discord and in the meantime are at rest.
Deinde cum dicit: principium autem etc., resumit ea quae dicta sunt in isto capitulo. Et primo resumit divisionem supra positam; secundo reprobationem primae partis, qua ponitur omnia quiescere semper, ibi: quod quidem igitur non possibile etc.; tertio reprobationem aliorum duorum membrorum, ibi: similiter autem et impossibile et cetera. 1017. Then at (786) he sums up what has been said in this chapter. First he recalls the divisions previously made; Secondly, he recalls the rejection of the first member which posited all things at rest, at 1018; Thirdly, the rejection of the other two members, at 1019.
Dicit ergo primo, quod ad manifestandum magis intentionem sequentium, debemus incipere ab iis quae nuper determinavimus, sumentes idem principium quod prius; scilicet quod entia oportet primo quod se habeant in aliqua harum trium dispositionum, scilicet quod vel omnia quiescant, vel omnia moveantur, vel quod quaedam quiescant et quaedam moveantur. Et hoc tertium iterum in tria dividitur: quia si eorum quae sunt, quaedam quiescunt et quaedam moventur, necesse est quod vel omnia sic se habeant quod quandoque quiescant et quandoque moveantur; vel quod quaedam semper quiescant, quaedam autem semper moveantur; vel quod cum iis duobus apponatur tertium membrum, scilicet quod alia sint quae quiescant aliquando et non semper, aliis quandoque motis et non semper. He says therefore first (786) that in order to make clearer the intention of what follows, we must begin with what has just been determined and use the same principle as before, namely, that beings must maintain themselves in one of three dispositions, i.e., either that all are at rest or all in motion or some at rest and some in motion. And this third is again divided into three members, for if all things are such that some are at rest and others in motion, then necessarily all must be at one time at rest and at another in motion, or some are always at rest and others always in motion, or to these two a third member may be added, namely, that there are others of which some are at rest not always but sometimes, while the others are in motion sometimes but not always.
Deinde cum dicit: quod quidem igitur etc., reprobat primum membrum. Et dicit quod supra dictum est, quod non sit possibile omnia quiescere semper, sed et nunc etiam aliquid est addendum. Et duo dicit contra hanc positionem. ita videtur secundum sensum, sed multa entium moventur, ut sensus iudicat. 1018. Then at (787) he rejects the first member and says that it was said above that it is not possible for all things to be always at rest; but something else must now be added. And he says two things against this position.
Primo quidem quod necesse est ponere aliquem motum saltem in anima. Quia si aliquis velit dicere quod secundum veritatem sic se habet quod nihil movetur, sicut dixerunt sequentes Melissum, qui posuit quod ens est infinitum et immobile: sed tamen non First, some motion must be posited at least in the soul. For should anyone want to say that according to truth it is a fact that nothing is being moved (as the followers of Melissus did, who posited that being is infinite and immobile), yet it is also a fact that this does not appear to be so according to sense, for many things appear to the senses to be moving.
Si ergo aliquis dicat quod ista opinio est falsa, qua opinamur quaedam moveri; adhuc sequitur quod motus sit. Quia si opinio falsa est, motus est; et universaliter si opinio est, motus est; et similiter si phantasia est, motus est. Et hoc ideo, quia phantasia est quidam motus sensitivae partis, factus a sensu secundum actum. Opinio etiam quidam motus est rationis, ex aliquibus ratiocinationibus procedens. Sed adhuc manifestius sequitur quod motus sit in opinione vel phantasia, si aliquando videatur nobis sic esse, aliquando aliter: quod contingit cum quandoque videntur nobis aliqua quiescere, quandoque vero non quiescere. Sic ergo omnino sequitur quod motus sit. If, therefore, anyone declares as false the opinion by which we believe that some things are in motion, it still follows that motion exists. For if there is false opinion, there is motion; and universally if there is opinion, there is motion and, likewise, if there is imagining, there is motion. The reason is that imagining is a motion of the sensitive part and is produced by the sense in act. Opinion also is a certain motion of the reason and proceeds from several acts of reasoning. But it follows even more strongly that there is motion in opinion and imagining, if things appear to be this at one time and that at another. This happens when things at one time seem to us to be at rest and at another time not to rest. Thus, it entirely follows that motion exists.
Secundo contra hanc opinionem dicit, quod apponere intentionem ad destruendum hanc opinionem, et quaerere rationem ad probandum illas res quas debemus habere in maiori dignitate quam quod ratione indigeant, quia scilicet habentur ut per se manifesta: hoc inquam facere nihil est aliud quam male iudicando discernere inter melius et peius in moralibus, et inter credibile et incredibile in logicis, et inter principium et non principium in demonstrativis. He says, secondly, against the opinion at issue, that to have the intention of destroying this opinion, and to look for an argument to prove those things that we ought to hold in a respect surpassing the need for proof, since they are accepted as self-evident. To do this, I say, is no different from judging poorly between what is better and what is worse in morals, and between what is credible and incredible in logical matters, and between a principle and a non-principle in matters of demonstration.
Qui enim quaerit rationem ad probandum ea quae per se sunt manifesta, et sic habentur ut principia, non cognoscit ea esse principia, dum ea per alia principia probare intendit. Similiter videtur quod non sciat cognoscere quid sit credibile et incredibile; quia id quod est per se credibile, per aliud probare intendit, ac si non esset per se credibile. Nec etiam inter melius et peius posse discernere videtur, qui magis manifesta per minus manifesta probat. Est autem per se manifestum aliqua moveri: non ergo ad hoc debet esse nostra intentio, ut hoc rationibus probare nitamur. For whoever looks for arguments to prove things which are self-evident and, consequently, held as principles, does not recognize them for principles so long as he intends to prove them through other principles. Likewise, it seems that he does not recognize what is credible and what is incredible, because he is trying to prove what is per se credible through something else, as though it were not per se credible. Nor does he seem capable of distinguishing between the better and the worse who tries to prove the more evident by means of the less evident. But it is self-evident that some things are in motion. Therefore, we should not address ourselves to trying to prove this by arguments.
Deinde cum dicit: similiter autem et impossibile etc., excludit alia duo membra praemissae divisionis. Et dicit quod sicut impossibile est omnia quiescere semper, ita etiam impossibile est omnia moveri semper; aut etiam quod alia semper moveantur et alia semper quiescant, ita quod nihil sit quod quandoque moveatur et quandoque quiescat. Contra omnia haec sufficit fidem facere per unum medium: quia scilicet videmus quod quaedam quandoque moventur et quandoque iterum quiescunt. Unde manifestum est quod impossibile est dicere quod omnia continue quiescant, quod erat primum membrum, et quod omnia continue moveantur, quod erat secundum membrum; vel quod quaedam semper moveantur et quaedam semper quiescant, et nihil sit medium. 1019. Then at (788) he rejects two more members of his original division. And he says that just as it is impossible for all things to be always at rest, so too is it impossible that all things be always in motion, or that some things are always in motion and some always at rest, so as to leave nothing which is sometimes in motion and sometimes at rest. Against all this, sufficient credence arises from one medium, namely, the fact that we see that some things are sometimes in motion and sometimes at rest. Hence, it is clear that it is impossible to say that all things are continually at rest—which was the first member—and that all things are continually in motion—which was the second member—or that some are always in motion and the remainder always at rest without any mediate possibility.
Deinde cum dicit: reliquum ergo etc., ostendit quid restat dicendum: et concludit ex praemissis, quod cum tria membra praemissae divisionis stare non possint, relinquitur considerandum quod membrum aliorum duorum sit verius: utrum scilicet quod omnia sint possibilia moveri et quiescere; aut quaedam sint possibilia moveri et quiescere, ita tamen quod aliqua sint quae semper quiescant, et aliqua quae semper moveantur. Hoc enim ultimum est quod demonstrare intendimus. Sic enim ostendetur primum motum esse sempiternum, et primum motorem esse immobilem. 1020. Then at (789) he shows what is left to be said, and he concludes from the foregoing that since three members of the division cannot stand, what remains is to consider which of the other two is the truer, whether, namely, all things are capable of both motion and rest, or whether some are capable of both motion and rest while still others are always at rest and others always in motion. This last is what we intend to demonstrate. In this way it will be shown that the first motion is eternal, and the first mover immobile.

Lectio 7
Universally, whatever is moved is moved by another
Chapter 4
Τῶν δὴ κινούντων καὶ κινουμένων τὰ μὲν κατὰ συμβεβηκὸς κινεῖ καὶ κινεῖται, τὰ δὲ καθ' αὑτά, κατὰ συμβεβηκὸς μὲν οἷον ὅσα τε τῷ ὑπάρχειν τοῖς κινοῦσιν ἢ κινουμένοις καὶ τὰ κατὰ μόριον, τὰ δὲ καθ' αὑτά, ὅσα μὴ τῷ ὑπάρχειν τῷ κινοῦντι ἢ τῷ κινουμένῳ, μηδὲ τῷ μόριόν τι αὐτῶν κινεῖν ἢ κινεῖσθαι. τῶν δὲ καθ' αὑτὰ τὰ μὲν ὑφ' ἑαυτοῦ τὰ δ' ὑπ' ἄλλου, καὶ τὰ μὲν φύσει τὰ δὲ βίᾳ καὶ παρὰ φύσιν. Now of things that cause motion or suffer motion, to some the motion is accidental, to others essential: thus it is accidental to what merely belongs to or contains as a part a thing that causes motion or suffers motion, essential to a thing that causes motion or suffers motion not merely by belonging to such a thing or containing it as a part. Of things to which the motion is essential some derive their motion from themselves, others from something else: and in some cases their motion is natural, in others violent and unnatural.
τό τε γὰρ αὐτὸ ὑφ' αὑτοῦ κινούμενον φύσει κινεῖται, οἷον ἕκαστον τῶν ζῴων (κινεῖται γὰρ τὸ ζῷον αὐτὸ ὑφ' αὑτοῦ, ὅσων δ' ἡ ἀρχὴ ἐν αὐτοῖς τῆς κινήσεως, ταῦτα φύσει φαμὲν κινεῖσθαι· διὸ τὸ μὲν ζῷον ὅλον φύσει αὐτὸ ἑαυτὸ κινεῖ, τὸ μέντοι σῶμα ἐνδέχεται καὶ φύσει καὶ παρὰ φύσιν κινεῖσθαι· διαφέρει γὰρ ὁποίαν τε ἂν κίνησιν κινούμενον τύχῃ καὶ ἐκ ποίου στοιχείου συνεστηκός), καὶ τῶν ὑπ' ἄλλου κινουμένων τὰ μὲν φύσει κινεῖται τὰ δὲ παρὰ φύσιν, παρὰ φύσιν μὲν οἷον τὰ γεηρὰ ἄνω καὶ τὸ πῦρ κάτω, ἔτι δὲ τὰ μόρια τῶν ζῴων πολλάκις κινεῖται παρὰ φύσιν, παρὰ τὰς θέσεις καὶ τοὺς τρόπους τῆς κινήσεως. Thus in things that derive their motion from themselves, e.g. all animals, the motion is natural (for when an animal is in motion its motion is derived from itself): and whenever the source of the motion of a thing is in the thing itself we say that the motion of that thing is natural. Therefore the animal as a whole moves itself naturally: but the body of the animal may be in motion unnaturally as well as naturally: it depends upon the kind of motion that it may chance to be suffering and the kind of element of which it is composed. And the motion of things that derive their motion from something else is in some cases natural, in other unnatural: e.g. upward motion of earthy things and downward motion of fire are unnatural. Moreover the parts of animals are often in motion in an unnatural way, their positions and the character of the motion being abnormal.
καὶ μάλιστα τὸ ὑπό τινος κινεῖσθαι τὸ κινούμενον ἐν τοῖς παρὰ φύσιν κινουμένοις ἐστὶ φανερὸν διὰ τὸ δῆλον εἶναι ὑπ' ἄλλου κινούμενον. μετὰ δὲ τὰ παρὰ φύσιν τῶν κατὰ φύσιν τὰ αὐτὰ ὑφ' αὑτῶν, οἷον τὰ ζῷα· οὐ γὰρ τοῦτ' ἄδηλον, εἰ ὑπό τινος κινεῖται, ἀλλὰ πῶς δεῖ διαλαβεῖν αὐτοῦ τὸ κινοῦν καὶ τὸ κινούμενον· ἔοικεν γὰρ ὥσπερ ἐν τοῖς πλοίοις καὶ τοῖς μὴ φύσει συνισταμένοις, οὕτω καὶ ἐν τοῖς ζῴοις εἶναι διῃρημένον τὸ κινοῦν καὶ τὸ κινούμενον, καὶ οὕτω τὸ ἅπαν αὐτὸ αὑτὸ κινεῖν. The fact that a thing that is in motion derives its motion from something is most evident in things that are in motion unnaturally, because in such cases it is clear that the motion is derived from something other than the thing itself. Next to things that are in motion unnaturally those whose motion while natural is derived from themselves—e.g. animals—make this fact clear: for here the uncertainty is not as to whether the motion is derived from something but as to how we ought to distinguish in the thing between the movent and the moved. It would seem that in animals, just as in ships and things not naturally organized, that which causes motion is separate from that which suffers motion, and that it is only in this sense that the animal as a whole causes its own motion.
μάλιστα δ' ἀπορεῖται τὸ λοιπὸν τῆς εἰρημένης τελευταίας διαιρέσεως· τῶν γὰρ ὑπ' ἄλλου κινουμένων τὰ μὲν παρὰ φύσιν ἐθήκαμεν κινεῖσθαι, τὰ δὲ λείπεται ἀντιθεῖναι (255a.) ὅτι φύσει. ταῦτα δ' ἐστὶν ἃ τὴν ἀπορίαν παράσχοι ἂν ὑπὸ τίνος κινεῖται, οἷον τὰ κοῦφα καὶ τὰ βαρέα. ταῦτα γὰρ εἰς μὲν τοὺς ἀντικειμένους τόπους βίᾳ κινεῖται, εἰς δὲ τοὺς οἰκείους, τὸ μὲν κοῦφον ἄνω τὸ δὲ βαρὺ κάτω, φύσει· τὸ δ' ὑπὸ τίνος οὐκέτι φανερόν, ὥσπερ ὅταν κινῶνται παρὰ φύσιν. The greatest difficulty, however, is presented by the remaining case of those that we last distinguished. Where things derive their motion from something else we distinguished the cases in which the motion is unnatural: we are left with those that are to be contrasted with the others by reason of the fact that the motion is natural. It is in these cases that difficulty would be experienced in deciding whence the motion is derived, e.g. in the case of light and heavy things. When these things are in motion to positions the reverse of those they would properly occupy, their motion is violent: when they are in motion to their proper positions—the light thing up and the heavy thing down—their motion is natural; but in this latter case it is no longer evident, as it is when the motion is unnatural, whence their motion is derived.
τό τε γὰρ αὐτὰ ὑφ' αὑτῶν φάναι ἀδύνατον· ζωτικόν τε γὰρ τοῦτο καὶ τῶν ἐμψύχων ἴδιον, It is impossible to say that their motion is derived from themselves: this is a characteristic of life and peculiar to living things.
καὶ ἱστάναι ἂν ἐδύνατο αὐτὰ αὑτά (λέγω δ' οἷον, εἰ τοῦ βαδίζειν αἴτιον αὑτῷ, καὶ τοῦ μὴ βαδίζειν), Further, if it were, it would have been in their power to stop themselves (I mean that if e.g. a thing can cause itself to walk it can also cause itself not to walk),
ὥστ' εἰ ἐπ' αὐτῷ τὸ ἄνω φέρεσθαι τῷ πυρί, δῆλον ὅτι ἐπ' αὐτῷ καὶ τὸ κάτω. ἄλογον δὲ καὶ τὸ μίαν κίνησιν κινεῖσθαι μόνην ὑφ' αὑτῶν, εἴγε αὐτὰ ἑαυτὰ κινοῦσιν. ἔτι πῶς ἐνδέχεται συνεχές τι καὶ συμφυὲς αὐτὸ ἑαυτὸ κινεῖν; and so, since on this supposition fire itself possesses the power of upward locomotion, it is clear that it should also possess the power of downward locomotion. Moreover if things move themselves, it would be unreasonable to suppose that in only one kind of motion is their motion derived from themselves. Again, how can anything of continuous and naturally connected substance move itself?
ᾗ γὰρ ἓν καὶ συνεχὲς μὴ ἁφῇ, ταύτῃ ἀπαθές· ἀλλ' ᾗ κεχώρισται, ταύτῃ τὸ μὲν πέφυκε ποιεῖν τὸ δὲ πάσχειν. οὔτ' ἄρα τούτων οὐθὲν αὐτὸ ἑαυτὸ κινεῖ (συμφυῆ γάρ), οὔτ' ἄλλο συνεχὲς οὐδέν, ἀλλ' ἀνάγκη διῃρῆσθαι τὸ κινοῦν ἐν ἑκάστῳ πρὸς τὸ κινούμενον, οἷον ἐπὶ τῶν ἀψύχων ὁρῶμεν, ὅταν κινῇ τι τῶν ἐμψύχων. In so far as a thing is one and continuous not merely in virtue of contact, it is impassive: it is only in so far as a thing is divided that one part of it is by nature active and another passive. Therefore none of the things that we are now considering move themselves (for they are of naturally connected substance), nor does anything else that is continuous: in each case the movent must be separate from the moved, as we see to be the case with inanimate things when an animate thing moves them.
Postquam philosophus suam intentionem manifestavit, hic incipit prosequi suam intentionem: scilicet non omnia quandoque moveri et quandoque quiescere; sed aliquid esse omnino immobile, aliquid autem quod semper movetur. Dividitur autem ista pars in duas: in prima ostendit primum movens esse immobile; in secunda ostendit primum mobile semper moveri, ibi: at vero si aliquod est et cetera. 1021. After revealing his aim, the Philosopher now begins to execute it, namely, to establish that not all things are sometimes in motion and sometimes at rest, but that something is entirely immobile, and something always in motion. The treatment is divided into two parts. In the first he shows that the first mover is immobile; In the second that the first mobile is always being moved, (L. 13).
Prima pars dividitur in duas: in prima ostendit primum movens esse immobile ex ordine moventium et mobilium; in secunda ex sempiternitate motus, ibi: et iterum considerans et cetera. The first part is divided into two sections: In the first he shows the immobility of the first mover from the order of movers and mobiles; In the second, from the eternity of motion, (L. 13).
Prima pars dividitur in partes duas: in prima ostendit primum movens esse immobile; in secunda ostendit ipsum esse perpetuum, ibi: quoniam autem oportet et cetera. The first is divided into two parts: In the first he shows that the first mover is immobile; In the second that the first mover is eternal, (L. 12).
Circa primum duo facit: primo ostendit quoddam quod est necessarium ad probationem sequentium, scilicet quod omne quod movetur ab alio moveatur; secundo ostendit propositum, ibi: hoc autem dupliciter et cetera. About the first he does two things: First he shows that to prove what follows depends on showing that whatever is moved is moved by another; Secondly, he shows the proposition, (L. 9).
Ostenderat siquidem supra in principio septimi, omne quod movetur ab alio moveri, ratione communi accepta ex parte ipsius motus: sed quia incepit applicare motum ad res mobiles, illud quod supra universaliter est ostensum, hic ostendit universaliter verificari in omnibus mobilibus et moventibus. Unde prima pars dividitur in partes duas: in prima ponit divisionem moventium et mobilium; in secunda manifestat propositum in singulis, ibi: et maxime moveri et cetera. He had indeed showed above, in the beginning of Book VII, that whatever is moved is moved by another, by a generic argument based on motion itself, but because he has now begun to apply motion to mobile things, he here shows that what was previously proved in a universal way is verified universally in all mobiles and movers. Hence the first part is divided into two parts: In the first he gives a division of movers and mobiles; In the second he explains his proposition in individual cases, at 1024.
Circa primum duo facit: primo dividit moventia et mobilia; secundo manifestat positam divisionem, ibi: quod enim ipsum a seipso et cetera. About the first he does two things: First he divides movers and mobiles; Secondly, he explains the division, at 1023.
Primo ergo ponit tres divisiones moventium et mobilium. Quarum prima est, quod moventium et mobilium quaedam movent seu moventur per accidens, quaedam autem per se. Et accipit hic per accidens large, secundum quod comprehendit sub se etiam quod est secundum partem. Unde exponens quod dixerat per accidens, subdit quod per accidens moveri aut movere dicitur dupliciter. Primo quidem dicuntur movere per accidens, quaecumque movere dicuntur ex eo quod insunt aliquibus moventibus; sicut cum dicitur musicum sanare, quia is cui inest musicum, sanat: et similiter dicuntur moveri per accidens, ex eo quod insunt iis quae moventur, vel sicut locatum in loco, prout dicimus hominem moveri quia navis movetur in qua est; vel sicut accidens in subiecto, prout dicimus album moveri quia corpus movetur. Alio modo dicuntur aliqua movere vel moveri per accidens, quia movent aut moventur secundum partem; sicut homo dicitur percutere aut percuti, quia manus percutitur aut percutit. 1022. He gives therefore first (790) three divisions of movers and mobiles. The first of these is that among movers and mobiles some move or are moved per accidens, and some per se. And he takes “per accidens” in a wide sense include what moves or is moved with respect to a part. Hence in explaining what he means by “per accidens, he adds that things cause motion or are moved per accidens in two ways. (1) Whatever things are said to cause motion by virtue of being present in things which move are said to cause it per accidens, as when it is said that a musician causes health, because a knowledge of music is present in the one who heals; and likewise things are said to be moved per accidens either on account of existing in what is being moved in the way that an object in place exists in a place, e.g., when we say that a man is being moved, because the ship on which he is is being moved, or on account of being an accident in a subjects as when we say that the white is being moved, because a body is being moved. (2) In another way, things are said to move or to be moved per accidens, because they move or are moved with respect to a part, as a man is said to strike or be struck, because his hand strikes or is struck.
Per se autem dicuntur moveri aut movere, per remotionem duorum praedictorum: quia scilicet nec dicuntur movere aut moveri ex eo quod sint in aliis quae movent aut moveantur; neque ex eo quod aliqua pars ipsorum moveat aut moveatur. But when these two per accidens ways of causing motion or being moved are eliminated, things are said to move or to be moved per se, i.e., when they are not said to cause motion or be moved by virtue of being in the cause of motion or in what is being moved, or because some part of them causes motion or is moved.
Omissis igitur iis quae movent et moventur per accidens, subdividit ea quae moventur per se. Primo quidem, quia eorum quae moventur per se, alia moventur a seipsis, sicut animalia, alia vero ab aliis, sicut inanimata. Therefore, leaving out what causes motion or is moved per accidens, he subdivides things that are moved per se into those which are moved by themselves, as are animals, and those moved by others, as are the non-living.
Tertiam divisionem ponit, quia alia moventur secundum naturam, alia extra naturam. He gives a third division, namely, that some things are moved according to nature and some not according to nature.
Deinde cum dicit: quod enim ipsum etc., manifestat qualiter inveniatur secundum naturam et extra naturam in iis quae moventur a seipsis, et quae moventur ab alio. 1023. Then at (791) he explains how to discern what is according to nature and what is not according to nature, both in things that are moved by themselves and in things that are moved by something else.
Et primo dicit de iis quae moventur a seipsis (sicut sunt animalia, quae movent seipsa), quod moventur secundum naturam. Quod probat per hoc quod moventur a principio intrinseco: illa autem dicimus a natura moveri, quorum principium motus in ipsis est. Unde manifestum est quod motus animalis, quo movet seipsum, si comparetur ad totum animal, est naturalis: quia est ab anima, quae est natura et forma animalis. Sed si comparetur ad corpus, contingit huiusmodi motum esse et naturalem et extra naturam: hoc enim considerandum erit secundum differentiam motus et elementi ex quo constat animal. Si enim animal constat ex elemento gravi praedominanti, sicut corpus humanum, et moveatur sursum, erit motus violentus quantum ad corpus: si vero moveatur deorsum, erit motus corpori naturalis. Si autem essent aliqua animalia corpore aerea, ut quidam Platonici posuerunt, de illis esset e contrario dicendum. First, with respect to things that are moved by themselves—such as are animals, which move themselves—he says that they are moved according to nature. And he proves this on the ground that they are moved by an intrinsic principle, and since things whose principle of motion is within are said to be moved by nature, it follows that an animal’s motion, by which it moves itself, if it is compared to the whole animal, is natural, because that motion proceeds from the soul which is the nature and form of the animal. But if it be compared to the body, an animal’s motion may be both natural and not according to nature. The difference depends on the type of motion and on the element of which the animal is composed. For if an animal consists of a predominant heavy element, as does the human body, and it is moved upwards, such a movement would be compulsory with respect to the body; but if it is moved downward, it will be a movement that is natural to the body. However, if there were animals whose bodies were composed of air, as Platonists held, then the contrary would be true.
Secundo manifestat qualiter inveniatur motus violentus et naturalis in iis quae moventur ab alio. Et dicit quod horum quaedam moventur secundum naturam, ut ignis sursum et terra deorsum: quaedam vero extra naturam, ut terra sursum et ignis deorsum, qui est motus violentus. Secondly, he explains how to discern compulsory and natural motions in things that are moved by another. Of these, some, he says, are moved according to nature, as fire upward and earth downward; others are moved outside their nature, as earth upward and fire downward, which is a compulsory motion.
Tertio ponit alium modum innaturalis motus in animalibus: secundum scilicet quod multoties partes animalium moventur extra naturam, si considerentur rationes et modi naturalis motus in partibus animalium; sicut homo brachia flectit ad anterius, tibias autem ad posterius; canes vero et equi et huiusmodi animalia anteriores pedes ad posterius, posteriores vero ad anterius. Si autem fiat motus in animalibus per contrarium, erit motus violentus et extra naturam. Thirdly, he mentions another type of unnatural motion in animals, namely, those in which the parts of animals are moved in an unnatural way, their positions and the character of the motion being abnormal. For example, a man’s arms bend (at the elbow) facing forward, while his legs bend (at the knee) facing backward; but dogs and horses and the like, bend the forelegs facing backward and the hind legs facing forward. If motions contrary to these are made, they will be compulsory and not according to nature.
Deinde cum dicit: et maxime moveri etc., probat omne quod movetur, ab alio moveri. Et primo ostendit in quibus sit manifestum; secundo ostendit de iis in quibus est dubium, ibi: maxime autem dubitatur et cetera. 1024. Then at (792) he proves that everything that is moved is moved by another. First he manifests it in cases that are evident; Secondly, in cases about which there is doubt, at 1025.
Relictis autem iis quae moventur per accidens, quia ipsa non moventur, sed dicuntur moveri ex eo quod quaedam alia moventur: inter ea quae per se moventur, maxime in his quae moventur per violentiam et extra naturam, manifestum est quod id quod movetur, ab alio movetur. Leaving aside things that are moved per accidens, because such things are not moved but are merely said to be moved when other things are moved, and confining ourselves to those which are moved per se, it is clear, especially in things moved by compulsion and outside their nature, that what is moved is moved by another.
Manifestum est enim quod ea quae per violentiam moventur, ab alio moventur, ex ipsa violenti definitione. Est enim violentum, ut dicitur in III Ethicorum, cuius principium est extra, nil conferente vim passo. For in the case of things moved by compulsion, it is clear from the very definition of compulsion that they are moved by another. For compulsion, as is said in Ethics III, is that whose principle is from without, with the thing suffering it contributing nothing.
Post ista vero quae moventur per violentiam, manifestum est quod id quod movetur ab alio movetur, in iis quae moventur secundum naturam a seipsis, sicut animalia dicuntur seipsa movere. In iis enim manifestum est quod aliquid ab alio movetur: sed dubium potest esse quomodo oporteat accipere in ipsis movens et quod movetur. Quantum enim ex primo aspectu apparet, et secundum quod multis videtur, sicut in navibus et in aliis artificialibus quae non sunt secundum naturam, diversum est quod movet ab eo quod movetur, sic et in animalibus: videtur enim quod hoc modo se habeat anima quae movet, ad corpus quod movetur, sicut nauta ad navim, ut dicitur in II de anima. Et per hunc modum videtur quod totum animal seipsum moveat, inquantum una pars eius aliam movet. Utrum autem se habeat anima ad corpus sicut nauta ad navim, in libro de anima inquirendum relinquit. Quod autem sic aliquid dicatur seipsum movere, inquantum una pars eius movet et alia movetur, in sequentibus ostendetur. After things that are moved by compulsion, it is clear that what is moved is moved by another if we consider things moved by themselves according to nature, as animals are said to move themselves. For in animals it is clear that something is being moved by something else—but there might yet be a question as to how to distinguish in them the mover and what is being moved. For at first glance it appears to many that what is true with respect to ships and other artifacts which do not exist according to nature, namely, that the part which causes motion is diverse from the part which is moved, applies to animals, for it seems that the soul which causes motion is related to its body which is moved, as the mariner is related to the ship, as is said in On the Soul II. In this way it seems that the whole animal moves itself insofar as one part moves another. But whether the soul is related to the body as a mariner to a ship he leaves to be investigated in his treatise On the Soul. However, the fact that a thing is said to move itself, insofar as one part thereof moves and another is moved, will be shown later.
Deinde cum dicit: maxime autem dubitatur etc., manifestat propositum in iis in quibus est magis dubium. Et circa hoc tria facit: primo ponit in quibus sit magis dubium omne quod movetur ab alio moveri, quia scilicet in gravibus et levibus, cum secundum naturam moventur; secundo ostendit quod huiusmodi non movent seipsa, ibi: et namque ipsa a seipsis etc.; tertio ostendit a quo moveantur, ibi: sed accidit et haec et cetera. 1025. Then at (793) he explains his proposition in regard to things in which it is more doubtful. About this he does three things. First he sets down those things in which it is more doubtful that whatever is moved is moved by another, namely, in the heavy and the light, when they are moved according to nature. Secondly, he shows that they do not move themselves, at 1026; Thirdly, he shows by what they are moved, (L. 8).
Dicit ergo primo, quod ex quo maxime manifestum est quod movetur ab alio moveri, in iis quae moventur per violentiam, et post haec in iis quae movent seipsa; maxime videtur dubium in residuo membro ultimae divisionis, scilicet in his quae non movent seipsa, et tamen moventur naturaliter. He says therefore first (793) that, since it is in things moved by compulsion, and after them in things which move themselves, that it is especially evident that whatever is being moved is moved by another, the greatest doubt appears to be in the remaining member of the last division, namely, in things that do not move themselves, but yet are moved naturally.
Ultimam autem divisionem dicit istam, scilicet quod eorum quae moventur non a seipsis sed ab alio, quaedam moventur extra naturam, quaedam vero e contrario moventur secundum naturam. Et in istis dubium est a quo moveantur: sicut sunt gravia et levia, quae quidem in contraria loca moventur per violentiam, sed in propria secundum naturam, leve scilicet sursum, grave vero deorsum; sed a quo moveantur non est manifestum cum moventur secundum naturam, sicut est manifestum cum moventur extra naturam. The “last” division to which he refers is that in which he divided things that are moved not by themselves but by another into those that are moved contrary to nature, and those that are moved according to nature. In these latter there is doubt as to what moves them: for example, heavy and light objects are moved to their proper places according to nature—i.e., the light upwards and the heavy downwards—and into contrary places by compulsion; but the source of their motion when they are moved according to nature is not clear, as it is when they are moved contrary to nature.
Deinde cum dicit: et namque ipsa a seipsis etc., probat quod huiusmodi non movent seipsa, quatuor rationibus. Quarum prima est, quod movere seipsum pertinet ad rationem vitae, et est proprie animatorum: motu enim et sensu discernimus animatum ab inanimato, ut dicitur in I de anima. Manifestum est autem haec non esse viva, seu animata. Non ergo movent seipsa. 1026. Then at (794) he proves with four arguments that these things do not move themselves. The first of which is that to move itself pertains to the notion of life and is peculiar to living things; for it is through motions and sensations that we distinguish the animate from the inanimate, as is said in On the Soul I. But it is manifest that the heavy and light as such are not alive, or animate. Therefore, they do not move themselves.
Secunda ratio ponitur ibi: et facere stare etc.: quae talis est. Quaecumque movent seipsa, possunt etiam sibi esse causa quietis; sicut videmus quod animalia per suum appetitum moventur et stant. Si ergo gravia et levia moverent seipsa motu naturali, possent facere stare seipsa; sicut si aliquis est sibi causa ambulandi, est etiam sibi causa non ambulandi. Hoc autem videmus esse falsum: quia huiusmodi non quiescunt extra propria loca, nisi propter aliquam causam extrinsecam prohibentem motum ipsorum. Ergo non movent seipsa. 1027. The second argument is given at (795); Things that move themselves can cause themselves to stop, as we see that animals are moved and stop by reason of their appetite, Therefore, if heavy and light things moved themselves with a natural motion, they could cause themselves to stop, in the way that a person who is the cause of his walking is so also of his ceasing to walk. But we see that this is false, because the heavy and the light do not stop outside their proper places, unless some external cause intervenes to halt their motion. Therefore, they do not move themselves.
Sed quia posset aliquis dicere quod huiusmodi, etsi non sint sibi causa standi extra propria loca, sunt tamen sibi causa standi in propriis locis, subiungit tertiam rationem ibi: quare si in ipso est etc.: quae talis est. Irrationabile est dicere, quod illa quae movent seipsa, moveantur solum a seipsis secundum unum motum, et non pluribus motibus: quia quod movet seipsum, non habet motum determinatum ab alio, sed ipsum sibi determinat motum; et quandoque determinat sibi hunc motum, et quandoque alium. Unde est in potestate eius quod movet seipsum quod determinet sibi hunc vel illum motum. Si ergo gravia et levia moverent seipsa, sequeretur quod si in potestate ignis esset quod moveretur sursum, quod in potestate eius esset quod moveretur deorsum; quod nunquam videmus accidere, nisi ex causa extrinseca. Non igitur movent seipsa. But because someone could say that although such things are not the cause of their own stopping outside their proper places, yet they are the cause of stopping in their proper places, he adds a third argument at (796): it is unreasonable to say that things which move themselves are so moved according to one motion alone and not by many, because what moves itself does not have its motion determined by another but determines its own motion for itself, so that at one time it determines this motion and at another time that one. Hence it is in the power of what moves itself to determine for itself this or that motion. Therefore, if heavy and light things moved themselves, it would follow that if it were in the power of fire to be moved upward, it would also be in its power to be moved downward, which is something we never see occurring, unless from an extrinsic cause. Therefore, they do not move themselves.
Est autem sciendum, quod istae duae rationes sunt probabiles secundum ea quae apparent de moventibus seipsa quae sunt apud nos, quae quandoque inveniuntur moveri hoc motu, quandoque alio, quandoque etiam quiescere. Unde non dixit impossibile est, sed irrationabile; quo modo loquendi in probabilibus uti consuevit. Ostendet enim inferius, quod si aliquid est movens seipsum, in quo movens est omnino immobile, quod illud semper movetur, et uno motu: sed tamen hoc non posset dici in gravibus et levibus, in quibus non est aliquid quod non moveatur per se vel per accidens, cum etiam generentur et corrumpantur. It should be recognized that these two arguments are probable in respect to what appears in things among us that move themselves, which are found at one time to be moved with this motion and at another time with that motion, and at another time to be at rest. Hence he does not say, “It is impossible,” but “It is unreasonable,” which is his manner of speaking when he talks of what is probable. For he will show later that if something is moving itself and it is an entirely immobile mover, that it is always being moved and with one motion. Yet that could not be said in regard to heavy and light things, in which there is nothing that is not moved either per se or per accidens, and they are also generated and cease to be.
Quartam rationem ponit ibi: amplius quomodo etc.: quae talis est. Nullum continuum movet seipsum: gravia autem et levia sunt continua: ergo nihil horum movet seipsum. 1028. He gives the fourth argument at (797): No continuum moves itself. But heavy and light bodies are continua. Therefore neither of these moves itself.
Quod autem nullum continuum seipsum moveat, sic probat. Quia movens ad motum se habet, sicut agens ad patiens: cum autem agens sit contrarium patienti, necesse est quod dividatur id quod est aptum natum agere, ab eo quod est aptum natum pati: secundum ergo quod aliqua sunt non contacta ad invicem, sed sunt omnino unum et continuum et quantitate et forma, secundum hoc non possunt pati ab invicem. Sic ergo sequitur quod nullum continuum moveat seipsum, sed necesse est quod movens dividatur ab eo quod movetur; sicut apparet cum res inanimatae moventur ab animatis, ut lapis a manu. Unde et in animalibus quae movent seipsa, est magis quaedam colligatio partium, quam perfecta continuatio: sic enim una pars potest moveri ab alia, quod non invenitur in gravibus et levibus. That no continuum moves itself he proves in the following manner: The mover is related to the moved as agent to patient. But since the agent is contrary to the patient, that which is apt to act must be divided from what is apt to be acted upon, Now, to the extent that things are not in mutual contact but are completely one and continuous in quantity and form, to that extent they can not be acted upon by one another, In this way, therefore, it follows that no continuum moves itself, but the mover must be divided from what is moved, as is evident when non-living things are moved by living things, as is a stone by the hand, Hence, too, in animals that move themselves, there is rather a connection of parts than a perfect continuity (for which reason one part can be moved by another), a situation that is not verified in the light and the heavy.

Lectio 8
What moves the heavy and light. Everything moved, moved by another.
Chapter 4 cont.
ἀλλὰ συμβαίνει καὶ ταῦτα ὑπό τινος ἀεὶ κινεῖσθαι· γένοιτο δ' ἂν φανερὸν διαιροῦσι τὰς αἰτίας. ἔστιν δὲ καὶ ἐπὶ τῶν κινούντων λαβεῖν τὰ εἰρημένα· τὰ μὲν γὰρ παρὰ φύσιν αὐτῶν κινητικά ἐστιν, οἷον ὁ μοχλὸς οὐ φύσει τοῦ βάρους κινητικός, τὰ δὲ φύσει, οἷον τὸ ἐνεργείᾳ θερμὸν κινητικὸν τοῦ δυνάμει θερμοῦ. ὁμοίως δὲ καὶ ἐπὶ τῶν ἄλλων τῶν τοιούτων. καὶ κινητὸν δ' ὡσαύτως φύσει τὸ δυνάμει ποιὸν ἢ ποσὸν ἢ πού, ὅταν ἔχῃ τὴν ἀρχὴν τὴν τοιαύτην ἐν αὑτῷ καὶ μὴ κατὰ συμβεβηκός (εἴη γὰρ ἂν τὸ αὐτὸ καὶ ποιὸν καὶ ποσόν, ἀλλὰ θατέρῳ θάτερον συμβέβηκεν καὶ οὐ καθ' αὑτὸ ὑπάρχει). τὸ δὴ πῦρ καὶ ἡ γῆ κινοῦνται ὑπό τινος βίᾳ μὲν ὅταν παρὰ φύσιν, φύσει δ' ὅταν εἰς τὰς αὑτῶν ἐνεργείας δυνάμει ὄντα. It is the fact that these things also always derive their motion from something: what it is would become evident if we were to distinguish the different kinds of cause. The above-mentioned distinctions can also be made in the case of things that cause motion: some of them are capable of causing motion unnaturally (e.g. the lever is not naturally capable of moving the weight), others naturally (e.g. what is actually hot is naturally capable of moving what is potentially hot): and similarly in the case of all other things of this kind. In the same way, too, what is potentially of a certain quality or of a certain quantity in a certain place is naturally movable when it contains the corresponding principle in itself and not accidentally (for the same thing may be both of a certain quality and of a certain quantity, but the one is an accidental, not an essential property of the other). So when fire or earth is moved by something the motion is violent when it is unnatural, and natural when it brings to actuality the proper activities that they potentially possess.
ἐπεὶ δὲ τὸ δυνάμει πλεοναχῶς λέγεται, τοῦτ' αἴτιον τοῦ μὴ φανερὸν εἶναι ὑπὸ τίνος τὰ τοιαῦτα κινεῖται, οἷον τὸ πῦρ ἄνω καὶ ἡ γῆ κάτω. But the fact that the term 'potentially' is used in more than one sense is the reason why it is not evident whence such motions as the upward motion of fire and the downward motion of earth are derived.
ἔστι δὲ δυνάμει ἄλλως ὁ μανθάνων ἐπιστήμων καὶ ὁ ἔχων ἤδη καὶ μὴ ἐνεργῶν. ἀεὶ δ', ὅταν ἅμα τὸ ποιητικὸν καὶ τὸ παθητικὸν ὦσιν, γίγνεται ἐνεργείᾳ τὸ δυ(255b.) νατόν, οἷον τὸ μανθάνον ἐκ δυνάμει ὄντος ἕτερον γίγνεται δυνάμει (ὁ γὰρ ἔχων ἐπιστήμην μὴ θεωρῶν δὲ δυνάμει ἐστὶν ἐπιστήμων πως, ἀλλ' οὐχ ὡς καὶ πρὶν μαθεῖν), ὅταν δ' οὕτως ἔχῃ, ἐάν τι μὴ κωλύῃ, ἐνεργεῖ καὶ θεωρεῖ, ἢ ἔσται ἐν τῇ ἀντιφάσει καὶ ἐν ἀγνοίᾳ. One who is learning a science potentially knows it in a different sense from one who while already possessing the knowledge is not actually exercising it. Wherever we have something capable of acting and something capable of being correspondingly acted on, in the event of any such pair being in contact what is potential becomes at times actual: e.g. the learner becomes from one potential something another potential something: for one who possesses knowledge of a science but is not actually exercising it knows the science potentially in a sense, though not in the same sense as he knew it potentially before he learnt it. And when he is in this condition, if something does not prevent him, he actively exercises his knowledge: otherwise he would be in the contradictory state of not knowing.
ὁμοίως δὲ ταῦτ' ἔχει καὶ ἐπὶ τῶν φυσικῶν· τὸ γὰρ ψυχρὸν δυνάμει θερμόν, ὅταν δὲ μεταβάλῃ, ἤδη πῦρ, καίει δέ, ἂν μή τι κωλύῃ καὶ ἐμποδίζῃ. In regard to natural bodies also the case is similar. Thus what is cold is potentially hot: then a change takes place and it is fire, and it burns, unless something prevents and hinders it.
ὁμοίως δ' ἔχει καὶ περὶ τὸ βαρὺ καὶ κοῦφον· τὸ γὰρ κοῦφον γίγνεται ἐκ βαρέος, οἷον ἐξ ὕδατος ἀήρ (τοῦτο γὰρ δυνάμει πρῶτον), καὶ ἤδη κοῦφον, καὶ ἐνεργήσει γ' εὐθύς, ἂν μή τι κωλύῃ. ἐνέργεια δὲ τοῦ κούφου τὸ ποὺ εἶναι καὶ ἄνω, κωλύεται δ', ὅταν ἐν τῷ ἐναντίῳ τόπῳ ᾖ. καὶ τοῦθ' ὁμοίως ἔχει καὶ ἐπὶ τοῦ ποσοῦ καὶ ἐπὶ τοῦ ποιοῦ. So, too, with heavy and light: light is generated from heavy, e.g. air from water (for water is the first thing that is potentially light), and air is actually light, and will at once realize its proper activity as such unless something prevents it. The activity of lightness consists in the light thing being in a certain situation, namely high up: when it is in the contrary situation, it is being prevented from rising. The case is similar also in regard to quantity and quality.
καίτοι τοῦτο ζητεῖται, διὰ τί ποτε κινεῖται εἰς τὸν αὑτῶν τόπον τὰ κοῦφα καὶ τὰ βαρέα. αἴτιον δ' ὅτι πέφυκέν ποι, καὶ τοῦτ' ἔστιν τὸ κούφῳ καὶ βαρεῖ εἶναι, τὸ μὲν τῷ ἄνω τὸ δὲ τῷ κάτω διωρισμένον. But, be it noted, this is the question we are trying to answer—how can we account for the motion of light things and heavy things to their proper situations? The reason for it is that they have a natural tendency respectively towards a certain position: and this constitutes the essence of lightness and heaviness, the former being determined by an upward, the latter by a downward, tendency.
δυνάμει δ' ἐστὶν κοῦφον καὶ βαρὺ πολλαχῶς, ὥσπερ εἴρηται· ὅταν τε γὰρ ᾖ ὕδωρ, δυνάμει γέ πώς ἐστι κοῦφον, καὶ ὅταν ἀήρ, ἔστιν ὡς ἔτι δυνάμει (ἐνδέχεται γὰρ ἐμποδιζόμενον μὴ ἄνω εἶναι)· ἀλλ' ἐὰν ἀφαιρεθῇ τὸ ἐμποδίζον, ἐνεργεῖ καὶ ἀεὶ ἀνωτέρω γίγνεται. ὁμοίως δὲ καὶ τὸ ποιὸν εἰς τὸ ἐνεργείᾳ εἶναι μεταβάλλει· εὐθὺς γὰρ θεωρεῖ τὸ ἐπιστῆμον, ἐὰν μή τι κωλύῃ· καὶ τὸ ποσὸν ἐκτείνεται, ἐὰν μή τι κωλύῃ. ὁ δὲ τὸ ὑφιστάμενον καὶ κωλῦον κινήσας ἔστιν ὡς κινεῖ ἔστι δ' ὡς οὔ, οἷον ὁ τὸν κίονα ὑποσπάσας ἢ ὁ τὸν λίθον ἀφελὼν ἀπὸ τοῦ ἀσκοῦ ἐν τῷ ὕδατι· κατὰ συμβεβηκὸς γὰρ κινεῖ, ὥσπερ καὶ ἡ ἀνακλασθεῖσα σφαῖρα οὐχ ὑπὸ τοῦ τοίχου ἐκινήθη ἀλλ' ὑπὸ τοῦ βάλλοντος. ὅτι μὲν τοίνυν οὐδὲν τούτων αὐτὸ κινεῖ ἑαυτό, δῆλον· ἀλλὰ κινήσεως ἀρχὴν ἔχει, οὐ τοῦ κινεῖν οὐδὲ τοῦ ποιεῖν, ἀλλὰ τοῦ πάσχειν. As we have said, a thing may be potentially light or heavy in more senses than one. Thus not only when a thing is water is it in a sense potentially light, but when it has become air it may be still potentially light: for it may be that through some hindrance it does not occupy an upper position, whereas, if what hinders it is removed, it realizes its activity and continues to rise higher. The process whereby what is of a certain quality changes to a condition of active existence is similar: thus the exercise of knowledge follows at once upon the possession of it unless something prevents it. So, too, what is of a certain quantity extends itself over a certain space unless something prevents it. The thing in a sense is and in a sense is not moved by one who moves what is obstructing and preventing its motion (e.g. one who pulls away a pillar from under a roof or one who removes a stone from a wineskin in the water is the accidental cause of motion): and in the same way the real cause of the motion of a ball rebounding from a wall is not the wall but the thrower. So it is clear that in all these cases the thing does not move itself, but it contains within itself the source of motion—not of moving something or of causing motion, but of suffering it.
εἰ δὴ πάντα τὰ κινούμενα ἢ φύσει κινεῖται ἢ παρὰ φύσιν καὶ βίᾳ, καὶ τά τε βίᾳ καὶ παρὰ φύσιν πάντα ὑπό τινος καὶ ὑπ' ἄλλου, τῶν δὲ φύσει πάλιν τά θ' ὑφ' αὑτῶν κινούμενα ὑπό τινος κινεῖται καὶ τὰ μὴ ὑφ' αὑτῶν, οἷον τὰ κοῦφα καὶ τὰ βαρέα (256a.) (ἢ γὰρ ὑπὸ τοῦ γεννήσαντος καὶ ποιήσαντος κοῦφον ἢ βαρύ, ἢ ὑπὸ τοῦ τὰ ἐμποδίζοντα καὶ κωλύοντα λύσαντος), ἅπαντα ἂν τὰ κινούμενα ὑπό τινος κινοῖτο. If then the motion of all things that are in motion is either natural or unnatural and violent, and all things whose motion is violent and unnatural are moved by something, and something other than themselves, and again all things whose motion is natural are moved by something—both those that are moved by themselves and those that are not moved by themselves (e.g. light things and heavy things, which are moved either by that which brought the thing into existence as such and made it light and heavy, or by that which released what was hindering and preventing it); then all things that are in motion must be moved by something.
Postquam ostendit quod gravia et levia non movent seipsa, hic ostendit a quo moveantur. Et primo ostendit a quo moveantur; secundo concludit principale intentum, ibi: si igitur omnia quae moventur et cetera. 1029. After showing that the heavy and the light do not move themselves, he shows by what they are moved. First he shows by what they are moved; Secondly, he concludes to his main intention, at 1036.
Circa primum duo facit: primo ostendit quod naturaliter moventur ab aliquo; secundo inquirit a quo moveantur, ibi: quoniam autem quod potentia et cetera. About the first he does two things: First he shows that they are naturally moved by something; Secondly, he investigates by what they are moved, at 1030.
Dicit ergo primo, quod etsi gravia et levia non moveant seipsa, tamen moventur ab aliquo. Et hoc potest manifestari, si distinguantur causae moventes. Sicut enim in his quae moventur, est accipere quaedam secundum naturam moveri, et quaedam extra naturam; ita et in moventibus quaedam movent extra naturam, ut vectis, idest baculus, qui non naturaliter motivus est corporis gravis, puta lapidis; quaedam vero movent secundum naturam, sicut quod est actu calidum naturaliter movet id quod secundum suam naturam est potentia calidum; et similiter est in aliis talibus. Et sicut quod est in actu naturaliter movet, ita id quod est in potentia naturaliter movetur, vel secundum qualitatem, vel secundum quantitatem, vel secundum ubi. He says therefore first (798) that although the heavy and the light do not move themselves, they are nevertheless moved by something. And this can be made clear if we distinguish moving causes. For just as in things that are moved, we must take it that (1) some things are moved according to nature and some not, so also in movers, some move not according to nature, e.g., a stick, which is not naturally capable of moving a heavy body such as a stone; and that (2) some things move according to nature, as what is actually hot naturally moves what is according to its nature potentially hot, and similarly in other cases. And just as what is in act causes motion naturally, so what is in potency is naturally moved, with respect either to quantity or quality or where.
Et quia in secundo dixerat quod illa moventur naturaliter, quorum principium motus in ipsis est per se, et non secundum accidens; ex quo posset videri quod id quod est in potentia tantum calidum, cum fit calidum, non movetur naturaliter, tanquam principio activo motus exterius existente: quasi ad hanc obiectionem excludendam subiungit: cum habeat principium huiusmodi in seipso, et non secundum accidens; quasi dicat quod ad hoc quod motus sit naturalis, sufficit quod huiusmodi principium, scilicet potentia, de qua fecerat mentionem, sit in eo quod movetur, per se et non per accidens, sicut scamnum est potentia combustibile, non inquantum est scamnum, sed inquantum est lignum. And because in Book II he had said that those things are moved naturally whose principle of motion exists in them per se and not by virtue of some concomitant attribute, which might lead one to suppose that what is only potentially hot is, when it becomes hot, not moved naturally in that it is being moved by an external active principle of its motion, he now adds, as though to preclude this objection, “since it has a principle of this kind in itself and not accidentally,” as if to say that in order that a motion be natural, it is enough that a principle of this kind, i.e., the potency, about which he made mention, exist in that which is moved per se and not per accidens, as a bench is potentially combustible, not precisely as bench but as wood.
Unde hoc quod dixerat, non secundum accidens, exponens, subdit quod contingit idem subiectum esse et quantum et quale, sed unum eorum per accidens se habet ad aliud, et non per se: quod ergo est potentia quale, est etiam potentia quantum, sed per accidens. Hence in explaining the expression “per accidens,” he adds that the same subject can be quantified and qualified, but one of these is related to the other per accidens; what is potentially of such and such a quality is also potentially quantified, but per accidens.
Quia igitur quod est in potentia, naturaliter movetur ab alio quod est in actu: nihil autem secundum idem est potentia et actu: sequitur quod neque ignis neque terra neque aliquid aliud moveatur a se, sed ab alio. Moventur quidem ignis et terra ab alio, sed per violentiam, cum motus eorum est extra naturalem ipsorum potentiam: sed naturaliter moventur, cum moventur in actus proprios, ad quos sunt in potentia secundum suam naturam. Therefore, because what is in potency is naturally moved by something else in act, and nothing is in potency and in act with respect to the same, it follows that neither fire nor earth nor anything else is moved by itself but by another. Fire and water are moved by another, but by compulsion, when their motion is outside their natural potency; but they are moved naturally when they are moved to their proper acts, to which they are in potency according to their nature.
Deinde cum dicit: quoniam autem quod potentia etc., ostendit a quo moveantur: et quia quod est in potentia movetur ab eo quod est in actu, primo distinguit potentiam; secundo ex hoc ostendit a quo huiusmodi moveantur, ibi: potentia autem est leve et cetera. 1030. Then at (799) he shows by what they are moved. And because what is in potency is moved by something in act, First he distinguishes potency; Secondly, from this he shows by what such things are moved, at 1035.
Circa primum tria facit: primo ostendit necessarium esse cognoscere quot modis aliquid dicitur esse in potentia; secundo manifestat, ibi: est autem potentia etc.; tertio solvit ex hoc quandam quaestionem, ibi: et tamen quaeritur et cetera. About the first he does three things: First he shows that it is necessary to know the ways in which something is said to be in potency; Secondly, he explains this at 1031; Thirdly, with this he solves a question, at 1033.
Dicit ergo primo, quod ideo non est manifestum a quo gravia et levia moventur suis motibus naturalibus, ut puta ignis sursum et terra deorsum, quia ens in potentia dicitur multipliciter. He says therefore that the reason why it is not evident by what heavy and light things are moved with respect to their natural motion (as fire upward and earth downward) is that the expression “being in potency” has many senses.
Deinde cum dicit: est autem potentia etc., distinguitur esse in potentia: et primo in intellectu; secundo in qualitate, ibi: similiter autem haec se habent etc.; tertio in motu locali, ibi: similiter autem se habet et cetera. 1031. Then at (800) he distinguishes “being in potency”: First in the understanding; Secondly, in quality, at 1032; Thirdly, in local motion, at 1033.
Dicit ergo primo, quod aliter est in potentia ad scientiam ille qui addiscit et nondum habet habitum scientiae, et ille qui iam habet habitum scientiae sed non considerat utens habitu. He says therefore first that one who is learning and does not yet have the habit of science is not in potency to science in the same way as one who already has the science but is not using it by considering.
Ex prima autem potentia in secundam reducitur aliquid, cum activum suo passivo coniungitur; et tunc passivum per praesentiam activi fit in tali actu, qui adhuc est in potentia; sicut addiscens per actionem docentis reducitur de potentia in actum, cui actui coniungitur altera potentia. Et sic existens in prima potentia, fit in alia potentia: quia iam habens scientiam, sed non considerans, quodammodo est in potentia ad actum scientiae, sed non eodem modo, sicut antequam addisceret. Ergo de prima potentia reducitur in actum cui coniungitur secunda potentia, per aliquod agens, scilicet per docentem. But something is reduced from the first potency to the second, when the active principle is united with the patient; and then the patient through the presence of the active principle comes to be with respect to such an act, but after that the patient is yet in potency: for example, a learner is through the action of the teacher reduced from potency to act, but when he is in this state of act, there is yet another potency present. Consequently, the thing existing in first potency comes to be in another state of potency; because one having science, and not considering, is in a sense in potency to an act of science, but not in the same way as he was before he learned. Therefore, from first potency he is reduced to an act to which is united a second potency, by some agent, namely, the teacher.
Sed quando sic se habet quod habet habitum scientiae, non oportet quod reducatur in secundum actum per aliquod agens, sed statim per seipsum operatur considerando, nisi sit aliquid prohibens, puta occupatio vel infirmitas aut voluntas. Vel si non impeditus non posset considerare, tunc non esset in habitu scientiae, sed in eius contrario, scilicet in ignorantia. But when he is in the state of possessing the habit of science, it is not necessary that he be reduced to second act by some agent; rather he operates immediately by himself, just by considering, i.e., unless he is prevented by other occupations or by sickness or by his will. On the other hand, if he were not impeded and still could not consider, then he would not be in the habit of science but in its contrary, namely, ignorance.
Deinde cum dicit: similiter autem haec etc., manifestat idem in qualitatibus. Et dicit quod sicut dictum est de potentia ad sciendum in anima, ita est etiam in corporibus naturalibus. Corpus enim cum est actu frigidum, est potentia calidum, sicut ignorans est potentia sciens: sed cum fuerit productum per transmutationem ut habeat formam ignis, tunc iam est ignis in actu, habens virtutem operandi; et operatur statim comburendo, nisi aliquid prohibeat in contrarium agendo, vel qualitercumque aliter impediat, puta subtrahendo combustibile; sicut dictum est quod postquam aliquis addiscendo factus est sciens, statim considerat, nisi aliquid impediat. 1032. Then at (801) he manifests the same thing in qualities. And he says that what was said with respect to the potency of anything in the mind applies also to natural bodies. For when a body is actually cold, it is potentially hot, just as an ignorant person is potentially a knower. But when this body has been so modified that it has the form of fire, then it is now actually fire and has the power to burn; and it acts at once and burns, unless it is prevented by something acting to the contrary or somehow preventing its acting, as by removing the combustible material. This is similar to what was said above, that when someone after learning becomes a knower, he at once considers, unless prevented by something.
Deinde cum dicit: similiter autem se habet et circa grave etc.; manifestat idem in motu locali gravium et levium. Et dicit quod similiter leve fit ex gravi, sicut calidum ex frigido; ut puta cum aer, qui est levis, fit ex aqua, quae est gravis. Haec ergo, scilicet aqua, primo est in potentia levis, et postmodum fit levis in actu; et tunc statim habet operationem suam, nisi aliquid prohibeat. Sed iam levis existens comparatur ad locum sicut potentia ad actum (actus enim levis, inquantum huiusmodi, est esse in aliquo loco determinato, scilicet sursum): sed prohibetur ne sit sursum, per hoc quod est in contrario loco, scilicet deorsum, quia non potest esse simul in duobus locis: unde illud quod detinet leve deorsum, prohibet ipsum esse sursum. Et sicut dictum est in motu locali, ita etiam dicendum est de motu secundum quantitatem vel qualitatem. 1033. Then at (802) he manifests the same thing in the local motion of the heavy and the light. And he says that a light thing comes to be from a heavy, as a hot thing comes to be from the cold, as, for example, when air which is light comes to be from water which is heavy. Therefore, this water is first potentially light and later becomes actually light, and then it has its own activity at once, unless something prevents. But now being light, it is related to a place as potency to act—for the act of the light as light is to be in some definite place, namely, above; but it is prevented from being up by the fact of being in a contrary place, namely, down, because it cannot be in two places at the same time. Hence, that which keeps a light thing down prevents it from being up. And what has been said of local motion is true also of motion with respect to quantity or quality.
Deinde cum dicit: et tamen quaeritur etc., solvit quandam quaestionem secundum praemissa. Licet enim actus levis sit esse sursum, tamen a quibusdam quaeritur quare gravia et levia moventur in propria loca. Sed causa huius est, quia habent naturalem aptitudinem ad talia loca. Hoc enim est esse leve, habere aptitudinem ad hoc quod sit sursum: et haec est etiam ratio gravis, habere aptitudinem ad hoc quod sit deorsum. Unde nihil est aliud quaerere quare grave movetur deorsum, quam quaerere quare est grave. Et sic illud idem quod facit ipsum grave, facit ipsum moveri deorsum. 1034. Then at (803) he uses the foregoing to answer a question. For although the act of the light is to be above, yet some ask why the heavy and the light are moved to their appropriate places. But the cause of this is that they have a natural aptitude for such places. For to be light is to have an aptitude for being above, and the nature of the heavy is to have an aptitude to be down. Hence, to ask why a heavy thing is moved downward is exactly the same as to ask why it is heavy. Accordingly, the very same thing that makes it heavy makes it be moved downward.
Deinde cum dicit: potentia autem est leve etc., ex praemissis ostendit quid moveat gravia et levia. Et dicit quod cum id quod est in potentia, moveatur ab eo quod est in actu, sicut dictum est, considerandum est quod multipliciter dicitur aliquid esse in potentia leve vel grave. 1035. Then at (804) he uses the foregoing to show what moves the heavy and the light. And he says that since what is in potency is moved by what is in act (as has been said), it must be considered that something is said in many senses to be potentially light or heavy.
Uno enim modo, cum adhuc est aqua, est in potentia ad leve: alio autem modo, cum iam ex aqua factus est aer, est tamen adhuc in potentia ad actum levis, quod est esse sursum, sicut habens habitum scientiae et non considerans, adhuc dicitur esse in potentia; contingit enim quod id quod est leve, impediatur ne sit sursum. For in one way, when something is yet water, it is in potency to lightness; in another way, when from the water air has now been made, it is still in potency to the act of what is light, which is to be above in the same way that one having the habit of science and not considering is said still to be in potency—for what is light can possibly be prevented from being up.
Si ergo auferatur illud impedimentum, statim agit ad hoc quod sit sursum ascendendo; sicut etiam dictum est in qualitate, quod quando est quale in actu, statim tendit in suam actionem; sicut ille qui est sciens, statim considerat, nisi aliquid prohibeat. Et similiter in motu quantitatis: quia ex quo facta est additio quanti ad quantum, statim sequitur extensio in corpore augmentabili, nisi aliquid prohibeat. If, therefore, that obstacle be removed, it immediately acts for the purpose of being up by ascending, as it was said with respect to quality that when a thing is actually of such and such a quality, it immediately tends to its act, as a knower immediately considers, unless he be prevented. And the same is true with respect to the motion to quantity, for from the fact that an addition of quantity has been made to a quantitative thing, extension immediately follows in an increasable body, unless something prevents.
Sic ergo patet quod illud quod movet, idest removet hoc quod est prohibens et sustinens, idest detinens, quodammodo movet et quodammodo non movet: puta si columna sustineat aliquod grave, et sic impediat ipsum descendere, ille qui divellit columnam, quodammodo dicitur movere grave columnae superpositum; et similiter ille qui removet lapidem qui impedit aquam effluere a vase, dicitur quodammodo movere aquam. Dicitur enim movere per accidens, et non per se: sicut si sphaera, idest pila, repercutiatur a pariete, per accidens quidem mota est a pariete, non autem per se; sed a primo proiiciente per se mota est. Paries enim non dedit ei aliquem impetum ad motum, sed proiiciens: per accidens autem fuit, quod dum a pariete impediretur ne secundum impetum ferretur, eodem impetu manente, in contrarium motum resilivit. Et similiter ille qui divellit columnam, non dat gravi superposito impetum vel inclinationem ad hoc quod sit deorsum: hoc enim habuit a primo generante, quod dedit ei formam quam sequitur talis inclinatio. Sic igitur generans est per se movens gravia et levia, removens autem prohibens, per accidens. Accordingly, it is clear that what moves, i.e., what removes the obstacle preventing and sustaining does in some sense cause motion and in other senses does not; for example, if a pillar supports something heavy and thus keeps it from descending, the one who casts down the pillar is said somehow to move the heavy object that was supported by the pillar. In like manner, one who removes a stopper that was preventing water from flowing out of a container is said in some sense to move the water; for he is said to move per accidens and not per se. Also when a ball rebounds from a wall, it is moved per accidens by the wall but per se by the one who first threw it. For it was not the wall but the thrower that gave it the impetus for motion; but it was per accidens that, being prevented by the wall from continuing according to its impetus, it rebounded into a contrary motion, the original impetus remaining. In like manner, the one who casts down the pillar did not give the heavy object resting upon it the impetus or inclination to be downward, for it had that from the first generator, which gave it the form upon which that inclination follows. Consequently, the generator is the per se mover of the light and the heavy, whereas the remover of obstacles is a per accidens mover.
Concludit igitur manifestum esse ex dictis, quod nihil horum, scilicet gravium et levium, movet seipsum: sed tamen motus eorum est naturalis, quia habent principium motus in seipsis; non quidem principium motivum aut activum, sed principium passivum, quod est potentia ad talem actum. He concludes, therefore, that it is clear from the foregoing that none of these, i.e., of the heavy and the light, moves itself; yet their motion is natural, because they have in themselves the principle of their motion, not indeed a moving or active principle but a passive one, which is a potency to such-and-such an act.
Ex quo patet contra intentionem philosophi esse, quod in materia sit principium activum, quod quidam dicunt esse necessarium ad hoc quod sit motus naturalis: sufficit enim ad hoc passivum principium, quod est potentia naturalis ad actum. From this it is evidently contrary to the intention of the Philosopher that in matter there be an active principle, which some declare is necessary for a natural motion; for a passive principle is sufficient, since it is a natural potency for act.
Deinde cum dicit: si igitur omnia quae moventur etc., concludit conclusionem principaliter intentam in toto capitulo. Et dicit quod si hoc verum est, quod omnia quae per se moventur, aut moventur secundum naturam, aut extra naturam et per violentiam; et de illis quae moventur per violentiam, manifestum est quod omnia moventur non solum a quodam movente, sed etiam a movente alio extrinseco; et iterum inter ea quae moventur secundum naturam, quaedam moventur a seipsis, in quibus manifestum est quod moventur ab aliquo, non quidem extrinseco, sed intrinseco; quaedam etiam sunt quae moventur secundum naturam, non tamen a seipsis, sicut gravia et levia, et haec etiam ab aliquo moventur, ut ostensum est (quia aut moventur per se a generante, quod facit ea esse gravia et levia; aut moventur per accidens ab eo quod solvit, idest removet, ea quae impediunt vel removent naturalem motum): sic ergo patet quod omnia quae moventur, moventur ab aliquo vel intrinseco motore vel extrinseco, quod dicit ab alio moveri. 1036. Then at (805) he concludes to the conclusion chiefly intended in the whole chapter. And he says that if it is true that all things which are per se moved are moved either according to nature, or outside their nature and by compulsion, and if of those which are moved by compulsion it is true that all are moved not only by a mover but even by an external mover that is other; and, again, if among things that are moved according to nature, some are moved by themselves—in which things it is clear that they are moved by something not extrinsic but intrinsic—while others, such as heavy and light things are moved according to nature not by themselves but by some mover) as has been explained—for they are moved either per se by the generator which makes them be heavy and light, or they are moved per accidens by whatever removes what impedes or removes their natural motion—it is accordingly clear that all things which are moved are moved by something, i.e., either by an intrinsic or an extrinsic mover; which is to be moved by something other.

Lectio 9
No process to infinity in movers. Not every mover need be moved.
Chapter 5
Τοῦτο δὲ διχῶς· ἢ γὰρ οὐ δι' αὐτὸ τὸ κινοῦν, ἀλλὰ δι' ἕτερον ὃ κινεῖ τὸ κινοῦν, ἢ δι' αὐτό, καὶ τοῦτο ἢ πρῶτον μετὰ τὸ ἔσχατον ἢ διὰ πλειόνων, οἷον ἡ βακτηρία κινεῖ τὸν λίθον καὶ κινεῖται ὑπὸ τῆς χειρὸς κινουμένης ὑπὸ τοῦ ἀνθρώπου, οὗτος δ' οὐκέτι τῷ ὑπ' ἄλλου κινεῖσθαι. Now this may come about in either of two ways. Either the movent is not itself responsible for the motion, which is to be referred to something else which moves the movent, or the movent is itself responsible for the motion. Further, in the latter case, either the movent immediately precedes the last thing in the series, or there may be one or more intermediate links: e.g. the stick moves the stone and is moved by the hand, which again is moved by the man: in the man, however, we have reached a movent that is not so in virtue of being moved by something else.
ἄμφω δὴ κινεῖν φαμέν, καὶ τὸ τελευταῖον καὶ τὸ πρῶτον τῶν κινούντων, ἀλλὰ μᾶλλον τὸ πρῶτον· ἐκεῖνο γὰρ κινεῖ τὸ τελευταῖον, ἀλλ' οὐ τοῦτο τὸ πρῶτον, καὶ ἄνευ μὲν τοῦ πρώτου τὸ τελευταῖον οὐ κινήσει, ἐκεῖνο δ' ἄνευ τούτου, οἷον ἡ βακτηρία οὐ κινήσει μὴ κινοῦντος τοῦ ἀνθρώπου. Now we say that the thing is moved both by the last and by the first movent in the series, but more strictly by the first, since the first movent moves the last, whereas the last does not move the first, and the first will move the thing without the last, but the last will not move it without the first: e.g. the stick will not move anything unless it is itself moved by the man.
εἰ δὴ ἀνάγκη πᾶν τὸ κινούμενον ὑπό τινός τε κινεῖσθαι, καὶ ἢ ὑπὸ κινουμένου ὑπ' ἄλλου ἢ μή, καὶ εἰ μὲν ὑπ' ἄλλου [κινουμένου], ἀνάγκη τι εἶναι κινοῦν ὃ οὐχ ὑπ' ἄλλου πρῶτον, εἰ δὲ τοιοῦτο τὸ πρῶτον, οὐκ ἀνάγκη θάτερον (ἀδύνατον γὰρ εἰς ἄπειρον ἰέναι τὸ κινοῦν καὶ κινούμενον ὑπ' ἄλλου αὐτό· τῶν γὰρ ἀπείρων οὐκ ἔστιν οὐδὲν πρῶτον)—εἰ οὖν ἅπαν μὲν τὸ κινούμενον ὑπό τινος κινεῖται, τὸ δὲ πρῶτον κινοῦν κινεῖται μέν, οὐχ ὑπ' ἄλλου δέ, ἀνάγκη αὐτὸ ὑφ' αὑτοῦ κινεῖσθαι. If then everything that is in motion must be moved by something, and the movent must either itself be moved by something else or not, and in the former case there must be some first movent that is not itself moved by anything else, while in the case of the immediate movent being of this kind there is no need of an intermediate movent that is also moved (for it is impossible that there should be an infinite series of movents, each of which is itself moved by something else, since in an infinite series there is no first term)—if then everything that is in motion is moved by something, and the first movent is moved but not by anything else, it much be moved by itself.
ἔτι δὲ καὶ ὧδε τὸν αὐτὸν τοῦτον λόγον ἔστιν ἐπελθεῖν. πᾶν γὰρ τὸ κινοῦν τί τε κινεῖ καὶ τινί. ἢ γὰρ αὑτῷ κινεῖ τὸ κινοῦν ἢ ἄλλῳ, οἷον ἄνθρωπος ἢ αὐτὸς ἢ τῇ βακτηρίᾳ, καὶ ὁ ἄνεμος κατέβαλεν ἢ αὐτὸς ἢ ὁ λίθος ὃν ἔωσεν. ἀδύνατον δὲ κινεῖν ἄνευ τοῦ αὐτὸ αὑτῷ κινοῦντος τὸ ᾧ κινεῖ· ἀλλ' εἰ μὲν αὐτὸ αὑτῷ κινεῖ, οὐκ ἀνάγκη ἄλλο εἶναι ᾧ κινεῖ, ἂν δὲ ᾖ ἕτερον τὸ ᾧ κινεῖ, ἔστιν τι ὃ κινήσει οὐ τινὶ ἀλλ' αὑτῷ, ἢ εἰς ἄπειρον εἶσιν. εἰ οὖν κινούμενόν τι κινεῖ, ἀνάγκη στῆναι καὶ μὴ εἰς ἄπειρον ἰέναι· εἰ γὰρ ἡ βακτηρία κινεῖ τῷ κινεῖσθαι ὑπὸ τῆς χειρός, ἡ χεὶρ κινεῖ τὴν βακτηρίαν· εἰ δὲ καὶ ταύτῃ ἄλλο κινεῖ, καὶ ταύτην ἕτερόν τι τὸ κινοῦν. ὅταν δή τινι κινῇ ἀεὶ ἕτερον, ἀνάγκη εἶναι πρότερον τὸ αὐτὸ αὑτῷ κινοῦν. εἰ οὖν κινεῖται μὲν τοῦτο, μὴ ἄλλο δὲ τὸ κινοῦν αὐτό, ἀνάγκη αὐτὸ αὑτὸ (256b.) κινεῖν· ὥστε καὶ κατὰ τοῦτον τὸν λόγον ἤτοι εὐθὺς τὸ κινούμενον ὑπὸ τοῦ αὑτὸ κινοῦντος κινεῖται, ἢ ἔρχεταί ποτε εἰς τὸ τοιοῦτον. This same argument may also be stated in another way as follows. Every movent moves something and moves it with something, either with itself or with something else: e.g. a man moves a thing either himself or with a stick, and a thing is knocked down either by the wind itself or by a stone propelled by the wind. But it is impossible for that with which a thing is moved to move it without being moved by that which imparts motion by its own agency: on the other hand, if a thing imparts motion by its own agency, it is not necessary that there should be anything else with which it imparts motion, whereas if there is a different thing with which it imparts motion, there must be something that imparts motion not with something else but with itself, or else there will be an infinite series. If, then, anything is a movent while being itself moved, the series must stop somewhere and not be infinite. Thus, if the stick moves something in virtue of being moved by the hand, the hand moves the stick: and if something else moves with the hand, the hand also is moved by something different from itself. So when motion by means of an instrument is at each stage caused by something different from the instrument, this must always be preceded by something else which imparts motion with itself. Therefore, if this last movent is in motion and there is nothing else that moves it, it must move itself. So this reasoning also shows that when a thing is moved, if it is not moved immediately by something that moves itself, the series brings us at some time or other to a movent of this kind.
πρὸς δὲ τοῖς εἰρημένοις καὶ ὧδε σκοποῦσι ταὐτὰ συμβήσεται ταῦτα. εἰ γὰρ ὑπὸ κινουμένου κινεῖται τὸ κινούμενον πᾶν, ἤτοι τοῦτο ὑπάρχει τοῖς πράγμασιν κατὰ συμ βεβηκός, ὥστε κινεῖν μὲν κινούμενον, οὐ μέντοι διὰ τὸ κινεῖσθαι αὐτό, ἢ οὔ, ἀλλὰ καθ' αὑτό. And if we consider the matter in yet a third way we shall get this same result as follows. If everything that is in motion is moved by something that is in motion, ether this being in motion is an accidental attribute of the movents in question, so that each of them moves something while being itself in motion, but not always because it is itself in motion, or it is not accidental but an essential attribute.
πρῶτον μὲν οὖν εἰ κατὰ συμβεβηκός, οὐκ ἀνάγκη κινεῖσθαι τὸ κινοῦν. εἰ δὲ τοῦτο, δῆλον ὡς ἐνδέχεταί ποτε μηδὲν κινεῖσθαι τῶν ὄντων· οὐ γὰρ ἀναγκαῖον τὸ συμβεβηκός, ἀλλ' ἐνδεχόμενον μὴ εἶναι. ἐὰν οὖν θῶμεν τὸ δυνατὸν εἶναι, οὐδὲν ἀδύνατον συμβήσεται, ψεῦδος δ' ἴσως. ἀλλὰ τὸ κίνησιν μὴ εἶναι ἀδύνατον· δέδεικται γὰρ πρότερον ὅτι ἀνάγκη κίνησιν ἀεὶ εἶναι. Let us consider the former alternative. If then it is an accidental attribute, it is not necessary that that is in motion should be in motion: and if this is so it is clear that there may be a time when nothing that exists is in motion, since the accidental is not necessary but contingent. Now if we assume the existence of a possibility, any conclusion that we thereby reach will not be an impossibility though it may be contrary to fact. But the nonexistence of motion is an impossibility: for we have shown above that there must always be motion.
καὶ εὐλόγως δὲ τοῦτο συμβέβηκεν. τρία γὰρ ἀνάγκη εἶναι, τό τε κινούμενον καὶ τὸ κινοῦν καὶ τὸ ᾧ κινεῖ. τὸ μὲν οὖν κινούμενον ἀνάγκη κινεῖσθαι, κινεῖν δ' οὐκ ἀνάγκη· τὸ δ' ᾧ κινεῖ, καὶ κινεῖν καὶ κινεῖσθαι (συμμεταβάλλει γὰρ τοῦτο ἅμα καὶ κατὰ τὸ αὐτὸ τῷ κινουμένῳ ὄν· δῆλον δ' ἐπὶ τῶν κατὰ τόπον κινούντων· ἅπτεσθαι γὰρ ἀλλήλων ἀνάγκη μέχρι τινός)· τὸ δὲ κινοῦν οὕτως ὥστ' εἶναι μὴ ᾧ κινεῖ, ἀκίνητον. ἐπεὶ δ' ὁρῶμεν τὸ ἔσχατον, ὃ κινεῖσθαι μὲν δύναται, κινήσεως δ' ἀρχὴν οὐκ ἔχει, καὶ ὃ κινεῖται μέν, οὐχ ὑπ' ἄλλου δὲ ἀλλ' ὑφ' αὑτοῦ, εὔλογον, ἵνα μὴ ἀναγκαῖον εἴπωμεν, καὶ τὸ τρίτον εἶναι ὃ κινεῖ ἀκίνητον ὄν. Moreover, the conclusion to which we have been led is a reasonable one. For there must be three things—the moved, the movent, and the instrument of motion. Now the moved must be in motion, but it need not move anything else: the instrument of motion must both move something else and be itself in motion (for it changes together with the moved, with which it is in contact and continuous, as is clear in the case of things that move other things locally, in which case the two things must up to a certain point be in contact): and the movent—that is to say, that which causes motion in such a manner that it is not merely the instrument of motion—must be unmoved. Now we have visual experience of the last term in this series, namely that which has the capacity of being in motion, but does not contain a motive principle, and also of that which is in motion but is moved by itself and not by anything else: it is reasonable, therefore, not to say necessary, to suppose the existence of the third term also, that which causes motion but is itself unmoved.
διὸ καὶ Ἀναξαγόρας ὀρθῶς λέγει, τὸν νοῦν ἀπαθῆ φάσκων καὶ ἀμιγῆ εἶναι, ἐπειδή γε κινήσεως ἀρχὴν αὐτὸν εἶναι ποιεῖ· οὕτω γὰρ μόνως ἂν κινοίη ἀκίνητος ὢν καὶ κρατοίη ἀμιγὴς ὤν. So, too, Anaxagoras is right when he says that Mind is impassive and unmixed, since he makes it the principle of motion: for it could cause motion in this sense only by being itself unmoved, and have supreme control only by being unmixed.
ἀλλὰ μὴν εἰ μὴ κατὰ συμβεβηκὸς ἀλλ' ἐξ ἀνάγκης κινεῖται τὸ κινοῦν, εἰ δὲ μὴ κινοῖτο, οὐκ ἂν κινοίη, ἀνάγκη τὸ κινοῦν, ᾗ κινεῖται, ἤτοι οὕτω κινεῖσθαι ὥς γε κατὰ τὸ αὐτὸ εἶδος τῆς κινήσεως, ἢ καθ' ἕτερον. We will now take the second alternative. If the movement is not accidentally but necessarily in motion—so that, if it were not in motion, it would not move anything—then the movent, in so far as it is in motion, must be in motion in one of two ways: it is moved either as that is which is moved with the same kind of motion, or with a different kind—
λέγω δ' ἤτοι τὸ θερμαῖνον καὶ αὐτὸ θερμαίνεσθαι καὶ τὸ ὑγιάζον ὑγιάζεσθαι καὶ τὸ φέρον φέρεσθαι, ἢ τὸ ὑγιάζον φέρεσθαι, τὸ δὲ φέρον αὐξάνεσθαι. either that which is heating, I mean, is itself in process of becoming hot, that which is making healthy in process of becoming healthy, and that which is causing locomotion in process of locomotion, or else that which is making healthy is, let us say, in process of locomotion, and that which is causing locomotion in process of, say, increase.
ἀλλὰ φανερὸν ὅτι ἀδύνατον· δεῖ γὰρ μέχρι (257a.) τῶν ἀτόμων διαιροῦντα λέγειν, οἷον εἴ τι διδάσκει γεωμετρεῖν, τοῦτο διδάσκεσθαι γεωμετρεῖν τὸ αὐτό, ἢ εἰ ῥιπτεῖ, ῥιπτεῖσθαι τὸν αὐτὸν τρόπον τῆς ῥίψεως· ἢ οὕτως μὲν μή, ἄλλο δ' ἐξ ἄλλου γένους, οἷον τὸ φέρον μὲν αὐξάνεσθαι, τὸ δὲ τοῦτο αὖξον ἀλλοιοῦσθαι ὑπ' ἄλλου, τὸ δὲ τοῦτο ἀλλοιοῦν ἑτέραν τινὰ κινεῖσθαι κίνησιν. ἀλλ' ἀνάγκη στῆναι· πεπερασμέναι γὰρ αἱ κινήσεις. τὸ δὲ πάλιν ἀνακάμπτειν καὶ τὸ ἀλλοιοῦν φάναι φέρεσθαι τὸ αὐτὸ ποιεῖν ἐστὶ κἂν εἰ εὐθὺς ἔφη τὸ φέρον φέρεσθαι καὶ διδάσκεσθαι τὸ διδάσκον (δῆλον γὰρ ὅτι κινεῖται καὶ ὑπὸ τοῦ ἀνωτέρω κινοῦντος τὸ κινούμενον πᾶν, καὶ μᾶλλον ὑπὸ τοῦ προτέρου τῶν κινούντων). ἀλλὰ μὴν τοῦτό γε ἀδύνατον· τὸ διδάσκον γὰρ συμβαίνει μανθάνειν, ὧν τὸ μὲν μὴ ἔχειν τὸ δὲ ἔχειν ἐπιστήμην ἀναγκαῖον. But it is evident that this is impossible. For if we adopt the first assumption we have to make it apply within each of the very lowest species into which motion can be divided: e.g. we must say that if some one is teaching some lesson in geometry, he is also in process of being taught that same lesson in geometry, and that if he is throwing he is in process of being thrown in just the same manner. Or if we reject this assumption we must say that one kind of motion is derived from another; e.g. that that which is causing locomotion is in process of increase, that which is causing this increase is in process of being altered by something else, and that which is causing this alteration is in process of suffering some different kind of motion. But the series must stop somewhere, since the kinds of motion are limited; and if we say that the process is reversible, and that that which is causing alteration is in process of locomotion, we do no more than if we had said at the outset that that which is causing locomotion is in process of locomotion, and that one who is teaching is in process of being taught: for it is clear that everything that is moved is moved by the movent that is further back in the series as well as by that which immediately moves it: in fact the earlier movent is that which more strictly moves it. But this is of course impossible: for it involves the consequence that one who is teaching is in process of learning what he is teaching, whereas teaching necessarily implies possessing knowledge, and learning not possessing it.
ἔτι δὲ μᾶλλον τούτων ἄλογον, ὅτι συμβαίνει πᾶν τὸ κινητικὸν κινητόν, εἴπερ ἅπαν ὑπὸ κινουμένου κινεῖται τὸ κινούμενον· ἔσται γὰρ κινητόν, ὥσπερ εἴ τις λέγοι πᾶν τὸ ὑγιαστικὸν [καὶ ὑγιάζον] ὑγιαστὸν εἶναι, καὶ τὸ οἰκοδομητικὸν οἰκοδομητόν, ἢ εὐθὺς ἢ διὰ πλειόνων· λέγω δ' οἷον εἰ κινητὸν μὲν ὑπ' ἄλλου πᾶν τὸ κινητικόν, ἀλλ' οὐ ταύτην τὴν κίνησιν κινητὸν ἣν κινεῖ τὸ πλησίον, ἀλλ' ἑτέραν, οἷον τὸ ὑγιαστικὸν μαθητικόν, ἀλλὰ τοῦτο ἐπαναβαῖνον ἥξει ποτὲ εἰς τὸ αὐτὸ εἶδος, ὥσπερ εἴπομεν πρότερον. τὸ μὲν οὖν τούτων ἀδύνατον, τὸ δὲ πλασματῶδες· ἄτοπον γὰρ τὸ ἐξ ἀνάγκης τὸ ἀλλοιωτικὸν αὐξητὸν εἶναι. οὐκ ἄρα ἀνάγκη ἀεὶ κινεῖσθαι τὸ κινούμενον ὑπ' ἄλλου, καὶ τούτου κινουμένου· στήσεται ἄρα. ὥστε ἤτοι ὑπὸ ἠρεμοῦντος κινήσεται τὸ κινούμενον πρῶτον, ἢ αὐτὸ ἑαυτὸ κινήσει. ἀλλὰ μὴν καὶ εἴ γε δέοι σκοπεῖν πότερον αἴτιον κινήσεως καὶ ἀρχὴ τὸ αὐτὸ αὑτὸ κινοῦν ἢ τὸ ὑπ' ἄλλου κινούμενον, ἐκεῖνο πᾶς ἂν θείη· τὸ γὰρ αὐτὸ καθ' αὑτὸ ὂν ἀεὶ πρότερον αἴτιον τοῦ καθ' ἕτερον καὶ αὐτοῦ ὄντος. ὥστε τοῦτο σκεπτέον λαβοῦσιν ἄλλην ἀρχήν, εἴ τι κινεῖ αὐτὸ αὑτό, πῶς κινεῖ καὶ τίνα τρόπον. Still more unreasonable is the consequence involved that, since everything that is moved is moved by something that is itself moved by something else, everything that has a capacity for causing motion has as such a corresponding capacity for being moved: i.e. it will have a capacity for being moved in the sense in which one might say that everything that has a capacity for making healthy, and exercises that capacity, has as such a capacity for being made healthy, and that which has a capacity for building has as such a capacity for being built. It will have the capacity for being thus moved either immediately or through one or more links (as it will if, while everything that has a capacity for causing motion has as such a capacity for being moved by something else, the motion that it has the capacity for suffering is not that with which it affects what is next to it, but a motion of a different kind; e.g. that which has a capacity for making healthy might as such have a capacity for learn. the series, however, could be traced back, as we said before, until at some time or other we arrived at the same kind of motion). Now the first alternative is impossible, and the second is fantastic: it is absurd that that which has a capacity for causing alteration should as such necessarily have a capacity, let us say, for increase. It is not necessary, therefore, that that which is moved should always be moved by something else that is itself moved by something else: so there will be an end to the series. Consequently the first thing that is in motion will derive its motion either from something that is at rest or from itself. But if there were any need to consider which of the two, that which moves itself or that which is moved by something else, is the cause and principle of motion, every one would decide the former: for that which is itself independently a cause is always prior as a cause to that which is so only in virtue of being itself dependent upon something else that makes it so. We must therefore make a fresh start and consider the question; if a thing moves itself, in what sense and in what manner does it do so?
Postquam philosophus ostendit quod omne quod movetur ab alio movetur, hic incipit ostendere quod necesse est devenire ad aliquod primum movens immobile. Et dividitur in partes duas: in prima ostendit quod necesse est devenire ad aliquod primum, quod vel sit immobile, vel moveat seipsum; in secunda ostendit quod etiam si deveniatur ad aliquod primum quod moveat seipsum, necesse est tamen ulterius devenire ad aliquod primum movens immobile, ibi: necesse igitur omne quod movetur et cetera. 1037. After showing that whatever is moved is moved by another, the Philosopher now begins to show that it is necessary to reach a first immobile mover. And his treatment is divided into two parts. In the first he shows that it is necessary to reach a first that is either immobile or moves itself; In the second he shows that even if a first that moves itself is reached, it is further necessary to reach a first mover that is immobile, (L.10).
Circa primum duo facit: primo ostendit quod non est possibile quod in infinitum aliquid ab alio moveatur; in secunda quod non est necessarium quod omne movens moveatur, ibi: ad dicta autem et cetera. About the first he does two things: First he shows that it is not possible that things be moved by another ad infinitum; Secondly, he shows that not every mover need be moved, at 1042.
Circa primum duo facit: primo ostendit propositum ascendendo in ordine mobilium et moventium; secundo descendendo, ibi: amplius autem et sic ipsam et cetera. About the first he does two things: First he explains the proposition by ascending in the order of mobiles and movers; Secondly, by descending, at 1041.
Circa primum duo facit: primo praemittit quaedam necessaria ad propositi ostensionem; secundo inducit rationem ad propositum ostendendum, ibi: si ergo necesse et cetera. About the first he does two things: First he premises things needed for manifesting his proposition; Secondly, he gives an argument that shows the proposition, 1040.
Praemittit autem duo: quorum primum est divisio moventis. Cum enim dictum sit quod omne motum ab aliquo movetur, contingit aliquid esse movens dupliciter. Uno modo quando non movet propter seipsum, idest propria virtute, sed quia est motum ab aliquo alio movente; et hoc est secundum movens. Alio modo aliquid movet propter seipsum, idest propria virtute, non quia est motum ab alio. Contingit autem quod tale movens moveat dupliciter. Uno modo ita quod primum movens moveat proximum post ultimum, idest id quod est sibi proximum post secundum movens; et hoc contingit quando primum movens movet mobile per unum tantum medium. Alio vero modo movens movet mobile per plura media, ut patet cum baculus movet lapidem et movetur a manu, quae movetur ab homine, qui non movet eo quod ab aliquo alio moveatur: sic ergo homo est primum movens propter seipsum, et movet lapidem per plura media; si autem moveret lapidem manu, moveret per unum medium tantum. 1038. Now he premises two things, of which the first (806) is a division of movers. For since it has been said that whatever is moved is moved by something, a thing might be a mover in two senses. In one sense, when it moves not on its own account, i.e., not by its own power, but because it has been moved by some other mover. This is a second mover. In another sense, something moves on its own account, i.e., by its own power and not because it has been moved by another. Now, such a mover can cause motion in two ways: First, in such a way that the first mover moves the one next to the last, i.e., the one which is nearest to it after the second mover; this happens when the first mover moves a mobile through just one intermediate. Secondly, in such a way that the mover moves a mobile through a number of intermediates, as when a stick moves a stone and the stick is moved by a hand, which is moved by a man who does not move as being moved by something else. In this way the man is a first mover on his own account and he moves the stone through a number of intermediates; however, if he moved the stone with his hand, he would be moving the tone through one intermediate only.
Secundo ibi: utraque igitur movere dicimus etc., ponit comparationem primi moventis et secundi. Cum enim tam primum movens quam ultimum movere dicamus, dicimus quod magis movet primum movens quam ultimum. Et hoc patet per duas rationes. Quarum prima est, quod primum movens movet secundum movens, sed non e converso. Secunda ratio est, quia secundum movens non potest movere sine primo, sed primum movens potest movere sine secundo; sicut baculus non potest movere lapidem nisi moveatur ab homine, sed homo potest movere etiam sine baculo. 1039. Secondly, at (807) he compares the first mover with the second. For since both the first mover and the ultimate are said to cause motion, we say that the first mover is more a mover than the ultimate mover. This is clear for two reasons: first, because the first mover moves the second mover but not vice versa; secondly, because the second mover cannot cause motion independently of the first, but the first can cause it independently of the second. For example, the stick cannot move the stone unless it is moved by the man, but the man can move the stone without using the stick.
Deinde cum dicit: si ergo necesse etc., ostendit propositum secundum praemissa. Ostensum est enim quod omne quod movetur, ab aliquo movetur. Illud autem a quo movetur, aut movetur aut non movetur; et si movetur, aut ab alio movetur aut non. Haec autem duo, scilicet quod movetur ab alio, et quod movetur non ab alio, sic se habent quod posito uno ponitur aliud, et non e converso. Quia si sit aliquid quod movetur ab alio, necesse est devenire ad aliquod primum quod non movetur ab alio; sed si ponatur aliquod primum huiusmodi, scilicet quod non moveatur ab alio, non est necessarium ulterius ponere alterum, scilicet quod movetur ab alio. 1040. Then at (808) he proves his proposition in the light of the foregoing. For it has been shown that whatever is being moved is being moved by another. But that by which it is moved is itself either moved or not moved; and if it is moved, it is either moved by another or not. Now these two, namely, being moved by another or not being moved by another, are such that if one is posited the other must be and not vice versa: that is, if there is something which is moved by another, it is necessary to come to a first that is not moved by another; but if such a first is posited, namely, a first that is not moved by another, it is not necessary further to posit another, namely, one that is moved by another.
Et hoc quidem per se manifestum est: sed primum poterat esse dubium, scilicet quod si invenitur aliquid quod movetur ab alio, quod inveniatur aliquod primum quod non movetur ab alio; et ideo consequenter hoc probat sic. This, indeed, is self-evident, but there could be some doubt about the first one, namely, that if there be found something moved by another, there be found a first that is not moved by another. For this reason, he proves this in the following manner.
Quia si aliquid movetur ab alio, et iterum illud ab alio, et nunquam est devenire ad aliquid quod non moveatur ab alio, sequitur quod sit procedere in infinitum in moventibus et motis. Et hoc quidem esse impossibile, supra probatum est in septimo: sed hic probat certiori via, quia in infinitis non est aliquid primum. Si ergo moventia et mota procedant in infinitum, non erit aliquid primum movens. Iam autem dictum est, quod si primum movens non movet, nec ultimum movet: non ergo erit aliquod movens: quod est manifeste falsum. Non est ergo procedere in infinitum in hoc quod aliquid moveatur ab alio. Si ergo detur quod omne quod movetur ab aliquo movetur, ut ostensum est; et iterum supponatur quod primum movens movetur: cum probatum sit quod non moveatur ab alio, necesse est quod moveatur a seipso. If something is moved by another and this in turn by another, and if something not moved by another is never reached, it follows that there is a process to infinity in movers and moved things. But this is impossible, as was proved in Book VII. However, he here proves it in a more certain way, from the fact that there is no first in an infinite series. Therefore, if movers and moved things go on ad infinitum, there will be no first mover. But it has already been said that if the first mover does not act, the last mover does not act and, consequently, there will be no mover, which is evidently false. Therefore, the process of something being moved by another cannot go on ad infinitum. If, therefore, it be conceded that whatever is being moved is being moved by another, as has been proved, and again, if it be supposed that the first mover is itself being moved but not by something else, it is necessarily being moved by itself.
Est autem in hac ratione attendendum, quod primum movens moveri non est hic probatum; supponit autem hoc secundum communem opinionem Platonicorum. Quantum autem ad virtutem rationis, non magis concluditur quod primum movens moveat seipsum, quam quod sit immobile: unde in sequentibus hanc eandem conclusionem sub disiunctione inducit, ut infra patebit. It should be noted that this argument is not proving that the first mover is being moved, but he is supposing this according to the common opinion of the Platonists. As to the force of the argument, it does not conclude more that the first mover moves itself than that it is immobile. Hence he later presents this same conclusion under a disjunction, as will be clear below.
Deinde cum dicit: amplius autem et sic ipsam etc., probat idem descendendo. Et est eadem ratio cum praemissa quantum ad virtutem inferendi, differens autem secundum ordinem processus: iterat autem eam ad maiorem manifestationem. 1041. Then at (809) he proves his proposition by descending. And it is the same argument as the preceding so far as its illative value is concerned, but differs with respect to the order of the process; he repeats it, however, for the sake of greater clarity.
Dicit ergo quod praedictam rationem contingit alio modo prosequi. Et praemittit propositiones habentes eandem rationem veritatis cum supra praemissis, sed alio ordine. Supra enim praemisit quod omne quod movetur ab alio movetur, et quod illud a quo movetur, movet vel propter seipsum, vel propter aliud prius movens; quod erat procedere ascendendo. He says therefore that the previous argument might be presented in another way. And he premises propositions that have the same truth value as the previous ones, but in a different order. For above he had premised that whatever is being moved is being moved by another and that that by which it is moved acts either on its own account or on account of something else previously moving it; and this was an ascending process.
Hic autem e converso descendendo procedit, dicens quod omne movens movet aliquid et movet aliquo, vel seipso vel alio inferiori movente; sicut homo movet lapidem vel ipse per seipsum vel per baculum, et ventus proiicit ad terram aliqua aut suo impulsu aut per lapidem quem movit. But now he uses a descending process, saying that every mover moves something and moves by means of something, i.e., either by itself or by means of some lesser mover, as a man moves a stone either by himself or by means of a stick and the wind casts something to the earth either by its own impulse or by means of a stone which it moves.
Iterum supra praemiserat quod ultimum movens non movet sine primo, sed e converso: loco cuius hic dicit, quod id quo aliquid movet sicut instrumento, impossibile est quod aliquid moveat sine principali movente quod movebat ipsum, sicut baculus sine manu; sed si aliquid movet per seipsum sicut principale movens, non est necesse esse aliud instrumentum quo moveat. Et hoc magis manifestum est in instrumentis quam in mobilibus ordinatis, licet habeat eandem veritatem; quia non quilibet consideraret secundum movens esse instrumentum primi. Sicut etiam supra dixerat deducendo, quod si sit aliquid quod movetur ab alio, necesse est esse aliquid quod non movetur, sed non e converso: ita hic dicit descendendo, quod si inveniatur quod illud quo movens movet, sit alterum, sicut instrumentum, necesse est esse aliquid quod movebit non aliquo instrumento, sed per seipsum, aut procedetur in infinitum in instrumentis; quod est idem ac si procederetur in infinitum in moventibus, quod est impossibile, ut supra ostensum est. Again, he had premised above that the last mover does not cause motion independently of the first mover, but vice versa. In place of that he here says that what a mover uses as an instrument in causing motion cannot itself cause motion without a principal mover moving it, as a stick cannot cause motion independently of the hand; but if something moves by itself as a principal mover, the addition of an instrument is not required. And this is more evident in instruments than in an ordered array of mobiles, although the same truth is present in both cases, because not every one would consider the second mover an instrument of the first. But as he deduced above that, if there is something that is being moved by another, there must be something that is not being moved, but not vice versa, so here in a descending process he says that if that by which the mover causes motion is another thing, as an instrument, there has to be something which causes motion not by an instrument but by itself. Otherwise, there is an infinite process with respect to instruments, which is the same as proceeding to infinity with respect to movers, and that is impossible, as has been proved above.
Si ergo est aliquid movens id quod movetur, necesse est stare et non in infinitum ire. Quia si baculus movet eo quod movetur a manu, sequitur quod manus moveat baculum; si autem et manum aliquid aliud movet, etiam sequitur e converso quod aliquod movens moveat manum; et ita oportet quod sicut proceditur in instrumentis motis, ita procedatur in moventibus quae movent instrumenta. Non est autem procedere in infinitum in moventibus, ut supra ostensum est; ergo neque in instrumentis. Cum ergo semper alterum quod movetur, moveatur alio movente, et non sit procedere in infinitum; necesse est esse aliquod primum movens quod moveat per seipsum, et non per aliquod instrumentum. If, therefore, there exists a mover of that which is being moved, a halt must be made and the process cannot go to infinity. For if the stick causes motion because it is moved by the hand, it follows that the hand moves the stick; if, however, something else is moving the hand, it also follows conversely that a mover is moving the hand. Consequently, the same process that was valid with respect to moved instruments is valid for movers of instruments. But with respect to movers, as was shown, an infinite process must be avoided; therefore, it must be avoided with respect to instruments. Therefore, since it is always so that a thing being moved is moved by another which moves, and an infinite process must be avoided, it is necessary that there be a first mover that moves by itself and not through an instrument.
Si ergo detur quod hoc primum quod movet per seipsum, movetur quidem, sed non est aliquid aliud movens ipsum (quia sic et ipsum esset instrumentum); sequitur ex necessitate quod ipsum seipsum moveat: supposito, secundum Platonicos, quod omne movens movetur. If, therefore, it be granted that this first which moves itself is indeed moved but there is no other moving it (because then it would be an instrument), it follows of necessity that it is moving itself—following the supposition of the Platonists that every mover is moved.
Unde et secundum istam rationem illud quod movetur, aut statim movebitur a movente quod movet seipsum, aut aliquando erit devenire in aliquod tale movens quod seipsum moveat. Hence also according to this argument, either what is being moved will be immediately moved by a mover that moves itself, or at some time such a mover that moves itself must be reached.
Deinde cum dicit: ad dicta autem etc.; ostendit quod non omne movens movetur, ut in prioribus rationibus supponebatur. Et circa hoc duo facit: primo probat quod non omne movens movetur; secundo tam ex hoc quam ex superioribus rationibus concludit principale propositum, ibi: non ergo necesse semper moveri et cetera. 1042. Then at (810) he shows that not every mover is being moved, as was supposed in the preceding arguments. About this he does two things: First he proves that not every mover is being moved; Secondly, from this and from the previous arguments he concludes to his main proposition, at 1049.
Dicit ergo primo, quod supra praedicta possunt etiam addi haec ad nostrum propositum ostendendum. Et circa hoc tria facit: primo praemittit quandam divisionem; secundo destruit unam partem, ibi: primum quidem igitur etc.; tertio destruit aliam partem, ibi: at vero si non secundum accidens et cetera. He says therefore first that to the above-mentioned things may be added the following in order to show our proposition. About this he does three things: First he premises a division; Secondly, he rejects one member$ at 1043; Thirdly, he rejects another, at 1046.
Dicit ergo primo, quod si omne quod movetur, movetur ab eo quod movetur, quod est omne movens moveri, hoc potest esse dupliciter: uno modo quod hoc inveniatur per accidens in rebus ut movens moveatur, ita scilicet quod movens non moveat propter id quod movetur (ut si dicamus aedificatorem esse musicum, non quia musicus est, sed per accidens); aut non est per accidens quod movens moveatur, sed per se. He says therefore first (830) that if whatever is being moved is being moved by another, which is tantamount to saying that every mover is moved, this can be in two ways: in one way, that it is per accidens in things that a mover is moved, i.e., the mover does not act in virtue of being moved (as if we should say that a musician is a builder not because he is a musician, but this is per accidens); or in a second way, that it is not per accidens but per se that a mover is moved.
Deinde cum dicit: primum quidem etc., destruit primum membrum tripliciter. Primo quidem tali ratione. Nihil quod est per accidens, est necessarium: quod enim inest alicui per accidens, non ex necessitate inest ei, sed contingit non inesse, sicut musicum aedificatori. Si igitur moventia per accidens moventur, sequitur quod contingat ea non moveri; sed cum tu ponas quod omne movens movetur, consequens est quod si non moventur moventia, quod non moveant; sequitur ergo quod aliquando nihil moveatur. Hoc autem est impossibile, quia ostensum est supra, quod necesse est motum semper esse. Istud autem impossibile non sequitur ex hoc quod supposuimus moventia non moveri: quia si hoc est per accidens quod movens moveatur, moventia non moveri erit possibile; possibili autem posito, nullum sequitur impossibile. Relinquitur ergo quod aliud ex quo sequitur, sit impossibile, scilicet quod omne movens moveatur. 1043. Then at (811) he rejects the first member in three ways. First, with this argument: Nothing per accidens is necessary, for what is in a thing per accidens is not present of necessity, but may happen not to be present, as musician in a builder. If, therefore, it is per accidens that movers are moved, it follows that it can happen that they not be moved. But once you posit that every mover is moved, it is a consequence, if movers are not moved, that they do not cause motion. It follows, therefore, that at some time, nothing is being moved. But this is impossible, for it has been proved above that it is necessary that motion always exist. This impossibility, however, does not follow from the supposition that movers are not moved; because if it is per accidens that a mover is moved, it will be possible for movers not to be moved, and if a possibility is posited, no impossibility follows. It remains, therefore, that the other statement from which it (the cessation of motion) followed is impossible, namely, the statement that every mover is moved.
Secundo ibi: et rationabiliter hoc accidit etc., probat idem alia probabili ratione: quae talis est. In motu tria inveniuntur: quorum unum est mobile quod movetur, aliud autem est movens, tertium est instrumentum quo movens movet. In istis autem tribus manifestum est quod id quod movetur, necesse est moveri, sed non est necesse quod moveat. Instrumentum autem quo movens movet, necesse est et movere et moveri (movetur autem a principali movente, et movet ultimum motum): unde et omne quod movet et movetur, habet rationem instrumenti. 1044. Secondly, at (812) he proves the same with another probable argument, which is this: Three things are found in motion: one is the mobile that is being moved; another is the mover, and the third is the instrument by which the mover causes motion. Now among these three, it is clear that the thing which is moved has to be moved, but it does not have to cause motion. The instrument, however, by which the mover causes motion, must both move and be moved—it is moved by the principal mover and it moves the last thing moved. For this reason, whatever “moves and is moved” has the character of an instrument.
Ideo autem instrumentum quo movens movet, et movetur et movet, quia communicat cum utroque, existens in quadam identitate ad id quod movetur. Et hoc maxime manifestum est in motu locali: necesse est enim quod a primo movente usque ad ultimum motum, omnia se tangant ad invicem; et sic patet quod instrumentum medium est idem per contactum cum mobili, et sic simul movetur cum ipso, inquantum communicat ipsi. Sed etiam communicat moventi, quia est movens; hoc modo tamen ut instrumentum quo movet, non sit immobile. Now, the reason why the instrument by which the mover causes motion both is moved and moves is that it partakes of both and exists in a sort of identity to what is moved. This is especially evident in local motion, for it is necessary that from the first mover to the last thing moved, all must touch one another. Accordingly, it is evident that an intermediate instrument is through contact the same as the mobile and is moved at once with it, insofar as it is in union with it. But it is also in union with the mover, because it is a mover—although under its aspect as the instrument by which the mover causes motion, it is not immobile.
Sic igitur ex praemissis apparet quod ultimum motum movetur quidem, sed non habet in se principium movendi neque seipsum neque aliud; et movetur quidem ab alio, sed non a seipso. Unde videtur esse rationabile, idest probabile (nec ad praesens curamus dicere quod sit necessarium), esse aliquod tertium, quod moveat cum sit immobile. Accordingly, therefore, it appears from the premises that the last thing moved is, indeed, being moved but it does not have in itself a principle for moving either itself or anything else, and it is moved indeed by something else and not by itself. Hence, it seems to be reasonable, i.e., probable (and in the present case we do not care to say that it is necessary) that there be a third thing which causes motion but is immobile.
Probabile enim est, quod si aliqua duo coniunguntur per accidens, et unum invenitur sine alio, quod etiam aliud inveniatur sine illo (sed quod possit inveniri sine illo, hoc est necessarium; quia quae per accidens coniunguntur, contingit non coniungi): sicut si album et dulce per accidens coniunguntur in zuccaro, et album invenitur sine dulci, ut in nive, probabile est quod et dulce inveniatur in aliqua re sine albo, ut in cassia. Si igitur movens moveri est per accidens, et invenitur moveri absque movere in aliquo, sicut in ultimo moto; probabile est quod inveniatur movere absque moveri, ut sit aliquod movens quod non movetur. For it is probable that if two things are joined per accidens, and one is found without the other, then the other might be found without it (but that it may be found without the other is necessary, because things joined per accidens may happen to be not joined); for example, if white and sweet are joined per accidens in sugar, and if white is found without sweet, as in snow, it is probable that sweet be found in some thing without white, as in cheese. If, therefore, it is per accidens that a mover be moved and something is found to be moved without moving something else, as happens in the last thing moved, it is probable that one may find moving without being moved, so that there would be a mover that is not moved.
Ex quo patet quod ista ratio non habet instantiam in substantia et accidente, et materia et forma, et in similibus, quorum unum invenitur sine alio sed non e converso: accidens enim per se inest substantiae, et materiae per se convenit ut habeat esse per formam. From this it is evident that this argument does not have force in substance and accident, and in matter and form, and in like things, of which one is found without the other but not vice versa; for accident per se exists in a substance, and to matter it belongs per se to have existence through form.
Tertio ibi: unde Anaxagoras dicit etc., probat idem testimonio Anaxagorae. Quia enim contingit inveniri aliquod movens quod non movetur, ideo Anaxagoras recte dixit, ponens intellectum impassibilem et immixtum. Et hoc ideo, quia ipse ponebat intellectum primum principium motus: sic autem solummodo poterit movere et imperare, absque hoc quod moveatur, si sit immixtus: quod enim commiscetur alteri, movetur quodammodo ad motum ipsius. 1045. Thirdly, at (813) he proves the same point on the testimony of Anaxagoras. For since it may be that a mover be found that is not moved, Anaxagoras spoke aright when he said that Mind is impassible and unmingled. He said this because he posited Mind as the first principle of motion, and the only way it could cause motion and command, without itself being moved, was that it be unmingled—for what is mingled with something else is in a certain way moved when that something else is moved.
Deinde cum dicit: at vero si non secundum accidens etc., prosequitur aliam partem divisionis; scilicet quod omne quod movetur, movetur ab aliquo quod movetur per se et non secundum accidens. 1046. Then at (814) he concentrates on the other part of the division, namely, that whatever is moved, is being moved by another which is moved per se and not according to an accident.
Et improbat hoc duabus rationibus: quarum prima talis est. Si hoc non est secundum accidens sed ex necessitate ut movens moveatur, et nunquam possit movere nisi moveatur, oportet hoc contingere duobus modis: quorum unus est ut movens moveatur secundum eandem speciem motus qua movet; alius est ut movens secundum unam speciem motus moveat, secundum alteram moveatur. Exponit autem consequenter primum modum, cum dicit: dico autem et cetera. Sic enim dicimus movens moveri secundum eandem speciem motus, puta si calefaciens calefiat, et sanans sanetur, et ferens secundum locum feratur. And he disproves this with two arguments, the first of which is: If it is not according to an accident but of necessity that a mover be moved and if it can never cause motion unless it is moved, this must happen in two ways: one of which is that the mover is moved according to the same species of motion as that which it causes; the other is that the mover moves according to one species of motion, and is moved according to another. He subsequently explains the first way at (815): We say that a mover is being moved according to the same species of motion if, for example, the thing that causes heating is heated, and the healer is healed, and something carrying locally is itself being carried locally.
Et secundum modum exponit cum dicit: vel sanans feratur, vel ferens augeatur; hoc enim est ut secundum aliam speciem motus moveat et moveatur. He explains the second way when he says: “Or else the healer is carried along, or the thing carrying along is growing.” These are examples of “moving and being moved” according to different species of motion.
Deinde ostendit impossibilitatem primi modi, cum dicit: sed manifestum et cetera. Manifestum est enim impossibile esse quod movens secundum eandem motus speciem moveatur. Non enim sufficiet stare in aliqua specie subalterna, sed oportebit pervenire per divisionem usque ad individua, idest usque ad species specialissimas: puta si aliquis doceat, non solum doceatur, sed idem doceat et doceatur; puta si docet geometriam, quod hoc idem doceatur; aut si movet specie motus localis quae est proiectio, quod secundum eundem motum proiectionis moveatur: et hoc est manifeste falsum. Then he shows the impossibility of the first way, at (816). For it is clearly impossible that a mover be moved according to the same species of motion. For it is not sufficient to stop at some subalternate species, but one Must divide until he reaches the “individuals,” i.e., the most special species. For example, if someone is teaching, it is not enough for him simply to be taught at the same time, but he must be teaching and being taught the same; e.g., if he is teaching geometry he must be at the same time being taught it; or if he is the cause of a local motion called throwing, he must himself be moved according to the same motion of throwing. This is clearly false.
Deinde destruit secundum modum, ut scilicet non moveatur movens secundum eandem speciem motus, sed quod movet uno genere motus, moveatur alio genere: puta quod movet secundum locum, moveatur per augmentum; et quod movet per augmentum, moveatur ab aliquo alio per alterationem; et illud alterans moveatur secundum aliquem alium motum. Then he dismisses the second ways namely, that the mover not be moved according to the same species of motion, but that it move according to one species and be moved according to another; for example, if it moves with a local motion, and is being moved with respect to growth; and if what causes the growth is being moved by some thing else according to alteration; and if this mover in turn is being moved with respect to some other motion.
Manifestum est autem quod motus non sunt infiniti, neque secundum genus neque secundum speciem. Est enim habitum in quinto, quod motus differunt genere et specie secundum differentias rerum in quibus sunt motus: genera autem rerum et species non sunt infinitae, ut alibi probavit; et sic neque genera aut species motus. Si ergo movens necesse est moveri alio genere aut alia specie motus, non erit procedere in infinitum, sed erit aliquod primum movens immobile. Now it is clear that motions are not infinite either in genus or species. For it was held in Book V that motions differ in genus and species according to the differences of the species in which motion occurs. But the genera and species of things are not infinite, as we proved elsewhere; accordingly, neither are the genera and species of motion. If, therefore, a mover is necessarily being moved according to some other genus or species of motion, one will not be able to proceed to infinity and there will be some first immobile mover.
Sed quia posset aliquis dicere, quod quando deficient omnes species motus, iterum redibitur ad primam; ut scilicet si primum motum acceptum movebatur localiter, distributis omnibus generibus et speciebus motuum per diversos motores, motor qui residuus erit movebitur motu locali: ad hoc excludendum consequenter dicit, quod tantum valet sic reflectere, ut dicatur quod alterans feratur (quod dicit, quia motum localem supra prius nominaverat, et alterationem ultimo) sic inquam reflectere idem est ac si statim a principio dicatur quod movens secundum locum movetur; et non solum in genere sed in specie, quod docens docetur. 1047. But because someone could say that when all the species of motion are exhausted, a return will be made to the first species, in such a way that if the first thing taken as moved was moved locally, and we distributed all the genera and species of motion to different movers until these genera and species were exhausted, the remaining mover will then be moved according to local motion, in order to exclude this he subsequently says that such a return is tantamount to saying that the cause of alteration is being moved locally (he uses this explanation because above in his example he mentioned local motion first and alteration last), the same, I say, as supposing from the very beginning that the mover according to local motion is being moved, and that the teacher is being taught not only generically but in the specific sense.
Et quod hoc tantundem valeat, probat consequenter. Omne enim quod movetur, magis movetur a superiori movente quam ab inferiori, et per consequens multo magis a primo movente. Si ergo id quod ponebatur moveri localiter, movetur a propinquo quidem movente quod augetur, ulterius autem ab eo quod alteratur, ultra autem ab eo quod movetur secundum locum: hoc quod movetur secundum locum, magis movebitur a primo quod movetur secundum locum, quam a secundo quod alteratur, aut a tertio quod augetur. And that this means nothing more, he proves consequently. For whatever is being moved is moved more by the higher mover than by the lower one, and, consequently, much more so by the first mover. If, therefore, the thing posited as being moved locally is being moved by a neighboring mover that is being increased, and it by a mover that is being altered, and it further by one that is being moved according to place, what is being moved according to place will be more moved by the first one moved according to place than by the second one which is being altered or by the third one which is being increased.
Ergo erit verum dicere quod movens secundum locum, movetur secundum locum; et similiter secundum unamquamque speciem motus. Hoc autem non solum est falsum, quia videtur instantiam habere in multis, sed etiam est impossibile. Sequeretur enim quod docens addiscat dum docet; quod est impossibile. Includit enim hoc contradictionem; quia de ratione docentis est quod habeat scientiam, de ratione autem addiscentis quod non habeat. Sic ergo patet quod non est necessarium movens moveri. Therefore it will be true to say that the mover according to place is being moved according to place, and the same for every sphere of motion. Now this is not only false, because it is seen to be belied in many cases, but it is also impossible. For it would follow that the teacher is learning while he is teaching—which is impossible. For this involves a contradiction, since it is the property of a teacher that he have science, and of a learner that he not have it. Accordingly, it is clear that it is not necessary for a mover to be moved.
Secundam rationem ponit ibi: amplius autem his magis irrationabile etc.: quae non differt a praecedenti nisi in hoc, quod prima deducebat ad quaedam inconvenientia particularia, puta quod proiiciens proiiceretur, aut docens addisceret; haec autem ducit ad inconveniens in communi. 1048. He gives a second argument at (817) which does not differ from the preceding one except in that the first leads to certain particular inconsistencies, for example, that a thrower would be thrown or that a teacher would be being taught. But this one leads to inconsistencies in general.
Unde dicit quod licet inconveniens sit quod docens addiscat, tamen adhuc est magis irrationabile; quia accidit quod omne motivum sit mobile, si nihil movetur nisi ab eo quod movetur. Sic enim sequetur quod omne movens sit mobile; puta si dicatur quod omne quod habet virtutem sanandi aut quod sanat in actu, est sanabile, et quod habet virtutem aedificandi, est aedificabile: quod est magis irrationabile quam quod docens addiscat; quia docens potuit prius addiscere, sed aedificans nunquam fuit aedificatus. Hence he says that although it is inconsistent that a teacher be learning, there is something still more unreasonable, for it turns out that every mover is mobile, if nothing is moved except by what is being moved. For it will thus follow that every mover is mobile, if, for example, one says that whatever has the power to heal, or is actually causing health, is healable, and that whatever has the power to build is buildable—which is more unreasonable than that a teacher be learning, for a teacher could have been learning before, but a builder was never built.
Hoc autem dupliciter sequitur. Si enim detur quod omne movens movetur secundum eandem speciem motus, sequitur quod mox, idest immediate, aedificans aedificetur et sanans sanetur: si autem detur quod non per eamdem speciem motus movens movetur, sequitur quod per plura media tandem in hoc veniatur. Et hoc exponit: quia si omne quod movet movetur ab alio, sed tamen non movetur secundum eundem motum statim quo movet, sed secundum alterum motum; puta si aliquid sit sanativum, non statim ipsum sanetur, sed moveatur motu disciplinae addiscendo: tamen, cum non sint infinitae species motus, sic ascendendo de mobili ad movens, pervenietur quandoque ad eandem speciem motus, sicut supra expositum est. Now this follows in two ways. For if it be conceded that every mover is being moved with respect to the same species of motion, it follows that a builder is being built immediately (i.e., without intermediary) and that a healer is being healed immediately. But if it be conceded that the mover is not being moved according to the same species of motion, it follows that we shall finally come to this after passing through a number of intermediates. And he explains this: If every mover is being moved by another but not being moved immediately with respect to the same species in which he is causing motion but according to some other species—for example, if a healer is not at once being healed but is being moved according to the motion of discipline by learning—yet, since the species of motion are not infinite, by thus ascending from mobile to mover one will at length reach the same species of motion, as was explained above.
Horum ergo duorum unum apparet manifeste impossibile, puta quod aedificans mox aedificetur; aliud autem videtur esse fictitium, scilicet quod per multa media in hoc veniatur. Inconveniens enim est, quod id quod natum est alterare, ex necessitate sit natum augmentari. Therefore, of these two, one appears plainly impossible, e.g., that the builder be immediately being built, while the other is seen as a fancy, namely, that one come to the same thing through a number of intermediates. For it is unacceptable that what is apt to cause alteration is of necessity apt to be increased in size.
Sic ergo consideratis praemissis rationibus, quarum primae concludebant quod non in infinitum hoc procedit, quod omne quod movetur moveatur ab alio; et secundae concludebant quod non omne movens moveatur: possumus ex omnibus praedictis rationibus concludere, quod non est necesse in infinitum quod moveatur ab alio moveri, ita quod semper movetur a movente quod movetur. Ergo necesse est quod stetur in aliquo primo. Hoc autem primum oportet quod vel sit immobile, vel sit movens seipsum. 1049. Accordingly, (818) having considered the foregoing arguments, the first of which concluded that this process—that whatever is being moved is being moved by another—must not go on ad infinitum, and the second of which concluded that not every mover is being moved, we can conclude from all the foregoing arguments that it is not necessary ad infinitum that what is being moved be moved by another in such a way that it is always being moved by a mover that is being moved. Therefore, it is necessary to stop at some first. However, this first must either be immobile or be moving itself.
Sed si consideretur quae sit prima causa motus in genere mobilium, utrum illud quod movet seipsum, aut mobile quod movetur ab alio: probabile est apud omnes, quod primum movens sit movens seipsum. Semper enim causa quae est per se, est prior ea quae est per alterum. Et propter hanc rationem Platonici posuerunt ante ea quae moventur ex alio, esse aliquid quod movet seipsum. But if we are considering which is the first cause of motion in the genus of mobiles, whether it is something that moves itself or a mobile that is moved by another, it is held as probable among all that the first mover moves itself. For a per se cause is always prior to what is a cause through another. For this reason, the Platonists held that prior to things that are moved by another there is something that moves itself.
Et ideo considerandum est de eo quod movet seipsum, facientes ex hoc aliud principium nostrae considerationis: scilicet ut consideremus, si aliquid movet seipsum, quomodo hoc est possibile. And therefore we must consider this thing that moves itself and make of this another beginning of our consideration, namely, that we consider that if something moves itself, how is this possible.

Lectio 10
In that which moves itself, one part moves and the other is moved.
Chapter 5 cont.
ἀναγκαῖον δὴ τὸ κινούμενον ἅπαν εἶναι διαιρετὸν εἰς ἀεὶ διαιρετά· τοῦτο γὰρ δέδεικται πρότερον ἐν τοῖς (257b.) καθόλου τοῖς περὶ φύσεως, ὅτι πᾶν τὸ καθ' αὑτὸ κινούμενον συνεχές. ἀδύνατον δὴ τὸ αὐτὸ αὑτὸ κινοῦν πάντῃ κινεῖν αὐτὸ αὑτό· Now everything that is in motion must be infinitely divisible, for it has been shown already in our general course on Physics, that everything that is essentially in motion is continuous. Now it is impossible that that which moves itself should in its entirety move itself:
φέροιτο γὰρ ἂν ὅλον καὶ φέροι τὴν αὐτὴν φοράν, ἓν ὂν καὶ ἄτομον τῷ εἴδει, καὶ ἀλλοιοῖτο καὶ ἀλλοιοῖ, ὥστε διδάσκοι ἂν καὶ μανθάνοι ἅμα, καὶ ὑγιάζοι καὶ ὑγιάζοιτο τὴν αὐτὴν ὑγίειαν. for then, while being specifically one and indivisible, it would as a Whole both undergo and cause the same locomotion or alteration: thus it would at the same time be both teaching and being taught (the same thing), or both restoring to and being restored to the same health.
ἔτι διώρισται ὅτι κινεῖται τὸ κινητόν· τοῦτο δ' ἐστὶν δυνάμει κινούμενον, οὐκ ἐντελεχείᾳ, τὸ δὲ δυνάμει εἰς ἐντελέχειαν βαδίζει, ἔστιν δ' ἡ κίνησις ἐντελέχεια κινητοῦ ἀτελής. τὸ δὲ κινοῦν ἤδη ἐνεργείᾳ ἔστιν, οἷον θερμαίνει τὸ θερμὸν καὶ ὅλως γεννᾷ τὸ ἔχον τὸ εἶδος. ὥσθ' ἅμα τὸ αὐτὸ κατὰ τὸ αὐτὸ θερμὸν ἔσται καὶ οὐ θερμόν. ὁμοίως δὲ καὶ τῶν ἄλλων ἕκαστον, ὅσων τὸ κινοῦν ἀνάγκη ἔχειν τὸ συνώνυμον. τὸ μὲν ἄρα κινεῖ τὸ δὲ κινεῖται τοῦ αὐτὸ αὑτὸ κινοῦντος. Moreover, we have established the fact that it is the movable that is moved; and this is potentially, not actually, in motion, but the potential is in process to actuality, and motion is an incomplete actuality of the movable. The movent on the other hand is already in activity: e.g. it is that which is hot that produces heat: in fact, that which produces the form is always something that possesses it. Consequently (if a thing can move itself as a whole), the same thing in respect of the same thing may be at the same time both hot and not hot. So, too, in every other case where the movent must be described by the same name in the same sense as the moved. Therefore when a thing moves itself it is one part of it that is the movent and another part that is moved.
ὅτι δ' οὐκ ἔστιν αὐτὸ αὑτὸ κινοῦν οὕτως ὥσθ' ἑκάτερον ὑφ' ἑκατέρου κινεῖσθαι, ἐκ τῶνδε φανερόν. But it is not self-moving in the sense that each of the two parts is moved by the other part: the following considerations make this evident.
οὔτε γὰρ ἔσται πρῶτον κινοῦν οὐδέν, εἴ γε αὐτὸ ἑαυτὸ κινήσει ἑκάτερον (τὸ γὰρ πρότερον αἰτιώτερον τοῦ κινεῖσθαι τοῦ ἐχομένου καὶ κινήσει μᾶλλον· διχῶς γὰρ κινεῖν ἦν, τὸ μὲν τὸ ὑπ' ἄλλου κινούμενον αὐτό, τὸ δ' αὑτῷ· ἐγγύτερον δὲ τὸ πορρώτερον τοῦ κινουμένου τῆς ἀρχῆς ἢ τὸ μεταξύ)· In the first place, if each of the two parts is to move the other, there will be no first movent. If a thing is moved by a series of movents, that which is earlier in the series is more the cause of its being moved than that which comes next, and will be more truly the movent: for we found that there are two kinds of movent, that which is itself moved by something else and that which derives its motion from itself: and that which is further from the thing that is moved is nearer to the principle of motion than that which is intermediate.
ἔτι οὐκ ἀνάγκη τὸ κινοῦν κινεῖσθαι εἰ μὴ ὑφ' αὑτοῦ· κατὰ συμβεβηκὸς ἄρα ἀντικινεῖ θάτερον. ἔλαβον τοίνυν ἐνδέχεσθαι μὴ κινεῖν· ἔστιν ἄρα τὸ μὲν κινούμενον τὸ δὲ κινοῦν ἀκίνητον. In the second place, there is no necessity for the movent part to be moved by anything but itself: so it can only be accidentally that the other part moves it in return. I take then the possible case of its not moving it: then there will be a part that is moved and a part that is an unmoved movent.
ἔτι οὐκ ἀνάγκη τὸ κινοῦν ἀντικινεῖσθαι, ἀλλ' ἢ ἀκίνητόν γέ τι κινεῖν ἀνάγκη ἢ αὐτὸ ὑφ' αὑτοῦ κινούμενον, εἴπερ ἀνάγκη ἀεὶ κίνησιν εἶναι. In the third place, there is no necessity for the movent to be moved in return: on the contrary the necessity that there should always be motion makes it necessary that there should be some movent that is either unmoved or moved by itself.
ἔτι ἣν κινεῖ κίνησιν, κινοῖτ' ἄν, ὥστε τὸ θερμαῖνον θερμαίνεται. In the fourth place we should then have a thing undergoing the same motion that it is causing—that which is producing heat, therefore, being heated.
ἀλλὰ μὴν οὐδὲ τοῦ πρώτως αὐτὸ αὑτὸ κινοῦντος οὔτε ἓν μόριον οὔτε πλείω κινήσει αὐτὸ αὑτὸ ἕκαστον. But as a matter of fact that which primarily moves itself cannot contain either a single part that moves itself or a number of parts each of which moves itself.
τὸ γὰρ ὅλον εἰ κινεῖται αὐτὸ ὑφ' αὑτοῦ, ἤτοι ὑπὸ τῶν αὐτοῦ τινὸς κινήσεται ἢ ἢ ὅλον ὑφ' ὅλου. εἰ μὲν οὖν τῷ κινεῖσθαί τι μόριον αὐτὸ ὑφ' αὑτοῦ, τοῦτ' ἂν εἴη τὸ πρῶτον αὐτὸ αὑτὸ κινοῦν (χωρισθὲν γὰρ τοῦτο μὲν κινήσει αὐτὸ αὑτό, τὸ δὲ ὅλον οὐκέτι)· εἰ δὲ ὅλον ὑφ' ὅλου κινεῖται, κατὰ συμβεβηκὸς ἂν ταῦτα κινοῖ αὐτὰ ἑαυτά. ὥστε εἰ μὴ ἀναγκαῖον, εἰλήφθω μὴ κινούμενα (258a.) ὑφ' αὑτῶν. τῆς ὅλης ἄρα τὸ μὲν κινήσει ἀκίνητον ὂν τὸ δὲ κινηθήσεται· μόνως γὰρ οὕτως οἷόν τέ τι αὐτοκίνητον εἶναι. For, if the whole is moved by itself, it must be moved either by some part of itself or as a whole by itself as a whole. If, then, it is moved in virtue of some part of it being moved by that part itself, it is this part that will be the primary self-movent, since, if this part is separated from the whole, the part will still move itself, but the whole will do so no longer. If on the other hand the whole is moved by itself as a whole, it must be accidentally that the parts move themselves: and therefore, their self-motion not being necessary, we may take the case of their not being moved by themselves. Therefore in the whole of the thing we may distinguish that which imparts motion without itself being moved and that which is moved: for only in this way is it possible for a thing to be self-moved.
ἔτι εἴπερ ἡ ὅλη αὐτὴ αὑτὴν κινεῖ, τὸ μὲν κινήσει αὐτῆς, τὸ δὲ κινήσεται. ἡ ἄρα ΑΒ ὑφ' αὑτῆς τε κινηθήσεται καὶ ὑπὸ τῆς Α. Further, if the whole moves itself we may distinguish in it that which imparts the motion and that which is moved: so while we say that AB is moved by itself, we may also say that it is moved by A.
Postquam philosophus ostendit quod in mobilibus et in moventibus non proceditur in infinitum, sed est devenire ad aliquod primum, quod vel est immobile, vel est seipsum movens; hic ostendit quod etiamsi perveniatur ad primum quod est seipsum movens, quod nihilominus oportet devenire ad primum quod est immobile. Et dividitur in partes tres: in prima ostendit quod movens seipsum dividitur in duas partes, quarum una movet et alia movetur; in secunda ostendit quomodo huiusmodi partes se habeant ad invicem, ibi: quoniam autem movet etc.; in tertia concludit ex praemissis quod necesse est devenire ad aliquod primum immobile, ibi: manifestum igitur ex his et cetera. 1050. After showing that in mobiles and movers there is no going on to infinity, but that a first is reached with is either immobile or self-moving, the Philosopher now shows that even if a first that moves itself is reached, it is nevertheless necessary to come to a first which is immobile. This treatment is divided into three parts. In the first he shows that what moves itself is divided into two parts, one of which is mover and the other moved; In the second how these parts are mutually related, (L. 11); In the third that it is necessary to come to a first which is immobile, (end of L, 11).
Circa primum duo facit: primo ostendit quod in eo quod movet seipsum, una pars movet et alia movetur, ex hoc quod totum non potest se totum movere; in secunda excludit alios modos, quibus aliquis opinari posset quod esset aliquid movens seipsum, ibi: quod autem non contingat et cetera. About the first he does two things: First he shows that in a thing that moves itself, one part is mover and the other is moved, because a whole cannot move its whole self; Secondly, he rejects other ways in which a thing that moves itself might be thought to do so, at 1054.
Circa primum tria facit: primo proponit quod movens seipsum non totum movet se totum; secundo probat propositum, ibi: totum enim feretur etc., tertio concludit principale intentum, ibi: hoc quidem igitur movet et cetera. About the first he does three things: First he proposes that what moves itself does not totally move itself as a whole; Secondly, he proves the proposition, at 1052; Thirdly, he concludes to the main conclusion intended—end of 1053.
Quia vero totum et pars locum non habent nisi in rebus divisibilibus, ideo ex probatis in sexto concludit primo, quod necesse est omne quod movetur esse divisibile in semper divisibilia: hoc enim est de ratione continui, omne autem quod movetur est continuum, si per se movetur (per accidens enim moveri aliquod indivisibile non est impossibile, ut punctum aut albedinem). Et hoc ostensum est prius in sexto huius: omnia enim quae ante hunc octavum dixit, vocat universalia naturae, quia in hoc octavo ea quae supra de motu in communi dixerat, incipit applicare ad res. Sic ergo cum id quod movetur sit divisibile, potest in omni quod movetur inveniri totum et pars. Si ergo sit aliquid quod moveat seipsum, erit in eo accipere totum et partem: sed totum non poterit movere seipsum totum (quod est penitus movere ipsum seipsum). 1051. Because whole and part have no place except in things that are divisible, Aristotle, therefore, from what he had proved in Book VI, concludes first that whatever is moved is necessarily divisible into parts that are always further divisible—for this pertains to the very notion of a continuum. Now, whatever is being moved is a continuum, if it is being moved per se (for it is not impossible for an indivisible, for example, a point or whiteness, to be moved per accidens). And this was shown previously in Book VI: for all the statements made prior to Book VIII he calls universals of nature, because in Book VIII he begins to apply to things the statements he previously made about motion in common. Accordingly, since what is moved is divisible, a whole and a part can be found in everything that is being moved. If, therefore, there is anything that moves itself, we shall be able to take a whole and a part in it; but a whole cannot move its whole self, i.e., in its entirety move itself.
Deinde cum dicit: totum enim feretur etc., probat propositum duabus rationibus: quarum prima talis est. Moventis seipsum simul et semel est unus motus numero: si igitur hoc modo aliquid moveat seipsum quod totum moveat totum, sequetur quod unum et idem erit movens et motum secundum unum et eundem motum, sive sit loci mutatio sive alteratio. Et hoc videtur inconveniens: quia movens et motum habent oppositionem ad invicem; opposita autem non possunt inesse eidem secundum idem. Non est ergo possibile quod secundum eundem motum sit aliquid idem movens et motum. 1052. Then at (820) he proves his proposition with two arguments, the first of which is this: The motion of a thing that moves itself at one time and in one motion is numerically one; if, therefore, a thing should move itself in such a way that the whole moves the whole, it will follow that one and the same will be mover and moved with respect to one and the same motion, whether it be local motion or alteration. But this is seen to be impossible: for mover and moved are mutually opposite, and opposites cannot exist in the same thing with respect to the same. It is therefore not possible that some same thing be mover and moved with respect to the same motion.
Cum enim aliquid simul movet et movetur, alius est motus secundum quem movet, et alius secundum quem movetur; sicut cum baculus motus a manu movet lapidem, alius numero est motus baculi et motus lapidis. Sic ergo sequetur ulterius quod aliquis docebit et docebitur simul secundum unum et idem scibile; et similiter quod aliquis sanabit et sanabitur secundum unam et eandem numero sanitatem. For when something is at once moving and being moved, the motion according to which it moves is different from the one according to which it is being moved, as when a stick, moved by the hand, moves a stone, the motion of the stick is numerically different from the motion of the stone. Accordingly, it will follow further that someone will be both teaching and be taught at the same time with respect to one and the same knowable thing, and, similarly, that someone will heal and be healed with respect to one and the same numerical health.
Secundam rationem ponit ibi: amplius determinatum est etc.; quae talis est. Determinatum est in tertio, quod id quod movetur est mobile, scilicet in potentia existens: quia quod movetur, inquantum est in potentia et non in actu movetur: ex hoc enim movetur aliquid, quod cum sit in potentia, tendit in actum. Nec tamen id quod movetur, est ita in potentia ut nullo modo sit in actu; quia ipse motus est quidam actus mobilis inquantum movetur: sed est actus imperfectus, quia est actus eius inquantum est adhuc in potentia. 1053. He gives the second argument at (821) which is this: It has been determined in Book III that what is being moved is a mobile, i.e., something existing in a state of potency, since what is being moved is being moved precisely because it is in potency and not in act, for a thing is considered to be in motion when, being in potency, it is tending toward act. However, that which is being moved is not in potency in such a way that it is in no wise in act, because the very motion is a kind of act of the mobile precisely as being moved; but it is an imperfect act, being the act of the mobile inasmuch as it is still in potency.
Sed illud quod movet, iam est in actu: non enim reducitur quod est in potentia in actum, nisi per id quod est actu; hoc autem est movens: sicut calefacit calidum, et generat illud quod habet speciem generativam, sicut hominem generat quod habet speciem humanam, et sic de aliis. Si ergo totum moveat se totum, sequitur quod idem secundum idem simul est calidum et non calidum; quia inquantum est movens erit actu calidum, inquantum est motum erit calidum in potentia. But what causes motion is already in act, for what is in potency is not reduced to act except by something in act, namely, the mover; for example, the hot causes heat and that generates which has the form to be generated, as one who has the human form generates a man, and so on for other things. If, therefore, the whole moves its whole self, it follows that the same thing is, with respect to the same, at once hot and not hot, because, insofar as it moves, it will be hot in act; insofar as it is moved, it will be hot in potency.
Et similiter est in omnibus aliis, in quibus movens est univocum, idest conveniens in nomine et ratione cum moto; sicut cum calidum facit calidum, et homo generat hominem. The same is true in all other cases in which the mover is univocal, i.e., agreeing in name and species with the thing moved, as when the hot makes the hot and a man generates a man.
Et hoc ideo dicit, quia sunt quaedam agentia non univoca, quae scilicet non conveniunt in nomine et ratione cum suis effectibus, sicut sol generat hominem. In quibus tamen agentibus, etsi non sit species effectus secundum eandem rationem, est tamen quodam modo altiori et universaliori. Et sic universaliter verum est quod movens est quodam modo in actu secundum id secundum quod mobile est in potentia. Si igitur totum moveat se secundum totum, sequitur quod idem sit simul actu et potentia; quod est impossibile. And he says this because there are some agents which are not univocal and which do not agree in name and notion with their effects, as the sun generates a man. In such agents, nevertheless, even though they do not possess the form of the effect according to the same notion, they do so in a higher and more universal sense. Consequently, it is universally true that the mover is somehow actually what the mobile is potentially. If, therefore, the whole moves its whole self, it follows that the same thing is at once in potency and in act—which is impossible.
Ex hoc ergo concludit principale intentum, quod moventis seipsum una pars movet et alia movetur. From this he concludes (822) the main proposition that, with respect to a thing that moves itself, one part is mover and the other part moved.
Deinde cum dicit: quod autem non contingat etc., excludit quosdam modos, quos aliquis posset existimare in motu moventis seipsum. Et primo ostendit quod moventis seipsum non movetur utraque pars ab altera; secundo ostendit quod pars moventis seipsum non movet seipsam, ibi: at vero neque ipsius primo seipsum et cetera. 1054. Then at (823) he rejects certain ways that someone might suppose to take place in the motion of a thing that moves itself. First he shows that with respect to a thing that moves itself, both parts are not moved by each other; Secondly, that with respect to a thing which moves itself, one part does not move itself, at 1059.
Circa primum duo facit: primo proponit quod intendit; secundo probat propositum, ibi: neque enim erit et cetera. About the first he does two things: First he proposes what he intends; Secondly, he proves his proposition, at 1055..
Dicit ergo primo, manifestum esse ex iis quae sequuntur, quod non contingit aliquid movere seipsum, hoc modo quod utraque pars eius moveatur a residua; sicut si ab moveat seipsum, quod a moveat b, et b moveat a. He says therefore first (823) that it is clear from what follows that a thing can not move itself in such a way that each part is moved by the other; for example, if AB moves itself, that A move B, and B move A.
Deinde cum dicit: neque enim erit primum etc., probat propositum quatuor rationibus. Et est attendendum, quod ad hanc conclusionem resumit rationes supra positas ad ostendendum quod non omne movens movetur ab alio. Unde ex praemissis abbreviate hic colligit quatuor rationes. 1055. Then at (824) he proves the proposition with four arguments. And it should be noted that for this conclusion he re-uses the reasons previously used to show that not every mover is being moved by another. Hence from the foregoing he here collects four abridged arguments.
Quarum primam sumit ex prima ratione, quam supra posuit duplici ordine, ad ostendendum quod non proceditur in infinitum in hoc quod semper aliquid ab alio moveatur, propter hoc quod non esset aliquod primum movens, quo remoto removerentur sequentia. Unde et hic primo praemittit idem inconveniens. The first of these he takes from the first argument presented above in a double (i.e., ascending and descending) order to show that the process of something else being moved by another does not go on always, ad infinitum, because then there would be no first mover—from whose non-existence would follow the non-existence of all coming after it. Hence in this place too, the Philosopher premises the same unacceptable outcome.
Dicit enim quod si in primo moto quod ponitur movens seipsum, utraque pars ab altera reciproce moveatur, sequetur quod non sit aliquod primum movens. Et hoc ideo, quia sicut supra dictum est, movens prius est magis causa movendi et magis movet, quam posterius movens. Et hoc ideo supra probabatur, quia dupliciter aliquid movet. Uno enim modo movet aliquid ex eo quod movetur ab alio, sicut baculus movet lapidem eo quod movetur a manu; et hoc est secundum movens: alio modo movet aliquid ex eo quod movetur ex seipso, sicut homo movet; et haec est dispositio primi moventis. Illud autem quod movet non eo quod movetur ab alio, magis est remotum ab ultimo quod movetur, et magis proximum primo moventi, quam medium, quod scilicet movet eo quod ab alio movetur. For he says that if, in the first thing moved which is supposed as moving itself, both parts are reciprocally being moved by each other, it will follow that there is no first mover. This follows because, as was said above, the prior mover is more the cause of motion, and moves more, than the subsequent mover. And this was proved above on the ground that something causes motion in two ways. In one way, something moves by being moved by another, as a stick moves a stone, because it is being moved by the hand, and this is a second mover. In another way, something moves by being moved of itself, as a man moves, and this is a condition of a first mover. Now what causes motion independently of being moved by another is farther removed from the last thing moved, and nearer to the first mover, than an intermediate which causes motion as being moved by another.
Debet ergo haec ratio sic formari. Si totius moventis seipsum utraque pars movet aliam reciproce, non magis movet una quam alia: sed primum movens magis movet quam secundum: ergo neutra earum erit primum movens. Quod est inconveniens: quia sic sequeretur quod illud quod movetur ex seipso, non esset propinquius primo principio motus (quod nullum sequitur esse), quam id quod movetur ab alio; cum tamen supra sit ostensum, quod movens seipsum sit primum in genere mobilium. Non ergo hoc est verum quod moventis seipsum utraque pars per aliam moveatur. This argument should be formulated in the following way: If both parts of a thing that moves itself move each other reciprocally, one is no more the cause of motion than the other. But the first mover is more a cause of motion than a second mover; therefore, neither of the parts will be a first mover. Now this is unacceptable, since it would then follow that what is moved of itself would be no nearer to the first principle of motion (whose existence would thereby be rejected) than what is moved by another, whereas it was proved above that a mover that moves itself is first in the genus of mobiles. Therefore, it is not true that both parts of a thing that moves itself are moved by each other.
Deinde cum dicit: amplius, non necesse est etc., sumit duas rationes ad idem, ex una ratione quam supra posuerat ad ostendendum quod non omne movens movetur, ita quod moveri conveniat moventi per accidens. In qua quidem ratione supra duas conclusiones intulit: primam scilicet quod movens contingit et non moveri; alteram quod motus non sit aeternus: et secundum has duas conclusiones, duas hic rationes format. 1056. Then at (825) he presents two arguments for the same taken from one he used above when he showed that not every mover is being moved, in the sense that being moved is found per accidens in the mover. In this argument he drew two conclusions above, namely, first, that a mover can happen not to be moved, and secondly, that motion is not eternal. In the light of these two conclusions he now forms two arguments.
Primo enim dicit quod non necesse est movens moveri nisi a seipso secundum accidens: et est sensus quod nisi accipiatur primum movens moveri a seipso, non erit etiam necesse quod movens primum moveatur secundum accidens; sicut quidam posuerunt quod omne movens movetur, et tamen hoc est ei per accidens. For he says first of all “it is not necessary for a mover to be moved except by itself according to accident,” the sense of this being that unless the first mover be taken as being moved by itself, it will not also be necessary that the first mover be moved according to an accidents as some posited that every mover is being moved but that its being moved is in it per accidens.
Cum ergo ponitur quod moventis seipsum pars quae movet, e contra aequaliter movetur ab altera, hoc non erit nisi per accidens. Sed sicut supra accipiebamus, quod est per accidens contingit non esse: ergo contingit illam partem quae movet, non moveri. Sic ergo remanet quod moventis seipsum una pars movetur, et alia movet et non movetur. When therefore it is supposed that of a thing which moves itself, the part causing motion is equally being moved by the other, this will be only per accidens. But as we conceded above, whatever is per accidens is able not to be; therefore, it is possible for the part which causes motion, not to be moved. Thus, therefore, it remains that of a thing that moves itself one part is moved, and the other causes motion and is not moved.
Deinde cum dicit: amplius, non necesse est etc., ponit aliam rationem correspondentem secundae conclusioni, quam supra intulerat, scilicet quod sequitur motum non semper esse. Hic autem converso ordine sic arguit. Si necesse est motum semper esse, non necesse est movens cum movet e contrario moveri; sed necesse est quod vel movens sit immobile, vel quod ipsum moveatur a seipso. 1057. Then at (826) he gives another argument corresponding to the second conclusion that he inferred above, namely, that it follows that motion does not always exist, Here, however, he argues in reverse order. If it is necessary that motion always exist, it is not necessary that a mover, when it causes motion, be moved, but it is necessary that the mover be either immobile or that it be moved by itself.
Huius autem conditionalis ratio ex supra posita ratione apparet. Quia si movens non movet nisi moveatur; et tamen non inest ei moveri nisi per accidens; sequitur quod contingat ipsum non moveri; ergo per consequens neque movere, et sic non erit motus. Sed motum supra ostenderat esse sempiternum: ergo non necesse est movens, cum movet, contra moveri. Et ita non est verum, quod utraque pars moventis seipsum moveatur ab altera. The reason for this conditional is apparent from an argument given above. For if a mover does not cause motion unless it is being moved, and if being moved is only in it per accidens, it follows that it can happen not to be moved. Consequently, it can happen also not to cause motion, and as a result, there will be no motion. But motion was proved to be eternal. Therefore, it is not necessary for a mover to be moved, when it is causing motion, Consequently, it is not true that each part of a thing that moves itself is moved by the other.
Deinde cum dicit: amplius, si movet motum etc., ponit quartam rationem, quae sumitur ex ratione quam supra posuit ad ostendendum quod non inest per se moventi quod moveatur: quia sequeretur quod esset devenire in hoc, quod movens eodem motu moveretur quo movet, ut supra expositum est. 1058. Then at (827) he presents the fourth argument, which is taken from the argument previously given to prove that it is not essential to a mover that it be moved, because it would follow that we must come to this, that a mover would be being moved by the same motion which it is causing, as explained above.
Et ideo hic abbreviando hanc rationem, dicit quod si utraque pars ab altera moveatur, sequetur quod secundum eundem motum movet et movetur: unde sequitur quod calefaciens calefiat, quod est impossibile. And now abridging this argument he says that, if each part is being moved by the other, it will follow that it causes motion and is being moved with respect to the same motion. Hence, it follows that the heater is heated—which is impossible.
Ideo autem sequitur, si moventis seipsum utraque pars ab alia moveatur, quod secundum eundem motum aliquid movet et movetur; quia moventis seipsum est unus motus, et secundum illum oportebit quod pars quae movet moveatur. Now, the reason why it follows that the same thing is causing motion and being moved with respect to the same motion, when it is posited that each part of a thing which moves itself is moved by the other is that there is in the thing that moves itself just one motion, and it is according to that motion that the part causing motion will itself have to be moved.
Deinde cum dicit: at vero neque etc., excludit alium modum, scilicet quod moventis seipsum pars seipsam non movet. Et primo proponit quod intendit; secundo probat propositum, ibi: totum enim si movetur et cetera. 1059. Then at (828) he excludes another way, namely, the supposition that the part of a thing which moves itself does not move itself. First he proposes what he intends; Secondly, he proves his proposition, at 1060.
Dicit ergo primo, quod si accipiatur aliquid quod est primo movens seipsum, non potest dici neque quod una pars eius seipsam moveat, neque quod plures, ita quod quaelibet earum seipsam moveat. He says therefore first that if something that is first moving itself be assumed, it cannot be said either that one part of it moves itself or that a number of parts do so, in such a way that each of them moves itself.
Deinde cum dicit: totum enim si movetur ipsum etc., probat propositum duabus rationibus: quarum prima talis est. Si totum movetur ipsum a seipso, aut hoc conveniet ei ratione suae partis quae movetur a seipsa, aut ratione totius. 1060. Then at (829) he proves this with two arguments, the first of which is that if the whole is being moved by itself, this belongs to it either by reason of a part that is being moved by itself or by reason of the whole.
Si conveniat ei ratione suae partis, ergo illa pars erit primum seipsum movens, quia illa pars separata a toto movebit seipsam: sed totum iam non erit movens seipsum primum, ut ponebatur. If it belongs to it by reason of its part, then that part will be a first mover that moves itself, because that part separated from the whole will move itself, but then the whole will no longer be a first mover of itself, as was supposed.
Si vero dicatur quod totum movet seipsum ratione totius, ergo quod aliquae partes moveant seipsas, hoc non erit nisi per accidens. Quod autem est per accidens, non est necessarium: ergo in primo movente seipsum maxime oportet accipere quod partes non moveantur a seipsis. Totius ergo primi moventis seipsum, una pars movebit cum sit immobilis, alia movebitur. Istis enim solum duobus modis possibile esset quod pars movens moveretur, scilicet aut quod moveretur a parte altera quam movet, aut quod moveret seipsam. But if it be said that the whole moves itself by reason of the whole, then it will be only per accidens that some parts move themselves. But what is per accidens is not necessary. Therefore in the mover that first moves itself, it is most important to presume that the parts are not moved by themselves, Therefore, one part of the first mover that moves itself will cause motion, since it is immobile, and the other will be moved. For those are the only two ways in which it is possible that a part which causes motion could be moved, namely, either because that part would be moved by another part which it moves, or because that part would move itself.
Unde attendendum est quod Aristoteles, excludendo hos duos modos, intendit concludere quod pars movens in movente seipsum, sit immobilis; non autem quod movens seipsum dividatur in duas partes, quarum una sit movens, et alia mota: hoc enim sufficienter conclusum est per id quod primo ostendit, quod totum non movet seipsum totum. Hence it should be noticed that Aristotle in excluding these two ways intends to conclude that in a thing which moves itself, the part which causes motion is immobile, but not that what moves itself is divided into two parts, one of which causes motion and the other is moved; for this had been sufficiently concluded, when he first proved that the whole does not move itself as a whole.
Et sic patet quod non fuit necessarium Aristoteli inducere divisionem quinque membrorum, ut quidam dixerunt: quorum unum membrum sit, quod totum moveat totum; secundum quod totum moveat partem; tertium quod pars moveat totum; quartum quod duae partes vicissim se moveant; quintum quod una pars sit movens et alia mota. Si enim totum non movet totum, per eandem rationem sequitur quod totum non moveat partem, nec pars totum: quia utrobique sequeretur quod aliqua pars mota moveret seipsam. Unde hoc quod totum non movet totum, sufficit ad concludendum quod una pars sit movens et alia mota: sed ad concludendum quod pars movens non moveatur, probat duo alia, scilicet quod pars movens non moveatur a mota, et quod non moveatur a seipsa. Accordingly, it is clear that it was not necessary that Aristotle introduce a division of five members, as some claimed: one member of which is that the whole moves the whole; the second that the whole moves a part; the third that a part moves the whole; the fourth that two parts mutually move one another; the fifth that one part is a mover and the other moved. For if the whole does not move the whole, it follows for the same reason that the whole does not move the part, nor the part the whole; because in either case it would follows that a moved part would be moving itself. Hence the fact that the whole does not move the whole suffices for concluding that one part is a mover and the other is moved. But in order to conclude that the part which causes motion is not moved, he proves two other things, namely, that the part causing motion is not moved by a moved part, and that it is not moved by itself.
Et ad hoc secundum probandum inducit secundam rationem ibi: amplius si tota etc.: quae talis est. Si detur quod pars movens moventis seipsum, ipsa tota seipsam moveat, sequitur per supra probata, quod ipsius partis iterum una pars moveat et alia moveatur: iam enim ostensum est supra quod totum non movet seipsum aliter, nisi per hoc quod una pars eius movet et alia movetur. Sit ergo pars movens moventis seipsum, ab: per rationem ergo praemissam sequitur quod una pars eius sit movens, scilicet a, et alia mota, scilicet b. Si ergo ab moveat tota se totam, ut tu ponis, sequitur quod idem moveatur a duobus motoribus, scilicet a toto, quod est ab, et a parte, quae est a; quod est impossibile. Relinquitur ergo quod pars movens in movente seipsum, est omnino immobilis. 1061. And to prove this last point he presents a second argument (830): If it be granted that the motion-causing part of a thing that moves itself moves itself as a whole, it follows through what was proved above that a part of that part causes motion and the other part is moved. For it has been already proved above that a whole does not move itself in any other way than by one of its parts causing motion and the other being moved, So, let AB be the motion-causing part of a thing that moves itself; then by the previous argument it follows that one part of it is a mover, namely A, and the other part, namely B, is moved. Therefore, if AB as a whole moves itself as a whole, as you say, it follows that the same thing would be moved by two movers, namely, by the whole AB and by the part A—which is impossible. It remains, therefore, that the motion-causing part of a thing which moves itself is entirely immobile,

Lectio 11
How the parts of something moving itself are related.
Chapter 5 cont.
ἐπεὶ δὲ κινεῖ τὸ μὲν κινούμενον ὑπ' ἄλλου τὸ δ' ἀκίνη τον ὄν, καὶ κινεῖται τὸ μὲν κινοῦν τὸ δὲ οὐδὲν κινοῦν, τὸ αὐτὸ αὑτὸ κινοῦν ἀνάγκη ἐξ ἀκινήτου εἶναι κινοῦντος δέ, καὶ ἔτι ἐκ κινουμένου μὴ κινοῦντος δ' ἐξ ἀνάγκης, ἀλλ' ὁπότερ' ἔτυχεν. And since that which imparts motion may be either a thing that is moved by something else or a thing that is unmoved, and that which is moved may be either a thing that imparts motion to something else or a thing that does not, that which moves itself must be composed of something that is unmoved but imparts motion and also of something that is moved but does not necessarily impart motion but may or may not do so.
ἔστω γὰρ τὸ Α κινοῦν μὲν ἀκίνητον δέ, τὸ δὲ Β κινούμενόν τε ὑπὸ τοῦ Α καὶ κινοῦν τὸ ἐφ' ᾧ Γ, τοῦτο δὲ κινούμενον μὲν ὑπὸ τοῦ Β, μὴ κινοῦν δὲ μηδέν· εἴπερ γὰρ καὶ διὰ πλειόνων ἥξει ποτὲ εἰς τὸ Γ, ἔστω δι' ἑνὸς μόνου. τὸ δὴ ἅπαν ΑΒΓ αὐτὸ ἑαυτὸ κινεῖ. ἀλλ' ἐὰν ἀφέλω τὸ Γ, τὸ μὲν ΑΒ κινήσει αὐτὸ ἑαυτό, τὸ μὲν Α κινοῦν τὸ δὲ Β κινούμενον, τὸ δὲ Γ οὐ κινήσει αὐτὸ ἑαυτό, οὐδ' ὅλως κινήσεται. ἀλλὰ μὴν οὐδ' ἡ ΒΓ κινήσει αὐτὴ ἑαυτὴν ἄνευ τοῦ Α· τὸ γὰρ Β κινεῖ τῷ κινεῖσθαι ὑπ' ἄλλου, οὐ τῷ ὑφ' αὑτοῦ τινὸς μέρους. τὸ ἄρα ΑΒ μόνον αὐτὸ ἑαυτὸ κινεῖ. ἀνάγκη ἄρα τὸ αὐτὸ ἑαυτὸ κινοῦν ἔχειν τὸ κινοῦν ἀκίνητον δέ, καὶ τὸ κινούμενον μηδὲν δὲ κινοῦν ἐξ ἀνάγκης, Thus let A be something that imparts motion but is unmoved, B something that is moved by A and moves G, G something that is moved by B but moves nothing (granted that we eventually arrive at G we may take it that there is only one intermediate term, though there may be more). Then the whole ABG moves itself. But if I take away G, AB will move itself, A imparting motion and B being moved, whereas G will not move itself or in fact be moved at all. Nor again will BG move itself apart from A: for B imparts motion only through being moved by something else, not through being moved by any part of itself. So only AB moves itself. That which moves itself, therefore, must comprise something that imparts motion but is unmoved and something that is moved but does not necessarily move anything else:
ἁπτόμενα ἤτοι ἄμφω ἀλλήλων ἢ θατέρου θάτερον. and each of these two things, or at any rate one of them, must be in contact with the other.
εἰ μὲν οὖν συνεχές ἐστι τὸ κινοῦν (τὸ μὲν γὰρ κινούμενον ἀναγκαῖον εἶναι συνεχές), ἅψεται ἑκάτερον ἑκατέρου. δῆλον δὴ ὅτι τὸ πᾶν αὐτὸ ἑαυτὸ κινεῖ οὐ τῷ αὐτοῦ τι εἶναι τοιοῦτον οἷον αὐτὸ αὑτὸ κινεῖν, ἀλλ' ὅλον κινεῖ αὐτὸ ἑαυτό, κινούμενόν τε καὶ κινοῦν τῷ αὐτοῦ τι εἶναι τὸ κινοῦν καὶ τὸ κινούμενον. οὐ γὰρ ὅλον κι νεῖ οὐδ' ὅλον κινεῖται, ἀλλὰ κινεῖ μὲν ἡ τὸ Α, κινεῖται δὲ ἡ τὸ Β μόνον [τὸ δὲ Γ ὑπὸ τοῦ Α οὐκέτι· ἀδύνατον γάρ]. If, then, that which imparts motion is a continuous substance—that which is moved must of course be so—it is clear that it is not through some part of the whole being of such a nature as to be capable of moving itself that the whole moves itself: it moves itself as a whole, both being moved and imparting motion through containing a part that imparts motion and a part that is moved. It does not impart motion as a whole nor is it moved as a whole: it is A alone that imparts motion and B alone that is moved. It is not true, further, that G is moved by A, which is impossible.
ἀπορίαν δ' ἔχει, ἐὰν ἀφέλῃ τις ἢ τῆς Α, εἰ συνεχὲς τὸ κινοῦν μὲν ἀκίνητον δέ, ἢ τῆς Β τῆς κινουμένης· ἡ λοιπὴ ἆρα κινήσει τῆς Α ἢ τῆς Β κινηθήσεται; εἰ γὰρ τοῦτο, οὐκ ἂν εἴη πρώ τως κινουμένη ὑφ' αὑτῆς ἡ τὸ ΑΒ· ἀφαιρεθείσης γὰρ ἀπὸ τῆς ΑΒ, ἔτι κινήσει αὑτὴν ἡ λοιπὴ ΑΒ. Here a difficulty arises: if something is taken away from A (supposing that that which imparts motion but is unmoved is a continuous substance), or from B the part that is moved, will the remainder of A continue to impart motion or the remainder of B continue to be moved? If so, it will not be AB primarily that is moved by itself, since, when something is taken away from AB, the remainder of AB will still continue to move itself.
ἢ δυνάμει μὲν (258b.) ἑκάτερον οὐδὲν κωλύει ἢ θάτερον, τὸ κινούμενον, διαιρετὸν εἶναι, ἐντελεχείᾳ δ' ἀδιαίρετον· ἐὰν δὲ διαιρεθῇ, μηκέτι εἶναι ἔχον τὴν αὐτὴν φύσιν· ὥστ' οὐδὲν κωλύει ἐν διαιρετοῖς δυνάμει πρώτως ἐνεῖναι. Perhaps we may state the case thus: there is nothing to prevent each of the two parts, or at any rate one of them, that which is moved, being divisible though actually undivided, so that if it is divided it will not continue in the possession of the same capacity: and so there is nothing to prevent self-motion residing primarily in things that are potentially divisible.
φανερὸν τοίνυν ἐκ τούτων ὅτι ἔστιν τὸ πρώτως κινοῦν ἀκίνητον· εἴτε γὰρ εὐθὺς ἵσταται τὸ κινούμενον, ὑπό τι νος δὲ κινούμενον, εἰς ἀκίνητον τὸ πρῶτον, εἴτε εἰς κινούμενον μέν, αὐτὸ δ' αὑτὸ κινοῦν καὶ ἱστάν, ἀμφοτέρως συμβαίνει τὸ πρώτως κινοῦν ἅπασιν εἶναι τοῖς κινουμένοις ἀκίνητον. From what has been said, then, it is evident that that which primarily imparts motion is unmoved: for, whether the series is closed at once by that which is in motion but moved by something else deriving its motion directly from the first unmoved, or whether the motion is derived from what is in motion but moves itself and stops its own motion, on both suppositions we have the result that in all cases of things being in motion that which primarily imparts motion is unmoved.
Postquam philosophus ostendit quod movens seipsum dividitur in duas partes, quarum una movet et non movetur, alia autem movetur; hic ostendit quomodo huiusmodi partes se habeant ad invicem. Et circa hoc tria facit: primo proponit quod intendit; secundo ostendit propositum, ibi: sit enim a movens etc.; tertio concludit conclusionem principaliter intentam ex omnibus praemissis, ibi: manifestum igitur ex his et cetera. 1062. After showing that a thing which moves itself is divided into two parts, one of which causes motion and is not moved, and the other of which is moved, the Philosopher now shows how such parts are mutually related. About this he does three things: First he proposes what he intends; Secondly, he shows his proposition, at 1063; Thirdly, he reaches the conclusion chiefly intended by all the foregoing, at 1068.
Dicit ergo primo, quod cum movens dividatur in duo, quorum unum movetur etiam ab alio, aliud vero movens est immobile: et iterum mobile dividatur in duo; est enim quoddam mobile quod etiam movet, quoddam vero mobile quod nihil movet: oportet dicere quod movens seipsum componatur ex duabus partibus, quarum una sit sic movens quod tamen sit immobilis, alia vero sic moveatur quod tamen non moveat. He says therefore first (831) that since a mover is divided into two elements, one of which is also moved by something else, and the other of which is immobile, and again, since a mobile is divided into two, there being a mobile which also causes motion, and another which does not move anything, one must say that what moves itself is composed of two parts, one of which is such a mover as to be immobile, and the other of which is so moved as not to move anything else.
Quod autem subdit ex necessitate, dupliciter potest intelligi: quia si intelligatur quod pars mota moventis seipsum non moveat aliquid quod sit pars moventis seipsum, sic legenda est littera, quod necessitas remaneat affirmata, cadens super hoc quod dicit non movente. Probat enim statim impossibile esse, quod eius quod primo movet seipsum, sit tertia pars, quae moveatur a parte mota. Si vero intelligatur quod pars mota non moveat aliquid extrinsecum, sic hoc quod dicit ex necessitate, cadit sub negatione: non enim est de necessitate moventis seipsum, quod pars eius mota moveat aliquid extrinsecum; nec tamen est impossibile. And when he says that the latter does not move anything “of necessity,” it can mean two things: If it is understood as though the moved part of a self-mover does not move anything that is part of the self-mover, the word “necessity” should be interpreted in an affirmative sense, referring to his calling it “non-moving,” as meaning that of necessity it does not move anything else. For he at once proves that it is impossible for a thing that moves itself to have a third part which is moved by the moved part. But if the words are interpreted as meaning that the moved part does not move anything extrinsic, then the phrase, “of necessity,” must be given a negative meaning; for it is not necessary in a thing which moves itself that its moved part move something extrinsic, but neither is it impossible.
Qualiter autem hoc contingat, ostendit consequenter cum dicit: sit enim a movens et cetera. Et circa hoc duo facit: primo ostendit propositum; secundo solvit quandam dubitationem, ibi: dubitationem autem habet et cetera. 1063. How this happens he shows at (832). About this he does two things: First he explains his proposition; Secondly, he solves a doubt, at 1066.
Circa primum duo facit: primo ostendit qualiter partes moventis seipsum se habeant ad invicem; secundo qualiter secundum eas totum dicitur seipsum movere, ibi: si igitur continuum est et cetera. About the first he does two things: First he shows how the parts of a thing that moves itself are related; Secondly, how with respect to them a whole is said to move itself, at 1065.
Circa primum duo facit: primo ostendit quod in movente seipsum sunt solae duae partes, quarum una movet et non movetur, alia movetur et non movet; secundo quomodo hae duae partes ad invicem coniungantur, ibi: contacta autem utraque et cetera. About the first he does two things: First he shows that in a thing which moves itself there are just two parts, one of which causes motion and is not moved, and the other of which is moved and does not cause any motion; Secondly, how these two parts are joined to one another, at 1064.
Primum ostendit sic. Si dicatur quod pars mota moventis seipsum, iterum moveat aliquid aliud, quod sit pars eiusdem moventis seipsum: sit ergo prima pars moventis seipsum a, quod sit movens immobile: secunda vero pars sit b, quod moveatur ab a, et moveat tertiam partem, quae est c, quae sic moveatur a b, quod nihil aliud moveat quod sit pars moventis seipsum. Non enim potest dici quod fiat descensus in infinitum in partibus moventis seipsum, scilicet quod pars mota iterum moveat aliam: quia sic movens seipsum esset in infinitum, quod est impossibile, ut supra ostensum est. Erit ergo aliqua pars moventis seipsum, quae est mota non movens, quam dicimus c. Et licet contingat per multa media quae sunt moventia et mota, pervenire in ultimum motum quod dicitur c; accipiatur loco omnium mediorum, unum medium quod sit b. Sic ergo hoc totum quod est abc movet seipsum. A quo toto si auferatur haec pars quae est c, adhuc ipsum ab movebit seipsum: quia una pars eius est movens, scilicet a, et alia mota, scilicet b, quod requirebatur ad hoc quod aliquid sit movens seipsum, ut supra ostensum est. Sed c non movebit seipsum, neque aliquam aliam partem, secundum supposita. He explains the first part in this way (832): If it be said that the moved part of a thing that moves itself does in turn move something else which is part of the very thing that moves itself, then let A be the first immobile part of this self-moving thing. Let B be the second part and let it be both the one moved by A and the mover of a third part C. which is so moved by B as to move nothing else that is a part of this self-moving thing. For it cannot be said that there is an infinite descent in the parts of a thing which moves itself, such that a moved part in turn moves another, for then it would be moving itself ad infinitum, which is impossible, as was shown above. There will be, therefore, in that self-moving thing a part which is moved but is not a mover, i.e., the part C. And although it might be that it is through many intermediate moved movers that the last moved part C is reached, we can accept B as the one intermediate taken in place of all these intermediates. Thus, therefore, does this whole, which is ABC, move itself. If from this whole there be taken away the part C, AB will still move itself, because one of its parts is a mover, namely A, and the other moved, namely B, which was required for a thing to be able to move itself, as was shown above. But C will not move itself, or move any other part, as we have assumed.
Similiter etiam bc non movet seipsum sine a, quia b non movet nisi inquantum movetur ab alio quod est a, quod non est pars eius. Relinquitur ergo quod solum ab moveat seipsum primo et per se. Unde necesse est quod movens seipsum habeat duas partes, quarum una sit movens immobilis, alia vero sit mota, quam necesse est nihil movere quod sit pars moventis seipsum: hoc enim conclusum est per praemissam rationem. Likewise, even BC does not move itself without A, because B does not cause motion except inasmuch as it is moved by something else, which is A, which is not a part of BC. It remains, therefore, that only AB moves itself first and per se. Hence a thing which moves itself must have two parts, one of which is an immobile mover, and the other of which is moved and necessarily does not move anything that is part of the whole thing that moves itself, for this was concluded by the foregoing argument.
Vel nihil movens ex necessitate: quia non est de necessitate moventis seipsum, quod pars mota moveat aliquid aliud etiam extrinsecum. Or else it “moves nothing of necessity”—since it is not a necessity of a self-mover that the moved part move anything else, even anything extrinsic.
Deinde cum dicit: contacta autem utraque etc., ostendit quomodo hae duae partes se habeant ad invicem. 1064. Then at (833) he shows how these two parts are mutually related.
Ubi considerandum est, quod Aristoteles nondum probavit primum movens non habere aliquam magnitudinem, quod infra probabit. Quidam autem antiqui philosophi posuerunt nullam substantiam absque aliqua magnitudine esse. Unde Aristoteles ante probationem hoc sub dubio secundum suam consuetudinem derelinquens, dicit quod duas partes moventis seipsum, quarum una est movens et alia mota, necesse est aliquo modo coniungi, ad hoc quod sint partes unius totius. Non autem per continuationem, quia supra dixit quod movens seipsum et motum non possunt continuari, sed necesse est ea dividi: unde relinquitur quod oportet has duas partes coniungi per contactum; aut ita ut ambae partes contingant se invicem, si ambae partes habeant magnitudinem; aut ita quod altera tantum pars contingatur ab alia, et non e converso, quod erit si movens non habet magnitudinem. Quod enim est incorporeum, potest quidem tangere corpus sua virtute movendo ipsum, non autem contingitur a corpore: duo autem corpora se invicem tangunt. Here it must be considered that Aristotle has not yet proved that the first mover has no magnitude, as will be proved later. But some of the earlier philosophers posited that no substance can exist without magnitude. Hence Aristotle is keeping with his custom when he leaves this matter doubtful until it is proved; and he says that the two parts of a self-mover, of which one is a mover and the other moved, must be somehow conjoined if they are to be parts of one whole. But not by continuation, because above he has said that a self-mover and a moved thing cannot form a continuum but are necessarily divided. Hence it remains that these two parts must be joined by contact: either by both parts touching one another, if they have magnitude; or by just one of the parts touching the other and not vice versa, which will be the case if the mover has no magnitude. For what is incorporeal can indeed touch a body by means of its power and so move it, but it is not touched in turn by the body; two bodies, however, touch each other.
Deinde cum dicit: si igitur continuum est etc., ostendit qua ratione totum dicatur movens seipsum, una parte movente et alia mota. 1065. Then at (834) he shows by what reason a whole is said to move itself with one part causing motion and the other part being moved.
Et supponamus quantum ad praesens, quod utraque pars sit continua, idest magnitudinem habens; quia de eo quod movetur, in sexto probatum est quod sit aliquid continuum; et accipiatur nunc idem de movente, antequam veritas probetur. And let us suppose at first that each part is continuous, i.e., having a magnitude, because in Book VI it has been proved of anything that is moved that it is a continuum, and let the same thing be supposed at the present time for the mover, before the truth is proved.
Hac igitur suppositione facta, ipsi toti composito ex duobus tria attribuuntur, scilicet moveri, movere, et movere seipsum. Sed hoc quod est movere seipsum, attribuitur ei non propter hoc quod aliqua pars eius moveat seipsam, sed ipsum totum seipsum movet: sed hoc quod est movere et moveri, attribuitur toti ratione partis. Non enim totum movet neque totum movetur; sed movet una pars eius, scilicet a, reliqua vero pars eius solum movetur, scilicet b: iam enim ostensum est quod non est aliqua tertia pars, ut c, quae moveatur ab ipso b. Impossibile est enim hoc, si accipiatur id quod primo movet seipsum, sicut supra ostensum est. Therefore, using this supposition, three things are attributed to this whole composed of two parts: it is moved, it causes motion, and it moves itself. But self-movement is attributed to it not because a part moves itself but because the entire whole move itself, while to cause motion, and to be moved, are attributed to the whole by reason of the part. For the whole neither moves nor is moved, but one part A moves, and the other part B is moved only; and it has already been shown that there is no third part C which is moved by B. For this is impossible, if we are dealing with a thing that moves itself primarily, as has been shown above.
Deinde cum dicit: dubitationem autem habet etc., movet quandam dubitationem circa praemissa. Et primo movet eam; secundo solvit, ibi: aut potentia quidem et cetera. 1066. Then at (835) he raises a doubt about the foregoing. First he raises it; Secondly, he solves it, at 1067.
Habet autem haec dubitatio ortum ex hoc quod supra probaverat, quod in primo movente seipsum non sunt nisi duae partes, quarum una movet et alia movetur; quia si esset tertia, etiam ea remota compositum ex primis duabus movet seipsum, et sic ipsum est primum movens seipsum. This doubt springs from what he had previously proved, namely, that in a thing that moves itself in a primary sense, there are but two parts, of which one moves and the other is moved, on the ground that, if there were a third, even if this third were removed, the composite of the first two would still move itself, and thus the latter is the primary self-mover.
Ex hoc ergo sequitur dubitatio talis. Ponamus quod pars moventis seipsum quae est movens immobile, ut a, sit quoddam continuum: de parte autem eius quae movetur, scilicet b, manifestum est quod est aliquid continuum, secundum prius probata. Omne autem continuum est divisibile: est ergo dubitatio, si auferatur aliqua pars per divisionem ab a aut a b, utrum reliqua pars moveat aut moveatur. Quia si reliqua pars moveat aut moveatur, adhuc residua pars de ab movebit seipsum, et sic ab non primo movebat seipsum. Et sic sequitur ulterius, quod nihil erit primo movens seipsum. From this, therefore, the following doubt follows (835). Let us suppose that the immobile but motion-causing part A of a self-moving whole is a continuum. Now it is clear that its part B, which is the moved part, is a continuum, according to what has been previously proved. But every continuum is divisible. Therefore the doubt is this: If through division a part be removed from A or R, would the remaining part be a mover or a moved part? Because if it is either, the part of AB that remains will move itself and, accordingly, AB will not be some-thing that moves itself in a primary sense. Thus it further follows that nothing will be a self-mover in a primary sense.
1067. Then at (836) he resolves this doubt.
Deinde cum dicit: aut potentia quidem etc., solvit positam dubitationem. Ubi considerandum est quod Aristoteles prius in sexto probavit quod in motu non est aliquid primum, neque ex parte mobilis neque ex parte temporis neque ex parte rei in qua est motus, praecipue in augmento et motu locali: et hoc ideo, quia tunc loquebatur de motu in communi, et de mobili secundum quod est quoddam continuum, nondum applicando ad determinatas naturas. Et secundum hoc sequeretur quod non esset aliquid primo motum, et per consequens nec aliquid primo movens, si movens sit continuum: et ita etiam non esset aliquid primo movens seipsum. Now it should be remembered here that in Book VI Aristotle has proved that there is no first in motion, either on the part of the mobile, or of the time or of the sphere of motion, and that this is especially true in growth and local motion: the reason being that he was then speaking of motion in common and of the mobile as it is a certain continuum, without yet making application to particular natures. And according to this, it would follow that there would not be anything that is first moved and, consequently, no first mover, if the mover were a continuum. Likewise, there would also not be anything that is a first mover.
Sed nunc iam Aristoteles loquitur de motu, applicando ad determinatas naturas: et ideo ponit aliquid esse primo movens seipsum. But now Aristotle is speaking of motion and applying his doctrine to definite natures and for that reason he posits that there is a first mover of self.
Et solvit praemissam dubitationem sic: quod nihil prohibet esse divisibile in potentia ex eo quod sunt continua (scilicet movens et motum) si utrumque sit continuum, aut ad minus alterum tantum, scilicet quod movetur, quod necesse est esse continuum. Sed tamen possibile est quod aliquod continuum, sive sit movens sive motum, habeat talem naturam, ut non possit actu dividi, sicut patet de corpore solis. Et si contingat quod aliquod continuum dividatur, non retinebit eandem potentiam ad hoc quod moveat vel moveatur, quam prius habebat; quia huiusmodi potentia sequitur aliquam formam; forma autem naturalis requirit quantitatem determinatam. Unde si sit corpus incorruptibile, dividi non potest in actu. Si autem sit corruptibile, si dividatur in actu, non retinebit eandem potentiam, sicut patet in corde. Unde nihil prohibet in iis quae sunt divisibilia in potentia, esse unum primum. And he resolves the doubt in the following manner, stating, namely, that there is nothing to prevent the mover and moved from being divisible in potency, due to the fact that they are continua, i.e., if both are continua, or at least one of them, namely, the one that is moved, which necessarily is a continuum. But yet it is possible that some continuum, whether it be a mover or something moved, have such a nature that it cannot be actually divided, as is evident of the body of the Sun. And if it happens that some continuum is divided, it will not retain the same potency for causing motion or being moved as it had before—because such a potency follows upon the form, and a natural form requires a determinate quantity. Hence, if it is an incorruptible body, it cannot be actually divided. But if it is a corruptible one, then if it be divided, it will not retain the same potency, as is evident with respect to the heart. Hence, there is nothing to prevent, in things potentially divisible, there being one first.
Deinde cum dicit: manifestum igitur ex his etc., infert conclusionem principaliter intentam ex omnibus praemissis. Et dicit manifestum esse ex praemissis, quod necesse est ponere primum movens immobile. Cum enim non procedatur in infinitum in moventibus et motis ab alio, sed necesse sit stare ad aliquod primum, quod est immobile vel movens seipsum; sive moventia et mota stent ad aliquod primum immobile, sive ad aliquod primum quod movet seipsum, utrobique accidit quod primum movens sit immobile; propter hoc quod moventis etiam seipsum una pars est movens immobile, ut nunc ostensum est. 1068, Then at (837) he infers the conclusion mainly intended from all this. And he says that from the foregoing it is clear that it is necessary to posit a first mover that is immobile. For since there is not an infinite process in movers and moved things, but a halt must be made at a first which is immobile or self-moving, then, whether the movers and moved stop at some first immobile or at some first that moves itself, in either case it turns out that the first mover is immobile, because one part even of a thing that moves itself is an immobile mover, as has just been proved.

Lectio 12
The first mover is not moved, but is one and perpetual.
Chapter 6
Ἐπεὶ δὲ δεῖ κίνησιν ἀεὶ εἶναι καὶ μὴ διαλείπειν, ἀνάγκη εἶναί τι ἀΐδιον ὃ πρῶτον κινεῖ, εἴτε ἓν εἴτε πλείω· καὶ τὸ πρῶτον κινοῦν ἀκίνητον. Since there must always be motion without intermission, there must necessarily be something, one thing or it may be a plurality, that first imparts motion, and this first movent must be unmoved.
ἕκαστον μὲν οὖν ἀΐδιον εἶναι τῶν ἀκινήτων μὲν κινούντων δὲ οὐδὲν πρὸς τὸν νῦν λόγον· Now the question whether each of the things that are unmoved but impart motion is eternal is irrelevant to our present argument:
ὅτι δ' ἀναγκαῖον εἶναί τι τὸ ἀκίνητον μὲν αὐτὸ πάσης ἐκτὸς μεταβολῆς, καὶ ἁπλῶς καὶ κατὰ συμβεβηκός, κινητικὸν δ' ἑτέρου, δῆλον ὧδε σκοποῦσιν. but the following considerations will make it clear that there must necessarily be some such thing, which, while it has the capacity of moving something else, is itself unmoved and exempt from all change, which can affect it neither in an unqualified nor in an accidental sense.
ἔστω δή, εἴ τις βούλεται, ἐπί τινων ἐνδεχόμενον ὥστε εἶναί ποτε καὶ μὴ εἶναι ἄνευ γενέσεως καὶ φθορᾶς (τάχα γὰρ ἀναγκαῖον, εἴ τι ἀμερὲς ὁτὲ μὲν ἔστιν ὁτὲ δὲ μὴ ἔστιν, ἄνευ τοῦ μεταβάλλειν ὁτὲ μὲν εἶναι ὁτὲ δὲ μὴ εἶναι πᾶν τὸ τοιοῦτον). καὶ τῶν ἀρχῶν τῶν ἀκινήτων μὲν κινητικῶν δ' ἐνίας ὁτὲ μὲν εἶναι ὁτὲ δὲ μὴ εἶναι, ἐνδεχέσθω καὶ τοῦτο. ἀλλ' οὔ τί γε πάσας δυνατόν· Let us suppose, if any one likes, that in the case of certain things it is possible for them at different times to be and not to be, without any process of becoming and perishing (in fact it would seem to be necessary, if a thing that has not parts at one time is and at another time is not, that any such thing should without undergoing any process of change at one time be and at another time not be). And let us further suppose it possible that some principles that are unmoved but capable of imparting motion at one time are and at another time are not. Even so, this cannot be true of all such principles,
δῆλον γὰρ ὡς αἴτιον τοῖς αὐτὰ ἑαυτὰ κινοῦσίν ἐστί τι τοῦ ὁτὲ μὲν εἶναι ὁτὲ δὲ μή. τὸ μὲν γὰρ αὐτὸ ἑαυτὸ κινοῦν ἅπαν ἔχειν ἀνάγκη μέγεθος, εἰ μηδὲν κινεῖται ἀμερές, τὸ δὲ κινοῦν οὐδεμία ἀνάγκη ἐκ τῶν εἰρημένων. τοῦ δὴ τὰ μὲν γίγνεσθαι τὰ δὲ φθείρεσθαι, καὶ τοῦτ' εἶναι συνεχῶς, οὐδὲν αἴτιον τῶν ἀκινήτων μὲν μὴ ἀεὶ δ' ὄντων, οὐδ' αὖ τωνδὶ μὲν ταδί [κινούντων], τούτων δ' ἕτερα. τοῦ γὰρ ἀεὶ καὶ συνεχοῦς οὔτε ἕκαστον αὐτῶν οὔτε πάντα αἴτια· τὸ μὲν γὰρ οὕτως ἔχειν ἀΐδιον καὶ ἐξ ἀνάγκης, τὰ δὲ πάντα ἄπειρα, καὶ οὐχ ἅμα πάντα ὄντα. δῆλον τοίνυν ὅτι, εἰ καὶ μυριάκις ἔνια [ἀρχαὶ] (259a.) τῶν ἀκινήτων μὲν κινούντων δέ, καὶ πολλὰ τῶν αὐτὰ ἑαυτὰ κινούντων, φθείρεται, τὰ δ' ἐπιγίγνεται, καὶ τόδε μὲν ἀκίνητον ὂν τόδε κινεῖ, ἕτερον δὲ τοδί, ἀλλ' οὐδὲν ἧττον ἔστιν τι ὃ περιέχει, καὶ τοῦτο παρ' ἕκαστον, ὅ ἐστιν αἴτιον τοῦ τὰ μὲν εἶναι τὰ δὲ μὴ καὶ τῆς συνεχοῦς μεταβολῆς· καὶ τοῦτο μὲν τούτοις, ταῦτα δὲ τοῖς ἄλλοις αἴτια κινήσεως. εἴπερ οὖν ἀΐδιος ἡ κίνησις, ἀΐδιον καὶ τὸ κινοῦν ἔσται πρῶτον, εἰ ἕν· εἰ δὲ πλείω, πλείω τὰ ἀΐδια. since there must clearly be something that causes things that move themselves at one time to be and at another not to be. For, since nothing that has not parts can be in motion, that which moves itself must as a whole have magnitude, though nothing that we have said makes this necessarily true of every movent. So the fact that some things become and others perish, and that this is so continuously, cannot be caused by any one of those things that, though they are unmoved, do not always exist: nor again can it be caused by any of those which move certain particular things, while others move other things. The eternity and continuity of the process cannot be caused either by any one of them singly or by the sum of them, because this causal relation must be eternal and necessary, whereas the sum of these movents is infinite and they do not all exist together. It is clear, then, that though there may be countless instances of the perishing of some principles that are unmoved but impart motion, and though many things that move themselves perish and are succeeded by others that come into being, and though one thing that is unmoved moves one thing while another moves another, nevertheless there is something that comprehends them all, and that as something apart from each one of them, and this it is that is the cause of the fact that some things are and others are not and of the continuous process of change: and this causes the motion of the other movents, while they are the causes of the motion of other things. Motion, then, being eternal, the first movent, if there is but one, will be eternal also: if there are more than one, there will be a plurality of such eternal movents.
ἓν δὲ μᾶλλον ἢ πολλά, καὶ πεπερασμένα ἢ ἄπειρα, δεῖ νομίζειν. τῶν αὐτῶν γὰρ συμβαινόντων αἰεὶ τὰ πεπερασμένα μᾶλλον ληπτέον· ἐν γὰρ τοῖς φύσει δεῖ τὸ πεπερασμένον καὶ τὸ βέλτιον, ἂν ἐνδέχηται, ὑπάρχειν μᾶλλον. ἱκανὸν δὲ καὶ ἕν, ὃ πρῶτον τῶν ἀκινήτων ἀΐδιον ὂν ἔσται ἀρχὴ τοῖς ἄλλοις κινήσεως. We ought, however, to suppose that there is one rather than many, and a finite rather than an infinite number. When the consequences of either assumption are the same, we should always assume that things are finite rather than infinite in number, since in things constituted by nature that which is finite and that which is better ought, if possible, to be present rather than the reverse: and here it is sufficient to assume only one movent, the first of unmoved things, which being eternal will be the principle of motion to everything else.
φανερὸν δὲ καὶ ἐκ τοῦδε ὅτι ἀνάγκη εἶναί τι ἓν καὶ ἀΐδιον τὸ πρῶτον κινοῦν. δέδεικται γὰρ ὅτι ἀνάγκη ἀεὶ κίνησιν εἶναι. εἰ δὲ ἀεί, ἀνάγκη συνεχῆ εἶναι· καὶ γὰρ τὸ ἀεὶ συνεχές, τὸ δ' ἐφεξῆς οὐ συνεχές. ἀλλὰ μὴν εἴ γε συνεχής, μία. μία δ' ἡ ὑφ' ἑνός τε τοῦ κινοῦντος καὶ ἑνὸς τοῦ κινουμένου· εἰ γὰρ ἄλλο καὶ ἄλλο κινήσει, οὐ συνεχὴς ἡ ὅλη κίνησις, ἀλλ' ἐφεξῆς. ἔκ τε δὴ τούτων πιστεύσειεν ἄν τις εἶναί τι πρῶτον ἀκίνητον, The following argument also makes it evident that the first movent must be something that is one and eternal. We have shown that there must always be motion. That being so, motion must also be continuous, because what is always is continuous, whereas what is merely in succession is not continuous. But further, if motion is continuous, it is one: and it is one only if the movent and the moved that constitute it are each of them one, since in the event of a thing's being moved now by one thing and now by another the whole motion will not be continuous but successive. Moreover a conviction that there is a first unmoved something may be reached not only from the foregoing arguments,
Postquam philosophus ostendit quod in iis quae moventur ab alio, non est procedere in infinitum, sed est devenire ad aliquod primum, quod vel est immobile vel movet seipsum: et ostendit ulterius quod moventis seipsum una pars est movens immobile, et sic utrobique accidit quod primum movens sit immobile; quia tamen in moventibus se quae sunt apud nos, scilicet animalibus corruptibilibus, contingit quod pars movens in movente seipsum est corruptibilis et movetur per accidens, scilicet anima: vult hic ostendere quod primum movens est incorruptibile, et non movetur nec per se nec per accidens. Et circa hoc duo facit: primo proponit quod intendit; secundo probat, ibi: sit autem si aliquis velit et cetera. 1069. Having shown that in things moved by another there is not a process to infinity but a first must be reached which is either immobile or a mover of self, and having shown that, of a thing that moves itself, one part is an immobile mover, and that, consequently, in either case there is a first mover that is immobile, now, because among self-movers which exist among us, namely, perishable animals, it happens that the motion-causing part in the thing which moves itself is perishable and moved per accidens, namely, the soul, the Philosopher wishes to show here that the first mover is imperishable and is not moved either per se or per accidens. About this he does two things: First he proposes what he intends; Secondly, he proves it, at 1072.
Circa primum tria facit: primo resumit ea quae supra ostensa sunt; secundo praetermittit quoddam quod videbatur posse valere ad suum propositum, ibi: unumquodque igitur etc.; tertio exponit suum propositum, ibi: quoniam autem necessarium est esse et cetera. About the first he does three things: First he reviews what has been previously manifested; Secondly, he omits something that seemed useful for his proposition, at 1070; Thirdly, he explains his proposition, at 1071,
Dicit ergo primo, quod supra ostensum est quod motus semper est et nunquam deficit: et quia omnis motus est ab aliquo movente, in moventibus autem non est procedere in infinitum, necesse est esse aliquod primum movens. Et quia nondum probatum est quod primum movens sit unum, ideo sub dubio derelinquit utrum sit unum vel plura. Et ulterius ostensum est quod primum movens est immobile, sive statim ascendendo de motis ad moventia perveniatur ad primum immobile, sive perveniatur ad primum movens seipsum, cuius una pars est movens immobile. He says therefore first (838) that it was shown above that motion always exists and never fails. And since all motion is from a mover, and in movers there is not a process to infinity, it is necessary that there be a first mover. And since it has not yet been proved that the first mover is one, he accordingly lets it remain doubtful whether it is one or many. Further, it has been shown that the first mover is immobile, whether by ascending from moved to movers one immediately reaches a first immobile mover, or whether what is reached is a first mover that moves itself, one part of which is an immobile mover.
Fuit autem quorundam positio, quod omnia principia moventia in iis quae movent seipsa, sunt perpetua: posuit enim Plato omnes animas animalium perpetuas. Et si vera esset haec opinio, iam statim Aristoteles haberet propositum quantum ad hoc quod primum movens sit perpetuum. Sed opinio Aristotelis est, quod de partibus animae solus intellectus est incorruptibilis; cum tamen etiam aliae partes animae sint moventes. 1070. Some have opined that all moving principles in things that move themselves are imperishable, for Plato posited all the souls of animals to be perpetual. And if this opinion were true, Aristotle would have his proposition clinched at once, so far as the first mover’s being eternal is concerned. But the opinion of Aristotle is that among the parts of the soul, only the intellect is imperishable, even though other parts of the soul are movers.
Et ideo hoc consequenter praetermittit, dicens: unumquodque igitur et cetera. Et dicit quod ad rationem quae prae manibus habetur, nihil pertinet an unumquodque principiorum quae movent et sunt immobilia, sit perpetuum, quamvis hoc aliqui posuerunt, ponentes omnes animas incorruptibiles. Et dicit hoc non esse ad praesentem rationem, quia hoc non supposito, habebit propositum. Consequently he omits this at (839) where he says that as far as the present argument is concerned it is of no moment whether each of the principles that move themselves and are immobile is imperishable, even though some have posited this by positing that all souls are imperishable. And he says that this does not affect the present argument, because he will prove his proposition without using this supposition.
Deinde cum dicit: quoniam autem necessarium etc., exponit quid intendit probare. Et dicit quod considerando ea quae sequuntur, manifestum potest esse quod, etsi non omne movens immobile sit perpetuum, necesse est tamen esse aliquid immobile, ita quod nullo modo ab extrinseco moveatur, nec simpliciter nec per accidens, et tamen sit motivum alterius. 1071. Then at (840) he explains what he intends to prove. And he says that by considering the things that follow, it can be plain that even though not every immobile mover is imperishable, there must be something immobile in such a way that it is no way moved from without, either absolutely or per accidens, and yet is a mover of something else.
Dicit autem ab omni exterius mutatione, non intendens excludere motum, idest operationem, quae est in operante, prout intelligere dicitur motus, et prout appetitus movetur ab appetibili. Huiusmodi enim motus non excluditur a primo movente de quo intendit. When he says “immobile with respect to any change from without,” he does not mean to exclude a motion, i.e., an operation, which is in the one operating in the sense that to understand is called a “motion,” and in the sense that the appetite is moved by the desirable object. A motion of this sort is not excluded from the first mover which Aristotle is discussing.
Deinde cum dicit: sit autem si aliquis etc., probat quod dixerat, scilicet quod sit aliquod primum movens perpetuum et penitus immobile. Et primo probat hoc per moventia se, quae quandoque sunt et quandoque non sunt; secundo per principia moventia, quae quandoque movent et quandoque non movent, ibi: et iterum considerans et cetera. 1072. Then at (841) he proves what he had said, namely, that there exists a first mover that is eternal and entirely immobile. First he proves this through self-movers that at one time exist and at another time do not; Secondly, through moving principles which sometimes are causing motion and sometimes not, (L. 13).
Circa primum tria facit: primo ostendit quod oportet esse aliquod primum movens perpetuum; secundo quod tale movens magis debet esse unum quam plura, ibi: unum autem magis etc.; tertio ostendit utrumque simul, scilicet quod est unum primum movens et perpetuum, ibi: manifestum igitur ex his et cetera. About the first he does three things: First he shows that there must be a first mover that is eternal; Secondly, that such a mover should be one rather than many, at 1075; Thirdly, he shows both at once, i.e., that there is one first mover and that it is eternal, at 1076.
Circa primum duo facit: primo excludit quandam rationem, per quam aliquis posset niti ad probandum propositum; secundo procedit ad propositum ostendendum, ibi: manifestum est enim et cetera. About the first he does two things: First he rejects an argument by which some could try to prove this proposition; Secondly, he goes on to explain his proposition, at 1074.
Posset autem aliquis sic procedere. Omne quod non potest quandoque esse et quandoque non esse, est perpetuum: sed primum movens, cum sit immobile, ut ostensum est, non potest quandoque esse et quandoque non esse; quia quod quandoque est et quandoque non est, generatur et corrumpitur; quod autem generatur et corrumpitur, movetur: ergo primum movens est perpetuum. 1073. Now, someone could proceed as follows (841): Whatever cannot at one time be and at another not be is eternal; but the first mover, since it is immobile, as has been shown above, cannot be at one time and not be at another time, for whatever is such is generated and ceases to be, which involves its being moved. Therefore, the first mover is eternal.
Aristoteles autem de hac ratione non curat: quia potest aliquis dicere si vult, quod in quibusdam contingit quod quandoque sint et quandoque non sint, absque hoc quod generentur et corrumpantur per se loquendo, et per consequens absque hoc quod per se moveantur. Necesse est enim, si aliquid impartibile, quod scilicet non sit compositum ex materia et forma, quandoque sic est et quandoque non est, quod omne tale sine mutatione sui quandoque sit et quandoque non sit; sicut potest dici de puncto et de albedine et de quolibet huiusmodi: ostensum est enim in sexto quod omne quod movetur est partibile, et in VII Metaphys. quod omne quod generatur est compositum ex materia et forma. Huiusmodi quidem igitur impartibilia per se quidem non generantur neque mutantur, sed per accidens, generatis aut mutatis aliis. But Aristotle does not have any use for this argument, because someone could say, if he wants, that in some things it happens that at one time they exist and at another time they do not, without their being generated or ceasing to be, speaking per se, and consequently without their being moved per se. For if something not divisible into parts, which is, namely, not composed of matter and form, is at one time in a certain way, and at another time is not, then necessarily every such thing—without any self-change—does at one time exist and at another time not exist, as may be said of a point, and of whiteness, and of anything of this sort, for it has been shown in Book VI that whatever is moved can be divided into parts, and in Metaphysics VII that whatever is generated is composed of matter and form. Such non-divisible things, therefore, are neither generated nor changed per se, but per accidens, when other things are generated or changed.
Ex quo etiam patet quod si aliquid neque per se neque per accidens movetur, quod illud est perpetuum: et si est perpetuum, neque per accidens neque per se movetur, secundum hoc quod est perpetuum. Si ergo conceditur esse contingens quod aliquid quandoque sit et quandoque non sit, absque eo quod generetur et corrumpatur; etiam et hoc concedatur esse contingens, quod quaedam principia moventia immobilia, ita tamen quod possint moveri per accidens, quandoque sint et quandoque non sint. Nequaquam tamen possibile est omnia principia moventia et immobilia talia esse, ut quandoque sint et quandoque non sint. From this it is also plain that if something is moved neither per se nor per accidens, it is eternal; and that if it is eternal, it is moved neither per se nor per accidens, insofar as it is eternal. If, therefore, it is conceded to be contingent for something to exist at one time and not at another without its being generated or ceasing to be, then let it also be conceded to be contingent that certain immobile moving principles, which are yet mobile per accidens, exist at one time and do not exist at another. Nevertheless it is not at all possible that all such principles which are movers and immobile be such that they exist at one time and not exist at another.
Deinde cum dicit: manifestum est enim etc., ostendit propositum. Et dicit quod si quaedam moventia seipsa quandoque sunt et quandoque non sunt, necesse est quod sit aliqua causa generationis et corruptionis ipsorum, qua quandoque sunt et quandoque non sunt: quia omne quod movetur, habet causam sui motus; quod autem quandoque est et quandoque non est, si sit compositum, generatur et corrumpitur. Movens autem seipsum necesse est quod habeat magnitudinem, quia movetur, et ostensum est in sexto quod nihil impartibile movetur. 1074. Then at (842) he proves his proposition. And he says that if some things which move themselves exist at one time and not at another, then there must be a cause of their generation and ceasing-to-be, by virtue of which they exist at one time and do not exist at another, because whatever is moved has a cause of its motion. But what exists at one time and not at another, if it is a composite, is generated and ceases-to-be. Now, a thing that moves itself must possess magnitude, since it is moved, and it has been shown in Book VI that nothing indivisible into parts is moved.
Sed ex dictis non potest haberi quod sit necessarium movens habere magnitudinem, et sic non movetur per se, si quandoque sit et quandoque non sit. Si autem generationis et corruptionis eorum quae movent seipsa, est aliqua causa, oportet quod etiam huius sit aliqua causa, quod eorum generatio et corruptio perpetue continuatur. But from the foregoing it cannot be held that it is necessary for the mover to have magnitude, and thus it is not moved per se, if it exists at one time and does not exist at another. But if there is a cause of the generation and perishing of things that move themselves, then there must also be a cause to account for their generation and perishing being continued forever.
Non autem potest dici quod huius continuitatis causa sit aliquod illorum immobilium quae non semper sunt: neque etiam potest dici quod sempiternae generationis et corruptionis quorundam moventium seipsa, sint causa quaedam moventia immobilia quae non semper sunt, et aliorum alia. Et hoc exponit subdens, quod huius continuae et sempiternae generationis non potest esse causa neque unum ipsorum neque omnia. But it cannot be said that the cause of this continuity is one of those immobiles that do not always exist, nor can it be said that the cause of the eternal generation and perishing of some things that move themselves are certain immobile movers which do not always exist, and of that of others, certain others. And he explains this when he says that not one, nor all of them, can be the cause of this continuous and eternal generation.
Et quod unum non possit esse causa, sic ostendit: quia illud quod non est semper, non potest esse causa eius quod est semper perpetuum et ex necessitate. Quod autem omnia non possint esse causa, ostendit per hoc quod omnia huiusmodi principia corruptibilia, si generatio est perpetua, sunt infinita et non simul sunt: impossibile est autem unum effectum dependere ex infinitis causis. That one of them cannot be the cause he thus proves: What does not exist forever cannot be the cause of what is forever perpetual and necessary. That all cannot be the cause he proves for the reason that all such perishable principles, if generation is perpetual, are infinite and do not all exist at once. But it is impossible for one effect to depend on an infinitude of causes.
Et iterum ea quae non simul sunt, non possunt esse causa alicuius; licet possit esse quod eorum quae non simul sunt, quaedam disponant et quaedam causent, ut patet in guttis successive cadentibus, quae causant lapidis effossionem: sed si aliqua multa sunt directe causa alicuius, oportet quod simul sint. And again, things that do not exist at once cannot be the cause of one thing, although it could be said that when things do not exist all at once, some dispose and some cause, as is plain with respect to drops that fall successively and wear away a stone. But if a number of things are a direct cause of anything, they must exist all together.
Sic igitur manifestum est quod si sint mille millia principia moventia et immobilia; et si sint etiam multa quae moveant seipsa, quorum quaedam corrumpantur et alia generentur; et inter ista, quaedam sint mobilia et quaedam moventia: nihilominus tamen oportet esse aliquid super omnia, quod sua virtute contineat omnia quae praedicto modo generantur et corrumpuntur: quod quidem sit causa continuae mutationis ipsorum, per quam quandoque sunt et quandoque non sunt; et per quam haec sunt causa generationis et motus his et haec aliis: quia omne generans est causa generationis generato, sed tamen generantia corruptibilia habent quod sint causa generationis, ab aliquo primo incorruptibili. Si ergo motus, per quem quaedam quandoque sunt et quandoque non sunt, est perpetuus, ut supra ostensum est; et effectus perpetuus non potest esse nisi a causa perpetua: necesse est quod primum movens sit perpetuum, si est unum; et si sunt plura prima moventia, quod etiam illa plura sint perpetua. Accordingly, therefore, it is manifest that if there are a million principles that are movers and immobile, and if there are many things that move themselves, of which some perish and others come to be, and among these, some are mobile and some movers, nevertheless there must be something above all of them that by its power contains all the things which are generated and perish in the above-mentioned way and which would be the cause of the continual change affecting them by which they sometimes are and sometimes are not and through which these latter are the cause of coming-to-be and of motion for others, and these for yet others. For every generator is a cause of generation to the thing generated, but it is from some imperishable first principle that perishable generators possess the characteristic of being causes of generation. If, therefore, the motion through which some things at one time exist and at another do not is perpetual, as has been shown above, and a perpetual effect cannot exist except from a perpetual cause, then, necessarily, the first mover is perpetual, if it is one; and if there are more than one first mover, they too are perpetual.
Deinde cum dicit: unum autem magis etc., ostendit quod magis debeat poni unum principium perpetuum quam multa. Et dicit quod sicut oportet existimare magis esse principia finita quam infinita, ita oportet existimare quod sit magis unum primum principium quam plura. Si enim eadem accidant vel consequantur in effectibus ex positione finitorum principiorum, quae ex positione infinitorum, magis est accipiendum quod sint principia finita quam infinita: quia in his quae sunt secundum naturam, semper est magis accipiendum illud quod est melius, si sit possibile, quia ea quae sunt secundum naturam, sunt optime disposita; melius autem est finitum principium quam infinitum, et unum quam multa. Sufficit autem ad causandum perpetuitatem motus, quod sit unum primum principium immobile, si sit perpetuum: non ergo sunt ponenda plura prima principia. 1075. Then at (843) he shows that one perpetual principle ought to be posited rather than many. And he says that just as finite principles ought to be preferred to infinite, so one first principle rather than many. For if the same effects happen or follow from positing finite principles as from positing infinite principles, one should assume that the principles are finite rather than infinite, because in things that are according to nature, the preference must be given to what is better, if it is possible, because things that are according to nature are disposed the best. Now, a finite principle is better than an infinite one, and one better than many. But one first immobile principle, if it is perpetual, is sufficient for causing the perpetuity of motion. Therefore, many first principles should not be posited.
Deinde cum dicit: manifestum igitur ex his etc., concludit ex praedictis quod necesse est esse aliquod unum primum movens et perpetuum. 1076. Then at (844) he concludes from the foregoing that it is necessary that there be one first mover which is imperishable.
Et quamvis hoc ex superioribus sufficienter probatum videatur, posset tamen aliquis calumniose dicere, quod causa continuitatis generationis est aliquod primum movens seipsum perpetuum: sed motor illius moventis seipsum, non est perpetuum et unum, sed movetur a diversis moventibus, quorum quaedam corrumpuntur et quaedam generantur. And although this seems to be sufficiently proved from the foregoing, yet someone could cavil that the cause of the continuity of generation is a perpetual first mover of self, but the mover of that is not perpetual and one but moved by diverse movers, of which some cease to be and some come to be.
Sed hoc intendit excludere: quia si motus est perpetuus, ut supra probaverat, necesse est quod motus primi moventis seipsum, quod ponitur causa totius perpetuitatis motus, sit sempiternus et continuus: si enim non esset continuus, non esset sempiternus. Sed quod consequenter est, non est continuum: ad hoc autem quod motus sit continuus, necesse est quod sit unus: ad hoc vero quod sit unus, necesse est quod sit ab uno movente et unius mobilis. Si vero sit aliud et aliud movens, non erit totus motus continuus, sed consequenter se habens. But this he intends to dismiss, because if motion is perpetual, as he had proved above, then necessarily the motion of the first mover of self, which is posited as the cause of the entire perpetuity of motion, is eternal and continuous, for if it were not continuous, it would not be eternal. However, what is successive is not continuous, whereas in order that a motion be continuous it must be one; and in order to be one, it must be from one mover and in one mobile. But if the mover is other and other, the motion will not be a whole continuous motion, but a successive one.
Necesse est ergo omnino quod primum movens sit unum et perpetuum. Movens autem immobile quod movetur per accidens, non est perpetuum, ut supra dictum est. Relinquitur ergo quod primum movens sit omnino immobile, et per se et per accidens. Therefore, it is absolutely necessary that the first mover be one and perpetual. But an immobile mover that is moved per accidens is not perpetual, as has been said above. It remains, therefore, that the first mover is utterly immobile, both per se and per accidens.

Lectio 13
The first mover perpetual and wholly unmoved, as shown from moving principles
Chapter 6 cont.
καὶ πάλιν ἐπιβλέψας ἐπὶ τὰς ἀρχάς [τῶν κινούντων]. τὸ μὲν δὴ εἶναι ἄττα τῶν ὄντων ἃ ὁτὲ μὲν κινεῖται ὁτὲ δὲ ἠρεμεῖ φανερόν. καὶ διὰ τούτου γέγονε δῆλον ὅτι οὔτε πάντα κινεῖται οὔτε πάντα ἠρεμεῖ οὔτε τὰ μὲν ἀεὶ ἠρεμεῖ τὰ δὲ ἀεὶ κινεῖται· τὰ γὰρ ἐπαμφοτερί ζοντα καὶ δύναμιν ἔχοντα τοῦ κινεῖσθαι καὶ ἠρεμεῖν δείκνυσιν περὶ αὐτῶν. but also by considering again the principles operative in movents. Now it is evident that among existing things there are some that are sometimes in motion and sometimes at rest. This fact has served above to make it clear that it is not true either that all things are in motion or that all things are at rest or that some things are always at rest and the remainder always in motion: on this matter proof is supplied by things that fluctuate between the two and have the capacity of being sometimes in motion and sometimes at rest.
ἐπεὶ δὲ τὰ μὲν τοιαῦτα δῆλα πᾶσι, βουλόμεθα δὲ δεῖξαι καὶ τοῖν δυοῖν ἑκατέρου τὴν φύσιν, ὅτι ἔστιν τὰ μὲν ἀεὶ ἀκίνητα τὰ δὲ ἀεὶ κινούμενα, προϊόντες δ' ἐπὶ τοῦτο καὶ θέντες ἅπαν τὸ κινούμενον ὑπό τινος κινεῖ σθαι, καὶ τοῦτ' εἶναι ἢ ἀκίνητον ἢ κινούμενον, καὶ κινούμενον ἢ ὑφ' αὑτοῦ ἢ ὑπ' ἄλλου ἀεί, προήλθομεν ἐπὶ τὸ λαβεῖν ὅτι τῶν κινουμένων ἐστὶν ἀρχὴ κινουμένων μὲν ὃ αὐτὸ ἑαυτὸ (259b.) κινεῖ, πάντων δὲ τὸ ἀκίνητον, ὁρῶμεν δὲ καὶ φανερῶς ὄντα τοιαῦτα ἃ κινεῖ αὐτὰ ἑαυτά, οἷον τὸ τῶν ἐμψύχων καὶ τὸ τῶν ζῴων γένος, The existence of things of this kind is clear to all: but we wish to explain also the nature of each of the other two kinds and show that there are some things that are always unmoved and some things that are always in motion. In the course of our argument directed to this end we established the fact that everything that is in motion is moved by something, and that the movent is either unmoved or in motion, and that, if it is in motion, it is moved either by itself or by something else and so on throughout the series: and so we proceeded to the position that the first principle that directly causes things that are in motion to be moved is that which moves itself, and the first principle of the whole series is the unmoved. Further it is evident from actual observation that there are things that have the characteristic of moving themselves, e.g. the animal kingdom and the whole class of living things.
ταῦτα δὲ καὶ δόξαν παρεῖχε μή ποτε ἐνδέχεται κίνησιν ἐγγίγνεσθαι μὴ οὖσαν ὅλως, διὰ τὸ ἐν τούτοις ὁρᾶν ἡμᾶς τοῦτο συμβαῖνον (ἀκίνητα γάρ ποτε ὄντα κινεῖ ται πάλιν, ὡς δοκεῖ), τοῦτο δὴ δεῖ λαβεῖν, ὅτι μίαν κίνησιν αὑτὰ κινεῖ, καὶ ὅτι ταύτην οὐ κυρίως· οὐ γὰρ ἐξ αὐτοῦ τὸ αἴτιον, ἀλλ' ἔνεισιν ἄλλαι κινήσεις φυσικαὶ τοῖς ζῴοις, ἃς οὐ κινοῦνται δι' αὑτῶν, οἷον αὔξησις φθίσις ἀναπνοή, ἃς κινεῖται τῶν ζῴων ἕκαστον ἠρεμοῦν καὶ οὐ κινούμενον τὴν ὑφ' αὑτοῦ κίνησιν. τούτου δ' αἴτιον τὸ περιέχον καὶ πολλὰ τῶν εἰσιόντων, οἷον ἐνίων ἡ τροφή· πεττομένης μὲν γὰρ καθεύδουσιν, διακρινομένης δ' ἐγείρονται καὶ κινοῦσιν ἑαυτούς, τῆς πρώτης ἀρχῆς ἔξωθεν οὔσης, διὸ οὐκ ἀεὶ κινοῦνται συνεχῶς ὑφ' αὑτῶν· ἄλλο γὰρ τὸ κινοῦν, αὐτὸ κινούμενον καὶ μεταβάλλον πρὸς ἕκαστον τῶν κινούντων ἑαυτά. ἐν πᾶσι δὲ τούτοις κινεῖται τὸ κινοῦν πρῶτον καὶ τὸ αἴτιον τοῦ αὐτὸ ἑαυτὸ κινεῖν ὑφ' αὑτοῦ, κατὰ συμβεβηκὸς μέντοι· μεταβάλλει γὰρ τὸν τόπον τὸ σῶμα, ὥστε καὶ τὸ ἐν τῷ σώματι ὂν καὶ τῇ μοχλείᾳ κινοῦν ἑαυτό. This being so, then, the view was suggested that perhaps it may be possible for motion to come to be in a thing without having been in existence at all before, because we see this actually occurring in animals: they are unmoved at one time and then again they are in motion, as it seems. We must grasp the fact, therefore, that animals move themselves only with one kind of motion, and that this is not strictly originated by them. The cause of it is not derived from the animal itself: it is connected with other natural motions in animals, which they do not experience through their own instrumentality, e.g. increase, decrease, and respiration: these are experienced by every animal while it is at rest and not in motion in respect of the motion set up by its own agency: here the motion is caused by the atmosphere and by many things that enter into the animal: thus in some cases the cause is nourishment: when it is being digested animals sleep, and when it is being distributed through the system they awake and move themselves, the first principle of this motion being thus originally derived from outside. Therefore animals are not always in continuous motion by their own agency: it is something else that moves them, itself being in motion and changing as it comes into relation with each several thing that moves itself. (Moreover in all these self-moving things the first movent and cause of their self-motion is itself moved by itself, though in an accidental sense: that is to say, the body changes its place, so that that which is in the body changes its place also and is a self-movent through its exercise of leverage.)
ἐξ ὧν ἔστιν πιστεῦσαι ὅτι εἴ τί ἐστι τῶν ἀκινήτων μὲν κινούντων δὲ καὶ αὑτὰ κατὰ συμβεβηκός, ἀδύνατον συνεχῆ κίνησιν κινεῖν. ὥστ' εἴπερ ἀνάγκη συνεχῶς εἶναι κίνησιν, εἶναί τι δεῖ τὸ πρῶτον κινοῦν ἀκίνητον καὶ κατὰ συμβεβηκός, εἰ μέλλει, καθάπερ εἴπομεν, ἔσεσθαι ἐν τοῖς οὖσιν ἄπαυστός τις καὶ ἀθάνατος κίνησις, καὶ μενεῖν τὸ ὂν αὐτὸ ἐν αὑτῷ καὶ ἐν τῷ αὐτῷ· τῆς γὰρ ἀρχῆς μενούσης ἀνάγκη καὶ τὸ πᾶν μένειν συνεχὲς ὂν πρὸς τὴν ἀρχήν. Hence we may confidently conclude that if a thing belongs to the class of unmoved movents that are also themselves moved accidentally, it is impossible that it should cause continuous motion. So the necessity that there should be motion continuously requires that there should be a first movent that is unmoved even accidentally, if, as we have said, there is to be in the world of things an unceasing and undying motion, and the world is to remain permanently self-contained and within the same limits: for if the first principle is permanent, the universe must also be permanent, since it is continuous with the first principle.
οὐκ ἔστιν δὲ τὸ αὐτὸ τὸ κινεῖσθαι κατὰ συμβεβηκὸς ὑφ' αὑτοῦ καὶ ὑφ' ἑτέρου· τὸ μὲν γὰρ ὑφ' ἑτέρου ὑπάρχει καὶ τῶν ἐν τῷ οὐρανῷ ἐνίαις ἀρχαῖς, ὅσα πλείους φέρεται φοράς, θάτερον δὲ τοῖς φθαρτοῖς μόνον. (We must distinguish, however, between accidental motion of a thing by itself and such motion by something else, the former being confined to perishable things, whereas the latter belongs also to certain first principles of heavenly bodies, of all those, that is to say, that experience more than one locomotion.)
ἀλλὰ μὴν εἴ γε ἔστιν τι ἀεὶ τοιοῦτον, κινοῦν μέν τι ἀκίνητον δὲ αὐτὸ καὶ ἀΐδιον, ἀνάγκη καὶ τὸ πρῶτον ὑπὸ τούτου (260a.) κινούμενον ἀΐδιον εἶναι. And further, if there is always something of this nature, a movent that is itself unmoved and eternal, then that which is first moved by it must be eternal.
ἔστιν δὲ τοῦτο δῆλον μὲν καὶ ἐκ τοῦ μὴ ἂν ἄλλως εἶναι γένεσιν καὶ φθορὰν καὶ μεταβολὴν τοῖς ἄλλοις, εἰ μή τι κινήσει κινούμενον· τὸ μὲν γὰρ ἀκίνητον [τὴν αὐτὴν] ἀεὶ τὸν αὐτὸν κινήσει τρόπον καὶ μίαν κίνησιν, ἅτε οὐδὲν αὐτὸ μεταβάλλον πρὸς τὸ κινούμενον. τὸ δὲ κινούμενον ὑπὸ τοῦ κινουμένου μέν, ὑπὸ τοῦ ἀκινήτου δὲ κινουμένου ἤδη, διὰ τὸ ἄλλως καὶ ἄλλως ἔχειν πρὸς τὰ πράγματα, οὐ τῆς αὐτῆς ἔσται κινήσεως αἴτιον, ἀλλὰ διὰ τὸ ἐν ἐναντίοις εἶναι τόποις ἢ εἴδεσιν ἐναντίως παρέξεται κινούμενον ἕκαστον τῶν ἄλλων, καὶ ὁτὲ μὲν ἠρεμοῦν ὁτὲ δὲ κινούμενον. Indeed this is clear also from the consideration that there would otherwise be no becoming and perishing and no change of any kind in other things, which require something that is in motion to move them: for the motion imparted by the unmoved will always be imparted in the same way and be one and the same, since the unmoved does not itself change in relation to that which is moved by it. But that which is moved by something that, though it is in motion, is moved directly by the unmoved stands in varying relations to the things that it moves, so that the motion that it causes will not be always the same: by reason of the fact that it occupies contrary positions or assumes contrary forms at different times it will produce contrary motions in each several thing that it moves and will cause it to be at one time at rest and at another time in motion.
φανερὸν δὴ γέγονεν ἐκ τῶν εἰρημένων καὶ ὃ κατ' ἀρχὰς ἠποροῦμεν, τί δή ποτε οὐ πάντα ἢ κινεῖται ἢ ἠρεμεῖ, ἢ τὰ μὲν κινεῖται ἀεὶ τὰ δ' ἀεὶ ἠρεμεῖ, ἀλλ' ἔνια ὁτὲ μὲν ὁτὲ δ' οὔ. τούτου γὰρ τὸ αἴτιον δῆλόν ἐστι νῦν, ὅτι τὰ μὲν ὑπὸ ἀκινήτου κινεῖται ἀϊδίου, διὸ ἀεὶ κινεῖται, τὰ δ' ὑπὸ κινουμένου καὶ μεταβάλλοντος, ὥστε καὶ αὐτὰ ἀναγκαῖον μεταβάλλειν. τὸ δ' ἀκίνητον, ὥσπερ εἴρηται, ἅτε ἁπλῶς καὶ ὡσαύτως καὶ ἐν τῷ αὐτῷ διαμένον, μίαν καὶ ἁπλῆν κινήσει κίνησιν. The foregoing argument, then, has served to clear up the point about which we raised a difficulty at the outset—why is it that instead of all things being either in motion or at rest, or some things being always in motion and the remainder always at rest, there are things that are sometimes in motion and sometimes not? The cause of this is now plain: it is because, while some things are moved by an eternal unmoved movent and are therefore always in motion, other things are moved by a movent that is in motion and changing, so that they too must change. But the unmoved movent, as has been said, since it remains permanently simple and unvarying and in the same state, will cause motion that is one and simple.
Postquam philosophus ostendit quod primum movens est perpetuum et omnino immobile, ratione sumpta ex perpetuitate generationis et corruptionis animalium, quae movent seipsa; hic intendit idem ostendere, ratione sumpta ex principiis moventibus. Et circa hoc tria facit: primo commemorat ea quae dicta sunt a principio huius tractatus; secundo ex praemissis accipit rationem ad propositum, ibi: ex quibus est scire etc.; tertio concludit solutionem cuiusdam dubitationis supra motae, ibi: manifestum igitur factum est ex dictis et cetera. 1077. After showing that the first mover is perpetual and utterly immobile on account of the perpetuity of the generation and perishing of animals, which move themselves, the Philosopher now intends to prove the same with an argument based on the moving principles. About this he does three things: First he reviews things said from the beginning of this treatise; Secondly, from these he forms an argument for his proposition, at 1081; Thirdly, he finishes the solution of a doubt mentioned above, at 1085.
Circa primum tria resumit: primo destructionem quarundam improbabilium positionum. Et dicit quod non solum ex praemissis potest aliquis scire quod est aliquod primum movens immobile, sed etiam per considerationem principiorum motus. Et sicut supra dictum est, manifestum est ad sensum quod in rebus naturalibus inveniuntur quaedam, quae aliquando moventur et aliquando quiescunt. 1078. About the first he reviews three things: First (845), the destruction of certain improbable positions. And he says that anyone can know that there is a first immobile. mover not only from the foregoing, but also by considering the principles of motion. And as was said above, it is evident to sense that among natural things are found some that are at one time being moved and at another time at rest.
Et ex hoc manifestatum est supra quod nulla trium positionum est vera: neque illa quae dicit quod omnia moventur semper; neque illa quae dicit quod omnia quiescunt semper; neque illa quae dicit quod omnia quae quiescunt, quiescunt semper, et omnia quae moventur, moventur semper. Huius enim rei veritatem demonstrant illa quae sub utroque inveniuntur, scilicet motu et quiete, dum habent potentiam ut quandoque moveantur et quandoque quiescant. From this it was explained above that none of these three positions is true: the position that all things are always being moved; the position that all things are always at rest; and the position that all things which rest, always rest, and those being moved, are always being moved. The truth of this matter is demonstrated by the very things found under both, namely, under motion and under rest, since they have the potency to be moved at one time, and to be at rest at another.
Secundo ibi: quoniam autem huiusmodi etc., commemorat processum supra habitum ad investigandum primum motorem immobilem. Et dicit quod quia ista quae quandoque moventur et quandoque quiescunt, sunt omnibus manifesta: ne iterum aliquis sequeretur quartam positionem, ponens omnia entia esse huiusmodi ut quandoque moveantur et quandoque quiescant; volumus demonstrare duplicem naturam diversam, ostendentes scilicet quod quaedam sunt quae sunt semper immobilia, et iterum quod quaedam sunt quae semper moventur. 1079. Secondly, he recalls the process he went through when investigating the first immobile mover. And he says that because things which at one time are being moved and at another time are at rest are plain to all, lest anyone follow a fourth position that all beings are such that they are at one time being moved and at another time at rest, we want to demonstrate two differing natures by showing, namely, that there are certain things that are always immobile, and certain things again that are always being moved.
Et circa hoc procedentes, proposuimus primo quod omne quod movetur, movetur ab aliquo; et quod necesse est hoc a quo aliquid movetur, aut esse immobile aut moveri; et si movetur, aut a seipso aut ab alio. Et cum non sit procedere in infinitum ut ab alio moveatur, oportet devenire ad hoc quod sit quoddam primum principium motus: ita quidem quod in genere eorum quae moventur, est primum principium quod movet seipsum; sed ulterius simpliciter inter omnia, primum principium est quod est immobile. Nec debet reputari inconveniens quod aliquid moveat seipsum: quia videmus manifeste esse multa talia in genere animatorum et animalium. And in dealing with this matter we proposed first that whatever is being moved is being moved by something and that this thing by which something is being moved is either immobile or is itself being moved, and if it is being moved, then either by itself or by another. And since one cannot proceed to infinity in the series of “being moved by another,” we must come to this that there is some first principle of motion, such that in the genus of things that are moved there is a first principle which moves itself, and beyond that, absolutely among all, there is a first principle which is immobile. Nor ought it to be thought strange that something move itself, because we plainly see many such in the genus of living things and animals.
Tertio ibi: haec autem et opinionem etc., commemorat quandam obiectionem supra positam et solutam. Cum enim probasset motus perpetuitatem, posuit obiectionem in contrarium ex rebus animatis, quae cum prius quieverunt, incipiunt quandoque moveri. Et hoc est quod hic dicit, quod ista animata quae movent seipsa, videbantur opinionem inducere quod contingit in toto universo motum fieri cum prius non fuerit; propter hoc quod videmus in eis hoc contingere, quod cum prius non moverentur, incipiunt quandoque moveri. 1080. Thirdly, at (847) he recalls an objection mentioned and solved above. For since he had proved the eternity of motion, he cited to the contrary an objection based on living things which after having been at rest begin at a certain time to be moved. And what he says here is that those living things which move themselves seem to foster the opinion that in the entire universe motion begins after previously not having been, on the ground that we see this happen in things, namely, that they at one time begin to be moved, when previously they were not being moved.
Et ad huius solutionem oportet hic accipere, quod animalia movent seipsa secundum unum motum, scilicet secundum motum localem: hic enim solus motus invenitur in animalibus appetitui subiectus. Et tamen nec secundum hunc motum proprie animalia seipsa movent, ita scilicet quod huius motus alia causa non praeexistat. Non enim animali ex seipso est prima causa quod localiter moveatur: sed praecedunt alii motus, non voluntarii, sed naturales, vel ab interiori vel ab exteriori, secundum quos animalia non movent seipsa; sicut patet de motu augmenti et decrementi et respirationis, secundum quos motus animalia moventur, quamvis quiescant secundum motum localem, quo moventur a seipsis. To solve this it is necessary to accept that animals move themselves with respect to one motion, namely, local motion; for only this motion, based on appetite, is found in animals. And yet animals do not properly move themselves even with respect to this motion as though another cause of this motion does not pre-exist. For no animal is of itself the first cause of being moved locally, but other motions precede—not voluntary but natural—either from within or from without, according to which the animals do not move themselves, as is plain in the motions of growth and decrease, and respiration, according to which animals are moved, although they rest with respect to local motion by which they are moved by themselves.
Horum autem motuum naturalium causa est vel continens extrinsecum, scilicet caelum et aer, a quo immutantur corpora animalium exterius; vel aliquid intrans corpora animalium, sicut aer intrat per respirationem, et alimentum intrat per comestionem et potum. Et ex huiusmodi transmutationibus, sive ab interiori sive ab exteriori causatis, contingit quod animalia quandoque incipiunt moveri, cum prius non moverentur; sicut patet ex transmutatione quae est circa alimentum: quia dum decoquitur alimentum, propter vapores resolutos animalia dormiunt; sed quando alimentum est iam digestum et dissolutum, vaporibus residentibus, evigilant animalia et surgunt et movent seipsa motu locali; cum tamen primum principium motionis sit aliquid extrinsecum a natura animalis quod movet seipsum. The cause of these local motions is either an extrinsic container—namely, the heavens and air—by which the bodies of animals are changed externally, or something enters the bodies of animals, as air enters through breathing and as food enters through eating and drinking. And from such transmutations, caused either from within or from without, it happens that animals at a certain time begin to be moved, when previously they were not being moved, as is plain from the change which arises from food: for while the food is undergoing heat the animals sleep on account of the vapors being broken down, but when the food is now digested and dissolved, and the vapors are left, the animals awaken and get up and move themselves from place to place. In all this, nevertheless, the first principle of motion is something extrinsic to the nature of the animal that moves itself.
Et inde est quod animalia non semper moventur a seipsis: quia respectu uniuscuiusque animalis moventis seipsum, invenitur aliquod aliud prius movens, quod movetur et movet. Si enim esset omnino immobile, semper eodem modo se haberet in movendo: et ita etiam motus animalis esset sempiternus. Sed quia hoc movens extraneum quod movet animalia, etiam ipsum movetur, non semper eodem modo movet. That is the reason why animals are not always moved by themselves, because with respect to any animal moving itself there is found some previous mover, which is being moved and causes motion. For if it were entirely immobile, it would always maintain itself in the same way in causing motion and, consequently, the motion also of the animal would be perpetual. But because this extrinsic mover that moves animals is itself moved, it does not always move in the same way.
Unde nec animalia semper eodem modo movent seipsa, quia in his omnibus primum movens quod est causa animali movendi seipsum, sicut anima, sic movet quod movetur, non quidem per se sed per accidens: quia corpus mutatur secundum locum, mutato autem corpore, mutatur, et id quod in corpore existit, per accidens, scilicet anima. Et sic ex necessitate mutatur totum movens seipsum, ut non sit in eadem dispositione movendi. Hence, neither do animals always move themselves in the same way, because in all these things the first mover which is the cause of the animal’s moving itself, such as the soul, causes motion in such a way that it is itself being moved not per se but per accidens, for the body is changed with respect to place, and when the body has been changed, that which exists in the body, namely, the soul, is also changed per accidens, And thus the whole that moves itself is changed of necessity, so that it does not maintain itself in the same disposition for causing motion.
Deinde cum dicit: ex quibus est scire etc., ex praemissis ostendit propositum: et primo quod primum movens sit immobile; secundo quod primus motus sit sempiternus, ibi: at vero si aliquid est et cetera. 1081. Then at (848) from the foregoing he proves his proposition. First that the first mover is immobile; Secondly, that the first motion is perpetual, at 1083.
Circa primum duo facit: primo ostendit propositum; secundo excludit quandam obiectionem, ibi: non est autem idem moveri secundum accidens et cetera. About the first he does two things: First he proves the proposition; Secondly, he dismisses an objection, at 1082.
Dicit ergo primo, quod ex praemissis possumus scire quod si aliquod principium est movens immobile, quod tamen movetur secundum accidens, non potest facere continuum motum et sempiternum. Ista enim causa est assignata quare animalium animae non movent semper, quia moventur per accidens. Sed ostensum est supra quod necesse est motum universi esse continuum et sempiternum. Ergo necesse est primam causam moventem in toto universo esse immobilem, ita quod nec etiam secundum accidens moveatur. He says therefore first (848) that from the foregoing we can know that if some principle is an immobile mover nevertheless moved per accidens, it cannot cause a continuous and perpetual motion. For the reason assigned for saying that animals do not always move is that they are moved per accidens. But it has been shown above that the motion of the universe must be continuous and perpetual. Therefore, it is necessary that the first moving cause in the whole universe be immobile, in such a way as not to be moved even per accidens.
Sed sicut supra dictum est, in rebus naturalibus inveniri debet quidam motus immortalis et incessabilis, et quod totum ens, idest dispositio huius universi, maneat in sua dispositione et in eodem statu. Ex immobilitate enim principii quod ponitur manere immobile, sequitur quod totum universum habeat quandam permanentiam sempiternam, secundum quod continuatur primo principio immobili, recipiendo influentiam ab ipso. But, as was said above, in natural things a motion that is immortal and unceasing ought to be found, and the disposition of this universe should be maintained in its disposition and in the same state. For from the immobility of the principle that is set down as remaining immobile, it follows that the entire universe has an eternal permanence, insofar as it is joined to the first immobile principle and receives an influence from it.
Deinde cum dicit: non est autem idem etc., excludit quandam obiectionem. Dixerat enim quod si aliquod movens movetur per accidens, non movet motu sempiterno. Hoc autem videtur habere instantiam, quia secundum eius positionem motus inferiorum orbium, puta solis et lunae et aliorum planetarum, sunt sempiterni; et tamen motores eorum videntur moveri per accidens, si sequamur ea quae superius dixit. Ea enim ratione dixit animam animalis per accidens moveri, quia corpus animalis movetur quodam alio motu ab exteriori principio, qui non est ab anima: similiter autem apparet quod orbis solis movetur quodam alio motu, quasi delatus ex motu primi orbis, secundum quod revolvitur ab oriente in occidentem; isto autem motu non movetur a proprio motore, sed e converso ab occidente in orientem. 1082. Then at (849) he excludes an objection. For he had said that if a mover is moved per accidens, it does not move with an undying motion. Now this seems to give rise to an objection, because, according to his position, the motions of the inferior orbs, such as the sun and moon and other planets are eternal, and yet their movers seem to be moved per accidens, if we follow what he had just said. For he said that the reason why the soul of an animal is moved per accidens is that the animal's body is moved by an external principle, which is not from the soul; in like manner, it appears that the orb of the sun is moved by some other motion as though carried along by the motion of the first orb, insofar as it revolves from east to west; this is not the way it is moved by its proper mover, but contrariwise, from west to east.
Hanc ergo obiectionem excludit, dicens quod moveri secundum accidens potest attribui alicui vel secundum seipsum, vel secundum alterum; et hoc non est idem. Motoribus igitur orbium planetarum attribui potest moveri per accidens, non ita quod ipsi per accidens moveantur, sed ita quod orbes ab eis moti per accidens moventur, delati ex motu superioris orbis. Et hoc est quod dicit, quod moveri per accidens ab altero, idest ratione alterius, inest quibusdam principiis caelestium motuum, quantum ad motores orbium qui moventur pluribus motibus, scilicet motu proprio et motu superioris orbis: sed alterum, scilicet moveri per accidens secundum seipsum, invenitur solum in corruptibilibus, sicut in animabus animalium. Et huius diversitatis ratio est, quia motores superiorum orbium non constituuntur in suo esse ex sua unione ad corpora, et eorum connexio est invariabilis; et ideo quamvis corpora orbium moveantur, ipsi non moventur per accidens: sed animae quae movent animalia, constituuntur in suo esse secundum unionem ad corpora, et variabiliter eis connectuntur; et ideo secundum transmutationem corporum ipsae etiam animae dicuntur per accidens mutari. He dismisses this objection, saying that “being moved per accidens” can be attributed to something either with respect to itself or with respect to something else, and this is not the same. Now “being moved per accidens” can be attributed to the movers of the orbs of the planets, not in the sense that these movers are moved per accidens, but that the orbs moved by them are moved per accidens in being influenced by the motion of the superior orb. And this is what he says, that “to be moved per accidens from another,” i.e., by reason of another, is attributed to certain principles of heavenly motions, in the case of the movers of the orbs which are moved by more than one motion, namely, by their own and by that of the superior orb. But the other case, that a thing be moved per accidens with respect to itself is found only in perishable things, as in the souls of animals. The reason for this diversity is that the movers of the superior orbs are not constituted existents through being united to bodies, and their connection with the latter is unvarying; and therefore, although the bodies of the orbs are moved, the motors are not moved per accidens. But the souls which move animals depend for their existence on being united to their bodies, and they are connected in a way subject to variation, and accordingly, as the bodies are affected by change, the souls themselves are said to be changed per accidens.
Deinde cum dicit: at vero si aliquid est etc., probat quod primus motus est sempiternus. Et hoc duabus rationibus: quarum prima dependet ex praemissis, et talis est. Motus qui non est semper, invenitur esse a motore qui movetur per se vel per accidens, ut ex praedictis patet: cum ergo primum movens sit immobile et perpetuum, ita quod nec per se nec per accidens movetur, necesse est quod primum mobile, quod movetur ab hoc motore penitus immobili, perpetuo moveatur. 1083. Then at (850) he proves that the first motion is perpetual. And he does this with two arguments, the first of which depends on the foregoing and is this: A motion which is not perpetual is found to be from a mover that is moved per se or per accidens, as is evident from above. Since, therefore, the first mover is immobile and perpetual, and is moved neither per se nor per accidens, then, necessarily, the first mobile, which is moved by this utterly immobile mover is moved with a perpetual motion.
Est autem attendendum, quod supra probavit immobilitatem primi motoris, per perpetuitatem motus supra ostensam: hic autem e converso, per immobilitatem primi motoris probat perpetuitatem motus: esset autem sua probatio circularis, si de eodem motu intelligeret. Now, it should be noted that above he proved the immobility of the first mover by means of the perpetuity of motion, shown above. Here, on the contrary, through the immobility of the first mover he proves the perpetuity of motion, But this would be arguing in a circle, if the same motion were meant in both arguments.
Unde dicendum est quod supra probavit immobilitatem primi motoris ex perpetuitate motus in communi; unde dixit quod in his quae sunt, est incessabilis quidam et immortalis motus: hic autem per immobilitatem primi motoris probat perpetuitatem primi motus. Ex quo manifestum est falsum esse quod Commentator dicit, quod supra in principio huius octavi probavit motum primum esse perpetuum. Hence it must be said that above he proves the immobility of the first mover from the perpetuity of motion in general; that is why he said that among the things that exist, there is an unceasing and immortal motion. But here through the immobility of the first mover he proves the perpetuity of the first motion. From which it is plain that what the Commentator says is false, namely, that in the beginning of this Book VIII Aristotle proved that the first motion is perpetual.
Secundam rationem ponit ibi: hoc autem est manifestum etc., quae sumitur ex perpetuitate generationis. Et dicit quod primum motum esse perpetuum, manifestum est etiam ex eo quod non est possibile aliter esse generationem et corruptionem et huiusmodi mutationes non temporales, nisi sit aliquid quod moveat et moveatur: quod enim omnis mutatio sit ab aliquo motore, iam supra ostensum est. Oportet ergo generationem et corruptionem et huiusmodi mutationes esse ab aliquo motore. Non autem possunt esse immediate a motore immobili, quia immobile semper movebit eundem motum et eodem modo; quia non mutabitur eius dispositio et habitudo ad mobile; manente autem eadem habitudine motoris ad mobile, semper manet idem motus. Non autem generatio et corruptio semper eodem modo sunt, sed quandoque aliquid generatur, quandoque corrumpitur: non ergo sunt immediate a motore immobili, sed a motore mobili. Quod autem movetur a motore moto, quod tamen movetur a motore immobili, in alternatione diversorum motuum potest habere perpetuitatem: quia propter id quod movens mobile aliter et aliter se habet ad res motas, non causabit eundem motum semper; sed magis, propter id quod in diversis locis (si moveatur motu locali) vel in diversis speciebus (si moveatur motu alterationis) causabit contrarium motum in aliis, et faciet quandoque quiescere, quandoque autem moveri. Dicit autem contrariis locis aut speciebus, quia nondum est probatum qua specie motus primum mobile moveatur; sed hoc infra inquiret. 1084. The second argument is given at (851) and is taken from the perpetuity of generation. And he says that the first motion is perpetual for another reason, namely, that the only way temporal generation and ceasing-to-be, and changes of this sort, can exist is that something move and be moved, for it has been proved above that every change is caused by some mover. Therefore, coming-to-be and ceasing-to-be and change of this kind ought to be from a mover, But they cannot be immediately from the immobile mover, because the immobile will always cause the same motion and in the same way, for its relation to the mobile is not variable; and, given a relation between mover and moved that remains the same, the motion remains always the same, However, coming-to-be and ceasing-to-be are not always in the same state, but at one time something is generated and at another it ceases to be. Therefore, these changes are not immediately from the immobile mover but from a mobile mover. Now, whatever is moved by a moved mover which in turn is moved by the immobile mover can retain perpetuity in spite of the alternation of diverse motions, because, since the mobile mover stands in varying relation to the things moved, it will not always cause the same motion. Rather, since it occupies differing positions (if moved with local motion), or assumes differing forms (if moved with a motion of alteration), it will produce a contrary motion in other things and will cause them to be at one time at rest and at another time in motion. He says “in contrary positions or forms,” because it has not yet been proved by what form of motion the first mobile is moved; but he will inquire into this later.
Sic igitur inquantum movetur, est causa diversitatis motuum; inquantum vero movetur a motore immobili, est causa perpetuitatis in hac mutationum diversitate. Ipsa ergo perpetuitas generationis ostendit primum motum esse perpetuum, et a motore immobili moveri. Thus, therefore, insofar as it is moved, it is a cause of the diversity of motions; but insofar as it is moved by the immobile mover, it is the cause of the perpetuity in this diversity of changes. Therefore, the very perpetuity of generation shows that the first motion is perpetual and brought about by the immobile mover.
Est autem sciendum quod hae rationes, quibus Aristoteles probare nititur primum motum esse perpetuum, non ex necessitate concludunt: potest enim contingere absque omni mutatione primi motoris, quod non semper moveat, sicut supra ostensum est in principio huius octavi. But it should be understood that these arguments by which Aristotle tries to prove that the first motion is perpetual do not conclude of necessity, for it can happen without any change in the first mover that it not always cause motion, as was shown above in the beginning of this Book VIII.
Deinde cum dicit: manifestum igitur factum est etc., infert quandam conclusionem, quam supra dimiserat insolutam; scilicet quare quaedam moventur semper, et quaedam non semper. 1085. Then at (852) he draws a conclusion which he left unsettled above, namely, why some things are always in motion and some not always.
Et dicit quod huius causa manifesta est ex praemissis: quae enim moventur a motore immobili et perpetuo, moventur semper; quae autem moventur a motore mutato, non semper moventur: quia immobile, ut prius dictum est, cum simpliciter et similiter et in eadem dispositione maneat, movebit unum motum et simplicem. And he says that the cause of this is now plain from what has gone before: Things which are moved by an immobile and eternal mover are always in motion; things which are moved by a changed mover are not always in motion—for the immobile, as previously stated, since it remains absolutely alike and in the same state, will cause a motion that is one and simple.

Lectio 14
Many reasons why local motion is the first motion
Chapter 7
Οὐ μὴν ἀλλὰ καὶ ἄλλην ποιησαμένοις ἀρχὴν μᾶλλον ἔσται περὶ τούτων φανερόν. σκεπτέον γὰρ πότερον ἐνδέχεταί τινα κίνησιν εἶναι συνεχῆ ἢ οὔ, καὶ εἰ ἐνδέχεται, τίς αὕτη, καὶ τίς πρώτη τῶν κινήσεων· δῆλον γὰρ ὡς εἴπερ ἀναγκαῖον μὲν ἀεὶ κίνησιν εἶναι, πρώτη δὲ ἥδε καὶ συνεχής, ὅτι τὸ πρῶτον κινοῦν κινεῖ ταύτην τὴν κίνησιν, ἣν ἀναγκαῖον μίαν καὶ τὴν αὐτὴν εἶναι καὶ συνεχῆ καὶ πρώτην. This matter will be made clearer, however, if we start afresh from another point. We must consider whether it is or is not possible that there should be a continuous motion, and, if it is possible, which this motion is, and which is the primary motion: for it is plain that if there must always be motion, and a particular motion is primary and continuous, then it is this motion that is imparted by the first movent, and so it is necessarily one and the same and continuous and primary.
τριῶν δ' οὐσῶν κινήσεων, τῆς τε κατὰ μέγεθος καὶ τῆς κατὰ πάθος καὶ τῆς κατὰ τόπον, ἣν καλοῦμεν φοράν, ταύτην ἀναγκαῖον εἶναι πρώτην. ἀδύνατον γὰρ αὔξησιν εἶναι ἀλλοιώσεως μὴ προϋπαρχούσης· τὸ γὰρ αὐξανόμενον ἔστιν μὲν ὡς ὁμοίῳ αὐξάνεται, ἔστιν δ' ὡς ἀνομοίῳ· τροφὴ γὰρ λέγεται τῷ ἐναντίῳ τὸ ἐναντίον. προσγίγνεται δὲ πᾶν γιγνόμενον ὅμοιον ὁμοίῳ. ἀνάγκη οὖν ἀλλοίωσιν εἶναι τὴν εἰς τἀναντία μεταβολήν. (260b.) ἀλλὰ μὴν εἴ γε ἀλλοιοῦται, δεῖ τι εἶναι τὸ ἀλλοιοῦν καὶ ποιοῦν ἐκ τοῦ δυνάμει θερμοῦ ἐνεργείᾳ θερμόν. δῆλον οὖν ὅτι τὸ κινοῦν οὐχ ὁμοίως ἔχει, ἀλλ' ὁτὲ μὲν ἐγγύτερον ὁτὲ δὲ πορρώτερον τοῦ ἀλλοιουμένου ἐστίν. ταῦτα δ' ἄνευ φορᾶς οὐκ ἐνδέχεται ὑπάρχειν. εἰ ἄρα ἀνάγκη ἀεὶ κίνησιν εἶναι, ἀνάγκη καὶ φορὰν ἀεὶ εἶναι πρώτην τῶν κινήσεων, καὶ φορᾶς, εἰ ἔστιν ἡ μὲν πρώτη ἡ δ' ὑστέρα, τὴν πρώτην. Now of the three kinds of motion that there are—motion in respect of magnitude, motion in respect of affection, and motion in respect of place—it is this last, which we call locomotion, that must be primary. This may be shown as follows. It is impossible that there should be increase without the previous occurrence of alteration: for that which is increased, although in a sense it is increased by what is like itself, is in a sense increased by what is unlike itself: thus it is said that contrary is nourishment to contrary: but growth is effected only by things becoming like to like. There must be alteration, then, in that there is this change from contrary to contrary. But the fact that a thing is altered requires that there should be something that alters it, something e.g. that makes the potentially hot into the actually hot: so it is plain that the movent does not maintain a uniform relation to it but is at one time nearer to and at another farther from that which is altered: and we cannot have this without locomotion. If, therefore, there must always be motion, there must also always be locomotion as the primary motion, and, if there is a primary as distinguished from a secondary form of locomotion, it must be the primary form.
ἔτι δὲ πάντων τῶν παθημάτων ἀρχὴ πύκνωσις καὶ μάνωσις· καὶ γὰρ βαρὺ καὶ κοῦφον καὶ μαλακὸν καὶ σκληρὸν καὶ θερμὸν καὶ ψυχρὸν πυκνότητες δοκοῦσιν καὶ ἀραιότητες εἶναί τινες. πύκνωσις δὲ καὶ μάνωσις σύγκρισις καὶ διάκρισις, καθ' ἃς γένεσις καὶ φθορὰ λέγεται τῶν οὐσιῶν. συγκρινόμενα δὲ καὶ διακρινόμενα ἀνάγκη κατὰ τόπον μεταβάλλειν. ἀλλὰ μὴν καὶ τοῦ αὐξανομένου καὶ φθίνοντος μεταβάλλει κατὰ τόπον τὸ μέγεθος. Again, all affections have their origin in condensation and rarefaction: thus heavy and light, soft and hard, hot and cold, are considered to be forms of density and rarity. But condensation and rarefaction are nothing more than combination and separation, processes in accordance with which substances are said to become and perish: and in being combined and separated things must change in respect of place. And further, when a thing is increased or decreased its magnitude changes in respect of place.
ἔτι καὶ ἐντεῦθεν ἐπισκοποῦσιν ἔσται φανερὸν ὅτι ἡ φορὰ πρώτη. τὸ γὰρ πρῶτον, ὥσπερ ἐφ' ἑτέρων, οὕτω καὶ ἐπὶ κινήσεως ἂν λέγοιτο πλεοναχῶς. λέγεται δὲ πρότερον οὗ τε μὴ ὄντος οὐκ ἔσται τἆλλα, ἐκεῖνο δὲ ἄνευ τῶν ἄλλων, καὶ τὸ τῷ χρόνῳ, καὶ τὸ κατ' οὐσίαν. Again, there is another point of view from which it will be clearly seen that locomotion is primary. As in the case of other things so too in the case of motion the word 'primary' may be used in several senses. A thing is said to be prior to other things when, if it does not exist, the others will not exist, whereas it can exist without the others: and there is also priority in time and priority in perfection of existence.
ὥστ' ἐπεὶ κίνησιν μὲν ἀναγκαῖον εἶναι συνεχῶς, εἴη δ' ἂν συνεχῶς ἢ συνεχὴς οὖσα ἢ ἐφεξῆς, μᾶλλον δ' ἡ συνεχής, καὶ βέλτιον συνεχῆ ἢ ἐφεξῆς εἶναι, τὸ δὲ βέλτιον ἀεὶ ὑπολαμβάνομεν ἐν τῇ φύσει ὑπάρχειν, ἂν ᾖ δυνατόν, δυνατὸν δὲ συνεχῆ εἶναι (δειχθήσεται δ' ὕστερον· νῦν δὲ τοῦτο ὑποκείσθω), καὶ ταύτην οὐδεμίαν ἄλλην οἷόν τε εἶναι ἀλλ' ἢ φοράν, ἀνάγκη τὴν φορὰν εἶναι πρώτην. οὐδεμία γὰρ ἀνάγκη οὔτε αὔξεσθαι οὔτε ἀλλοιοῦσθαι τὸ φερόμενον, οὐδὲ δὴ γίγνεσθαι ἢ φθείρεσθαι· τούτων δὲ οὐδεμίαν ἐνδέχεται τῆς συνεχοῦς μὴ οὔσης, ἣν κινεῖ τὸ πρῶτον κινοῦν. Let us begin, then, with the first sense. Now there must be motion continuously, and there may be continuously either continuous motion or successive motion, the former, however, in a higher degree than the latter: moreover it is better that it should be continuous rather than successive motion, and we always assume the presence in nature of the better, if it be possible: since, then, continuous motion is possible (this will be proved later: for the present let us take it for granted), and no other motion can be continuous except locomotion, locomotion must be primary. For there is no necessity for the subject of locomotion to be the subject either of increase or of alteration, nor need it become or perish: on the other hand there cannot be any one of these processes without the existence of the continuous motion imparted by the first movent.
ἔτι χρόνῳ πρώτην· τοῖς γὰρ ἀϊδίοις μόνον ἐνδέχεται κινεῖσθαι ταύτην. Secondly, locomotion must be primary in time: for this is the only motion possible for things.
ἀλλ' ἐφ' ἑνὸς μὲν ὁτουοῦν τῶν ἐχόντων γένεσιν τὴν φορὰν ἀναγκαῖον ὑστάτην εἶναι τῶν κινήσεων· μετὰ γὰρ τὸ γενέσθαι πρῶτον ἀλλοίωσις καὶ αὔξησις, φορὰ δ' ἤδη τετελειωμένων κίνησίς ἐστιν. (261a.) ἀλλ' ἕτερον ἀνάγκη κινούμενον εἶναι κατὰ φορὰν πρότερον, ὃ καὶ τῆς γενέσεως αἴτιον ἔσται τοῖς γιγνομένοις, οὐ γιγνόμενον, οἷον τὸ γεννῆσαν τοῦ γεννηθέντος, ἐπεὶ δόξειέ γ' ἂν ἡ γένεσις εἶναι πρώτη τῶν κινήσεων διὰ τοῦτο, ὅτι γενέσθαι δεῖ τὸ πρᾶγμα πρῶτον. τὸ δ' ἐφ' ἑνὸς μὲν ὁτουοῦν τῶν γιγνομένων οὕτως ἔχει, ἀλλ' ἕτερον ἀναγκαῖον πρότερόν τι κινεῖσθαι τῶν γιγνομένων ὂν αὐτὸ καὶ μὴ γιγνόμενον, καὶ τούτου ἕτερον πρότερον. ἐπεὶ δὲ γένεσιν ἀδύνατον εἶναι πρώτην (πάντα γὰρ ἂν εἴη τὰ κινούμενα φθαρτά), δῆλον ὡς οὐδὲ τῶν ἐφεξῆς κινήσεων οὐδεμία προτέρα· λέγω δ' ἐφεξῆς αὔξησιν, εἶτ' ἀλλοίωσιν καὶ φθί σιν καὶ φθοράν· πᾶσαι γὰρ ὕστεραι γενέσεως, ὥστ' εἰ μηδὲ γένεσις προτέρα φορᾶς, οὐδὲ τῶν ἄλλων οὐδεμία μεταβολῶν. It is true indeed that, in the case of any individual thing that has a becoming, locomotion must be the last of its motions: for after its becoming it first experiences alteration and increase, and locomotion is a motion that belongs to such things only when they are perfected. But there must previously be something else that is in process of locomotion to be the cause even of the becoming of things that become, without itself being in process of becoming, as e.g. the begotten is preceded by what begot it: otherwise becoming might be thought to be the primary motion on the ground that the thing must first become. But though this is so in the case of any individual thing that becomes, nevertheless before anything becomes, something else must be in motion, not itself becoming but being, and before this there must again be something else. And since becoming cannot be primary—for, if it were, everything that is in motion would be perishable—it is plain that no one of the motions next in order can be prior to locomotion. By the motions next in order I mean increase and then alteration, decrease, and perishing. All these are posterior to becoming: consequently, if not even becoming is prior to locomotion, then no one of the other processes of change is so either.
ὅλως τε φαίνεται τὸ γιγνόμενον ἀτελὲς καὶ ἐπ' ἀρχὴν ἰόν, ὥστε τὸ τῇ γενέσει ὕστερον τῇ φύσει πρότερον εἶναι. τελευταῖον δὲ φορὰ πᾶσιν ὑπάρχει τοῖς ἐν γενέσει. διὸ τὰ μὲν ὅλως ἀκίνητα τῶν ζώντων δι' ἔνδειαν [τοῦ ὀργάνου], οἷον τὰ φυτὰ καὶ πολλὰ γένη τῶν ζῴων, τοῖς δὲ τελειουμένοις ὑπάρχει. ὥστ' εἰ μᾶλλον ὑπάρχει φορὰ τοῖς μᾶλλον ἀπειληφόσιν τὴν φύσιν, καὶ ἡ κίνησις αὕτη πρώτη τῶν ἄλλων ἂν εἴη κατ' οὐσίαν, Thirdly, that which is in process of becoming appears universally as something imperfect and proceeding to a first principle: and so what is posterior in the order of becoming is prior in the order of nature. Now all things that go through the process of becoming acquire locomotion last. It is this that accounts for the fact that some living things, e.g. plants and many kinds of animals, owing to lack of the requisite organ, are entirely without motion, whereas others acquire it in the course of their being perfected. Therefore, if the degree in which things possess locomotion corresponds to the degree in which they have realized their natural development, then this motion must be prior to all others in respect of perfection of existence:
διά τε ταῦτα καὶ διότι ἥκιστα τῆς οὐσίας ἐξίσταται τὸ κινούμενον τῶν κινήσεων ἐν τῷ φέρεσθαι· κατὰ μόνην γὰρ οὐδὲν μεταβάλλει τοῦ εἶναι, ὥσπερ ἀλλοιουμένου μὲν τὸ ποιόν, αὐξανομένου δὲ καὶ φθίνοντος τὸ ποσόν. and not only for this reason but also because a thing that is in motion loses its essential character less in the process of locomotion than in any other kind of motion: it is the only motion that does not involve a change of being in the sense in which there is a change in quality when a thing is altered and a change in quantity when a thing is increased or decreased.
μάλιστα δὲ δῆλον ὅτι τὸ κινοῦν αὐτὸ αὑτὸ μάλιστα ταύτην κινεῖ κυρίως, τὴν κατὰ τόπον· καίτοι φαμὲν τοῦτο εἶναι τῶν κινουμένων καὶ κινούντων ἀρχὴν καὶ πρῶτον τοῖς κινουμένοις, τὸ αὐτὸ αὑτὸ κινοῦν. ὅτι μὲν τοίνυν τῶν κινήσεων ἡ φορὰ πρώτη, φανερὸν ἐκ τούτων· Above all it is plain that this motion, motion in respect of place, is what is in the strictest sense produced by that which moves itself; but it is the self-movent that we declare to be the first principle of things that are moved and impart motion and the primary source to which things that are in motion are to be referred. It is clear, then, from the foregoing arguments that locomotion is the primary motion.
Postquam philosophus ostendit quod primum movens est immobile et primus motus est perpetuus, hic incipit ostendere quis sit primus motus, et quale sit primum movens. Et dividitur in partes duas: in prima ostendit quis sit primus motus; in secunda quale sit primum movens, ibi: quod autem hoc necesse est etc.: 1086. After showing that the first mover is immobile, and the first motion perpetual, the Philosopher here begins to show which motion is the first and what kind of being the first mover is. And it is divided into two parts: In the first he shows which is the first motion; In the second, what kind of being the first mover is, (L. 21).
circa primum duo facit: primo dicit de quo est intentio; secundo exequitur propositum, ibi: tribus autem existentibus et cetera. About the first he does two things: First he states his intention; Secondly, he carries out his proposal, at 1087.
Dicit ergo primo, quod ad hoc quod praemissa certius considerentur, oportet ab alio principio incipere, ut scilicet consideremus utrum sit aliquis motus, quem contingat esse in infinitum continuum: et si contingat aliquem motum talem esse, quis est hic, et quis est etiam primus motuum. He says therefore first that in order that the consideration of the foregoing be more certain, we must begin from another starting-point and consider whether there is any motion which may be infinitely continuous and, if so, which it is, and which is the first of all motions,
Et ne aliquis putaret alium esse quem contingit esse continuum, et qui est primus, ad hoc excludendum subiungit manifestum esse quod, cum necessarium sit motum semper esse, et quod primus est in sempiternum continuus, propter hoc quod causatur a primo movente immobili; necesse est quod sit unus et idem motus quem contingit esse in sempiternum continuum, et qui est primus. And lest anyone should think that the one which may be continuous and the one which is first are two different motions, in order to exclude this he adds that it is plain that since it is necessary for motion always to exist, and the first is forever continuous, for it is caused by the first immobile mover, then necessarily it is one and the same motion which is eternally continuous and which is first.
Deinde cum dicit: tribus autem existentibus etc., ostendit propositum: et primo per rationes; secundo per antiquorum dicta, ibi: quod autem secundum locum mutatio et cetera. 1087. Then at (854) he proves the proposition. First with arguments; Secondly, by referring to the sayings of the ancients, (L. 20).
Circa primum duo facit: primo ostendit quod motus localis est primus; secundo quis motus localis, ibi: quae autem loci mutatio et cetera. About the first he does two things: First he shows that local motion is the first; Secondly, which local motion, (L. 15).
Primum ostendit tripliciter: primo quidem per proprietates motuum; secundo per distinctionem prioris et posterioris, ibi: amplius et hinc considerantibus etc.; tertio per ordinem mobilium, ibi: maxime autem manifestum est et cetera. The first he proves in three ways: First through the properties of motions; Secondly, through the difference between prior and subsequent, 1090; Thirdly, by reason of the order of mobiles, at 1096.
Circa primum ponit duas rationes: circa quarum primam sic procedit. 1088. With respect to the first he gives two arguments, in regard to the first of which he proceeds thus:
Primo enim proponit quod intendit: et dicit quod cum sint tres species motus, unus quidem qui est secundum quantitatem, qui vocatur augmentum et diminutio; alius autem qui est secundum passibilem qualitatem, et vocatur alteratio; tertius autem qui est secundum locum, et vocatur loci mutatio: necesse est quod iste sit primus inter omnes. First he proposes what he intends, and says that since there are three species of motion, one with respect to quantity and called “growth and decrease,” another with respect to passible quality and called “alteration,” and a third with respect to place and called “local motion,” the last one must be the first of all.
Et hoc secundo probat sic: quia impossibile est quod augmentum sit primus motus. Augmentum enim esse non potest nisi alteratio praeexistat; quia illud quo aliquid augmentatur, est quodammodo dissimile et quodammodo simile. Quod enim sit dissimile, patet; quia illud quo aliquid augmentatur est alimentum, quod est in principio contrarium ei quod nutritur, propter diversitatem dispositionis. Sed quando iam additur ut augmentum faciat, necesse est quod sit simile. De dissimilitudine autem non transitur ad similitudinem, nisi per alterationem. Necesse est ergo quod ante augmentum praecedat alteratio, per quam alimentum de una contraria dispositione mutetur in aliam. Secondly, he proves this on the ground that it is impossible for growth to be the first motion, For growth cannot take place unless an alteration precedes it, because that by which something is increased is somehow unlike and somehow like, That it is unlike is plain, because that by which something is increased is food, which in the beginning is contrary to what is nourished, on account of the diversity of disposition. But when it is added and causes increase, it is necessarily like. Now the transition from unlike to like does not take place except through alteration. Therefore, it is necessary that before growth, there must occur alteration through which food is changed from one contrary disposition to the other.
Tertio vero ostendit quod ante omnem alterationem praecedat motus localis: quia si aliquid alteratur, necesse est quod sit aliquid alterans, quod potentia calidum faciat esse actu calidum. Si autem hoc alterans semper esset eodem modo propinquum in eadem distantia ad alteratum, non magis faceret calidum nunc quam prius: manifestum est ergo quod movens in alteratione non similiter distat ab eo quod alteratur, sed aliquando est propinquius, aliquando remotius; quod non potest contingere sine loci mutatione. Si ergo necesse est motum semper esse, necesse est loci mutationem semper esse, cum sit prima motuum. Et si inter loci mutationes una est prior alia, necesse est, si praemissa sunt vera, quod prima sit sempiterna. Thirdly, he shows that before every alteration there is a previous local motion, for if something is altered, it is necessary that there be something causing alteration, that makes the potentially hot come to be actually hot. But if this cause of alteration were always in the same way near at an equal distance to the thing altered, then it would not make it any hotter now than previously. Therefore, it is plain that the mover in alteration does not remain the same distance from what is altered, but is at one time closer and at another time farther away—and this cannot happen without a change of place. If, therefore, motion must always exist, then local motion must always exist, since it is the first of all motions. And if one local motion is prior to all other local motions, then, necessarily, if the foregoing is true, this first motion must be eternal,
Secundam rationem ponit ibi: amplius autem omnium etc.: quae talis est. Alteratio, sicut in septimo probatum est, fit secundum passiones vel passibiles qualitates; inter quas, secundum antiquorum opinionem, principium esse videtur densitas et raritas; quia et grave et leve, et molle et durum, et calidum et frigidum videntur consequi rarum et densum, et secundum ea distingui (in elementis enim densa quidem inveniuntur gravia et frigida, rara vero calida et levia). Et hoc quidem aliqualiter verum est, si in passionibus ordo attendatur secundum propinquitatem ad materiale principium: nam rarum et densum maxime videntur ad materiam pertinere, ut patet ex his quae in quarto sunt dicta. Densitas autem et raritas videntur esse quaedam congregatio et disgregatio; secundum quas, scilicet congregationem et disgregationem, antiqui philosophi ponebant fieri generationem et corruptionem substantiarum. Qua quidem opinione nunc utitur ut probabili, antequam veritatem generationis et corruptionis ostendat in libro de generatione. Illa autem quae congregantur et disgregantur, ex hoc ipso secundum locum mutari videntur. Loci ergo mutatio principium est alterationis. 1089. The second argument he gives at (855) and it is this: Alteration, as was proved in Book VII, occurs with respect to passions and passible qualities, among which, according to the opinions of the ancients, density and rarity seem to be a principle, because the heavy and the light, the soft and the hard, and the hot and the cold, seem both to result from, and to be distinguished by reason of, the dense and the rare (for among the elements the dense are found to be the heavy and the cold, and the rare the hot and the light). Now this opinion is true to a certain extent, if the passible qualities be ranged according to their proximity to the material principle, for the rare and the dense seem especially to pertain to matter, as is clear from what was said in Book IV. But density and rarity seem to be instances of commingling and separation, according to which the ancient philosophers explained the generation and ceasing-to-be of substances. This opinion Aristotle uses as probable before manifesting the truth about generation and ceasing-to-be in his book On Generation. But things commingled and separated seem by that very fact to be changed with respect to place. Hence, change of place is a principle of alteration.
Sed attendendum quod congregatio et disgregatio corporum existentium in actu ad motum localem pertinent: congregatio vero et disgregatio, secundum quod eadem materia continetur sub magnis vel parvis dimensionibus, non pertinent ad motum localem, sed ad motum alterationis. Et secundum hoc Aristoteles supra in quarto assignavit rationem rari et densi. Sed hic loquitur secundum quod erat probabile ex opinione aliorum philosophorum. It should be noted, however, that although the commingling and separation that affect bodies actually existing pertain to local motion, yet the commingling and separation according to which the same matter is contained under larger or smaller dimensions do not pertain to local motion but to the motion of alteration, And it is was in this sense that in Book IV Aristotle explained the nature of the dense and of the rare. But here he is speaking according to what is probable according to the opinion of other philosophers.
Sicut autem motus localis requiritur ad alterationem, ita etiam requiritur ad augmentum. Necesse est enim quod eius quod augetur et decrescit, magnitudo mutetur secundum locum; quia quod augetur excrescit in maiorem locum, quod autem decrescit in minorem contrahitur. Sic ergo patet quod motus localis est naturaliter prior et alteratione et augmento. Yet, just as local motion is required for alteration, so also for growth. For it is necessary that the magnitude of what is increased or decreased be moved with respect to place, because what is increased expands into a larger place, and what decreases shrinks into a lesser place. Therefore, in this way it is plain that local motion is naturally prior to both alteration and growth.
Deinde cum dicit: amplius et hinc considerantibus etc., probat idem, distinguendo modos prioris et posterioris. Et dicit quod ex hac consideratione manifestum erit quod loci mutatio est prima inter motus; quia sicut in aliis rebus prius aliquid altero dicitur multipliciter, ita et in motu. Dicitur enim uno modo prius, quo non existente, non erunt alia, sed illud potest esse sine aliis: sicut unum est prius duobus, quia duo non possunt esse nisi sit unum, unum autem potest esse si non sint duo. Secundo dicitur aliquid prius tempore: quod scilicet est remotius a praesenti nunc in praeterito, vel propinquius in futuro, ut in quarto dictum est. Tertio dicitur aliquid prius secundum substantiam, idest secundum substantiae complementum; sicut actus est prior potentia, et perfectum imperfecto. 1090. And he says that from this consideration it will be clear that change of place is the first of motions, for, just as in other things, so too in motion, one thing is said to be “prior” to another in various ways. For in one way something is said to be “prior” in the sense that, if it does not exist, neither do the other things, while it itself can exist without the others, as “one” is prior to “two,” because “two” cannot exist unless there is “one”, but “one” can exist, even if there are not two. In a second way, something is said to be “prior” in times namely, in the past, when something is more distant from the present “now,” or in the future, when something is closer to the present, as was said in Book IV. Thirdly, something is said to be “prior” according to substance, i.e., with respect to what completes a substance, as act is prior to potency, and the perfect to the imperfect.
Secundo ibi: quare quoniam motum etc., probat motum localem esse primum tribus modis praedictis; et primo quantum ad primum; secundo quantum ad secundum, ibi: adhuc tempore etc.; tertio quantum ad tertium, ibi: omnino autem videtur et cetera. 1091. Secondly, at (857) he proves that local motion is the first among the three above-mentioned kinds of motion: First, as to the first; Secondly, as to the second, at 1092; Thirdly, as to the third, at 1094.
Dicit ergo primo, quod cum necesse sit semper motum esse, ut supra probatum est, hoc potest intelligi dupliciter: uno modo quod sit aliquis continuus motus; alio modo secundum quod sunt motus consequenter se habentes, inter quos nihil sit medium. Magis autem salvatur sempiternitas motus, si motus sit continuus: et iterum dignius est esse continuum, quam consequenter, quia plus habet de ratione unitatis et perpetuitatis; semper autem in natura debemus accipere quod dignius est, si sit possibile. Est autem possibile aliquem motum esse in infinitum continuum; non autem aliquem alium nisi loci mutationem: quod nunc quidem supponatur, posterius quidem probabitur. Ex quo apparet necesse esse ponere motum localem esse primum. He says therefore first (857) that since it is necessary for motion always to exist, as was proved previously, this can be understood in two ways: first, as meaning that there exists a continuous motion; secondly, as meaning that there are motions which exist one after the other, and nothing exists between them. Now, the perpetuity of motion is better saved if motion is continuous; moreover, it is a greater thing, if it be continuous rather than successive, because the former possesses more unity and perpetuity, and in nature we ought always to take what is more noble, if possible. But it is possible that there be a motion that is infinitely continuous, provided it be a local motion. (This is assumed for the present, but later it will be proved.) From this it is plain that local motion must be taken to be the first motion.
Alii enim motus non requiruntur ad hoc quod sit motus localis. Nulla enim necessitas est, ut id quod movetur secundum locum, augmentetur vel alteretur; quia non est necesse quod corpus quod movetur secundum locum, generetur aut corrumpatur; augmentum autem et alteratio locum habent solum in iis quae generantur et corrumpuntur. Sed nullum horum motuum esse contingit, nisi sit ille motus sempiternus, et quem movet primum movens, quem diximus non esse nisi motum localem. Sic igitur motus localis potest esse sine aliis, sed non e converso. Est ergo primus, primo modo prioritatis. For other motions are not required for the existence of local motion. For in order that a thing be moved with respect to place it need be neither increased nor altered, because a body that is in local motion does not have to be subject to generation and corruption, and we know that growth and alteration affect only things that are generated and cease to be. However, none of these motions can occur unless there is that eternal motion, caused by the first mover, the motion, namely, that is none other than local motion. Consequently, local motion can exist without the others but not they without it. Therefore, it is first according to the first way of being “prior.”
Deinde cum dicit: adhuc tempore prior est etc., probat quod sit prius tempore. Et circa hoc duo facit: primo ostendit quod simpliciter loquendo est prius tempore; quia id quod est perpetuum, simpliciter loquendo, est prius tempore quam non perpetuum: solum autem motum localem contingit esse perpetuum, ut dictum est: ergo simpliciter loquendo est primus tempore. 1092. Then at (858) he proves that it is prior in time, About this he does two things. First he shows that, absolutely speaking, it is prior in time, because what is perpetual is, absolutely speaking, prior in time to what is not perpetual. But only local motion can be perpetual, as has been said, therefore, absolutely speaking, it is first in time.
Secundo ibi: sed in uno quidem etc., excludit quandam obiectionem, per quam videtur hoc removeri. Quia si consideremus aliquod unum corpus quod de novo generetur, loci mutatio est postrema tempore inter omnes motus; quia primo generatur, postea alteratur et augetur, et demum habet motum secundum locum, quando iam perfectum est, ut patet in homine et in pluribus animalibus. 1093. Secondly, at (859) he dismisses an objection through which this seems to be made invalid. Because if we consider some one body that is newly generated, local motion seems to be the last change to affect it. For first it is generated, then it is altered and increased, and finally it undergoes local motion, when it is now perfect, as is clear in man and in many animals.
Sed per hoc non excluditur quin simpliciter motus localis sit primus tempore: quia ante omnes istos motus qui sunt in hoc generato, necesse est praecedere quendam motum localem in aliquo priori mobili, quod sit causa generationis his quae generantur sicut generans est causa eius quod generatur, ita tamen quod ipsum non est generatum. But this does not disprove the statement that, absolutely speaking, local motion is first in point of time, because before all those motions which are found in this generated thing, a local motion had to exist in some prior mobile, which is the cause of the generation for those that are generated, as the generator is the cause of what comes to be in such a way as not to be itself generated.
Quod autem motus qui praecedit generationem sit motus localis, et quod sit simpliciter primus motuum, ostendit subdens: quoniam generatio videtur esse prima motuum in his quae generantur, quia primo oportet rem fieri quam moveatur; et hoc verum est in quocumque generato: sed tamen necesse est esse aliquod prius motum quam ea quae generantur, et quod ipsum non sit generatum; vel si est generatum, quod etiam illo priori sit aliud prius; et sic vel procedetur in infinitum, quod est impossibile, ut supra ostensum est, vel pervenietur ad aliquod primum. That the motion which precedes generation is a local motion and that, absolutely speaking, it is the first of motions, he proves on the ground that generation is seen to be the first of motions in things that are generated, because a thing must first be made before it is moved—and this is true in everything generated. But there must be something moved prior to what is generated and which is itself not generated, or if it is generated, then there was something prior to it. In this way we must go on ad infinitum, which is impossible, as was proved above, or come to some first.
Sed impossibile est generationem esse primam, quia sic sequeretur quod omnia quae moventur essent corruptibilia: omne enim generabile est corruptibile. Si ergo primum mobile generatur, sequitur quod sit corruptibile, et per consequens omnia consequentia mobilia. Si ergo generatio non est prima simpliciter, manifestum est quod nullus consequentium motuum potest esse simpliciter primus. Et dico consequentes motus, augmentum, alterationem, decrementum, et tandem corruptionem, qui omnes motus tempore generationem sequuntur. Si ergo generatio non est prior loci mutatione, sequitur quod nulla aliarum mutationum possit esse prior simpliciter quam loci mutatio. Et ita, cum necesse sit esse aliquam primam simpliciter, sequitur quod loci mutatio sit prima. But that first cannot be generation, for then it would follow that all changeable things are perishable, because everything that can be generated is able to perish. Therefore, if the first mobile is something generated, it follows that it is perishable, and as a consequence, all the subsequent mobiles. But if generation is not absolutely first, it is clear that none of the motions that follow it is absolutely first. And I say motions that follow, meaning growth, alteration, decrease and ceasing-to-be, all of which follow generation in time. If, therefore, generation is not prior to local change, it follows that none of the other changes can be absolutely prior to local change, And so, since some change must be absolutely first, it follows that local change is first.
Deinde cum dicit: omnino autem videtur etc., probat quod motus localis sit primus perfectione. Et hoc ostendit dupliciter. Primo sic: omne quod fit, dum fit, est imperfectum, et tendit ad principium, idest ut assimiletur principio suae factionis, quod est primum naturaliter. Ex quo patet quod id quod est posterius in generatione, est prius secundum naturam. Sed in processu generationis in omnibus generabilibus ultimo invenitur loci mutatio, non solum in eodem, sed etiam considerando totum progressum naturae generabilium; inter quae quaedam viventia sunt penitus immobilia secundum locum propter indigentiam organi, sicut plantae, quae non habent organa motus processivi, et similiter multa genera animalium; sed perfectis animalibus inest motus localis. Si igitur loci mutatio inest illis quae magis comprehendunt naturam, idest quae magis perveniunt ad perfectionem naturae, sequitur quod motus localis sit primus secundum substantiae perfectionem inter omnes motus. 1094. Then at (860) he proves that local motion is first in the order of perfection, And this he proves in two ways. First, in this way: Everything that is coming to be is, while it is coming to beg imperfect and tending to its principle, i.e., to a likeness to the principle that made it, and which is naturally first. From this it is clear that what is subsequent in the order of generation is prior in the order of nature. But in the process of generation, in all things generable, local change is found to be last, not only in one and the same thing, but also in the total progress of the nature of things that can be generated. Among these, some living things are completely immobile with respect to place on account of a lack of organ, as are plants, which do not have the organs required for progressive motion, and also many types of animals. But in the perfect animals local motion is found. If, therefore, local motion is present in things which comprehend nature in a higher degree, i.e., which attain to a greater perfection of nature, it follows that local motion is among all motions the first with respect to the perfection of substance.
Secundo ibi: et quia nequaquam etc., ostendit idem sic. Quanto aliquis motus minus removet a mobili, tanto subiectum eius est perfectius, et sic ipse motus etiam quodammodo est perfectior. Secundum autem motum localem solum nihil removetur quod insit subiecto mobili: secundum enim alterationem fit transmutatio secundum qualitatem, in augmento vero et decremento secundum quantitatem, quae insunt subiecto; transmutatio vero generationis et corruptionis attenditur secundum formam quae constituit substantiam subiecti; motus autem localis est solum secundum locum, qui exterius continet. Relinquitur ergo quod motus localis sit maxime perfectus. 1095. Secondly, at (861) he proves the same thing in this way; The less a motion takes away from the mobile, the more perfect is its subject, and in this regard, a motion is somehow more perfect. But it is only according to local motion that nothing in the mobile subject is taken away: for in alteration, a transmutation with respect to a quality in the subject takes place, and in growth and decrease, a change with respect to the quantity of the subject takes place; moreover, the change involved in generation and ceasing-to-be affects the very form which constitutes the substance of the subject. But local motion is only with respect to place, which contains the subject externally. It remains, therefore, that local motion is the most perfect.
Deinde cum dicit: maxime autem manifestum est etc., probat quod motus localis sit primus, ex parte mobilis. Manifestum est enim quod movens seipsum propriissime movet se secundum motum localem. Cum igitur movens seipsum sit principium aliorum moventium et mobilium, et per consequens sit primum inter omnia quae moventur; sequitur quod motus localis, qui est ei proprius, sit primus inter omnes motus. 1096. Then at (862) from the side of the mobile he shows that local motion is first. For it is plain that what moves itself, most properly moves itself according to local motion. Since, therefore, it is something which moves itself that is the principle of other movers and mobiles and is consequently the first among all things that are moved, it follows that local motion, which is proper to it, is first among all motions.
Sic igitur concludit ex praemissis, quod loci mutatio sit prima inter omnes motus. In this way, therefore, he concludes from the foregoing that change of place is the first of all motions.

Lectio 15
Local motion alone can be continuous and perpetual.
Chapter 7 cont.
τίς δὲ φορὰ πρώτη, νῦν δεικτέον. ἅμα δὲ καὶ τὸ νῦν καὶ πρότερον ὑποτεθέν, ὅτι ἐνδέχεταί τινα κίνησιν εἶναι συνεχῆ καὶ ἀΐδιον, φανερὸν ἔσται τῇ αὐτῇ μεθόδῳ. We have now to show which kind of locomotion is primary. The same process of reasoning will also make clear at the same time the truth of the assumption we have made both now and at a previous stage that it is possible that there should be a motion that is continuous and eternal. Now it is clear from the following considerations that no other than locomotion can be continuous.
ὅτι μὲν οὖν τῶν ἄλλων κινήσεων οὐδεμίαν ἐνδέχεται συνεχῆ εἶναι, ἐκ τῶνδε φανερόν. ἅπασαι γὰρ ἐξ ἀντικειμένων εἰς ἀντικείμενά εἰσιν αἱ κινήσεις καὶ μεταβολαί, οἷον γενέσει μὲν καὶ φθορᾷ τὸ ὂν καὶ τὸ μὴ ὂν ὅροι, ἀλλοιώσει δὲ τὰ ἐναντία πάθη, αὐξήσει δὲ καὶ φθίσει ἢ μέγεθος καὶ μικρότης ἢ τελειότης μεγέθους καὶ ἀτέλεια· ἐναντίαι δ' αἱ (261b.) εἰς τὰ ἐναντία. τὸ δὲ μὴ αἰεὶ κινούμενον τήνδε τὴν κίνησιν, ὂν δὲ πρότερον, ἀνάγκη πρότερον ἠρεμεῖν. φανερὸν οὖν ὅτι ἠρεμήσει ἐν τῷ ἐναντίῳ τὸ μεταβάλλον. Every other motion and change is from an opposite to an opposite: thus for the processes of becoming and perishing the limits are the existent and the non-existent, for alteration the various pairs of contrary affections, and for increase and decrease either greatness and smallness or perfection and imperfection of magnitude: and changes to the respective contraries are contrary changes. Now a thing that is undergoing any particular kind of motion, but though previously existent has not always undergone it, must previously have been at rest so far as that motion is concerned. It is clear, then, that for the changing thing the contraries will be states of rest.
ὁμοίως δὲ καὶ ἐπὶ τῶν μεταβολῶν· ἀντίκειται γὰρ φθορὰ καὶ γένεσις ἁπλῶς καὶ ἡ καθ' ἕκαστον τῇ καθ' ἕκαστον. ὥστ' εἰ ἀδύνατον ἅμα μεταβάλλειν τὰς ἀντικειμένας, οὐκ ἔσται συνεχὴς ἡ μεταβολή, ἀλλὰ μεταξὺ ἔσται αὐτῶν χρόνος. And we have a similar result in the case of changes that are not motions: for becoming and perishing, whether regarded simply as such without qualification or as affecting something in particular, are opposites: therefore provided it is impossible for a thing to undergo opposite changes at the same time, the change will not be continuous, but a period of time will intervene between the opposite processes.
οὐδὲν γὰρ διαφέρει ἐναντίας ἢ μὴ ἐναντίας εἶναι τὰς κατ' ἀντίφασιν μεταβολάς, εἰ μόνον ἀδύνατον ἅμα τῷ αὐτῷ παρεῖναι (τοῦτο γὰρ τῷ λόγῳ οὐδὲν χρήσιμον), The question whether these contradictory changes are contraries or not makes no difference, provided only it is impossible for them both to be present to the same thing at the same time: the point is of no importance to the argument.
οὐδ' εἰ μὴ ἀνάγκη ἠρεμῆσαι ἐν τῇ ἀντιφάσει, μηδ' ἐστὶν μεταβολὴ ἠρεμίᾳ ἐναντίον (οὐ γὰρ ἴσως ἠρεμεῖ τὸ μὴ ὄν, ἡ δὲ φθορὰ εἰς τὸ μὴ ὄν), ἀλλ' εἰ μόνον μεταξὺ γίγνεται χρόνος· οὕτω γὰρ οὐκ ἔστιν ἡ μεταβολὴ συνεχής· οὐδὲ γὰρ ἐν τοῖς πρότερον ἡ ἐναντίωσις χρήσιμον, ἀλλὰ τὸ μὴ ἐνδέχεσθαι ἅμα ὑπάρχειν. Nor does it matter if the thing need not rest in the contradictory state, or if there is no state of rest as a contrary to the process of change: it may be true that the non-existent is not at rest, and that perishing is a process to the non-existent. All that matters is the intervention of a time: it is this that prevents the change from being continuous: so, too, in our previous instances the important thing was not the relation of contrariety but the impossibility of the two processes being present to a thing at the same time.
οὐ δεῖ δὲ ταράττεσθαι ὅτι τὸ αὐτὸ πλείοσιν ἔσται ἐναντίον, οἷον ἡ κίνησις καὶ στάσει καὶ κινήσει τῇ εἰς τοὐναντίον, ἀλλὰ μόνον τοῦτο λαμβάνειν, ὅτι ἀντίκειταί πως καὶ τῇ κινήσει καὶ τῇ ἠρεμίᾳ ἡ κίνησις ἡ ἐναντία, καθάπερ τὸ ἴσον καὶ τὸ μέτριον τῷ ὑπερέχοντι καὶ τῷ ὑπερεχομένῳ, καὶ ὅτι οὐκ ἐνδέχεται ἅμα τὰς ἀντικειμένας οὔτε κινήσεις οὔτε μεταβολὰς ὑπάρχειν. And there is no need to be disturbed by the fact that on this showing there may be more than one contrary to the same thing, that a particular motion will be contrary both to rest and to motion in the contrary direction. We have only to grasp the fact that a particular motion is in a sense the opposite both of a state of rest and of the contrary motion, in the same way as that which is of equal or standard measure is the opposite both of that which surpasses it and of that which it surpasses, and that it is impossible for the opposite motions or changes to be present to a thing at the same time.
ἔτι δ' ἐπί τε τῆς γενέσεως καὶ τῆς φθορᾶς καὶ παντελῶς ἄτοπον ἂν εἶναι δόξειεν, εἰ γενόμενον εὐθὺς ἀνάγκη φθαρῆναι καὶ μηδένα χρόνον διαμεῖναι. ὥστε ἐκ τούτων ἂν ἡ πίστις γένοιτο ταῖς ἄλλαις· φυσικὸν γὰρ τὸ ὁμοίως ἔχειν ἐν ἁπάσαις. Furthermore, in the case of becoming and perishing it would seem to be an utterly absurd thing if as soon as anything has become it must necessarily perish and cannot continue to exist for any time: and, if this is true of becoming and perishing, we have fair grounds for inferring the same to be true of the other kinds of change, since it would be in the natural order of things that they should be uniform in this respect.
Postquam philosophus ostendit quod motus localis est primus inter omnes motus, hic ostendit quis motus localis sit primus. Et quia, sicut supra dixit, necesse est eundem esse motum continuum et primum, dividitur haec pars in partes duas: in prima ostendit quis motus possit esse semper continuus; in secunda ostendit quod ille motus est primus, ibi: quod autem lationum circularis et cetera. 1097. After proving that local motion is the first of all motions, the Philosopher now shows which local motion is the first. And because, as he said above, the motion must be the same which is continuous and first, this treatment is divided into two parts: First he shows which motion can be always continuous; Secondly, he shows that such a motion is the first, (L. 19).
Prima autem pars dividitur in partes tres: in prima ostendit quod nullus motus potest esse continuus nisi localis; in secunda quod nullus motus localis potest esse continuus praeter circularem, ibi: quoniam autem contingit esse quendam etc.; in tertia ostendit quod motum circularem contingit esse continuum, ibi: qui autem in circulari et cetera. The first part is divided into three sections: In the first he shows that no motion but local can be continuous; In the second that no local motion but a circular one can be continuous, (L. 16); In the third that a circular motion can be continuous, (L. 19).
Circa primum duo facit: primo proponit quod intendit; secundo probat propositum, ibi: omnes enim ex oppositis et cetera. About the first he does two things; First he proposes what he intends; Secondly, he proves his proposition, at 1098.
Dicit ergo primo, quod cum ostensum sit quod loci mutatio est prima inter omnes species motus, nunc ostendendum est quae loci mutatio sit prima; quia eius etiam sunt multae species, ut in septimo ostensum est. He says therefore first that since it has been shown that change of place is the first among all types of motion, we must now show which change of place is first, because there are many types of it, as was proved in Book VII.
Et simul etiam secundum eandem methodum, idest artem, idest secundum eandem artificialem considerationem, erit manifestum id quod nunc paulo supra diximus, et quod etiam prius suppositum est in principio huius octavi, quod contingit aliquem motum esse continuum et perpetuum. Oportet enim quod idem sit primus et continuus, ut supra ostensum est; et ideo sub eadem consideratione utrumque eorum cadit. And at the same time, according to the same method, i.e., art, i.e., according to the same technical consideration, there will be plain what we have just said and what was also previously assumed at the beginning of Book VIIII namely, that there exists a motion which is continuous and perpetual. Now the first and the continuous must be the same, as was proved above. For that reason both of them fall under the same consideration.
Quod ergo nulla alia species motus praeter loci mutationem possit esse continua et perpetua, manifestum est ex his quae dicentur. That no other type of motion, however, but local motion can be continuous and perpetual will be clear from what will be said.
Deinde cum dicit: omnes enim ex oppositis etc., ostendit propositum. Et circa hoc duo facit: primo ostendit quod nulla alia species mutationis praeter localem potest esse continua et perpetua, una et eadem existens; secundo quod nec duae mutationes aliae oppositae possunt sibi succedere sine interpositione quietis, ibi: amplius in generatione et cetera. 1098. Then at (864) he proves the proposition. And about this he does two things: First he shows that no other species of change but local can be continuous and perpetual, remaining one and the same; Secondly, that two changes which are opposite cannot succeed one another without an interval of rest, at 1103.
Circa primum duo facit: primo ostendit propositum; secundo excludit quasdam obiectiones, ibi: nihil enim differt et cetera. About the first he does two things: First he proves the proposition; Secondly, he excludes some objections, at 1100.
Circa primum duo facit: primo ostendit propositum in motibus; secundo in mutationibus, ibi: similiter autem et in mutationibus et cetera. About the first he does two things: First he proves the proposition in motions; Secondly, in changes, at 1099.
Proponit ergo primo unam propositionem, quae communiter vera est tam in motibus quam in mutationibus, quod scilicet omnes motus et mutationes sunt ex oppositis in opposita: a qua generalitate excipitur quodammodo loci mutatio, ut in fine sexti dictum est. Generatio enim et corruptio, quae sunt mutationes, habent pro terminis esse et non esse; alterationis vero termini oppositi sunt contrariae passiones, idest passibiles qualitates, ut calidum et frigidum, album et nigrum; augmenti vero et diminutionis oppositi termini sunt magnum et parvum, sive perfectum et imperfectum in magnitudine seu quantitate. He proposes therefore first (864) one proposition which is true in common both for changes and motions, namely, that all changes and motions are from opposites to opposites. But local motion is in a sense excluded from this generality, as was said at the end of Book VI. For generation and ceasing-to-be, which are changes, have, for their termini, existence and non-existence; the opposite termini of alteration are contrary passions, i.e., passible qualities, such as hot and cold, black and white; and the opposite termini of growth and decrease are large and small, or perfect and imperfect in magnitude, or quantity.
Manifestum est autem ex his quae dicta sunt in quinto, quod motus qui sunt in contraria sunt contrarii: motus igitur qui est in album, contrarium est motui qui est in nigrum. Sed contraria non possunt esse simul: ergo dum aliquid movetur ad album, non simul movetur ad nigrum. Quod ergo incipit moveri ab albo in nigrum motu denigrationis, etiamsi moveretur motu dealbationis dum fieret album, tamen manifestum est quod non poterat simul moveri motu denigrationis. Quod autem prius existebat, si non semper movebatur aliquo motu determinato, necesse est dicere quod prius quiescebat quiete opposita huic motui: quia omne quod est natum moveri, vel quiescit vel movetur. But it is plain from what was said in Book V that motions toward contrary termini are contrary. Therefore, a motion to white is contrary to a motion to black. But contraries cannot be together; therefore, while something is being moved to white, it cannot at the same time be undergoing a motion to back, Hence what begins to be moved from white to black by the motion of blackening, even though it should be moved by the motion of whitening while becoming white, it could not simultaneously be moved by the motion of blackening, But what was existing previously, if it was not always being moved by some definite motion, must be considered as having been previously resting with a rest opposite to this motion, for whatever is apt to be moved is either at rest or being moved.
Manifestum est ergo quod id quod movetur in aliquod contrarium, aliquando quiescebat quiete opposita tali motui. Nullus ergo motus qui est in aliquod contrarium, potest esse continuus et perpetuus. Therefore, it is plain that what is being moved to a contrary was at one time resting with a rest opposite to that motion. Hence no motion to a contrary can be continuous and perpetual.
Si ergo huic conclusioni addatur quod primo positum est, scilicet quod omnis motus alterationis vel augmenti vel decrementi sit in aliquod contrarium, sequetur quod nullus huiusmodi motus possit esse continuus et perpetuus. If, therefore, to this conclusion be added what was first assumed, namely, that every motion of alteration, or growth or decrease is to a contrary, it follows that none of these motions can be continuous and perpetual.
Deinde cum dicit: similiter autem etc., ostendit idem in mutationibus, idest in generatione et corruptione; quia generatio et corruptio opponuntur et universaliter secundum communem oppositionem entis et non entis, et iterum in singulari, sicut generatio ignis opponitur corruptioni ignis, secundum oppositionem esse ipsius et non esse. 1099. Then at (865) he proves the same thing for changes, i.e., for generation and ceasing-to-be: these, indeed, are opposed universally according to the common opposition of being and non-being, and also in the singular thing, as the generation of fire is opposed to the ceasing-to-be of fire, according to the opposition of its existence and its non-existence.
Unde si impossibile est simul esse oppositas mutationes, sequetur quod nulla mutatio sit continua et perpetua, eodem modo sicut et prius de motibus: sed necesse erit inter duas generationes eiusdem, intervenire medium tempus in quo erat corruptio; et similiter inter corruptiones tempus generationis. Hence, if opposite changes cannot co-exist, it will follow that no change is continuous and perpetual in the same way that it followed previously for motions, and that between two generations of the same thing, there must intervene a time in which ceasing-to-be occurred. In like manner, a time of generation interrupts instances of ceasing-to-be.
Deinde cum dicit: nihil enim differt etc., excludit tres obiectiones. Primo quia posset aliquis dicere quod cum mutationes opponantur secundum oppositionem terminorum; termini autem generationis et corruptionis non sunt contrarii, sed oppositi secundum contradictionem; videtur sequi quod generatio et corruptio non sunt contraria: et sic non erit eadem ratio de eis et de motibus qui sunt contrarii. 1100. Then at (866) he dismisses three objections. First of all, someone could say that since changes are opposed according to the opposition of their termini, whereas the termini of generation and ceasing-to-be are not contrary but contradictory, it seems to follow that generation and ceasing-to-be are not contrary; consequently, the same argument will not apply to them and to motions that are contrary.
Huic ergo obiectioni respondet, dicens quod nihil differt mutationes quae differunt secundum contradictorios terminos, esse contrarias vel non contrarias, dummodo hoc solum verum sit, quod impossibile sit ambas eidem simul inesse. Hoc enim quod est esse contrarium vel non contrarium, nihil est utile ad rationem praemissam. To this objection he replies that it makes no difference whether changes which differ according to contradictory termini are contrary or not contrary, as long as this alone is true, that it is impossible for both to be in the same thing at the same time, For to be contrary or not contrary has no bearing on the argument given.
Secundam obiectionem excludit ibi: neque si non necesse et cetera. Posset enim aliquis dicere, quod necesse est illud quod non semper movetur prius quiescere, quia motus opponitur quieti; sed hoc non habet locum in mutationibus generationis et corruptionis, quibus non opponitur quies proprie loquendo, ut in quinto dictum est. 1101. The second objection he dismisses at (867). For someone could say that it is necessary for what is not always being moved to be previously at rest, because motion is the opposite of rest. But this does not occur in generation and ceasing-to-be, to which, properly speaking, rest is not opposed, as was said in Book V.
Huic ergo obiectioni respondet, dicens quod nihil etiam differt quantum ad propositam rationem, si non est necesse quiescere in aliquo contradictoriorum terminorum; neque etiam si mutatio non contrariatur quieti (quia fortasse illud quod non est, non potest quiescere: corruptio autem est in non esse: unde videtur quod in termino corruptionis non possit esse quies): sed hoc solum sufficit ad propositum, si sit tempus medium inter duas generationes aut inter duas corruptiones. Sic enim consequens erit quod neutra istarum mutationum sit continua. To this objection he responds that it makes no difference to the argument given whether there is rest in either of the contradictory termini or not, or whether change is not contrary to rest (because perhaps what does not exist cannot rest, and ceasing-to-be tends to non-existence, whence it seems that rest cannot occur in the terminus of a ceasing-to-be): but the proposition is sufficiently proved if an intermediate time exists between two generations or two instances of ceasing-to-be. For the consequence will be that neither of these changes is continuous.
Post hoc autem redit ad primam obiectionem: et dicit quod ideo non differt contrarias aut non contrarias esse secundum contradictionem mutationes, quia neque etiam in prioribus, in quibus agebatur de motibus, non erat utile ad propositum quod in eis est contrarietas, sed quod non contingit eos simul esse; quod non est proprium contrariorum, sed commune omnibus oppositis. After this he returns once more to the first objection and says that the reason why it makes no difference whether the changes between contradictory termini are contrary or not is that in the earlier discussions about motions likewise, it was not the question of contrariety that played a part in the proofs but the fact that the two changes could not occur at one and the same time. And this is not a peculiarity of contraries, but is common to all opposites.
Tertiam obiectionem excludit ibi: non oportet autem turbari et cetera. Dixerat enim supra, motus esse contrarios qui sunt in contraria: cum ergo motus sit contrarius quieti, videtur sequi quod uni sint duo contraria; quod est impossibile, ut probatur in X Metaphys. 1102. The-third objection he dismisses at (868). For he had said previously that motions which tend to contraries are contrary. Therefore, since motion is contrary to rest, it seems to follow that one thing has two contraries—which is impossible, as is proved in Metaphysics X.
Ad hoc ergo excludendum dicit, quod non oportet de hoc turbari, quod videtur sequi idem esse contrarium pluribus, scilicet motus et quieti et motui qui est in contrarium. Sed hoc solum debemus accipere, quod unus motus contrarius opponitur quodammodo et motui contrario et quieti; motui quidem contrario secundum directam contrarietatem, quieti autem magis secundum oppositionem privativam; quae tamen habet aliquid de contrarietate, inquantum quies opposita est finis et complementum contrarii motus: sicut etiam aequale et commensurabile opponitur quodammodo duobus, scilicet excellenti et ei quod excellitur, sive magno et parvo, quibus opponitur secundum privationem magis, ut patet in X Metaphys. Et iterum hoc oportet accipere, quod non contingit simul esse neque oppositos motus neque oppositas mutationes. In order to exclude this he says that there is no need to be disturbed about the fact that one thing seems to be contrary to two things, i.e., a motion contrary to rest and to the motion which is to a contrary. Rather, the only thing we ought to take is that one contrary motion is in some manner opposed both to another contrary motion and to rest, to another contrary motion according to direct contrariety; but to rest, more according to privative opposition. Yet this latter opposition has some contrariety, inasmuch as an opposite rest is the end and complement of a contrary motion, just as “equal and commensurable” is opposed in a way to two things, namely, to the excelling and to what is excelled, i.e., to the large and the small, to which two it is opposed rather according to privation, as is plain in Metaphysics X. And once more, what is important to grasp is that opposite motions or opposite changes do not occur at one and the same time.
Deinde cum dicit: amplius in generatione et corruptione etc., ostendit quod non solum inter duos motus vel mutationes eiusdem speciei oportet esse medium tempus; et quod nulla mutatio una, quae est in aliquod oppositorum, potest esse perpetua et continua; sed etiam quod impossibile est quod oppositi motus aut mutationes sic succedant sibi invicem, quod non intercidat tempus medium. Hoc enim videtur penitus esse inconveniens in generatione et corruptione, si quando aliquid factum est, generatione completa, statim necesse sit quod corruptio incipiat; et quod nullo tempore permaneat id quod generatum est. Frustra enim aliquid generaretur, nisi generatum in esse permaneret. 1103. Then at (869) he shows that there must not only be a time between two motions or changes of the same species, and that no single change which tends to one of two opposites can be perpetual and continual, but also that it is impossible for opposite motions or changes so to follow one upon the other that there is no time between them. For it seems to be utterly at odds with generation and ceasing-to-be that when something has come to be and its generation is complete, that immediately it begin to cease to be, so that there would be no period of time in which the generated thing would be permanent. For a thing would be generated in vain, if the generated thing were not to remain in existence.
Unde ex his mutationibus potest fieri fides in aliis: hoc enim est naturale quod similiter se habet in omnibus, quia natura semper eodem modo operatur. Sicut ergo inconveniens videtur quod id quod generatur, statim cum generatum est corrumpatur; ita inconveniens videtur quod id quod dealbatur, statim cum factum est album denigretur, et quod id quod augetur statim decrescat. In omnibus enim his naturae intentio frustraretur. Hence from these changes of generation and ceasing-to-be, we can understand the others. For the natural is what occurs in a like way in all things, since nature always acts in the same way. Therefore, just as it seems unacceptable for something to cease to be as soon as it is generated, so, toot it seems unacceptable that a thing should start becoming black as soon as it became white, and..that a thing should begin to shrink as soon as it is grown. For in all these cases, the intention of nature would be frustrated.

Lectio 16
No change of place can be continuous and perpetual except the circular
Chapter 8
Ὅτι δ' ἐνδέχεται εἶναί τινα ἄπειρον, μίαν οὖσαν καὶ συνεχῆ, καὶ αὕτη ἐστὶν ἡ κύκλῳ, λέγωμεν νῦν. Let us now proceed to maintain that it is possible that there should be an infinite motion that is single and continuous, and that this motion is rotatory motion.
πᾶν μὲν γὰρ κινεῖται τὸ φερόμενον ἢ κύκλῳ ἢ εὐθεῖαν ἢ μικτήν, ὥστ' εἰ μηδ' ἐκείνων ἡ ἑτέρα συνεχής, οὐδὲ τὴν ἐξ ἀμφοῖν οἷόν τ' εἶναι συγκειμένην· The motion of everything that is in process of locomotion is either rotatory or rectilinear or a compound of the two: consequently, if one of the former two is not continuous, that which is composed of them both cannot be continuous either.
ὅτι δὲ τὸ φερόμενον τὴν εὐθεῖαν καὶ πεπερασμένην οὐ φέρεται συνεχῶς, δῆλον· ἀνακάμπτει γάρ, τὸ δ' ἀνακάμπτον τὴν εὐθεῖαν τὰς ἐναντίας κινεῖται κινήσεις· ἐναντία γὰρ κατὰ τόπον ἡ ἄνω τῇ κάτω καὶ ἡ εἰς τὸ πρόσθεν τῇ εἰς τοὔπισθεν καὶ ἡ εἰς ἀριστερὰ τῇ εἰς δεξιά· τόπου γὰρ ἐναντιώσεις αὗται. τίς δ' ἐστὶν ἡ μία καὶ (262a.) συνεχὴς κίνησις, διώρισται πρότερον, ὅτι ἡ τοῦ ἑνὸς καὶ ἐν ἑνὶ χρόνῳ καὶ ἐν ἀδιαφόρῳ κατ' εἶδος (τρία γὰρ ἦν, τό τε κινούμενον, οἷον ἄνθρωπος ἢ θεός, καὶ ὅτε, οἷον χρόνος, καὶ τρίτον τὸ ἐν ᾧ· τοῦτο δ' ἐστὶν τόπος ἢ πάθος ἢ εἶδος ἢ μέγεθος). τὰ δ' ἐναντία διαφέρει τῷ εἴδει, καὶ οὐχ ἕν· τόπου δ' αἱ εἰρημέναι διαφοραί. σημεῖον δ' ὅτι ἐναντία ἡ κίνησις ἡ ἀπὸ τοῦ Α πρὸς τὸ Β τῇ ἀπὸ τοῦ Β πρὸς τὸ Α, ὅτι ἱστᾶσιν καὶ παύουσιν ἀλλήλας, ἐὰν ἅμα γίγνωνται. καὶ ἐπὶ κύκλου ὡσαύτως, οἷον ἡ ἀπὸ τοῦ Α ἐπὶ τὸ Β τῇ ἀπὸ τοῦ Α ἐπὶ τὸ Γ (ἱστᾶσι γάρ, κἂν συνεχεῖς ὦσιν καὶ μὴ γίγνηται ἀνάκαμψις, διὰ τὸ τἀναντία φθείρειν καὶ κωλύειν ἄλληλα)· ἀλλ' οὐχ ἡ εἰς τὸ πλάγιον τῇ ἄνω. Now it is plain that if the locomotion of a thing is rectilinear and finite it is not continuous locomotion: for the thing must turn back, and that which turns back in a straight line undergoes two contrary locomotions, since, so far as motion in respect of place is concerned, upward motion is the contrary of downward motion, forward motion of backward motion, and motion to the left of motion to the right, these being the pairs of contraries in the sphere of place. But we have already defined single and continuous motion to be motion of a single thing in a single period of time and operating within a sphere admitting of no further specific differentiation (for we have three things to consider, first that which is in motion, e.g. a man or a god, secondly the 'when' of the motion, that is to say, the time, and thirdly the sphere within which it operates, which may be either place or affection or essential form or magnitude): and contraries are specifically not one and the same but distinct: and within the sphere of place we have the above-mentioned distinctions. Moreover we have an indication that motion from A to B is the contrary of motion from B to A in the fact that, if they occur at the same time, they arrest and stop each other. And the same is true in the case of a circle: the motion from A towards B is the contrary of the motion from A towards G: for even if they are continuous and there is no turning back they arrest each other, because contraries annihilate or obstruct one another. On the other hand lateral motion is not the contrary of upward motion.
μάλιστα δὲ φανερὸν ὅτι ἀδύνατον εἶναι συνεχῆ τὴν ἐπὶ τῆς εὐθείας κίνησιν, ὅτι ἀνακάμπτον ἀναγκαῖον στῆναι, οὐ μόνον ἐπ' εὐθείας, ἀλλὰ κἂν κύκλον φέρηται. οὐ γὰρ ταὐτὸν κύκλῳ φέρεσθαι καὶ κύκλον· ἔστιν γὰρ ὁτὲ μὲν συνείρειν κινούμενον, ὁτὲ δ' ἐπὶ τὸ αὐτὸ ἐλθὸν ὅθεν ὡρμήθη ἀνακάμψαι πάλιν. ὅτι δ' ἀνάγκη ἵστασθαι, ἡ πίστις οὐ μόνον ἐπὶ τῆς αἰσθήσεως ἀλλὰ καὶ ἐπὶ τοῦ λόγου. ἀρχὴ δὲ ἥδε. τριῶν γὰρ ὄντων, ἀρχῆς μέσου τελευτῆς, τὸ μέσον πρὸς ἑκάτερον ἄμφω ἐστίν, καὶ τῷ μὲν ἀριθμῷ ἕν, τῷ λόγῳ δὲ δύο. ἔτι δὲ ἄλλο ἐστὶν τὸ δυνάμει καὶ τὸ ἐνεργείᾳ, ὥστε τῆς εὐθείας τῶν ἐντὸς τῶν ἄκρων ὁτιοῦν σημεῖον δυνάμει μέν ἐστι μέσον, ἐνεργείᾳ δ' οὐκ ἔστιν, ἐὰν μὴ διέλῃ ταύτῃ καὶ ἐπιστὰν πάλιν ἄρξηται κινεῖσθαι· οὕτω δὲ τὸ μέσον ἀρχὴ γίγνεται καὶ τελευτή, ἀρχὴ μὲν τῆς ὕστερον, τελευτὴ δὲ τῆς πρώτης (λέγω δ' οἷον ἐὰν φερόμενον τὸ Α στῇ ἐπὶ τοῦ Β καὶ πάλιν φέρηται ἐπὶ τὸ Γ). ὅταν δὲ συνεχῶς φέρηται, οὔτε γεγονέναι οὔτε ἀπογεγονέναι οἷόν τε τὸ Α κατὰ τὸ Β σημεῖον, ἀλλὰ μόνον εἶναι ἐν τῷ νῦν, ἐν χρόνῳ δ' οὐδενὶ πλὴν οὗ τὸ νῦν ἐστιν διαί ρεσις, ἐν τῷ ὅλῳ [τῷ ΑΒΓ]. (εἰ δὲ γεγονέναι τις θήσει καὶ ἀπογεγονέναι, ἀεὶ στήσεται τὸ Α φερόμενον· ἀδύνατον (262b.) γὰρ τὸ Α ἅμα γεγονέναι τε ἐπὶ τοῦ Β καὶ ἀπογεγονέναι. ἐν ἄλλῳ ἄρα καὶ ἄλλῳ σημείῳ χρόνου. χρόνος ἄρα ἔσται ὁ ἐν μέσῳ. ὥστε ἠρεμήσει τὸ Α ἐπὶ τοῦ Β. ὁμοίως δὲ καὶ ἐπὶ τῶν ἄλλων σημείων· ὁ γὰρ αὐτὸς λόγος ἐπὶ πάντων. ὅταν δὴ χρήσηται τὸ φερόμενον Α τῷ Β μέσῳ καὶ τελευτῇ καὶ ἀρχῇ, ἀνάγκη στῆναι διὰ τὸ δύο ποιεῖν, ὥσπερ ἂν εἰ καὶ νοήσειεν.) ἀλλ' ἀπὸ μὲν τοῦ Α σημείου ἀπογέγονε τῆς ἀρχῆς, ἐπὶ δὲ τοῦ Γ γέγονεν, ὅταν τελευτήσῃ καὶ στῇ. But what shows most clearly that rectilinear motion cannot be continuous is the fact that turning back necessarily implies coming to a stand, not only when it is a straight line that is traversed, but also in the case of locomotion in a circle (which is not the same thing as rotatory locomotion: for, when a thing merely traverses a circle, it may either proceed on its course without a break or turn back again when it has reached the same point from which it started). We may assure ourselves of the necessity of this coming to a stand not only on the strength of observation, but also on theoretical grounds. We may start as follows: we have three points, starting-point, middle-point, and finishing-point, of which the middle-point in virtue of the relations in which it stands severally to the other two is both a starting-point and a finishing-point, and though numerically one is theoretically two. We have further the distinction between the potential and the actual. So in the straight line in question any one of the points lying between the two extremes is potentially a middle-point: but it is not actually so unless that which is in motion divides the line by coming to a stand at that point and beginning its motion again: thus the middle-point becomes both a starting-point and a goal, the starting-point of the latter part and the finishing-point of the first part of the motion. This is the case e.g. when A in the course of its locomotion comes to a stand at B and starts again towards G: but when its motion is continuous A cannot either have come to be or have ceased to be at the point B: it can only have been there at the moment of passing, its passage not being contained within any period of time except the whole of which the particular moment is a dividing-point. To maintain that it has come to be and ceased to be there will involve the consequence that A in the course of its locomotion will always be coming to a stand: for it is impossible that A should simultaneously have come to be at B and ceased to be there, so that the two things must have happened at different points of time, and therefore there will be the intervening period of time: consequently A will be in a state of rest at B, and similarly at all other points, since the same reasoning holds good in every case. When to A, that which is in process of locomotion, B, the middle-point, serves both as a finishing-point and as a starting-point for its motion, A must come to a stand at B, because it makes it two just as one might do in thought. However, the point A is the real starting-point at which the moving body has ceased to be, and it is at G that it has really come to be when its course is finished and it comes to a stand.
Postquam philosophus ostendit quod nulla mutatio potest esse continua et perpetua nisi localis, hic ostendit quod nulla loci mutatio potest esse continua et perpetua nisi circularis. Et circa hoc duo facit: primo ostendit propositum demonstrative; secundo logice, ibi: rationabiliter autem et cetera. 1104. After showing that no change but local can be continuous and perpetual, the Philosopher now shows that no local change can be continuous and perpetual, unless it be a circular one. About this he does two things: First he proves his proposition by a demonstration; Secondly, dialectically, (L. 18).
Circa primum duo facit: primo ostendit propositum; secundo ex veritate demonstrata solvit quasdam dubitationes, ibi: unde et ad dubitationem et cetera. About the first he does two things: First he proves his proposition; Secondly, from the proven truth he solves some doubts, (L. 17).
Circa primum tria facit: primo dicit quid principaliter intendat. Intendit enim ostendere quod possibile est esse quendam motum, qui unus existens, in infinitum continuetur; et quod talis motus est solus circularis. Et hoc primo ostendet. About the first he does three things: First he mentions what he chiefly intends. For he intends to prove that it is possible that there be a motion which, being one, might be continued ad infinitum, and that such a motion can be none but a circular one. This is the first thing he proves.
Secundo ibi: omne quidem enim movetur etc., ostendit quomodo procedendum sit. Quia enim omne quod localiter fertur, movetur vel circulariter, vel motu recto, vel motu composito ex utroque, sicut si aliquid moveretur per chordam et arcum; manifestum est quod si quis duorum simplicium motuum, scilicet vel circularis vel rectus, non potest esse in infinitum continuus, quod multo minus ille qui est compositus ex utroque. Unde oportet praetermittere motum compositum, et agere de simplicibus. 1105. Secondly, at (871) he shows how to proceed. And he says that whatever is moved locally is moved with either a circular motion or a straight one or in a motion that combines these two, e.g., a motion through a chord and an arc. Hence it is clear that if either of the two simple motions, namely, the circular or the rectilinear, cannot be infinitely continuous, much less their combination. Therefore one must omit the latter and attend to the simple ones.
Tertio ibi: quod autem quod fertur etc., ostendit quod motus rectus qui est super magnitudinem rectam et finitam, non possit esse in infinitum continuus; et ita nullus motus rectus continuus potest esse in infinitum, nisi poneretur aliqua magnitudo infinita in actu; quod supra improbatum est in III physicorum. 1106. Thirdly, at (872) he shows that a rectilinear motion upon a straight and finite magnitude cannot be infinitely continuous and that consequently no rectilinear motion can be infinitely continuous unless an actually infinite magnitude is assumed—and this was proved impossible in Physics III above.
Ostendit autem hoc duplici ratione: quarum prima talis est. Si aliquis super rectam magnitudinem et finitam movetur in infinitum, oportet quod hoc fiat per reflexionem. Ostensum est enim in sexto, quod magnitudinem finitam pertransit aliquid tempore finito; cum ergo pervenitur ad terminum magnitudinis finitae, cessabit motus, nisi mobile revertatur per reflexionem ad principium magnitudinis unde cepit moveri. Sed illud quod reflectitur secundum motum rectum, movetur contrariis motibus. Quod sic probat. He proves his point with two arguments, of which the following is the first. If anything be moved ad infinitum upon a finite magnitude, it has to be done by reflexion. For it has been proved in Book VI that something will traverse a finite magnitude in finite time. When, therefore, the boundary of the finite magnitude is reached, the motion will cease, unless the mobile is returned by reflexion to the beginning of the magnitude whence the motion began. But what is reflected in a rectilinear motion is being moved with contrary motions. And this he now proves;
Contrarii motus sunt quorum termini sunt contrarii, ut in quinto habitum est. Sed contrarietates loci sunt sursum et deorsum, ante et retro, dextrum et sinistrum: omne autem quod reflectitur, secundum aliquam istarum contrarietatum necesse est quod reflectatur: omne ergo quod reflectitur, movetur contrariis motibus. Contrary motions are ones whose terminal points are contrary, as was proved in Book V. But the contrarieties of place are up and down, ahead and behind, right and left. Now, whatever is reflected must be reflected according to one or other of these contrarieties. Therefore, whatever is reflected is moved with contrary motions.
Ostensum est autem supra in quinto, quis motus sit unus et continuus, ille scilicet qui est unius subiecti et in uno tempore et in eadem re non differenti secundum speciem. Haec enim tria considerantur in omni motu: primum est tempus; secundum est subiectum quod movetur, ut homo aut Deus, secundum eos qui corpora caelestia deos dicebant; tertium autem est in quo movetur, quod quidem in motu locali est locus, in alteratione passio, idest passibilis qualitas, in generatione et corruptione species, in augmento et diminutione magnitudo. But it was shown in Book V which motion is one and continuous: the one, namely, which is of one subject, in one time, and in the same category that does not differ specifically. For these three elements are considered in every motion: first, there is the time; secondly, the subject being moved, such as a man or a god, according to those who call the heavenly bodies “gods”; thirdly, there is that in which the motion occurs: in local motion it is a place; in alteration it is a passion, i.e., a passible quality; in generation and ceasing-to-be it is a form; in growth and decrease it is a magnitude.
Manifestum est autem quod contraria differunt secundum speciem: unde motus contrarii non possunt esse unus et continuus. Praedicta autem sex sunt loci differentiae; et sic oportet quod sint contraria, quia cuiuslibet generis differentiae sunt contrariae. Relinquitur ergo quod impossibile sit, id quod reflectitur moveri uno motu continuo. Now it is clear that contraries differ with respect to species; hence contrary motions cannot be one and continuous, But the six things listed above are differences of place and, consequently, they must be contrary, because the differences of any genus are contrary. It remains, therefore, that it is impossible for that which moves by a reflected motion to be moved by one continuous motion.
Et quia posset aliquis dubitare an id quod reflectitur contrariis motibus moveatur, propter hoc quod non apparet manifesta et determinata contrarietas in loco, sicut in aliis generibus in quibus est motus, ut supra in quinto dictum est: ideo addit quoddam signum ad hoc idem ostendendum, praeter rationem supra positam ex contrarietate terminorum. 1107. And because someone could doubt whether what is reflected is being moved with contrary motions, on the ground that there does not appear a manifest and determinate contrariety in place, such as does appear in the other genera in which motion occurs, as was said in Book V, he therefore, in order to show the same point, adds a certain sign over and above the argument above, which was based on the contrariety of termini.
Et dicit quod signum huius est, quod motus qui est ab a in b, sit contrarius ei qui est a b in a, sicut contingit in motu reflexo: quia huiusmodi motus, si simul fiant, stant et repausant ad invicem, idest unus impedit alium et facit eum stare. And he says that the sign of this is that a motion from A to B is contrary to one from B to A, as happens in a reflex motion, because such motions, if they take place simultaneously, “arrest and stop each other,” i.e., are such that one impedes the other and stops it.
Et non solum hoc contingit in reflexione motus recti, sed etiam in reflexione motus circularis. Signentur enim in aliquo circulo tria signa, scilicet abc: constat quod si incipiat moveri ab a in b, et postea moveatur ab a in c versus aliam partem, quod erit reflexio; et isti duo motus impediunt se, et unus sistit, idest facit stare, alium. Sed si continue moveatur aliquid ab a in b, et per b iterum in c, non erit reflexio. Ideo autem motus reflexi impediunt se invicem tam in recto quam in circulo, quia hoc est de natura contrariorum, quod se impediant et corrumpant. And this happens not only in reflex straight motion but in reflex circular motions. For let three points A, B and C be designated on a circle. It is evident that if something begins to be moved from A to B and later is moved from A to C, there was reflexion and those two motions block one another and one arrests the other, i.e., causes the other to stop. But if something is moved without interruption from A to B and again from B to C, there is no reflexion. But the reason why reflex motions impede one another, both in straight and in circular motions, is that it is the nature of contraries to impede and destroy one another.
Motus autem qui sunt diversi et non contrarii, non se impediunt; sicut motus qui est sursum et qui est in latus, puta in dextrum vel sinistrum, non se impediunt, sed simul potest aliquid moveri et sursum et in dextrum. Motions, however, that are diverse but not contrary, do not impede one another, as, for example, an upward motion and a motion to the side, i.e., to the right or left, do not obstruct one another; rather something can at the same time be moved upwards and to the right.
Deinde cum dicit: maxime autem manifestum etc., ponit secundam rationem ad ostendendum quod motus reflexus non potest esse in infinitum continuus: quae quidem ratio accipitur ex quiete, quam necesse est intervenire. Dicit ergo quod maxime ex hoc manifestum est quod impossibile est motum rectum esse continuum in infinitum, quia necesse est id quod reflectitur quiescere inter duos motus. Et hoc verum est non solum si moveatur per lineam rectam, sed etiam si feratur secundum circulum. 1108. Then at (873) he gives a second argument to show that reflex motions cannot be continuous ad infinitum, and it is an argument based on the pause that must intervene. He says, therefore, that it is above all the fact that what is reflected must rest between two motions which makes it clear that it is impossible for a rectilinear motion to be infinitely continuous. And this is true not only if something is moved through a straight line but also if it is carried along according to a circle.
Et ne aliquis intelligat ferri secundum circulum, idem esse quod ferri circulariter, ad hoc excludendum subdit, quod non est idem ferri circulo, idest circulariter secundum proprietatem circuli, et ferri circulum, idest pertransire suo motu circulum. Contingit enim aliquando quod secundum quandam continuationem sit motus eius quod movetur, dum scilicet pertransit partem post partem secundum ordinem partium circuli; et hoc est ferri circulariter. Quandoque autem contingit quod pertransit circulum, quando redierit ad principium unde incepit moveri, non pertransire ultra secundum ordinem partium circuli, sed redire retro; et hoc est reflecti. Sive ergo fiat reflexio in linea recta, sive in linea circulari, necesse est quod interveniat quies media. And lest anyone suppose that being carried along “according to a circle” is the same as being carried along “circularly,” to exclude this he adds that it is not the same to be carried along circularly according to the characteristics of a circle and to be carried along a circle, i.e., to traverse a circle. For sometimes it occurs that the motion of what is moved is according to a certain continuity, as, namely, it traverses part after part according to the order of parts of the circle, and this is “to be carried along circularly.” But sometimes it occurs that what traverses a circle has not, when it returns to the point whence the motion began, travelled in an onward direction according to the order of the parts of the circle, but has returned backwards—and this is “to be reflected.” Whether, therefore, the reflexion occurs in a straight line or a circular line, a pause must intervene.
Et huius rei fides accipi potest non solum ex sensu, quia sensibiliter hoc apparet, sed etiam ex ratione. 1109. Belief in this can be based not only on sense, for it is sensibly evident, but also on an argument.
Cuius quidem rationis principium hoc sumendum est, quod cum tria sint in magnitudine quae pertransitur, scilicet principium, medium et finis, medium utrumque est respectu utriusque; quia respectu finis est principium, et respectu principii est finis; et sic cum sit unum subiecto, est duo ratione. Iterum aliud principium est sumendum, quod aliud est quod est in potentia et quod est in actu. The principle of this argument is that, since three things are involved in a magnitude that is traversed, namely, a beginning, a middle, and an end, the middle is both, when compared to both. For in respect to the end, the middle is a beginning, and in respect to the beginning, it is an end. Consequently, while it is one as to subject, it is two in conception. Another principle to be taken is that what is in potency is other than what is in act.
His ergo visis, considerandum est ex dictis, quod quodlibet signum, idest quodlibet punctum signatum, infra terminos lineae supra quam aliquid movetur, medium est in potentia; sed non est medium in actu, nisi fiat divisio secundum motum, ita scilicet quod in illo puncto id quod movetur stet, et iterum ab illo puncto incipiat moveri: quia sic medium illud fiet actu principium et finis; principium quidem posterioris, inquantum inde incipit rursus moveri, finis autem primi, inquantum scilicet ibi terminatus est primus motus per quietem. Keeping these things in mind, it should be considered, from what has been said, that each sign, i.e., each designated point between termini of a line ever which something is being moved, is potentially a middle, but it is not one unless a division with respect to the motion takes place in such a way that at a given point the thing in motion stops and then resumes its motion at that point. Now, in this way that middle will become an actual beginning and an actual end, i.e., the beginning of the subsequent (inasmuch as the mobile resumes its motion from it) and an end of the first motion (inasmuch as the first motion was terminated there by reason of rest).
Sit enim una linea in cuius principio sit a, in medio b, in fine c. Moveatur ergo ab a in b, et ibi stet; et iterum incipiat moveri a b, et feratur usque in c. Sic enim manifestum erit quod b est actu finis prioris motus, et principium posterioris. For let there be a line at whose beginning is A, at whose middle is B, and at whose end is C. Then let something be moved from A to B and stop there; then let it begin to be moved from B and be carried along to C. In this example, it is plain that B is actually the end of the prior motion and the beginning of the subsequent one.
Sed si aliquid feratur continue ab a in c sine interpositione alicuius quietis, non est possibile dicere mobile factum esse, idest advenire, neque abesse, idest abscedere, neque in hoc signo quod est a, neque in hoc signo quod est b; sed solum hoc potest dici, quod in a vel in b sit in quodam nunc (non autem in aliquo tempore, nisi forte secundum hoc quod aliquid dicitur esse alicubi in tempore, quia est ibi in nunc temporis. Et ita quod movetur continue ab a in c in aliquo tempore, erit in b in nunc, quod est divisio quaedam illius temporis: et sic dicetur esse in b in illo toto tempore, eo modo loquendi quo dicitur aliquid moveri in die, quia movetur in parte illius diei). But if something be moved continuously from A to C without any interval of rest, it is not possible to say that the mobile has “come to be,” i.e., has arrived at, or has “ceased to be,” i.e., has left, either the point A or the point B. Only this can be said, namely, that it is in A or in B at a certain “now.” (But not at a certain time, unless we should perchance say that a thing is somewhere in time because it is there in some “now” of time. And so what is being moved continuously from A to C in some time will be in B at an instant which is a divider of time. In this way, it will be said to be in B in that entire time, in the sense that we speak of something being moved in a day because it is in motion in a part of that day.)
Et quia hoc videbatur dubium, quod id quod fertur non adsit et absit cuicumque signo in magnitudine signato, quae motu pertransitur continuo, ostendit hoc consequenter: dicens quod si aliquis concedat quod mobile adsit et absit alicui signo in magnitudine signato, sequitur quod ibi quiescat. Impossibile est enim quod in eodem instanti adsit et absit mobile ab hoc signo quod est b: quia adesse alicubi et abesse sunt contraria, quae non possunt esse in eodem instanti. And because it seemed doubtful that what is in motion does not arrive at and leave each determinate point of a magnitude which is traversed by a continuous motion, he shows this. He says, then, that if someone grants that the mobile arrives at and then leaves some assigned point in the magnitude, it follows that it is at rest there. For it is impossible that in the same instant a mobile arrive at and leave this point B, because to arrive somewhere and to leave there are contraries, which cannot exist in the same instant.
Oportet ergo quod in alio et alio nunc temporis mobile adsit et absit alicui signo magnitudinis. Inter quaelibet autem duo nunc est tempus medium: ergo sequetur quod mobile quod est a, quiescit in b. Omne enim quod est alicubi per aliquod tempus, est in eodem prius et posterius. Et similiter est dicendum in omnibus aliis signis vel punctis, quia de omnibus eadem ratio est. Therefore, it must be at other and other “now’s” that the mobile arrives at and leaves a given point of the magnitude. But between any two “now’s” is an intermediate time. Therefore, it will follow that the mobile, A, rests in B. For anything that is somewhere for a time is there before and after. And the same must be said for all the other “signs” or points, because the same reasoning applies to all.
Unde manifestum est quod illud quod continue fertur per magnitudinem aliquam, in nullo intermedio signo magnitudinis adest et abest, idest accedit et recedit. Cum enim dicitur quod mobile adsit alicui signo, vel fiat in eo, vel accedat ad ipsum, per omnia huiusmodi significatur quod illud signum sit terminus motus. Cum autem dicitur quod absit vel abscedat, significatur quod sit principium motus. Non est autem actu medium signum magnitudinis nec principium nec finis motus, quia nec terminatur nec incipit ibi motus; sed in potentia tantum (posset enim ibi motus incipere vel terminari). Unde nec adest nec abest mobile a signo medio, sed simpliciter dicitur esse ibi in nunc. Esse enim mobile in aliquo signo magnitudinis, comparatur ad totum motum sicut nunc ad tempus. Hence it is plain that what is being carried along continuously over a magnitude is at no time arriving at, or departing from, any intermediate point. For when it is said that the mobile is “at” this point, or is “coming to be” in it or is “approaching” it, all these expressions imply that that point is a terminus of the motion. And when it is said that it “leaves” or “departs,” a beginning of motion is implied. But a designated point of a magnitude is not actually a middle or a beginning or an end, because the motion neither begins nor ends there; rather, it is these potentially only, because the motion could begin or end there. Hence the mobile neither arrives at nor leaves an intermediate point, but it is said to be there absolutely in a “now.” For the existence of a mobile at some point of the magnitude is compared to the whole motion as the “now” is compared to time.
Sed cum mobile quod est a, utatur ipso b ut medio, principio et fine in actu, necesse est quod ibi stet, propter hoc quod facit ipsum movendo et stando unum signum esse duo, scilicet principium et finem, sicut etiam contingit in intelligendo. Possumus enim simul intelligere unum punctum ut est unum subiecto: sed si seorsum intelligamus ipsum ut principium, seorsum autem ut finem, non simul hoc continget. Ita et cum id quod movetur, utitur aliquo signo ut uno, non erit ibi nisi in uno nunc. Si autem utitur eo ut duobus, scilicet ut principio et fine in actu, necesse erit quod sit ibi in duobus nunc, et per consequens in tempore medio, et ita quiescet. Manifestum est ergo quod id quod continue movetur ab a in c, in medio b neque affuit neque abfuit, idest neque accessit neque abscessit: sed a primo signo, quod est a, abfuit vel abscessit, quasi a principio in actu; in ultimo autem signo, quod est c, affuit vel accessit, quia ibi perficitur motus, et mobile quiescit. 1110. But when the mobile A uses B as an actual middle, beginning and end, then it must be at a stop there, because by moving and stopping it makes that one point to be two, namely, a beginning and an end, as happens also in understanding. For we can simultaneously understand one point as it is one in subject, but if we consider it separately as a beginning and separately as an end, this will not take place simultaneously. So too, when that which is being moved uses a point as one, it will be there only in the one “now.” But if it uses it as two, namely, as a beginning and end in act, it will be there for two “now’s,” and, consequently, for a middle time between them. And so it will be at rest. Therefore, it is plain that what is being moved continuously from A to C was neither present nor away from the intermediate B, i.e., it neither arrived at it nor departed from it; but it was away from and left, the first point A, as the actual beginning; and it was present in, or arrived at, the final point C, because there the motion is finished, and the mobile rests.
Et est attendendum quod in praemissis ponitur a quandoque quidem pro mobili, quandoque vero pro principio magnitudinis. It should be remarked that in the foregoing, “A” was sometimes taken as the mobile, and sometimes as the beginning of the magnitude.
Ex istis autem patet quod motus reflexus, sive in circulari sive in recta magnitudine, non potest esse continuus, sed intercidit quies media; quia idem signum est quod actu fit finis primi motus et principium reflexionis. Sed in motu circulari mobile non utitur aliquo signo ut principio vel fine in actu, sed quolibet signo magnitudinis utitur ut medio: et ideo motus circularis potest esse continuus, non autem reflexus. 1111. From all these things it is clear that a reflected motion, whether it occurs along a circular or a straight magnitude, cannot be continuous, but a rest intervenes, because the same point is actually the end of the first motion and beginning of the reflexed one. But in a circular motion the mobile does not use any point as an actual beginning and end, but each point is used as an intermediate. Therefore, a circular motion can be continuous, but a reflexed one cannot.

Lectio 17
Certain doubts resolved.
Chapter 8 cont.
διὸ καὶ πρὸς τὴν ἀπορίαν τοῦτο λεκτέον· ἔχει γὰρ ἀπορίαν τήνδε. εἰ γὰρ εἴη ἡ τὸ Ε τῇ Ζ ἴση καὶ τὸ Α φέροιτο συνεχῶς ἀπὸ τοῦ ἄκρου πρὸς τὸ Γ, ἅμα δ' εἴη τὸ Α ἐπὶ τῷ Β σημείῳ, καὶ τὸ Δ φέροιτο ἀπὸ τῆς Ζ ἄκρας πρὸς τὸ Η ὁμαλῶς καὶ τῷ αὐτῷ τάχει τῷ Α, τὸ Δ ἔμπροσθεν ἥξει ἐπὶ τὸ Η ἢ τὸ Α ἐπὶ τὸ Γ· τὸ γὰρ πρότερον ὁρμῆσαν καὶ ἀπελθὸν πρότερον ἐλθεῖν ἀνάγκη. So this is how we must meet the difficulty that then arises, which is as follows. Suppose the line E is equal to the line Z, that A proceeds in continuous locomotion from the extreme point of E to G, and that, at the moment when A is at the point B, D is proceeding in uniform locomotion and with the same velocity as A from the extremity of Z to H: then, says the argument, D will have reached H before A has reached G for that which makes an earlier start and departure must make an earlier arrival: the reason, then, for the late arrival of A is that it has not simultaneously come to be and ceased to be at B: otherwise it will not arrive later: for this to happen it will be necessary that it should come to a stand there.
οὐ γὰρ ἅμα γέγονε τὸ Α ἐπὶ τῷ Β καὶ ἀπογέγονεν ἀπ' αὐτοῦ, διὸ ὑστερίζει. εἰ γὰρ ἅμα, οὐχ ὑστεριεῖ, ἀλλ' ἀνάγκη ἔσται ἵστασθαι. οὐκ ἄρα θετέον, ὅτε τὸ Α ἐγένετο κατὰ τὸ Β, τὸ Δ ἅμα κινεῖσθαι ἀπὸ τοῦ Ζ ἄκρου (εἰ γὰρ ἔσται γεγονὸς τὸ Α ἐπὶ τοῦ Β, ἔσται καὶ τὸ ἀπογενέσθαι, καὶ οὐχ ἅμα), ἀλλ' ἦν ἐν τομῇ χρόνου καὶ οὐκ ἐν χρόνῳ. ἐνταῦθα μὲν οὖν ἀδύνατον οὕτως λέγειν ἐπὶ τῆς συνεχοῦς· ἐπὶ δὲ τοῦ ἀνακάμπτοντος ἀνάγκη λέγειν οὕτως. εἰ γὰρ ἡ τὸ Η φέροιτο πρὸς τὸ Δ καὶ πάλιν ἀνακάμψασα κάτω φέροιτο, τῷ ἄκρῳ ἐφ' οὗ Δ τελευτῇ καὶ ἀρχῇ κέχρηται, τῷ ἑνὶ σημείῳ ὡς δύο· διὸ στῆναι ἀνάγκη· καὶ οὐχ ἅμα γέγονεν ἐπὶ τῷ Δ καὶ ἀπελήλυθεν ἀπὸ τοῦ Δ· ἐκεῖ γὰρ ἂν ἅμα εἴη καὶ οὐκ εἴη ἐν τῷ αὐτῷ νῦν. ἀλλὰ μὴν τήν γε πάλαι λύσιν οὐ λεκτέον· οὐ γὰρ ἐνδέχεται λέγειν ὅτι ἐστὶν κατὰ τὸ Δ ἡ τὸ Η ἐν τομῇ, οὐ γέγονε δὲ οὐδ' ἀπογέγονεν. ἀνάγκη γὰρ ἐπὶ τέλος ἐλθεῖν τὸ ἐνεργείᾳ ὄν, μὴ δυνάμει. τὰ μὲν οὖν ἐν μέσῳ δυνάμει ἔστι, τοῦτο δ' ἐνεργείᾳ, καὶ τελευτὴ μὲν κάτωθεν, (263a.) ἀρχὴ δὲ ἄνωθεν· καὶ τῶν κινήσεων ἄρα ὡσαύτως. ἀνάγκη ἄρα στῆναι τὸ ἀνακάμπτον ἐπὶ τῆς εὐθείας. οὐκ ἄρα ἐνδέχεται συνεχῆ κίνησιν εἶναι ἐπὶ τῆς εὐθείας ἀΐδιον. Therefore we must not hold that there was a moment when A came to be at B and that at the same moment D was in motion from the extremity of Z: for the fact of A's having come to be at B will involve the fact of its also ceasing to be there, and the two events will not be simultaneous, whereas the truth is that A is at B at a sectional point of time and does not occupy time there. In this case, therefore, where the motion of a thing is continuous, it is impossible to use this form of expression. On the other hand in the case of a thing that turns back in its course we must do so. For suppose H in the course of its locomotion proceeds to D and then turns back and proceeds downwards again: then the extreme point D has served as finishing-point and as starting-point for it, one point thus serving as two: therefore H must have come to a stand there: it cannot have come to be at D and departed from D simultaneously, for in that case it would simultaneously be there and not be there at the same moment. And here we cannot apply the argument used to solve the difficulty stated above: we cannot argue that H is at D at a sectional point of time and has not come to be or ceased to be there. For here the goal that is reached is necessarily one that is actually, not potentially, existent. Now the point in the middle is potential: but this one is actual, and regarded from below it is a finishing-point, while regarded from above it is a starting-point, so that it stands in these same two respective relations to the two motions. Therefore that which turns back in traversing a rectilinear course must in so doing come to a stand. Consequently there cannot be a continuous rectilinear motion that is eternal.
τὸν αὐτὸν δὲ τρόπον ἀπαντητέον καὶ πρὸς τοὺς ἐρωτῶντας τὸν Ζήνωνος λόγον, [καὶ ἀξιοῦντας,] εἰ ἀεὶ τὸ ἥμισυ διιέναι δεῖ, ταῦτα δ' ἄπειρα, τὰ δ' ἄπειρα ἀδύνατον διεξελθεῖν, ἢ ὡς τὸν αὐτὸν τοῦτον λόγον τινὲς ἄλλως ἐρωτῶσιν, ἀξιοῦντες ἅμα τῷ κινεῖσθαι τὴν ἡμίσειαν πρότερον ἀριθμεῖν καθ' ἕκαστον γιγνόμενον τὸ ἥμισυ, ὥστε διελθόντος τὴν ὅλην ἄπειρον συμβαίνει ἠριθμηκέναι ἀριθμόν· τοῦτο δ' ὁμολογουμένως ἐστὶν ἀδύνατον. The same method should also be adopted in replying to those who ask, in the terms of Zeno's argument, whether we admit that before any distance can be traversed half the distance must be traversed, that these half-distances are infinite in number, and that it is impossible to traverse distances infinite in number—or some on the lines of this same argument put the questions in another form, and would have us grant that in the time during which a motion is in progress it should be possible to reckon a half-motion before the whole for every half-distance that we get, so that we have the result that when the whole distance is traversed we have reckoned an infinite number, which is admittedly impossible.
ἐν μὲν οὖν τοῖς πρώτοις λόγοις τοῖς περὶ κινήσεως ἐλύομεν διὰ τοῦ τὸν χρόνον ἄπειρα ἔχειν ἐν αὑτῷ· οὐδὲν γὰρ ἄτοπον εἰ ἐν ἀπείρῳ χρόνῳ ἄπειρα διέρχεταί τις· ὁμοίως δὲ τὸ ἄπειρον ἔν τε τῷ μήκει ὑπάρχει καὶ ἐν τῷ χρόνῳ. Now when we first discussed the question of motion we put forward a solution of this difficulty turning on the fact that the period of time occupied in traversing the distance contains within itself an infinite number of units: there is no absurdity, we said, in supposing the traversing of infinite distances in infinite time, and the element of infinity is present in the time no less than in the distance.
ἀλλ' αὕτη ἡ λύσις πρὸς μὲν τὸν ἐρωτῶντα ἱκανῶς ἔχει (ἠρωτᾶτο γὰρ εἰ ἐν πεπερασμένῳ ἄπειρα ἐνδέχεται διεξελθεῖν ἢ ἀριθμῆσαι), πρὸς δὲ τὸ πρᾶγμα καὶ τὴν ἀλήθειαν οὐχ ἱκανῶς· ἂν γάρ τις ἀφέμενος τοῦ μήκους καὶ τοῦ ἐρωτᾶν εἰ ἐν πεπερασμένῳ χρόνῳ ἐνδέχεται ἄπειρα διεξελθεῖν, πυνθάνηται ἐπ' αὐτοῦ τοῦ χρόνου ταῦτα (ἔχει γὰρ ὁ χρόνος ἀπείρους διαιρέσεις), οὐκέτι ἱκανὴ ἔσται αὕτη ἡ λύσις, But, although this solution is adequate as a reply to the questioner (the question asked being whether it is possible in a finite time to traverse or reckon an infinite number of units), nevertheless as an account of the fact and explanation of its true nature it is inadequate. For suppose the distance to be left out of account and the question asked to be no longer whether it is possible in a finite time to traverse an infinite number of distances, and suppose that the inquiry is made to refer to the time taken by itself (for the time contains an infinite number of divisions): then this solution will no longer be adequate,
ἀλλὰ τὸ ἀληθὲς λεκτέον, ὅπερ εἴπομεν ἐν τοῖς ἄρτι λόγοις. ἐὰν γάρ τις τὴν συνεχῆ διαιρῇ εἰς δύο ἡμίση, οὗτος τῷ ἑνὶ σημείῳ ὡς δυσὶ χρῆται· ποιεῖ γὰρ αὐτὸ ἀρχὴν καὶ τελευτήν. οὕτω δὲ ποιεῖ ὅ τε ἀριθμῶν καὶ ὁ εἰς τὰ ἡμίση διαιρῶν. οὕτω δὲ διαιροῦντος οὐκ ἔσται συνεχὴς οὔθ' ἡ γραμμὴ οὔθ' ἡ κίνησις· ἡ γὰρ συνεχὴς κίνησις συνεχοῦς ἐστιν, ἐν δὲ τῷ συνεχεῖ ἔνεστι μὲν ἄπειρα ἡμίση, ἀλλ' οὐκ ἐντελεχείᾳ ἀλλὰ δυνάμει. ἂν δὲ ποιῇ ἐντελεχείᾳ, οὐ ποιήσει συνεχῆ, ἀλλὰ στήσει, ὅπερ ἐπὶ τοῦ ἀριθμοῦντος τὰ ἡμίσεα φανερόν ἐστιν ὅτι συμβαίνει· τὸ γὰρ ἓν σημεῖον ἀνάγκη (263b.) αὐτῷ ἀριθμεῖν δύο· τοῦ μὲν γὰρ ἑτέρου τελευτὴ ἡμίσεος τοῦ δ' ἑτέρου ἀρχὴ ἔσται, ἂν μὴ μίαν ἀριθμῇ τὴν συνεχῆ, ἀλλὰ δύο ἡμισείας. ὥστε λεκτέον πρὸς τὸν ἐρωτῶντα εἰ ἐνδέχεται ἄπειρα διεξελθεῖν ἢ ἐν χρόνῳ ἢ ἐν μήκει, ὅτι ἔστιν ὡς, ἔστιν δ' ὡς οὔ. ἐντελεχείᾳ μὲν γὰρ ὄντα οὐκ ἐνδέχεται, δυνάμει δὲ ἐνδέχεται· ὁ γὰρ συνεχῶς κινούμενος κατὰ συμβεβηκὸς ἄπειρα διελήλυθεν, ἁπλῶς δ' οὔ· συμβέβηκε γὰρ τῇ γραμμῇ ἄπειρα ἡμίσεα εἶναι, ἡ δ' οὐσία ἐστὶν ἑτέρα καὶ τὸ εἶναι. and we must apply the truth that we enunciated in our recent discussion, stating it in the following way. In the act of dividing the continuous distance into two halves one point is treated as two, since we make it a starting-point and a finishing-point: and this same result is also produced by the act of reckoning halves as well as by the act of dividing into halves. But if divisions are made in this way, neither the distance nor the motion will be continuous: for motion if it is to be continuous must relate to what is continuous: and though what is continuous contains an infinite number of halves, they are not actual but potential halves. If the halves are made actual, we shall get not a continuous but an intermittent motion. In the case of reckoning the halves, it is clear that this result follows: for then one point must be reckoned as two: it will be the finishing-point of the one half and the starting-point of the other, if we reckon not the one continuous whole but the two halves. Therefore to the question whether it is possible to pass through an infinite number of units either of time or of distance we must reply that in a sense it is and in a sense it is not. If the units are actual, it is not possible: if they are potential, it is possible. For in the course of a continuous motion the traveller has traversed an infinite number of units in an accidental sense but not in an unqualified sense: for though it is an accidental characteristic of the distance to be an infinite number of half-distances, this is not its real and essential character.
δῆλον δὲ καὶ ὅτι ἐὰν μή τις ποιῇ τοῦ χρόνου τὸ διαιροῦν σημεῖον τὸ πρότερον καὶ ὕστερον ἀεὶ τοῦ ὑστέρου τῷ πράγματι, ἔσται ἅμα τὸ αὐτὸ ὂν καὶ οὐκ ὄν, καὶ ὅτε γέγονεν οὐκ ὄν. τὸ σημεῖον μὲν οὖν ἀμφοῖν κοινόν, καὶ τοῦ προτέρου καὶ τοῦ ὑστέρου, καὶ ταὐτὸν καὶ ἓν ἀριθμῷ, λόγῳ δ' οὐ ταὐτόν (τοῦ μὲν γὰρ τελευτή, τοῦ δ' ἀρχή)· τῷ δὲ πράγματι ἀεὶ τοῦ ὑστέρου πάθους ἐστίν. It is also plain that unless we hold that the point of time that divides earlier from later always belongs only to the later so far as the thing is concerned, we shall be involved in the consequence that the same thing is at the same moment existent and not existent, and that a thing is not existent at the moment when it has become. It is true that the point is common to both times, the earlier as well as the later, and that, while numerically one and the same, it is theoretically not so, being the finishing-point of the one and the starting-point of the other: but so far as the thing is concerned it belongs to the later stage of what happens to it.
χρόνος ἐφ' ᾧ ΑΓΒ, πρᾶγμα ἐφ' ᾧ Δ. τοῦτο ἐν μὲν τῷ Α χρόνῳ λευκόν, ἐν δὲ τῷ Β οὐ λευκόν· ἐν τῷ ἄρα Γ λευκὸν καὶ οὐ λευκόν. ἐν ὁτῳοῦν γὰρ τοῦ Α λευκὸν ἀληθὲς εἰπεῖν, εἰ πάντα τὸν χρόνον τοῦτον ἦν λευκόν, καὶ ἐν τῷ Β οὐ λευκόν· τὸ δὲ Γ ἐν ἀμφοῖν. Let us suppose a time ABG and a thing D, D being white in the time A and not-white in the time B. Then D is at the moment G white and not-white: for if we were right in saying that it is white during the whole time A, it is true to call it white at any moment of A, and not-white in B, and G is in both A and B.
οὐκ ἄρα δοτέον ἐν παντί, ἀλλὰ πλὴν τοῦ τελευταίου νῦν ἐφ' οὗ τὸ Γ· τοῦτο δ' ἤδη τοῦ ὑστέρου. καὶ εἰ ἐγίγνετο οὐ λευκὸν καὶ ἐφθείρετο <τὸ> λευκὸν ἐν τῷ Α παντί, γέγονεν ἢ ἔφθαρται ἐν τῷ Γ. ὥστε λευκὸν ἢ μὴ λευκὸν ἐν ἐκείνῳ πρῶτον ἀληθὲς εἰπεῖν, ἢ ὅτε γέγονεν οὐκ ἔσται, καὶ ὅτε ἔφθαρται ἔσται, ἢ ἅμα λευκὸν καὶ οὐ λευκὸν καὶ ὅλως ὂν καὶ μὴ ὂν ἀνάγκη εἶναι. We must not allow, therefore, that it is white in the whole of A, but must say that it is so in all of it except the last moment G. G belongs already to the later period, and if in the whole of A not-white was in process of becoming and white of perishing, at G the process is complete. And so G is the first moment at which it is true to call the thing white or not white respectively. Otherwise a thing may be non-existent at the moment when it has become and existent at the moment when it has perished: or else it must be possible for a thing at the same time to be white and not white and in fact to be existent and non-existent.
εἰ δ' ὃ ἂν ᾖ πρότερον μὴ ὄν, ἀνάγκη γίγνεσθαι ὄν, καὶ ὅτε γίγνεται μὴ ἔστιν, οὐχ οἷόν τε εἰς ἀτόμους χρόνους διαιρεῖσθαι τὸν χρόνον. εἰ γὰρ ἐν τῷ Α τὸ Δ ἐγίγνετο λευκόν, γέγονε δ' ἅμα καὶ ἔστιν ἐν ἑτέρῳ ἀτόμῳ χρόνῳ ἐχομένῳ δ', ἐν τῷ Β—εἰ ἐν τῷ Α ἐγίγνετο, οὐκ ἦν, ἐν δὲ τῷ Β ἐστί—, γένεσιν δεῖ τινὰ εἶναι μεταξύ, ὥστε καὶ (264a.) χρόνον ἐν ᾧ ἐγίγνετο. οὐ γὰρ ὁ αὐτὸς ἔσται λόγος καὶ τοῖς μὴ ἄτομα λέγουσιν, ἀλλ' αὐτοῦ τοῦ χρόνου, ἐν ᾧ ἐγίγνετο, γέγονε καὶ ἔστιν ἐν τῷ ἐσχάτῳ σημείῳ, οὗ οὐδὲν ἐχόμενόν ἐστιν οὐδ' ἐφεξῆς· οἱ δὲ ἄτομοι χρόνοι ἐφεξῆς. φανερὸν δ' ὅτι εἰ ἐν τῷ Α ὅλῳ χρόνῳ ἐγίγνετο, οὐκ ἔστιν πλείων χρόνος ἐν ᾧ γέγονεν καὶ ἐγίγνετο ἢ ἐν ᾧ ἐγίγνετο μόνον παντί. οἷς μὲν οὖν ἄν τις ὡς οἰκείοις πιστεύσειε λόγοις, οὗτοι καὶ τοιοῦτοί τινές εἰσιν· Further, if anything that exists after having been previously non-existent must become existent and does not exist when it is becoming, time cannot be divisible into time-atoms. For suppose that D was becoming white in the time A and that at another time B, a time-atom consecutive with the last atom of A, D has already become white and so is white at that moment: then, inasmuch as in the time A it was becoming white and so was not white and at the moment B it is white, there must have been a becoming between A and B and therefore also a time in which the becoming took place. On the other hand, those who deny atoms of time (as we do) are not affected by this argument: according to them D has become and so is white at the last point of the actual time in which it was becoming white: and this point has no other point consecutive with or in succession to it, whereas time-atoms are conceived as successive. Moreover it is clear that if D was becoming white in the whole time A, the time occupied by it in having become white in addition to having been in process of becoming white is no more than all that it occupied in the mere process of becoming white. These and such-like, then, are the arguments for our conclusion that derive cogency from the fact that they have a special bearing on the point at issue.
Postquam philosophus ostendit quod motus reflexus non potest esse continuus et unus, hic secundum praemissa solvit quasdam dubitationes. Et dividitur in partes tres, secundum tres dubitationes quas ex praemissis solvit: secunda pars incipit ibi: eodem autem modo obviandum est etc.; tertia ibi: manifestum autem et cetera. 1112. After showing that a reflex motion is neither continuous nor one, the Philosopher now settles some doubts on the basis of what has gone before. And it is divided into three parts according to the three doubts he resolves from the foregoing. The second part begins at 1115; The third, at 1119.
Circa primum duo facit: primo ponit dubitationem; secundo solvit eam, ibi: non ergo ponendum est et cetera. About the first he does two things: First he sets forth the doubt; Secondly, he solves it, at 1114.
Dicit ergo primo, quod hoc quod dictum est ad probandum quod motus reflexus non est continuus, potest etiam dici ad solvendum quandam dubitationem. Est enim una talis dubitatio. Sint duae magnitudines aequales, quarum una dicatur e et alia z. Sint etiam duo mobilia aequaliter velocia, quorum unum sit a et aliud sit d; et moveatur a continue ab extremo, idest principio magnitudinis, ad c; d vero feratur ad I. Et ponamus quod in magnitudine quae est e, signetur quoddam signum medium quod est b, quod tantum distet a c, quantum in magnitudine quae est z, distat z ab I. Et ponamus quod simul dum a in suo motu continuo accedit ad b signum, quod d mobile in suo motu continuo recedat a z, et veniat ad I. Cum ergo motus sint regulares et aeque veloces utriusque mobilis, sequetur quod prius veniet d in I, quam a veniat in c: quia quod prius recedit, prius perveniet ad finem aequalis magnitudinis; prius autem recessit d a z, quam a recederet a b, quia d recessit a z quando a pertingebat ad b. Ergo secundum hoc a non simul advenit in b, et recessit ab eo; et ita sequitur quod posterius recesserit quam advenerit: quia si simul adveniret et recederet, non posterius moveri inciperet. Et ita necessitas est quod a, dum continue fertur, quiescat in b: et sic motus continuus erit compositus ex quietibus, sicut Zeno ponebat, ut supra habitum est in sexto. 1113. He says therefore first (874) that what was said in order to prove that a reflex motion is not continuous may be applied to solving a certain doubt, which is this: Assume two equal magnitudes, one called E, and the other Z. Let A and D be two equally swift mobiles, such that A is continuously moved from the beginning of the magnitude (E) to C, and D (along Z) to I, And let us assume that in the magnitude E there is an intermediate point B, which is as far from C as a like point Z on Z is distant from I. Let us further assume that at the same time that A in its continuous motion is approaching B, D in its continuous motion is receding from Z and going to I. Now, since these motions are regular and equally swift, it will follow that D will arrive at I before A arrives at C, because the one which starts first will first arrive to the end of an equal distance. But D left Z before A left B, because D left Z when A was arriving at B. Therefore, according to this, A did not simultaneously arrive at B and leave B, and it consequently follows that it departed after it arrived, because if it arrives and departs at the same time, it will not have begun to move later. And so it is necessary that A, while being carried along, rest in B. Therefore a continuous motion will be composed of periods of rest, as Zeno claimed in Book VI.
Deinde cum dicit: non ergo ponendum etc., solvit motam dubitationem secundum praemissa. Supponebat enim obiectio praedicta quod a, dum continue movetur, accedit ad aliquod signum in medio magnitudinis positum, scilicet ad b, et quod simul dum accedit a ad b, d recedit a quodam alio signo, scilicet a z; quod est contra praemissa. Dictum est enim supra, quod cum aliquid continue fertur, neque potest adesse neque abesse, idest recedere et accedere, a signo medio. Ergo non est ponendum hoc quod obiectio supponebat, quod cum a affuit, idest accessit ad b, ipsum d simul recessit a z: quia si detur quod a accessit ad b, erit pari ratione dare quod recesserit, et quod hoc non fuerit simul, sed in duobus instantibus, ita quod in tempore intermedio quieverit. 1114. Then at (875) he resolves this doubt in the light of the foregoing. For the objection supposed that A in its continuous motion arrives at a point B in the magnitude and that at the same time that A arrived at B, D left the point Z—which is against what was had above. For it was said above that when something is being moved continuously, it can neither arrive at, nor depart from, any intermediate point. Therefore, what the objection assumes must not be assumed, i.e., that when A was at, i.e., approached B, D was departing from Z, because if it be granted that A arrived at B, then for the same reason it should be granted that it left B, and that this did not occur simultaneously, but in two instants, so that in the intermediate time between the two instants it was at rest.
Sed sicut dictum est prius, cum aliquid continue movebatur, in aliquo signo medio non aberat et aderat, sed simpliciter erat; non quidem per aliquod tempus, quia sic quiesceret, sed in decisione temporis, idest in aliquo nunc, quod dividit tempus. But as was said previously, when something was being continuously moved, it was neither departing from, nor approaching, a given point, but was simply there—and this not for a time, because then it would have been resting, but in a division of time, i.e., in some “now,” which divides time.
Hoc ergo quod obiectio supponebat, scilicet quod a adesset, et quod d abesset ab aliquo signo medio, impossibile est dicere in motu continuo. Sed in reflexo necesse est ut ita dicatur. Si enim aliquod mobile quod est I, feratur ad punctum quod est d, et iterum reflectatur, manifestum est quod mobile utitur ultimo quod est d, quasi principio et quasi fine, scilicet uno signo ut duobus: unde necesse est quod ibi quiescat. Therefore, what the objection assumed, namely, that A arrived at and that D left some intermediate point is impossible to state in a continuous motion. But in a reflex motion this must be stated. For if a mobile I is moved to the point D and is then rebounded, it is plain that the mobile uses the ultimate, which is D, as a beginning and as an end, i.e., the point is used for two things, hence it had to be at rest there.
Nec est dicendum quod simul accesserit ad ipsum d, et recesserit ab eodem: quia sequeretur quod simul in eodem instanti esset ibi et non esset. Omne enim quod motum est, est in termino ad quem movebatur; et omne quod incipit moveri, non est in termino a quo incipit moveri: hoc autem significatur, cum dicimus adesse vel accedere, quod est terminari motum ad punctum illud; cum autem dicimus abesse vel recedere, significamus motum incipere. Unde necesse est omne quod accedit vel adest ad aliquod signum, esse in eo: quod autem abest vel abscedit, non esse in eo. Quia ergo impossibile est simul esse et non esse in aliquo signo, per consequens impossibile est quod simul adsit et absit eidem, ut superius pluries est suppositum. Nor can it be said that it simultaneously arrived at and left D, because then it would have been, and not have been, there in the same instant. For whatever has been moved exists in the terminus to which it was being moved, and whatever begins to be moved is not in the terminus from which it begins to be moved. But when we use the expression “to be at” or “to approach,” we mean that a motion is being terminated at that point, and when we say “to be away from” or “to depart,” we mean that the motion is beginning. Hence, it is necessary that whatever arrives at, or is at, a point, be in it, while what is leaving it or is departing from it, be not in it. Since, therefore, it is impossible to be and not to be in a given point at the same time, it is consequently impossible to be at once at and away from the same, as the objection more than once assumed.
Est autem hic attendendum quod aliter utitur hic litteris quam supra. Utitur enim hic I pro mobili, d vero pro termino: supra autem e converso. It should be noted that here he uses different letters from those used above. Here I is the mobile and D the terminus; above, it was the opposite.
Non est autem in motu reflexo danda solutio, quae prius data est in motu continuo. Non enim potest dici quod mobile quod est I, sit in termino quod est d, a quo incipit reflecti, solum in decisione temporis, idest in nunc; et quod mobile neque affuerit neque defuerit eidem, sicut dicebatur in motu continuo: quia in motu reflexo necesse est venire ad finem qui est actu finis, et non in potentia tantum, sicut medium in motu continuo erat principium et finis solum in potentia. Illud ergo quod est in medio motus continui, est in potentia tantum principium et finis; sed hoc a quo incipit reflexio, est actu principium et finis: finis quidem motus qui erat deorsum, puta lapidis; principium autem est in actu motus reflexi qui est sursum, dum lapis cadens in terram resilit sursum. But the solution given for continuous motion is not to be used with respect to a reflex motion. For it cannot be said that the mobile I is in the terminus D, from which it began to be reflected, only in the division of time, i.e., only during the “now,” and that the mobile neither arrived at, nor departed from, the same, as was said with respect to a continuous motion. For in a reflex motion an end must be reached that is an actual end, and not merely a potential one, as the intermediate point in a continuous motion was only potentially a beginning and an end. Therefore, that which is an intermediate point of a continuous motion is only potentially a beginning and an end; but the point from which a reflex motion begins is actually a beginning and end. For example, it is the end of the downward motion of a stone, and the beginning of its upward motion, in the case of a stone falling to earth and bouncing upward.
Sicut ergo in magnitudine in qua est motus, signum a quo reflectitur est principium et finis in actu; ita et in ipsis motibus est accipere actu finem unius et principium alterius: quod non esset, nisi quies interveniret media. Necesse est ergo quod id quod reflectitur in linea recta, quiescat. Et ita sequitur quod in recta magnitudine non possit esse motus continuus et perpetuus: quia magnitudo recta non est infinita, et ita non posset esse in perpetuum motus rectus continuus, nisi reflecteretur. Therefore, just as in the magnitude in which a motion is occurring, a point from which the motion is reflexed is both an actual beginning and end, so also in the motions themselves, there is actually an end of one and a beginning of the other. And this would not be so, unless an interval of rest occurred. Therefore, it is necessary that what is reflected in a straight line be at rest. And so it follows that on a straight magnitude there cannot be a continuous and perpetual motion, because no straight magnitude is infinite. And so there could not be perpetual continuous rectilinear motion, unless reflexion is involved.
Deinde cum dicit: eodem autem modo obviandum etc., ponit secundam dubitationem. Et circa hoc tria facit: primo movet dubitationem; secundo excludit quandam solutionem supra in sexto positam, ibi: in primis igitur etc.; tertio ponit veram solutionem, ibi: sed verum dicendum et cetera. 1115. Then at (876) he presents the second doubt. About this he does three things: First he mentions the doubt; Secondly, he rejects a solution given in Book VI, at 1116; Thirdly, he gives the true solution, at 1118.
Dicit ergo primo, quod eodem modo per ea quae supra ostensa sunt, possumus obviare ad eos qui ponunt obiectionem Zenonis, qui sic volebant argumentari. Omne quod movetur oportet quod prius pertranseat medium quam perveniat ad finem: sed inter quoslibet duos terminos sunt infinita media, propter hoc quod magnitudo est divisibilis in infinitum; et ita impossibile est transire media, quia infinita non contingit transire: ergo nihil potest movendo ad aliquem terminum pervenire. He says therefore first (876) that by the same method, using the things shown above, one can block those who give the objection of Zeno and wish to argue in the following manner: Whatever is being moved must first cross what is intermediate before arriving at the end; but between any two termini there are infinite intermediates on account of a magnitude’s infinite divisibility; and so it is impossible to traverse the intermediates, because infinites cannot be traversed. Therefore, nothing can by motion arrive at any terminus.
Vel potest eadem dubitatio aliter formari, sicut quidam eam proponunt. Omne quod pertransit aliquod totum, prius pertransit medietatem: et cum medietas iterum dividatur in medietatem, oportet quod prius pertransierit medietatem medietatis: et ita omne quod movetur, numerat quamlibet medietatem, pertingendo ad ipsam. Sed medietates sic accipi possunt in infinitum: ergo sequitur quod si aliquid pertransit totam magnitudinem, quod numeravit numerum infinitum; quod est manifeste impossibile. Again, the same difficulty can be presented under another form, as some do in fact propose it: Whatever traverses a whole must previously traverse the half; and since the half is again divided in half, half of the half must be first traversed. And thus, whatever is being moved counts off every half as it reaches it. But such halves can be multiplied ad infinitum. Therefore, it follows that if anything traverses an entire magnitude, it has counted off an infinite number, which is plainly impossible.
Deinde cum dicit: in primis igitur rationibus etc., excludit solutionem quam supra in sexto posuerat ad hanc obiectionem: et primo recitat eam; secundo excludit, ibi: sed haec solutio et cetera. 1116. Then at (877) he rejects the solution he had presented above in Book VI. First he cites it; Secondly, he sets it aside, at 1117.
Dicit ergo primo quod praedicta obiectio soluta est supra in sexto, cum de motu in communi agebatur, per hoc quod sicut magnitudo dividitur in infinitum, ita et tempus; et sic eodem modo tempus habet in seipso infinita, sicut et magnitudo. Et ita non est inconveniens si infinita quae sunt in magnitudine, transeat aliquis in infinitis quae sunt in tempore: quia non est inconveniens quod infinita magnitudo transeatur tempore infinito; sed sicut in sexto ostensum est, infinitum eodem modo invenitur in magnitudine et in tempore. He says therefore first that the foregoing objection was answered in Book VI, when motion in general was being discussed, on the ground that just as a magnitude is divided infinitely, so also is time. Consequently, time possesses infinities in itself in the same way as a magnitude. And so it is not unfitting if the infinites in a magnitude be traversed in the infinites which are in time. For it is not inconsistent for an infinite magnitude to be traversed in an infinite time. But, as shown in Book VI, the infinite is found in magnitude and in time in the same way.
Deinde cum dicit: sed haec solutio etc., excludit hanc solutionem. Et dicit quod haec solutio sufficiens est ad obviandum interroganti qui sic interrogabat: an contingeret in tempore finito transire et numerare infinita. Quae quidem interrogatio repellebatur per hoc quod dicitur, quod tempus finitum habet infinita, in quibus possunt transiri infinita quae sunt in magnitudine. Sed ista solutio non sufficit ad rei veritatem: quia si aliquis praetermittat quaerere de magnitudine; et praetermittat interrogare an in tempore finito contingat infinita transire; et faciat hanc eandem interrogationem de ipso tempore, utrum scilicet infinita quae sunt in tempore possint transiri, propter hoc quod tempus in infinitum dividitur: ad hanc interrogationem non sufficiet praedicta solutio, et ideo oportet aliam solutionem quaerere. 1117. Then at (878) he sets aside this solution, And he says that this solution is sufficient to answer the questioner who asked whether it was possible in a finite time to traverse and count off infinites. This question was retorted by saying that a finite time possesses infinities in which the magnitudinal infinites can be traversed. But that solution does not reach the truth of the matter, because if someone should omit to ask about the magnitude and whether it is possible to traverse infinities in finite time, but asked rather this same question about time, namely, whether the infinites which are in time can be traversed—since time is divided ad infinitum—then the previous solution would not answer this question. Consequently, another solution must be sought.
Deinde cum dicit: sed verum dicendum est etc., ponit veram solutionem, secundum ea quae supra praemiserat. Et dicit quod secundum veritatem hoc dicendum est ad solutionem dubitationis motae, illud quod praemisimus in rationibus supra positis proxime, scilicet quod si aliquis dividat continuum in duo media, tunc utitur uno signo, scilicet in quo dividitur continuum, tanquam duobus, quia facit ipsum et principium unius partis, et finem alterius. Facit autem hoc numerando, et in duo media dividendo. 1118. Then at (879) he gives the true solution in the light of his premises above. And he says that the true solution of the present doubt requires us to repeat what was premised in the immediately foregoing arguments, namely, that if someone divides a continuum into two halves, he then uses the one point at which the continuum is divided as two, because he is making it serve both as the beginning of one part and as the end of the other. He does this by numbering, and by dividing into two halves.
Cum autem sic divisum fuerit continuum, iam non erit continuum, sive dividatur magnitudo, ut linea, sive dividatur motus: quia nec motus potest esse continuus nisi sit continui, scilicet et subiecti et temporis et magnitudinis super quam transit motus. Sic ergo dividens numerat, et numerando continuitatem solvit. But when a continuum has been divided in this manner, it is no longer a continuum, whether it be a magnitude, such as a line, that is divided, or a motion, for a motion cannot be continuous unless it is the motion of something continuous, namely, as to subjects and time and magnitude traversed. Therefore, the divided in effect counts and by counting breaks the continuity.
Sed in continuo dum continuitas durat, sunt infinita media non in actu, sed in potentia: quia si faciat aliquis aliquod medium esse in actu, hoc erit per divisionem, ut dictum est, in quantum accipietur ut principium unius et finis alterius; et sic non remanebit continuum, sed stabit; idest iam media in actu non erunt infinita, sed in eis erit status. Quod maxime accidit in eo qui vult numerare media: quia necesse est ei quod unum signum numeret quasi duo, inquantum est unius medietatis finis, et alterius principium. Et hoc dico quando non numeratur totum continuum ut unum, sed numerantur duae medietates in ipso. Si enim accipietur totum continuum ut unum, tunc iam dictum est quod signum medium non accipitur ut finis et principium in actu, sed in potentia tantum. But so long as continuity endures in a continuum, there is an infinity of intermediates not in act but in potency, for if someone should make some middle actual, it will be due to division, as has been said, insofar as it is taken as the beginning of one and the end of the other. In that case, the continuum will not remain but will “stop,” i.e., the intermediates that are now in act will not be infinite but one will come to a stop in them. This shows up especially in the case of one who wishes to count the intermediates, because he will have to count one as two, inasmuch as it is the end of one half and the beginning of the other. And this, I say, takes place when the whole continuum is not counted as one, but two halves are counted in it, For if the whole continuum is taken as one, it has already been stated that then an intermediate point will not be taken as an actual end and beginning but potentially only.
His ergo visis, respondendum est ad eum qui interrogat an contingat infinita transire sive in tempore sive in magnitudine, quod quodammodo contingit, et quodammodo non contingit. Cum enim sint infinita in actu, non contingit ea transire: cum autem sint infinita in potentia, contingit. Et sic cum in continuo non sint infinita media nisi in potentia, contingit infinita transire: quia illud quod continue movetur, secundum accidens transivit infinita, scilicet in potentia. Per se enim transivit lineam finitam, cui accidit quod insint ei infinita media in potentia; sed ipsa linea secundum substantiam et rationem est alia ab illis mediis infinitis. Non enim linea componitur ex punctis: sed puncta possunt signari in linea, inquantum dividitur. With these facts in mind, the answer to be given to one who asks whether infinites in time or in a magnitude may be traversed is that in one sense it does happen, and in another it does not happen. For when one has infinites in act, it is impossible that they be traversed, but when they are potentially infinite, they can be traversed. And so, since the intermediates in a continuum are infinite only in potency, it does happen that infinites are traversed, because what is in continuous motion traverses per accidens what is infinite, namely, what is infinite in potency, But per se it has traversed a finite line which happens to have an infinitude of intermediates in potency. The line itself, however, in its nature and definition, is distinct from those infinite intermediates. For a line is not a composite of points, but points may be designated in a line insofar as it is divided.
Deinde cum dicit: manifestum autem et quia etc., solvit tertiam dubitationem. Et circa hoc tria facit: primo ponit dubitationem et solutionem; secundo manifestat utrumque per exempla, ibi: sit tempus etc.; tertio infert quoddam corollarium ex dictis, ibi: si autem quodcumque et cetera. 1119. Then at (880) he resolves the third doubt. About this he does three things: First he mentions the doubt and its solution; Secondly, he explains each with an example, at 1120; Thirdly, he draws a corollary from the foregoing, at 1122.
Ponit ergo dubitationem primo, quae solet fieri in generationibus et corruptionibus. Quod enim generatur, desinit non esse et incipit esse. Oportet autem aliud tempus assignari ei quod est esse rei generatae vel corruptae, et aliud ei quod est non esse: puta si ex aere generetur ignis, in toto tempore ab erat non ignis sed aer; in toto autem tempore bc est ignis. Cum ergo hoc signum temporis quod est b, sit utrique tempori commune, videtur quod in illo instanti communi sit simul esse ignis et non esse eiusdem. First therefore (880) he states the doubt that is wont to arise with respect to generation and ceasing-to-be. For what is generated ceases not to be, and begins to be. But the time assigned for the existence of a thing that is generated or has ceased to be, must be different from the one assigned to its non-existence. For example, if from air fire is generated, then in the whole time AB there was not fire but air, but in the entire time BC there is fire. Since, therefore, sign B of the whole time ABC is common to both times, it seems that in that common instant the fire both exists and does not exist.
Hanc ergo dubitationem philosophus solvens, dicit manifestum esse quod nisi aliquis illud signum temporis, quod dividit tempus prius a posteriori, faciat semper esse posterioris rei, idest quod in illo instanti hoc modo se habeat res sicut in tempore sequenti, sequitur quod idem sit ens et non ens simul, et sequitur quod quando aliquid factum est, sit non ens. Tunc enim factum est, quando generatio terminatur, scilicet in illo nunc quod dividit tempus prius et posterius: si ergo in toto tempore priori erat non ens, in hoc etiam nunc quando iam generatum est, est etiam non ens, quia istud nunc est finis prioris temporis. The Philosopher therefore solves this doubt, saying that it is plain that, unless someone holds that the point of time which divides a prior time from a later one, “always belongs to the later,” i.e., that in that instant the thing is in the state which it subsequently has, it follows that the same is simultaneously being and non-being, and that when something has been produced, it is non-being. For it is then produced when generation terminates, namely, in that “now” which divides the prior time and the later. If, therefore, in the entire prior time it was non-being, in that “now” also when it has already been generated, it is also non-being, since this “now” is the end of the prior time.
Quomodo autem ista inconvenientia non sequantur ostendit, subdens quod unum et idem numero signum, scilicet nunc, est commune utrique tempori, scilicet priori et posteriori: sed quamvis sit unum subiecto, non tamen est unum ratione, sed duo; est enim finis prioris temporis et principium posterioris. Sed si accipiatur in ipso nunc quod res est, idest si accipiatur secundum quod est unum re, semper tenet se cum posteriori passione. How these impossibilities do not follow he explains by adding that one and the came sign as to number, i.e., the “now” is common to both times, namely, to the prior and to the subsequent. But although it be one as to subject, it is not one in conception but two, for it is the end of the prior time and beginning of the subsequent. But if we take the “now” as it is a thing, i.e., if it be taken as it is one in reality, it always belongs with the subsequent state (passion).
Vel aliter: quamvis ipsum nunc sit finis temporis prioris et principium posterioris, et sic sit communis utrique; tamen secundum quod est rei, idest secundum quod comparatur ad rem quae movetur, semper est posterioris passionis; quia res quae movetur, in illo instanti est subiecta passioni posterioris temporis. Or in other words: Although the “now” is the end of the prior time and the beginning of the subsequent, and is thus common to both, yet accordingly as it belongs to the thing, i.e., insofar as it is compared to the thing which is being moved, it always belongs to the subsequent passion, because the thing being moved is in that instant being subject to the passion of the subsequent time.
Sic ergo obiectione et solutione posita, manifestat utrumque per exempla: et primo obiectionem, cum dicit: sit tempus et cetera. Dicit ergo: sit tempus acb; res autem quae movetur sit d; quod quidem d in a tempore sit album, in b autem non album. Videtur ergo sequi quod in c sit album et non album. Et quomodo hoc sequatur ostendit subdens: si enim in toto tempore a est album, sequitur quod in quolibet accepto in ipso a sit album; et similiter si in toto tempore b est non album, sequitur quod in quolibet ipsius accepto sit non album: cum ergo c sit acceptum in utroque, quia est huius finis et illius principium, videtur sequi quod in c sit album et non album. 1120. Having given the objection and its solution, he explains both with examples. And first the objection, at (881). He says therefore: Let ACB be the time, and D the thing that is being moved, so that, in time A, D is white, and in B it is non-white. It seems therefore to follow that in C it is white and non-white. How this follows he now explains: If it is white in the entire time A, then at any time taken in A it is white; and likewise, if it is non-white in the entire time B, it follows that at any time taken in B it is non-white. Since, therefore, C is taken in both—being both the end of the former and the beginning of the latter—it seems to follow that in C it is white and non-white.
Secundo ibi: non ergo dandum est etc., manifestat solutionem supra positam. Et dicit quod non est concedendum quod in quolibet accepto in a sit album, sed est excipiendum ultimum nunc, quod est c, quod quidem iam est postremum, idest ultimus terminus mutationis: puta si album vel fiebat vel corrumpebatur in toto a, in c non corrumpitur nec fit album, sed iam factum est et corruptum. Quod autem factum est, est; quod autem corruptum est, non est. Unde manifestum est quod in c primo verum est dicere hoc esse album, si ibi terminetur generatio albi, aut esse non album, si ibi terminetur corruptio albi. Aut si hoc non dicatur, sequentur inconvenientia supra posita, scilicet quod cum aliquid est iam generatum, adhuc est non ens, et cum corruptum est, adhuc est ens. Aut etiam sequitur quod aliquid simul sit album et non album, et universaliter ens et non ens. 1121. Secondly, at (882) he illustrates the solution given above. And he says that we must not concede that it is white at any point of time in A, for the ultimate “now,” which is C, must be excepted, for it is already “later,” i.e., it is the ultimate terminus of the change. For example, if the white was coming to be or ceasing to be in the entire time A, in C it is not ceasing to be or becoming white, but already become or ceased to be. But what has already been made, exists, and what has already ceased to be, does not exist. Hence it is clear that in C it is first true to say this is white, if the generation of white has terminated there, or this is not white, if the ceasing-to-be of white has terminated there. Or, if that is not stated, the above-mentioned incompatibilities follow, namely, that when something has been already generated, it is still non-existent, and when it has ceased to be it is still a being. Or, it also follows that something is at once white and non-white, and, universally, being and non-being.
Deinde cum dicit: si autem quodcumque etc., infert quoddam corollarium ex praemissis, scilicet quod tempus non dividatur in indivisibilia tempora: quia hoc posito, non poterit solvi praemissa dubitatio. 1122. Then at (883) he draws a certain corollary from the foregoing, namely, that time is not divided into indivisible times, because, should one suppose this, it would be impossible to solve the doubt previously mentioned.
Dicit ergo quod necesse est omne quod est prius non ens et postea ens, aliquando fieri ens: et iterum necesse est quod cum aliquid fit, non est. Si autem haec duo quae supponit, sunt vera, impossibile est quod tempus dividatur in indivisibilia tempora. Dividatur enim tempus in indivisibilia tempora: et sit primum tempus indivisibile a; secundum autem, consequenter se habens ad ipsum, sit b. D autem, quod prius non erat album, et postmodum est album, fiebat album in a, et tunc non erat album: oportet autem dare quod sit factum in aliquo tempore indivisibili et habito, idest consequenter se habente, scilicet in b, in quo iam est. Si autem fiebat album in a, sequitur quod in a non erat album: in b autem est album. Cum ergo inter non esse et esse sit generatio media, quia nihil transit de non esse in esse nisi per generationem, sequitur quod inter a et b sit generatio media: ergo erit aliquod tempus medium inter a et b, in quo fiebat album (quia hoc ponitur tempus b, d generationis). He says therefore that it is necessary that whatever is first a non-being, and later is a being, come to be at some time; and again, it is necessary that when something is coming to be, it is not existing. Now, if these two assumptions are true, it is impossible for time to be divided into times that are indivisible. For let a time be divided into indivisible times. Then let A be the first indivisible time, and B the second and subsequent time. Now D, which was previously not white and later is white, was becoming white in time A, and at that time was not white. But one must suppose that it has been made white in some indivisible time which is “had,”, i.e., subsequent, to A, namely, in time B in which it is now white. Now, if it was becoming white in A, it follows that in A it was not white; in B, however, it is white. Since, therefore, between non-existence and existence an instance of generation occurs, because nothing passes from non-existence to existence but by generation, it follows that an act of generation occurs between time A and time B. Therefore, there will be between A and B an intermediate time in which it was becoming white (since in time B, D is already generated).
Et similiter cum in illo medio tempore indivisibili fiat album, est non album: unde eadem ratione oportebit ponere aliud tempus adhuc medium, et sic in infinitum. Et hoc ideo, quia non potest poni quod in eodem tempore fiat et factum sit. And similarly, since in that intermediate indivisible time it is becoming white, it is not white: hence for the same reason it will be necessary to posit still another intermediate time and so on ad infinitum, because we cannot assume that it is becoming white and is white in the same period of time.
Sed non est eadem ratio si dicatur quod non sunt indivisibilia tempora in quae tempus dividitur. Dicemus enim secundum hoc, quod unum et idem tempus est in quo fiebat et factum est. Sed fiebat et erat non ens in toto tempore praecedenti: est autem factum et ens in ultimo nunc temporis; quod quidem non se habet ad tempus praecedens, sicut habitum aut consequenter, sed sicut terminus eius. Sed si ponantur tempora indivisibilia, necesse est quod consequenter se habeant. But the argument is not the same, if one states that the times are not divided into indivisible times. For according to this, we will say that it is one and the same time in which it was coming to be, and was produced. But it was coming to be, and was non-being, in the entire preceding time, and it was produced and a being in the final “now” of the time, which instant is not related to the preceding time as being “had” or subsequent, but as its terminus. But if one assumes indivisible times, they are necessarily (discrete and) consecutive.
Manifestum est autem secundum praemissa, quod non suppositis temporibus indivisibilibus, si aliquid fiat album in toto tempore a, non est maius tempus in quo factum est et fiebat, quam in quo fiebat solum. Quia in toto tempore fit, in ultimo autem termino temporis est factum: tempus autem et terminus temporis non sunt aliquid maius quam tempus tantum, sicut etiam punctum nihil magnitudinis adiicit lineae. Sed si ponantur tempora indivisibilia, manifestum est ex praemissis, quod oportet plus temporis esse in quo fit et factum est, quam in quo fit solum. But it is plain according to the foregoing that, if we do not assume indivisible times, then if something comes to be white in the entire time A, the time in which it was coming to be and was completely made, is no greater than the time in which it was coming to be alone. For it is coming to be in the entire time, but in the ultimate terminus of that time it was completely made. But time plus its terminus is not something greater than the time by itself, any more than a point adds any magnitude to a line. But if indivisible times are assumed, it is clear from the foregoing that there must be more time in coming to be and completely being, than in coming to be alone.
Ultimo autem epilogando concludit principale intentum, dicens quod praemissae rationes sunt, et similes eis, quibus credendum est tanquam propriis, quod motus reflexus non est continuus. Finally, in summary, he concludes to his main intention, saying that the foregoing arguments, and ones like them, are the appropriate ones to convince us that a reflex motion is not continuous.

Lectio 18
Dialectical reasons to show reflex motion is not continuous
Chapter 8 cont.
λογικῶς δ' ἐπισκοποῦσι κἂν ἐκ τῶνδε δόξειέ τῳ ταὐτὸ τοῦτο συμβαίνειν. If we look at the question from the point of view of general theory, the same result would also appear to be indicated by the following arguments.
ἅπαν γὰρ τὸ κινούμενον συνεχῶς, ἂν ὑπὸ μηδενὸς ἐκκρούηται, εἰς ὅπερ ἦλθεν κατὰ τὴν φοράν, εἰς τοῦτο καὶ ἐφέρετο πρότερον, οἷον εἰ ἐπὶ τὸ Β ἦλθε, καὶ ἐφέρετο ἐπὶ τὸ Β, καὶ οὐχ ὅτε πλησίον ἦν, ἀλλ' εὐθὺς ὡς ἤρξατο κινεῖσθαι· τί γὰρ μᾶλλον νῦν ἢ πρότερον; ὁμοίως δὲ καὶ ἐπὶ τῶν ἄλλων. τὸ δὴ ἀπὸ τοῦ Α [ἐπὶ τὸ Γ] φερόμενον, ὅταν ἐπὶ τὸ Γ ἔλθῃ, πάλιν ἥξει ἐπὶ τὸ Α συν εχῶς κινούμενον. Everything whose motion is continuous must, on arriving at any point in the course of its locomotion, have been previously also in process of locomotion to that point, if it is not forced out of its path by anything: e.g. on arriving at B a thing must also have been in process of locomotion to B, and that not merely when it was near to B, but from the moment of its starting on its course, since there can be, no reason for its being so at any particular stage rather than at an earlier one. So, too, in the case of the other kinds of motion. Now we are to suppose that a thing proceeds in locomotion from A to G and that at the moment of its arrival at G the continuity of its motion is unbroken and will remain so until it has arrived back at A. Then when it is undergoing locomotion from A to G it is at the same time undergoing also its locomotion to A from G: consequently it is simultaneously undergoing two contrary motions, since the two motions that follow the same straight line are contrary to each other.
ὅτε ἄρα ἀπὸ τοῦ Α φέρεται πρὸς τὸ Γ, τότε καὶ εἰς τὸ Α φέρεται τὴν ἀπὸ τοῦ Γ κίνησιν, ὥσθ' ἅμα τὰς ἐναντίας· ἐναντίαι γὰρ αἱ κατ' εὐθεῖαν. ἅμα δὲ καὶ ἐκ τούτου μεταβάλλει ἐν ᾧ οὐκ ἔστιν. εἰ οὖν τοῦτ' ἀδύνατον, ἀνάγκη ἵστασθαι ἐπὶ τοῦ Γ. οὐκ ἄρα μία ἡ κίνησις· ἡ γὰρ διαλαμβανομένη στάσει οὐ μία. With this consequence there also follows another: we have a thing that is in process of change from a position in which it has not yet been: so, inasmuch as this is impossible, the thing must come to a stand at G. Therefore the motion is not a single motion, since motion that is interrupted by stationariness is not single.
ἔτι καὶ ἐκ τῶνδε φανερὸν καθόλου μᾶλλον περὶ πάσης κινήσεως. εἰ γὰρ ἅπαν τὸ κινούμενον τῶν εἰρημένων τινὰ κινεῖται κινήσεων καὶ ἠρεμεῖ τῶν ἀντικειμένων ἠρεμιῶν (οὐ γὰρ ἦν ἄλλη παρὰ ταύτας), τὸ δὲ μὴ αἰεὶ κινούμενον τήνδε τὴν κίνησιν (λέγω δ' ὅσαι ἕτεραι τῷ εἴδει, καὶ μὴ εἴ τι μόριόν ἐστιν τῆς ὅλης) ἀνάγκη πρότερον ἠρεμεῖν τὴν ἀντικειμένην ἠρεμίαν (ἡ γὰρ ἠρεμία στέρησις κινήσεως)· εἰ οὖν ἐναντίαι μὲν κινήσεις αἱ κατ' εὐθεῖαν, ἅμα δὲ μὴ ἐνδέχεται κινεῖσθαι τὰς ἐναντίας, τὸ ἀπὸ τοῦ Α πρὸς τὸ Γ φερόμενον οὐκ ἂν φέροιτο ἅμα καὶ ἀπὸ τοῦ Γ πρὸς τὸ Α· ἐπεὶ δ' οὐχ ἅμα φέρεται, κινήσεται δὲ ταύτην τὴν κίνησιν, ἀνάγκη πρότερον ἠρεμῆσαι πρὸς τῷ Γ· αὕτη γὰρ ἦν ἡ ἀντικειμένη ἠρεμία τῇ ἀπὸ τοῦ Γ κινήσει. δῆλον τοίνυν (264b.) ἐκ τῶν εἰρημένων ὅτι οὐκ ἔσται συνεχὴς ἡ κίνησις. Further, the following argument will serve better to make this point clear universally in respect of every kind of motion. If the motion undergone by that which is in motion is always one of those already enumerated, and the state of rest that it undergoes is one of those that are the opposites of the motions (for we found that there could be no other besides these), and moreover that which is undergoing but does not always undergo a particular motion (by this I mean one of the various specifically distinct motions, not some particular part of the whole motion) must have been previously undergoing the state of rest that is the opposite of the motion, the state of rest being privation of motion; then, inasmuch as the two motions that follow the same straight line are contrary motions, and it is impossible for a thing to undergo simultaneously two contrary motions, that which is undergoing locomotion from A to G cannot also simultaneously be undergoing locomotion from G to A: and since the latter locomotion is not simultaneous with the former but is still to be undergone, before it is undergone there must occur a state of rest at G: for this, as we found, is the state of rest that is the opposite of the motion from G. The foregoing argument, then, makes it plain that the motion in question is not continuous.
ἔτι δὲ καὶ ὅδε ὁ λόγος μᾶλλον οἰκεῖος τῶν εἰρημένων. ἅμα γὰρ ἔφθαρται τὸ οὐ λευκὸν καὶ γέγονε λευκόν. εἰ οὖν συνεχὴς ἡ ἀλλοίωσις εἰς λευκὸν καὶ ἐκ λευκοῦ καὶ μὴ μένει τινὰ χρόνον, ἅμα ἔφθαρται τὸ οὐ λευκὸν καὶ γέγονε λευκὸν καὶ γέγονεν οὐ λευκόν· τριῶν γὰρ ἔσται ὁ αὐτὸς χρόνος. Our next argument has a more special bearing than the foregoing on the point at issue. We will suppose that there has occurred in something simultaneously a perishing of not-white and a becoming of white. Then if the alteration to white and from white is a continuous process and the white does not remain any time, there must have occurred simultaneously a perishing of not-white, a becoming of white, and a becoming of not-white: for the time of the three will be the same.
ἔτι οὐκ εἰ συνεχὴς ὁ χρόνος, καὶ ἡ κίνησις, ἀλλ' ἐφεξῆς. πῶς δ' ἂν εἴη τὸ ἔσχατον τὸ αὐτὸ τῶν ἐναντίων, οἷον λευκότητος καὶ μελανίας; Again, from the continuity of the time in which the motion takes place we cannot infer continuity in the motion, but only successiveness: in fact, how could contraries, e.g. whiteness and blackness, meet in the same extreme point?
Postquam philosophus ostendit rationibus propriis quod motus reflexus non est continuus, hic ostendit idem rationibus communibus et logicis. Et circa hoc duo facit: primo dicit de quo est intentio; secundo probat propositum, ibi: omne enim quod movetur et cetera. 1123. After proving with proper reasons that reflex motion is not continuous, the Philosopher now proves the same with common and logical reasons. About this he does two things: First he expresses his intention; Secondly, he proves his proposition, at 1124.
Dicit ergo primo, quod si aliquis velit rationabiliter, idest logice, intendere ad propositum ostendendum, videbitur hoc idem sequi, scilicet quod motus reflexus non est continuus, ex rationibus quae ponentur. He says therefore first that if someone wishes to prove “reasonably,” i.e., logically, the proposition in question, it will be seen from the reasons to be given that the same thing follows, namely, that reflex motion is not continuous.
Deinde cum dicit: omne enim quod movetur etc., ostendit propositum: et primo solum in motu reflexo locali; secundo communiter in omnibus motibus, ibi: amplius et ex his manifestum et cetera. 1124. Then at (885) he proves the proposition. First, for reflex local motion only; Secondly, in common for all motions, at 1126.
Prima ratio talis est. Omne quod movetur continue, a principio sui motus ferebatur sicut in finem ad hoc ad quod pervenit secundum loci mutationem, nisi fuerit aliquid prohibens (quia a prohibente potuisset in aliam partem deflecti). Exemplificat autem hanc propositionem, dicens quod si aliquid per motum localem pervenit ad b, non solum quando propinquum erat, sed statim quando incepit moveri, movebatur ad b: non est enim aliqua ratio quare magis moveatur ad b nunc quam prius. Et simile est in aliis motibus. The first argument is this: Everything in continuous motion has been, from the very beginning of its motion, in the process of being carried, as toward an end, to that at which it arrives according to change of place, unless there is some obstacle (because an obstacle could deflect it in another direction). He exemplifies this by saying that if something in local motion has arrived at B, it was being moved toward B not only when it was near B but at soon as it began to be moved. For there is no reason why it should be tending more toward B now than before. And the same is true in other motions.
Si autem ita sit quod motus reflexus sit continuus, verum erit dicere quod id quod movetur ab a in c, et iterum reflectitur in a, continue movetur. Ergo in prima parte motus qui est ab a in c, movebatur ad terminum ultimae partis qui est a; et sic dum movetur ab a, movetur ad a. Sequitur ergo quod simul moveatur contrariis motibus: quia in motibus rectis contrarium est moveri ab eodem et in idem; in motibus autem circularibus non est contrarium. Hoc autem est impossibile, quod aliquid simul moveatur contrariis motibus: ergo impossibile est quod motus reflexus sit continuus. But if a reflex motion should be continuous, it will be true to say that what is in motion from A to C, and is then reflected back to A, is in a continuous motion. Therefore, in the very first part of the motion from A to C it was being moved to its final terminus in the part A; in this way, while it is being moved from A, it is being moved toward A. It follows, therefore, that it is being simultaneously moved with contrary motions, because in the sphere of rectilinear motions, to be moved from a thing and to be moved toward the same are contrary. But in circular motions this is not contrary. Now it is impossible for something to be moved simultaneously with contrary motions. Therefore, it is impossible for a reflex motion to be continuous.
Deinde cum dicit: simul autem et ex hoc etc., ex eodem medio ducit ad aliud inconveniens. Si enim aliquid, dum movetur ab a, movetur ad a; non autem potest moveri ad a nisi ex aliquo contraposito, quod sit c, in quo mobile nondum fuit cum incipit moveri ab a: sequitur quod aliquid movetur ex illo termino in quo non est; quod est impossibile. Non enim potest aliquid recedere a loco in quo non est. Sic ergo impossibile est quod motus reflexus sit continuus. Et si hoc est impossibile, necesse est quod in puncto reflexionis mobile quiescat, scilicet in c. Ex quo patet quod non est unus motus; quia motus qui distinguitur per interpositionem quietis, non est unus. 1125. Then at (886) from the same middle he leads to another impossibility. For if something, while it is being moved from A, is being moved toward A, it cannot be moved toward A except from a counter-point C, in which the mobile was not yet present when it began to be moved from A. It follows, then, that something is being moved from a terminus at which it is not present—which is impossible. For it cannot leave a place in which it is not. Thus, it is impossible for a reflex motion to be continuous. And if this is impossible, then it is necessary that at the point of reflexion the mobile be at rest, i.e., in C. From which it is plain that it is not one motion, because a motion interrupted by rest is not one.
Deinde cum dicit: amplius et ex his etc., probat idem universalius in quolibet genere motus, tribus rationibus. Quarum prima talis est. Omne quod movetur, movetur aliqua specierum motus supra assignatarum: et similiter omne quod quiescit oportet quod quiescat aliqua quietum oppositarum praedictis motibus. Ostensum est enim supra in quinto, quod non potest esse alius motus praeter assignatos. 1126. Then at (887) he proves the same thing in a more universal way for every genus of motion, with three arguments. The first of them is this: Whatever is in motion is being moved with respect to one of the species of motion listed previously. In like manner, whatever is at. rest is so with respect to a rest that is opposite to one of the aforesaid species of motion. For it was shown above in Book V that no motions other than the ones listed are possible.
Accipiamus ergo aliquem motum distinctum ab aliis motibus hoc modo, quod sit differens specie ab aliis, sicut dealbatio differt a denigratione; non autem sic quod motus qui accipitur distinguatur ab aliis sicut una pars motus ab aliis partibus eiusdem motus, ut una pars dealbationis distinguitur ab aliis partibus dealbationis eiusdem. Accepto ergo uno tali motu sicut dictum est, verum est dicere quod illud quod non semper movetur hoc motu, ex necessitate prius quiescebat opposita quiete: sicut quod non semper dealbatur, aliquando quiescebat quiete opposita dealbationi. Sed haec propositio non esset vera, si aliqua pars determinata motus acciperetur: non enim est necesse ut id quod non semper movebatur hac parte dealbationis, quod antea quiesceret quiete opposita; quia antea etiam dealbabatur alia parte dealbationis. Et propter hoc signanter dixit: et non si aliqua pars est totius. Let us, therefore, take a motion that is distinct from other motions, in the sense of being specifically distinct from others, as whitening is distinct from blackening—but not distinct in the way that one part of a motion is distinct from other parts of the same motion, as one part of the motion of whitening is distinct from other parts of the same whitening. Taking, therefore, one motion in the way described, it is true to say that whatever is not forever being moved with this motion, was before of necessity at rest with an opposite rest, as whatever is not being forever whitened was at some time at rest with a rest opposite to whitening. But this proposition would not be true if some definite part of the motion should be taken, for it is not necessary that what was not forever being moved in this part of the whitening was previously at rest with an opposite rest, because before the thing was becoming white in some other part of the whitening. And because of this he states significantly: “...not some particular part of the whole.”
Hanc autem propositionem sic probat. Duorum privative oppositorum necesse est, cum unum non inest, alterum inesse susceptibili: quies autem opponitur motui privative: ergo si mobile erat quando sibi motus non inerat, ex necessitate sequitur quod tunc quies sibi inesset. This proposition he now proves: When one of two things that are in privative opposition is not in its recipient, the other must be. But rest is opposed to motion privatively. Therefore, if a mobile was existing at a time when motion was not in it, it follows of necessity that rest would then have been in it.
Hac ergo propositione probata, ex ratione supra posita assumit minorem, dicens quod si motus recti contrarii sunt qui est ab a ad c, et qui est a c ad a; et non contingit simul esse motus contrarios: manifestum est quod quando movebatur ab a ad c, non movebatur tunc a c ad a; et sic isto motu qui est a c ad a non semper movebatur. Accordingly, since this proposition has been proved, he takes the minor from the argument already presented above and says that, if rectilinear motions from A to C and from C to A are contrary, and contrary motions cannot coexist, it is plain that when something was being moved from A to C, it was not at the same time being moved from C to A. Consequently, it was not forever being moved with respect to the motion from C to A.
Unde secundum propositionem praemissam, necesse est quod mobile prius quiesceret quiete opposita. Ostensum est autem in quinto, quod motui qui est a c, opponitur quies quae est in c: ergo quiescebat in c. Non ergo motus reflexus erat unus et continuus, cum distinguatur per interpositionem quietis. Hence, according to the previous proposition, it is necessary that the mobile first rest with an opposite rest. For it has been shown in Book V that to a motion from C is opposed rest in C. Therefore, it was at rest in C, Therefore the reflex motion was not one and continuous, since it was interrupted by the interposition of rest.
Secundam rationem ponit ibi: amplius autem et haec ratio etc.: quae talis est. Simul corrumpitur non album et generatur album: et e contrario simul corrumpitur album et fit non album. Sed si motus reflexus in quolibet genere sit continuus, sequetur quod continue alteratio terminetur ad album, et incipiat ex albo recedere, et quod non quiescet ibi aliquo tempore: alioquin non esset continua alteratio, si interponeretur quies. Sed sicut dictum est, cum fit album, corrumpitur non album; et cum receditur ab albo, fit non album. Sequetur ergo quod simul corrumpatur non album, et fiat non album: quia ista tria sunt in eodem tempore, scilicet fieri album, et corrumpi non album, et iterum fieri non album: si tamen continuetur reflexio absque interpositione quietis. Hoc autem est manifeste impossibile, quod simul fiat non album et corrumpatur non album. Non ergo est possibile quod motus reflexus sit continuus. 1127. He presents the second argument at (888), and it is this: Non-white ceases to be and white comes to be simultaneously; similarly, white ceases to be and non-white comes to be simultaneously. But if reflex motion in every genus is continuous, it will follow that an alteration is terminated at whiteness, and begins to depart from whiteness, in such a way as to form a continuous motion, and that it does not rest there for any time; for if rest should intervene, the alteration would not be continuous. But, as has been said, when the white comes to be, the non-white ceases to be, and when departure from white occurs, non-white comes to be. Therefore, it will follow that non-white is ceasing to be and coming to be at the same time, for these three things are present at the same time, namely, the coming-to-be of white, the ceasing-to-be of non-white and the coming-to-be of non-white—that is, if the reflex motion is continuous without any interval of rest. This, however, is plainly impossible, namely, that non-white should be coming to be, and ceasing to be, at the same time. Therefore, a reflex motion cannot be continuous.
Haec autem ratio ad generationem et corruptionem pertinere videtur. Et propter hoc, hanc rationem dicit esse magis propriam quam praemissas, quia in contradictoriis magis apparet quod non possunt esse simul vera. Et tamen quod dicitur in generatione et corruptione, extenditur ad omnes motus; quia in quolibet motu est quaedam generatio et corruptio. Sicut enim in alteratione generatur et corrumpitur album vel non album, ita et in quolibet alio motu. Now, this argument is seen to refer to generation and ceasing-to-be. For this reason he says that this argument is more proper than the previous ones, because it is more apparent in contradictories that they cannot be true at the same time. And yet, what is said in generation and ceasing-to-be applies to all motions, since in every motion there is a kind of generation and ceasing-to-be. For just as in the case of alteration, white is generated, and non-white ceases to be, so too in every other motion.
Tertiam rationem ponit ibi: amplius non si continuum etc.: quae talis est. Sicut supra in quinto habitum est, non est necessarium si continuum est tempus, quod propter hoc motus sit continuus. Motus enim diversarum specierum, etsi succedant sibi in tempore continuo, non tamen sunt continui, sed consequenter se habentes; eo quod oportet continuorum esse unum communem terminum; contrariorum autem et specie differentium, ut albedinis et nigredinis, non potest esse unus communis terminus. Cum igitur motus qui est ab a in c, sit contrarius motui qui est a c in a in quocumque genere motus, ut supra in quinto ostensum est, impossibile est quod isti duo motus sint continui ad invicem, etiam si tempus eorum sit continuum, nulla interposita quiete. Relinquitur ergo quod motus reflexus nullo modo potest esse continuus. 1128. At (889) he gives the third argument, which is this: As was had in Book V, it is not necessary, if the time is continuous, that a motion be on that account continuous. For motions of diverse kinds, even though they succeed one another in continuous time, are not on that account continuous, but are, rather, consequent upon one another, for continua must have one common terminus. But there cannot be one common terminus in things that are contrary and specifically different, such as whiteness and blackness. Since, therefore, a motion from A to C is contrary to one from C to A in any genus of motion, as was shown in Book V, it is impossible that those two motions be continuous one to the other—even though the time be continuous—with no intervening rest. It remains, therefore, that a reflex motion can in no way be continuous.
Est autem considerandum quod rationes praemissae dicuntur logicae, quia procedunt ex quibusdam communibus, scilicet ex proprietate contrariorum. It should be noted that the foregoing arguments are called “logical” because they proceed from certain common things, namely, from the property of contraries.

Lectio 19
Proper reasons why circular motion can be continuous, and why it is the first
Chapter 8 cont.
ἡ δ' ἐπὶ τῆς περιφεροῦς ἔσται μία καὶ συνεχής· οὐθὲν γὰρ ἀδύνατον συμβαίνει· τὸ γὰρ ἐκ τοῦ Α κινούμενον ἅμα κινήσεται εἰς τὸ Α κατὰ τὴν αὐτὴν πρόθεσιν (εἰς ὃ γὰρ ἥξει, καὶ κινεῖται εἰς τοῦτο), ἀλλ' οὐχ ἅμα κινήσεται τὰς ἐναντίας οὐδὲ τὰς ἀντικειμένας· οὐ γὰρ ἅπασα ἡ εἰς τοῦτο τῇ ἐκ τούτου ἐναντία οὐδ' ἀντικειμένη, ἀλλ' ἐναντία μὲν ἡ κατ' εὐθεῖαν (ταύτῃ γὰρ ἔστιν ἐναντία κατὰ τόπον, οἷον τὰ κατὰ διάμε τρον· ἀπέχει γὰρ πλεῖστον), ἀντικειμένη δὲ ἡ κατὰ τὸ αὐτὸ μῆκος. ὥστ' οὐδὲν κωλύει συνεχῶς κινεῖσθαι καὶ μηδένα χρόνον διαλείπειν· ἡ μὲν γὰρ κύκλῳ κίνησίς ἐστιν ἀφ' αὑτοῦ εἰς αὑτό, ἡ δὲ κατ' εὐθεῖαν ἀφ' αὑτοῦ εἰς ἄλλο· On the other hand, in motion on a circular line we shall find singleness and continuity: for here we are met by no impossible consequence: that which is in motion from A will in virtue of the same direction of energy be simultaneously in motion to A (since it is in motion to the point at which it will finally arrive), and yet will not be undergoing two contrary or opposite motions: for a motion to a point and a motion from that point are not always contraries or opposites: they are contraries only if they are on the same straight line (for then they are contrary to one another in respect of place, as e.g. the two motions along the diameter of the circle, since the ends of this are at the greatest possible distance from one another), and they are opposites only if they are along the same line. Therefore in the case we are now considering there is nothing to prevent the motion being continuous and free from all intermission: for rotatory motion is motion of a thing from its place to its place, whereas rectilinear motion is motion from its place to another place.
καὶ ἡ μὲν ἐν τῷ κύκλῳ οὐδέποτε ἐν τοῖς αὐτοῖς, ἡ δὲ κατ' εὐθεῖαν πολλάκις ἐν τοῖς αὐτοῖς. τὴν μὲν οὖν ἀεὶ ἐν ἄλλῳ καὶ ἄλλῳ γιγνομένην ἐνδέχεται κινεῖσθαι συνεχῶς, τὴν δ' ἐν τοῖς αὐτοῖς πολλάκις οὐκ ἐνδέχεται· ἀνάγκη γὰρ ἅμα κινεῖσθαι τὰς ἀντικειμένας. ὥστ' οὐδ' ἐν τῷ ἡμικυκλίῳ οὐδ' ἐν ἄλλῃ περιφερείᾳ οὐδεμιᾷ ἐνδέχεται συνεχῶς κινεῖσθαι· πολλάκις γὰρ ἀνάγκη ταὐτὰ κινεῖσθαι καὶ τὰς ἐναντίας μεταβάλλειν μεταβολάς· οὐ γὰρ συνάπτει τῇ ἀρχῇ τὸ πέρας. ἡ δὲ τοῦ κύκλου συνάπτει, καὶ ἔστι μόνη τέλειος. Moreover the progress of rotatory motion is never localized within certain fixed limits, whereas that of rectilinear motion repeatedly is so. Now a motion that is always shifting its ground from moment to moment can be continuous: but a motion that is repeatedly localized within certain fixed limits cannot be so, since then the same thing would have to undergo simultaneously two opposite motions. So, too, there cannot be continuous motion in a semicircle or in any other arc of a circle, since here also the same ground must be traversed repeatedly and two contrary processes of change must occur. The reason is that in these motions the starting-point and the termination do not coincide, whereas in motion over a circle they do coincide, and so this is the only perfect motion.
φανερὸν δὲ ἐκ ταύτης τῆς διαιρέσεως ὅτι οὐδὲ τὰς ἄλλας ἐνδέχεται κινήσεις εἶναι συνεχεῖς· ἐν ἁπάσαις γὰρ ταὐτὰ συμβαίνει κινεῖσθαι πολλάκις, οἷον ἐν ἀλλοιώσει τὰ μεταξύ, καὶ ἐν τῇ τοῦ ποσοῦ τὰ ἀνὰ μέσον μεγέθη, καὶ ἐν γενέσει καὶ φθορᾷ ὡσαύτως· οὐδὲν γὰρ διαφέρει ὀλίγα ἢ πολλὰ ποιῆσαι, ἐν (265a.) οἷς ἐστὶν ἡ μεταβολή, οὐδὲ μεταξὺ θεῖναί τι ἢ ἀφελεῖν· ἀμφοτέρως γὰρ συμβαίνει ταὐτὰ κινεῖσθαι πολλάκις. This differentiation also provides another means of showing that the other kinds of motion cannot be continuous either: for in all of them we find that there is the same ground to be traversed repeatedly; thus in alteration there are the intermediate stages of the process, and in quantitative change there are the intervening degrees of magnitude: and in becoming and perishing the same thing is true. It makes no difference whether we take the intermediate stages of the process to be few or many, or whether we add or subtract one: for in either case we find that there is still the same ground to be traversed repeatedly.
δῆλον οὖν ἐκ τούτων ὅτι οὐδ' οἱ φυσιολόγοι καλῶς λέγουσιν οἱ πάντα τὰ αἰσθητὰ κινεῖσθαι φάσκοντες ἀεί· κινεῖσθαι γὰρ ἀνάγκη τούτων τινὰ τῶν κινήσεων, καὶ μάλιστα κατ' ἐκείνους [ἐστὶν] ἀλλοιοῦσθαι· ῥεῖν γάρ φασιν ἀεὶ καὶ φθίνειν, ἔτι δὲ καὶ τὴν γένεσιν καὶ τὴν φθορὰν ἀλλοίωσιν λέγουσιν. ὁ δὲ λόγος νῦν εἴρηκε καθόλου περὶ πάσης κινήσεως ὅτι κατ' οὐδεμίαν κίνησιν ἐνδέχεται κινεῖσθαι συνεχῶς ἔξω τῆς κύκλῳ, ὥστε οὔτε κατ' ἀλλοίωσιν οὔτε κατ' αὔξησιν. ὅτι μὲν οὖν οὔτ' ἄπειρός ἐστι μεταβολὴ οὐδεμία οὔτε συνεχὴς ἔξω τῆς κύκλῳ φορᾶς ἔστω τοσαῦθ' ἡμῖν εἰρημένα. Moreover it is plain from what has been said that those physicists who assert that all sensible things are always in motion are wrong: for their motion must be one or other of the motions just mentioned: in fact they mostly conceive it as alteration (things are always in flux and decay, they say), and they go so far as to speak even of becoming and perishing as a process of alteration. On the other hand, our argument has enabled us to assert the fact, applying universally to all motions, that no motion admits of continuity except rotatory motion: consequently neither alteration nor increase admits of continuity. We need now say no more in support of the position that there is no process of change that admits of infinity or continuity except rotatory locomotion.
Chapter 9
Ὅτι δὲ τῶν φορῶν ἡ κυκλοφορία πρώτη, δῆλον. πᾶσα γὰρ φορά, ὥσπερ καὶ πρότερον εἴπομεν, ἢ κύκλῳ ἢ ἐπ' εὐθείας ἢ μικτή. ταύτης δὲ ἀνάγκη προτέρας εἶναι ἐκείνας· ἐξ ἐκείνων γὰρ συνέστηκεν. τῆς δ' εὐθείας ἡ κύκλῳ· ἁπλῆ γὰρ καὶ τέλειος μᾶλλον. ἄπειρον μὲν γὰρ οὐκ ἔστιν εὐθεῖαν φέρεσθαι (τὸ γὰρ οὕτως ἄπειρον οὐκ ἔστιν· ἅμα δ' οὐδ' εἰ ἦν, ἐκινεῖτ' ἂν οὐδέν· οὐ γὰρ γίγνεται τὸ ἀδύνατον, διελθεῖν δὲ τὴν ἄπειρον ἀδύνατον)· ἡ δ' ἐπὶ τῆς πεπερασμένης ἀνακάμπτουσα μὲν συνθετὴ καὶ δύο κινήσεις, μὴ ἀνακάμπτουσα δὲ ἀτελὴς καὶ φθαρτή. πρότερον δὲ καὶ φύσει καὶ λόγῳ καὶ χρόνῳ τὸ τέλειον μὲν τοῦ ἀτελοῦς, τοῦ φθαρτοῦ δὲ τὸ ἄφθαρτον. It can now be shown plainly that rotation is the primary locomotion. Every locomotion, as we said before, is either rotatory or rectilinear or a compound of the two: and the two former must be prior to the last, since they are the elements of which the latter consists. Moreover rotatory locomotion is prior to rectilinear locomotion, because it is more simple and complete, which may be shown as follows. The straight line traversed in rectilinear motion cannot be infinite: for there is no such thing as an infinite straight line; and even if there were, it would not be traversed by anything in motion: for the impossible does not happen and it is impossible to traverse an infinite distance. On the other hand rectilinear motion on a finite straight line is if it turns back a composite motion, in fact two motions, while if it does not turn back it is incomplete and perishable: and in the order of nature, of definition, and of time alike the complete is prior to the incomplete and the imperishable to the perishable.
ἔτι προτέρα ἣν ἐνδέχεται ἀΐδιον εἶναι τῆς μὴ ἐνδεχομένης· τὴν μὲν οὖν κύκλῳ ἐνδέχεται ἀΐδιον εἶναι, τῶν δὲ ἄλλων οὔτε φορὰν οὔτε ἄλλην οὐδεμίαν· στάσιν γὰρ δεῖ γενέσθαι, εἰ δὲ στάσις, ἔφθαρται ἡ κίνησις. Again, a motion that admits of being eternal is prior to one that does not. Now rotatory motion can be eternal: but no other motion, whether locomotion or motion of any other kind, can be so, since in all of them rest must occur and with the occurrence of rest the motion has perished.
Postquam philosophus ostendit quod nullus motus localis potest esse continuus praeter circularem, hic ostendit quod motus circularis potest esse continuus et primus. Et primo ostendit hoc per proprias rationes; secundo per rationes logicas et communes, ibi: rationabiliter autem accidit et cetera. 1129. After showing that no local motion but a circular one can be continuous, the Philosopher now shows that a circular motion can be continuous and first. First of all he shows this with proper arguments; Secondly, with logical and common arguments, (L. 20).
Circa primum duo facit: primo ostendit quod motus circularis sit continuus; secundo quod sit primus, ibi: quod autem lationum et cetera. About the first he does two things: First he shows that a circular motion is continuous; Secondly, that it is the first, at 1134.
Circa primum duo facit: primo ponit duas rationes ad ostendendum quod motus circularis potest esse continuus; secundo ex eisdem rationibus concludit quod nullus alius motus potest esse continuus, ibi: manifestum autem et ex hac divisione et cetera. About the first he does two things: First he gives two arguments to prove that circular motion can be continuous; Secondly, from the same arguments he concludes that no other motion can be continuous, at 1132.
Quod autem motus circularis possit esse unus continuus, prima ratione sic probat. Illud dicitur esse possibile, ad quod nullum sequitur impossibile; nullum autem sequitur impossibile, si dicamus quod motus circularis sit in perpetuum continuus. 1130. But that a circular motion can be one continuous motion he proves at (890) with his first argument: That from which nothing impossible follows is said to be possible. But nothing impossible follows from the statement that a circular motion is forever continuous.
Quod patet ex hoc quod in motu circulari, illud quod movetur ex aliquo, puta a, simul movetur in idem signum secundum eandem positionem, idest secundum eundem processum mobilis, eodem ordine partium servato. Quod in motu reflexo non contingit; quia cum aliquid retrocedit, disponitur secundum contrarium ordinem partium in movendo: quia vel oportet quod pars mobilis quae in primo motu erat prior, in reflexione fiat posterior; vel oportet quod illa pars mobilis quae in primo motu aspiciebat ad unam differentiam loci, puta dextrum vel sursum, in reflexione aspiciat ad contrarium. Sed in motu circulari servatur eadem positio, dum aliquid movetur ad id a quo recedit. Sic ergo poterit dici quod etiam a principio sui motus, dum recedebat ab a, movebatur ad hoc ad quod tandem perveniet, scilicet ad ipsum a. This is plain from the fact that, in a circular motion, that which is being moved from somewhere, e.g., from A, is at the same time being moved to the same point “according to the same position,” i.e., according to the same progress of the mobile, the same order of parts having been maintained. This, however, does not happen in a reflex motion, because when something turns back, it is disposed according to a contrary order of parts in its motion. For either that part of the mobile to the fore in the first motion must be at the rear in the reflexion, or that part which was facing one difference of place, for example, the right or above, in reflexion must face a contrary direction. But in a circular motion the same position is maintained, while a thing is being moved toward the point from which it departed. Consequently, it could be said that even from the very beginning of its motion, while it was departing from A, it was being moved toward that which it would finally reach, namely, the very same A.
Nec propter hoc sequitur hoc impossibile, quod simul moveatur motibus contrariis aut oppositis, sicut sequebatur in motu recto. Non enim omnis motus qui est ad aliquem terminum, est contrarius aut oppositus motui qui est ex illo eodem termino; sed ista contrarietas invenitur in linea recta, secundum quam attenditur contrarietas in loco. Non enim attenditur contrarietas inter duos terminos secundum lineam circularem, quaecumque pars sit circumferentiae; sed secundum diametrum. Contraria enim sunt quae maxime distant: maxima autem distantia inter duos terminos non mensuratur secundum lineam circularem, sed secundum lineam rectam. Possunt enim inter duo puncta infinitae lineae curvae describi, sed non nisi una linea recta: id autem quod est unum, est mensura in quolibet genere. Nor does this lead to the impossibility of being moved with contrary or opposite motions at one and the same time, as followed in rectilinear motion. For not every motion to some terminal is contrary or opposite to one from the same terminal, but such contrariety is present in the straight line, according to which, contrariety in place is gauged. For contrariety between two termini is not forthcoming according to a circular line, whatever part of the circumference be taken, but according to the diameter. Contraries, indeed, are things most far apart; but the greatest distance between two termini is not measured according to a circular line, but according to a straight line. For between two points an infinite number of curves can be described but only one straight line, But the measure in any genus is that which is one.
Sic igitur patet quod si sit aliquis circulus, et dividatur per medium, et sit diameter eius ab; motus qui est per diametrum ab a in b, est contrarius motui qui est per eundem diametrum a b in a. Sed motus qui est per semicirculum ab a in b, non est contrarius motui qui est per alium semicirculum a b in a. Contrarietas autem erat quae impediebat quod motus reflexus non posset esse continuus, ut ex superioribus rationibus apparet. Nihil ergo prohibet, contrarietate sublata, motum circularem esse continuum, et tamen nullo tempore deficere. Consequently, it is plain that if one takes a circle, and it be divided in half, and AB be its diameter, a motion through the diameter from A to B is contrary to a motion over the same diameter from B to A. But a motion over the semicircle from A to B is not contrary to a motion from B to A over the other semicircle. But it was contrariety that prevented a reflex motion from being continuous, as appears from the reasons given above. Nothing, therefore, once contrariety has been removed, prevents a circular motion from being continuous and also not failing at any time.
Et huius ratio est, quia motus circularis habet suum complementum per hoc quod est ab eodem in idem; et sic per hoc non impeditur eius continuatio. Sed motus rectus habet suum complementum per hoc quod est ab eodem in aliud: unde si ab illo alio revertatur in idem a quo inceperat moveri, non erit unus motus continuus, sed duo. And the reason for this is that a circular motion is completed by the fact that it is from the same to the same, and thus its continuity is not impaired by this. But a rectilinear motion is completed by its being from one thing to another; hence, if it returns from that other to the same from which it began, it will be not one continuous motion, but two.
Deinde cum dicit: et qui quidem etc., ponit secundam rationem, dicens quod motus circularis non est in eisdem; sed motus rectus multoties est in eisdem. 1131. Then at (891) he gives the second argument, saying that a circular motion does not exist in identical things, but a rectilinear motion is very often in identical things.
Quod sic intelligendum est. Si enim aliquid moveatur ab a in b per diametrum, et iterum a b in a per eundem diametrum, necesse est quod per eadem media redeat per quae prius transierat: et sic pluries per eadem fertur. Sed si aliquid moveatur ab a in b per semicirculum, et iterum a b in a per alium semicirculum, quod est circulariter moveri, manifestum est quod non redit ad idem per eadem media. Now what this means is that, if something is moved from A to B across a diameter, and again from B to A across the same diameter, it has to return across the same middles through which it previously travelled, Consequently, it is being carried over the same middle a number of times. But if something is moved through a semicircle from A to B, and again from B to A through the other semicircle—and this is motion in the circular manner—it is clear that it does not return to the same point over the same middles.
Est autem de ratione oppositorum, quod circa idem considerentur: et sic manifestum est quod moveri ab eodem in idem secundum motum circularem, est absque oppositione; sed moveri ab eodem in idem secundum motum reflexum, est cum oppositione. Now, it is of the nature of opposites that they be considered with relation to the same thing. And thus it is clear that to be moved from the same to the same with a circular motion is without opposition, but to be moved from the same to the same with a reflex motion is with opposition.
Sic igitur patet quod motus circularis, qui non redit ad idem per eadem media, sed semper pertransit aliud et aliud, potest esse unus et continuus, quia non habet oppositionem: sed ille motus, reflexus scilicet, qui dum redit in idem, pluries in eisdem mediis fit pertranseundo, non potest esse in perpetuum continuus; quia necesse esset quod aliquid simul moveretur contrariis motibus, ut supra ostensum est. In this way it is plain that a circular motion which does not return to the same over the same middles, but always goes over something other, can be one and continuous, because it does not have opposition. But that motion, namely, the reflex motion, which, in returning to the same, traverses more than once the same middles, cannot be forever continuous, because that would require something being moved with contrary motions at one and the same time, as was proved above.
Et ex eadem ratione concludi potest, quod neque motus qui est in semicirculo, neque in quacumque alia circuli portione, potest esse in perpetuum continuus; quia in his motibus necesse est quod multoties pertranseantur eadem media, et quod moveantur contrariis motibus, quasi debeat fieri reditus ad principium. Et hoc ideo, quia neque in linea recta, neque in semicirculo, neque in quacumque circuli portione, copulatur finis principio, sed distant ab invicem principium et finis: sed in solo circulo finis copulatur principio. And from the same argument it can be concluded that a motion confined to a semicircle, or to any portion of a circle, cannot be continuous in perpetuity, because such motions require repeated traversing of the same middles and involve being moved with contrary motions, as though a return to the beginning should be made. The reason is because the end is not joined to the beginning when you are dealing with a straight line, or a semicircle, or an arc of a circle; rather the beginning and end are apart. It is only in a circle that the end is joined to the beginning.
Et ideo solus motus circularis est perfectus: unumquodque enim perfectum est ex hoc quod attingit suum principium. And for this reason only a circular motion is a perfect motion, since a thing is perfect from attaining its principle.
Deinde cum dicit: manifestum autem et ex hac divisione etc., ostendit ex eadem ratione quod in nullo alio genere potest esse aliquis motus continuus. Et primo ostendit propositum; secundo infert quoddam corollarium ex dictis, ibi: manifestum igitur ex his et cetera. 1132. Then at (892) he proves from the same argument that in no other genus of motion can there be continuous motion. First he proves the proposition; Secondly, he draws a corollary from what was said, at 1133.
Dicit ergo primo, quod etiam ex ista distinctione quae ponitur inter motum circularem et alios motus locales, manifestum est quod nec in aliis generibus motus contingit esse aliquos motus in infinitum continuos: quia in omnibus aliis generibus motus, si debeat aliquid moveri ab eodem in idem, sequitur quod multoties pertranseat eadem. Sicut in alteratione oportet quod pertranseat medias qualitates: ex calido enim transitur in frigidum per tepidum; et si debeat rediri ex frigido in calidum, oportet quod per tepidum transeatur. Et idem apparet in motu qui est secundum quantitatem: quia si quod movetur de magno in parvum, iterum redeat ad magnum, oportet quod bis sit in media quantitate. Et simile est etiam in generatione et corruptione: si enim ex igne fiat aer, et iterum ex aere fiat ignis, oportet quod medias dispositiones bis transeat (sic enim medium potest poni in generatione et corruptione, secundum quod accipitur cum transmutatione dispositionum). He says therefore first (892) that also from this distinction between circular motion and other local motions, it is plain that neither in the other genera of motion can there be any infinitely continuous motions, because in all the other genera of motion if anything is to be moved from the same to the same, it follows that the same will be repeatedly traversed. For example, in alteration the intermediate qualities must be passed through—for the passage from hot to cold is through tepid, and if a return is to be made from cold to hot, tepid must be traversed again. The same is apparent in a motion according to quantity—for if that which is moved from large to small, should return again to large, the intermediate quantity must be traversed twice. Generation and corruption present a similar situation—for if air comes to be from fire, and then again fire from air, the intermediate dispositions must be traversed twice (for a middle may be placed in generation and ceasing-to-be, insofar as taken along with the dispositional changes).
Et quia media transire contingit in diversis mutationibus diversimode, subiungit quod nihil differt vel pauca vel multa media facere, per quae aliquid moveatur de extremo in extremum; neque accipere aliquod medium positive, ut pallidum inter album et nigrum, vel remotive, ut inter bonum et malum quod neque bonum neque malum est: quia qualitercumque media se habeant, semper accidit quod eadem multoties pertranseantur. And because the intermediates are traversed in different ways in changes that are diverse, he adds that it makes no difference whether many or few intermediates are introduced through which something is moved from one extreme to the other, or whether the intermediate is taken in a positive sense, as pallid between white and black, or in a remotive sense, as, between good and evil, that which is neither good nor evil-for, be they what they may, it always happens that the same are traversed a number of times.
Deinde cum dicit: manifestum igitur etc., concludit ex praemissis, quod antiqui naturales non bene dixerunt, ponentes omnia sensibilia semper moveri: quia oporteret quod moverentur secundum aliquem praedictorum motuum, de quibus ostendimus quod non possunt esse in perpetuum continui; et maxime quia, secundum quod illi dicunt, motus semper continuus est alteratio. 1133. Then at (893) he concludes from the foregoing that the early natural philosophers did not phrase the matter well when they said that all sensible things are forever in motion, because that would necessitate their being moved with respect to one of the aforesaid motions, concerning which we have shown that they cannot be forever continuous; and especially because they said that the ever-continuous motion is alteration.
Dicunt enim quod omnia semper defluunt et corrumpuntur; et adhuc dicunt quod generatio et corruptio nihil est aliud quam alteratio: et sic dum dicunt omnia semper corrumpi, dicunt omnia semper alterari. For they assert that all things are always perishing and ceasing to be, and yet they say that generation and ceasing-to-be are nothing more than alteration, and so in saying that all things are forever ceasing to be, they are saying that all things are forever being altered.
Probatum est autem per rationem supra inductam, quod nullo motu contingit semper moveri nisi circulari: et sic relinquitur quod neque secundum alterationem, neque secundum augmentum, possunt omnia semper moveri, ut illi dicebant. But it was proved in the argument given above that nothing can be moved forever except by a circular motion. Thus it remains that neither according to alteration, nor growth, can all things be forever in motion, as they said.
Ultimo autem principale intentum epilogando concludit, scilicet quod nulla mutatio possit esse infinita et continua nisi circularis. Finally, he concludes by way of summary to the chief proposition, namely, that no change can be infinite and continuous except a circular one.
Deinde cum dicit: quod autem lationum etc., probat quod motus circularis sit primus motuum, duabus rationibus: quarum prima talis est. Omnis motus localis, ut prius dictum est, aut est circularis aut rectus aut commixtus. Circularis autem et rectus sunt priores commixto, quia ex illis constituitur. Inter illos autem duos, circularis est prior recto: circularis enim est simplicior et perfectior recto. Quod sic probat. Motus enim rectus non potest procedere in infinitum. Hoc enim esset dupliciter. Uno modo sic quod esset magnitudo per quam transit motus rectus infinita: quod est impossibile. Sed etiam si esset aliqua magnitudo infinita, nihil moveretur ad infinitum. Quod enim impossibile est esse, nunquam fit aut generatur; impossibile est autem transire infinitum; nihil ergo movetur ad hoc quod infinita pertranseat. Non ergo potest esse motus rectus infinitus super magnitudinem infinitam. Alio modo posset intelligi motus rectus infinitus, super magnitudine finita per reflexionem. Sed motus qui est reflexus non est unus, ut supra probatum est, sed est compositus ex duobus motibus. 1134. Then at (894) he proves with two arguments that circular motion is the first of motions. The first argument is this: Every local motion, as stated above, is either circular, or straight, or a combination of the two. But circular and straight are prior to the combination. which is composed of them. But between these two, the circular is prior to the straight, for the circular is simpler and more perfect than the straight. And this he proves as follows: Straight motion cannot go on infinitely. For this would occur in two ways: First in such a way that the magnitude traversed by the straight motion would be infinite—which is impossible. But even if there were some infinite magnitude, nothing would be moved to infinity. For what is impossible to be, never comes to be or is generated; but it is impossible to traverse the infinite; therefore, nothing is moved toward the end of traversing the infinite. Therefore, there cannot be an infinite straight motion over an infinite magnitude. In a second way, an infinite straight motion can be understood as being a reflex motion over a finite magnitude. But a reflex motion is not one, as was proved above, but is a composition of two motions.
Si autem super linea recta finita non fiat reflexio, erit motus imperfectus et corruptus: imperfectus quidem, quia possibile est ei fieri additionem; corruptus autem, quia cum pervenerit ad terminum magnitudinis, cessabit motus. But if a reflexion does not occur upon a finite straight line, the motion will be imperfect and destroyed: imperfect, because further addition can be made to it; destroyed, because when the terminus of the magnitude is reached, the motion will cease.
Sic ergo patet quod motus circularis qui non est compositus ex duobus, et qui non corrumpitur cum venit ad terminum (cum sit idem eius principium et finis), est simplicior et perfectior quam motus rectus. Perfectum autem est prius imperfecto, et similiter incorruptibile corruptibili, et natura et ratione et tempore, sicut supra ostensum est, cum probabatur loci mutationem esse priorem aliis motibus. Necesse est ergo motum circularem esse priorem recto. From all this it is clear that a circular motion which is not composed of two, and which is not destroyed when it comes to a terminus (for its beginning and terminus are identical), is simpler and more perfect than a straight motion. Now the perfect is prior to the imperfect, and likewise the imperishable is prior to the perishable, in nature and notion and time, as was shown above when it was proved that local change is prior to other motions. Therefore, it is necessary that circular motion be prior to straight.
Deinde cum dicit: amplius prior etc., ponit secundam rationem: quae talis est. Motus qui potest esse perpetuus, est prior eo qui perpetuus esse non potest; quia perpetuum est prius non perpetuo, et tempore et natura. Circularis autem motus potest esse perpetuus, et nullus aliorum motuum, cum oporteat eis succedere quietem: ubi autem quies supervenerit, corrumpitur motus. Relinquitur ergo quod motus circularis sit prior omnibus aliis motibus. Haec autem quae in hac ratione supponit, ex superioribus patent. 1135. Then at (895) he gives the second argument, which is this; A motion which can be perpetual is prior to one that cannot be perpetual, because the perpetual is prior to the non-perpetual, both in time and in nature. But a circular motion and no other can be perpetual, for the others must be followed by rest, and where rest intervenes, motion is destroyed. What is left, therefore, is that circular motion is prior to all the other motions. (The premises of this argument are plain from what has been said previously.)

Lectio 20
Dialectical reasons why circular motion is continuous and first.
Confirmation from the ancients
Chapter 9 cont.
εὐλόγως δὲ συμβέβηκε τὸ τὴν κύκλῳ μίαν εἶναι καὶ συνεχῆ, καὶ μὴ τὴν ἐπ' εὐθείας· τῆς μὲν γὰρ ἐπ' εὐθείας ὥρισται καὶ ἀρχὴ καὶ τέλος καὶ μέσον, καὶ πάντ' ἔχει ἐν αὑτῇ, ὥστ' ἔστιν ὅθεν ἄρξεται τὸ κινούμενον καὶ οὗ τελευτήσει (πρὸς γὰρ τοῖς πέρασιν ἠρεμεῖ πᾶν, ἢ ὅθεν ἢ οὗ), τῆς δὲ περιφεροῦς ἀόριστα· τί γὰρ μᾶλλον ὁποιονοῦν πέρας τῶν ἐπὶ τῆς γραμμῆς; ὁμοίως γὰρ ἕκαστον καὶ ἀρχὴ καὶ μέσον καὶ τέλος, ὥστ' ἀεί τε (265b.) εἶναι ἐν ἀρχῇ καὶ ἐν τέλει καὶ μηδέποτε. διὸ κινεῖταί τε καὶ ἠρεμεῖ πως ἡ σφαῖρα· τὸν αὐτὸν γὰρ κατέχει τόπον. αἴτιον δ' ὅτι πάντα συμβέβηκε ταῦτα τῷ κέντρῳ· καὶ γὰρ ἀρχὴ καὶ μέσον τοῦ μεγέθους καὶ τέλος ἐστίν, ὥστε διὰ τὸ ἔξω εἶναι τοῦτο τῆς περιφερείας οὐκ ἔστιν ὅπου τὸ φερόμενον ἠρεμήσει ὡς διεληλυθός (ἀεὶ γὰρ φέρεται περὶ τὸ μέσον, ἀλλ' οὐ πρὸς τὸ ἔσχατον), διὰ δὲ τὸ τοῦτο μένειν ἀεί τε ἠρεμεῖ πως τὸ ὅλον καὶ κινεῖται συνεχῶς. Moreover the result at which we have arrived, that rotatory motion is single and continuous, and rectilinear motion is not, is a reasonable one. In rectilinear motion we have a definite starting-point, finishing-point, middle-point, which all have their place in it in such a way that there is a point from which that which is in motion can be said to start and a point at which it can be said to finish its course (for when anything is at the limits of its course, whether at the starting-point or at the finishing-point, it must be in a state of rest). On the other hand in circular motion there are no such definite points: for why should any one point on the line be a limit rather than any other? Any one point as much as any other is alike starting-point, middle-point, and finishing-point, so that we can say of certain things both that they are always and that they never are at a starting-point and at a finishing-point (so that a revolving sphere, while it is in motion, is also in a sense at rest, for it continues to occupy the same place). The reason of this is that in this case all these characteristics belong to the centre: that is to say, the centre is alike starting-point, middle-point, and finishing-point of the space traversed; consequently since this point is not a point on the circular line, there is no point at which that which is in process of locomotion can be in a state of rest as having traversed its course, because in its locomotion it is proceeding always about a central point and not to an extreme point: therefore it remains still, and the whole is in a sense always at rest as well as continuously in motion.
συμβαίνει δ' ἀντιστρόφως· καὶ γὰρ ὅτι μέτρον τῶν κινήσεων ἡ περιφορά, πρώτην ἀναγκαῖον αὐτὴν εἶναι (ἅπαντα γὰρ μετρεῖται τῷ πρώτῳ), καὶ διότι πρώτη, μέτρον ἐστὶν τῶν ἄλλων. Our next point gives a convertible result: on the one hand, because rotation is the measure of motions it must be the primary motion (for all things are measured by what is primary): on the other hand, because rotation is the primary motion it is the measure of all other motions.
ἔτι δὲ καὶ ὁμαλῆ ἐνδέχεται εἶναι τὴν κύκλῳ μόνην· τὰ γὰρ ἐπ' εὐθείας ἀνωμαλῶς ἀπὸ τῆς ἀρχῆς φέρεται καὶ πρὸς τὸ τέλος· πάντα γὰρ ὅσῳπερ ἂν ἀφίστηται [πλεῖον] τοῦ ἠρεμοῦντος, φέρεται θᾶττον· τῆς δὲ κύκλῳ μόνης οὔτ' ἀρχὴ οὔτε τέλος ἐν αὐτῇ πέφυκεν, ἀλλ' ἐκτός. Again, rotatory motion is also the only motion that admits of being regular. In rectilinear locomotion the motion of things in leaving the starting-point is not uniform with their motion in approaching the finishing-point, since the velocity of a thing always increases proportionately as it removes itself farther from its position of rest: on the other hand rotatory motion is the only motion whose course is naturally such that it has no starting-point or finishing-point in itself but is determined from elsewhere.
ὅτι δ' ἡ κατὰ τόπον φορὰ πρώτη τῶν κινήσεων, μαρτυροῦσι πάντες ὅσοι περὶ κινήσεως πεποίηνται μνείαν· τὰς γὰρ ἀρχὰς αὐτῆς ἀποδιδόασιν τοῖς κινοῦσι τοιαύτην κίνησιν. διάκρισις γὰρ καὶ σύγκρισις κινήσεις κατὰ τόπον εἰσίν, οὕτω δὲ κινοῦσιν ἡ φιλία καὶ τὸ νεῖκος· τὸ μὲν γὰρ διακρίνει, τὸ δὲ συγκρίνει αὐτῶν. καὶ τὸν νοῦν δέ φησιν Ἀναξαγόρας διακρίνειν τὸν κινήσαντα πρῶτον. ὁμοίως δὲ καὶ ὅσοι τοιαύτην μὲν οὐδεμίαν αἰτίαν λέγουσιν, διὰ δὲ τὸ κενὸν κινεῖσθαί φασιν· καὶ γὰρ οὗτοι τὴν κατὰ τόπον κίνησιν κινεῖσθαι τὴν φύσιν λέγουσιν (ἡ γὰρ διὰ τὸ κενὸν κίνησις φορά ἐστιν καὶ ὡς ἐν τόπῳ), τῶν δ' ἄλλων οὐδεμίαν ὑπάρχειν τοῖς πρώτοις ἀλλὰ τοῖς ἐκ τούτων οἴονται· αὐξάνεσθαι γὰρ καὶ φθίνειν καὶ ἀλλοιοῦσθαι συγκρινομένων καὶ διακρινομένων τῶν ἀτόμων σωμάτων φασίν. τὸν αὐτὸν δὲ τρόπον καὶ ὅσοι διὰ πυκνότητα ἢ μανότητα κατασκευάζουσι γένεσιν καὶ φθοράν· συγκρίσει γὰρ καὶ διακρίσει ταῦτα διακοσμοῦσιν. ἔτι δὲ παρὰ τούτους οἱ τὴν ψυχὴν αἰτίαν ποιοῦντες κινήσεως· τὸ γὰρ αὐτὸ αὑτὸ κινοῦν ἀρχὴν εἶναί φασιν τῶν κινουμένων, κινεῖ δὲ τὸ ζῷον καὶ πᾶν τὸ ἔμ(266a.) ψυχον τὴν κατὰ τόπον αὑτὸ κίνησιν. καὶ κυρίως δὲ κινεῖσθαί φαμεν μόνον τὸ κινούμενον [τὴν] κατὰ τόπον [κίνησιν]· ἂν δ' ἠρεμῇ μὲν ἐν τῷ αὐτῷ, αὐξάνηται δ' ἢ φθίνῃ ἢ ἀλλοιούμενον τυγχάνῃ, πῂ κινεῖσθαι, ἁπλῶς δὲ κινεῖσθαι οὔ φαμεν. As to locomotion being the primary motion, this is a truth that is attested by all who have ever made mention of motion in their theories: they all assign their first principles of motion to things that impart motion of this kind. Thus 'separation' and 'combination' are motions in respect of place, and the motion imparted by 'Love' and 'Strife' takes these forms, the latter 'separating' and the former 'combining'. Anaxagoras, too, says that 'Mind', his first movent, 'separates'. Similarly those who assert no cause of this kind but say that 'void' accounts for motion—they also hold that the motion of natural substance is motion in respect of place: for their motion that is accounted for by 'void' is locomotion, and its sphere of operation may be said to be place. Moreover they are of opinion that the primary substances are not subject to any of the other motions, though the things that are compounds of these substances are so subject: the processes of increase and decrease and alteration, they say, are effects of the 'combination' and 'separation' of atoms. It is the same, too, with those who make out that the becoming or perishing of a thing is accounted for by 'density' or 'rarity': for it is by 'combination' and 'separation' that the place of these things in their systems is determined. Moreover to these we may add those who make Soul the cause of motion: for they say that things that undergo motion have as their first principle 'that which moves itself': and when animals and all living things move themselves, the motion is motion in respect of place. Finally it is to be noted that we say that a thing 'is in motion' in the strict sense of the term only when its motion is motion in respect of place: if a thing is in process of increase or decrease or is undergoing some alteration while remaining at rest in the same place, we say that it is in motion in some particular respect: we do not say that it 'is in motion' without qualification.
ὅτι μὲν οὖν ἀεί τε κίνησις ἦν καὶ ἔσται τὸν ἅπαντα χρόνον, καὶ τίς ἀρχὴ τῆς ἀϊδίου κινήσεως, ἔτι δὲ τίς πρώτη κίνησις, καὶ τίνα κίνησιν ἀΐδιον ἐνδέχεται μόνην εἶναι, καὶ τὸ κινοῦν πρῶτον ὅτι ἀκίνητον, εἴρηται. Our present position, then, is this: We have argued that there always was motion and always will be motion throughout all time, and we have explained what is the first principle of this eternal motion: we have explained further which is the primary motion and which is the only motion that can be eternal: and we have pronounced the first movent to be unmoved.
Postquam philosophus ostendit per proprias rationes, quod motus circularis est continuus et primus; hic ostendit idem per quasdam logicas et communes rationes. Et ponit tres rationes. 1136. After proving with proper reasons that a circular motion is continuous and first, the Philosopher now proves the same with certain logical and common reasons. And he gives three arguments.
Circa quarum primam dicit, quod rationabiliter accidit quod motus circularis sit unus et continuus in perpetuum, non autem motus rectus. Quia in recto determinatur principium, medium et finis, et omnia haec tria est assignare in ipsa linea recta: et ideo est in ipsa linea unde incipiat motus, et ubi finiatur; quia omnis motus quiescit apud terminos, scilicet vel a quo vel ad quem (has enim duas quietes supra in quinto distinxerat). Sed in linea circulari termini non sunt distincti: nulla enim est ratio quare unum punctum signatum in linea circulari, sit magis terminus quam aliud; quia unumquodque similiter est et principium et medium et finis. Et sic quodammodo quod movetur circulariter, semper est in principio et in fine, inquantum scilicet quodlibet punctum signatum in circulo potest accipi ut principium vel finis: et quodammodo nunquam est in principio vel fine, inquantum scilicet nullum punctum circuli est principium vel finis in actu. With respect to the first (896) he says that it is reasonable that a circular motion but not a straight one be one and forever continuous. For in a straight motion there are determined a beginning, middle, and end, and all three of these can be designated in a straight line, Therefore in a straight line there exist that whence the motion begins, and where it ends, since all motion rests at its termini, namely, the terminus from which or to which (he having distinguished these two states of rest in Book V). But in a circular line the termini are not distinct, for there is no reason why in a circle some designated point should be a terminus more than another, since each and every one alike is a beginning and an intermediate and an end. Consequently, the things which are moved circularly are in a sense always in the beginning and in the end, insofar, namely, as any point at all in a circle may be taken as a beginning or end, while in another sense, they are never in the beginning or end, inasmuch as no point in the circle is a beginning or end in act.
Unde sequitur quod sphaera quodammodo movetur, et quodammodo quiescit: quia sicut in sexto dictum est, sphaera dum movetur semper obtinet eundem locum secundum subiectum, et quantum ad hoc quiescit; alium tamen et alium secundum rationem, et quantum ad hoc movetur. Hence it follows that a sphere is in one sense in motion and in another sense at rest, because, as was said in Book VI, while the sphere is being moved it always keeps the same place as to subject, and in this respect it is at rest; but yet the place is always other and other in conception, and in this respect it is being moved.
Ideo autem in ipsa linea circulari non distinguitur principium, medium et finis, quia haec tria pertinent ad centrum; a quo sicut a principio procedunt lineae ad circumferentiam, et ad ipsum terminantur lineae a circumferentia protractae; et est etiam medium totius magnitudinis secundum aequidistantiam ad omnia signa circumferentiae. Now, the reason why a beginning, intermediate and end are not distinguished in a circular line is that these three belong to the center, from which, as from a beginning, lines proceed to the circumference and at which lines drawn from the circumference end. Moreover, it is the middle of the entire magnitude by virtue of its equidistance to all the points of the circumference.
Et ideo, quia principium et finis circularis magnitudinis est extra circulationem, scilicet in centro, ad quod non pertingit quod circulariter movetur; non est assignare in motu circulari ubi quiescat illud quod fertur, cum pervenerit ad ipsum: quia quod circulariter movetur, semper fertur circa medium, sed non fertur ad ultimum, quia non fertur ad medium quod est principium et ultimum. And therefore, since the beginning and end of a circular magnitude are outside its circularity—for they are in the center which is never reached by a thing moving circularly—no place can be assigned at which a thing in circular motion should be at rest, because anything in circular motion is always carried about the middle but not to what is ultimate, because it is not carried to the middle, which is the beginning and the ultimate.
Et propter hoc, totum quod sphaerice movetur, quodammodo semper quiescit, et quodammodo continue movetur, ut dictum est. On this account, a whole that is being moved in a spherical manner is in one sense always at rest and in another in continuous motion, as has been said.
Ex his ergo quae dicta sunt, sic ratio extrahi potest. Omnis motus qui nunquam est in principio et fine, est continuus: sed motus circularis est huiusmodi: ergo et cetera. Et per idem medium probatur quod motus rectus non possit esse continuus. From all this the following argument may be extracted: Every motion that is never in its beginning and end is continuous. But a circular motion is of this kind. Therefore, etc, And with this same middle term, it is proved that a straight motion cannot be continuous.
Deinde cum dicit: accidit autem conversim etc., ponit secundam rationem, dicens quod haec duo conversim se sequuntur, scilicet quod motus circularis sit mensura omnium motuum, et quod sit primus motuum: omnia enim mensurantur primo sui generis, ut in X Metaphys. ostenditur. Et sic ista proposito convertibilis est: omne quod est mensura, est primum sui generis; et omne quod est primum, est mensura. Sed motus circularis est mensura omnium aliorum motuum, ut patet ex his quae in fine quarti sunt dicta: ergo motus circularis est primus motuum. Vel si supponatur quod motus circularis sit primus motuum propter supra dictas rationes, concludetur quod sit mensura aliorum motuum. 1137. Then at (897) he gives the second argument, saying that these two follow one another conversely, namely, that a circular motion is the measure of all motions and that it is the first of all motions—for all things are measured by what is first in their genus, as is proved in Metaphysics X. Accordingly, this is a convertible proposition: Whatever is a measure is the first in its genus; whatever is first is a measure. But circular motion is the measure of all other motions, as is clear from what was said at the end of Book IV. Therefore, circular motion is the first of motions. On the other hand, if one suppose that a circular motion is the first of motions on account of the arguments given above, it will be concluded that it is the measure of the other motions.
Tertiam rationem ponit ibi: amplius autem et regularem etc., dicens quod solus motus circularis potest esse regularis: quia quae in linea recta moventur, irregulariter feruntur a principio usque ad finem. 1138. The third argument he gives at (898), saying that only a circular motion can be regular, since things in motion in a straight line are being carried along in an irregular manner from beginning to end.
Est enim motus irregularis, ut in quinto dictum est, qui non est aequaliter velox per totum: quod necesse est accidere in omni motu recto; quia in motibus naturalibus, quanto aliqua quae moventur plus distant a prima quiete, a qua incipit motus, velocius moventur; in motu autem violento, quanto plus distant ab ultima quiete, ad quam terminatur motus, tanto velocius moventur. Nam motus naturalis intenditur in fine: violentus autem in principio. For, as was said in Book V, a motion is irregular which is not equally swift throughout, and this must occur in every straight motion, since in natural motions the further things in motion are distant from the first rest, from which the motion started, the swifter they are moved; and in a violent motion, the farther they are distant from the ultimate rest, at which the motion terminates, the swifter they travel. For every natural motion is more intense near the end, but a violent motion at the beginning.
Hoc autem in motu circulari locum non habet: quia in circulo principium et finis non est natum esse inter ipsam circulationem, quae fit per circumferentiam, sed extra, idest in centro, ut dictum est. Unde nulla est ratio quare intendatur vel remittatur motus circularis quasi per approximationem ad principium vel finem; cum semper aequaliter appropinquat centro, quod est principium et finis. But this has no place in a circular motion in place, because in a circle the beginning and end do not exist somewhere in the circling which occurs along the circumference, but outside it, i.e., in the center, as was explained. Hence, there is no reason why a circular motion should be intensified or weakened on account of a nearness to its beginning or end, since it is always equally approaching the center, which is the beginning and ends
Manifestum est autem ex his quae in quinto dicta sunt, quod motus regularis est magis unus quam irregularis: et sic motus circularis est prior naturaliter quam motus rectus. Quanto enim aliquid est magis unum, tanto naturaliter prius est. Now, it is plain from what was said in Book V that a regular motion is more one motion than an irregular one. Consequently, a circular motion is naturally prior to a straight motion. For the more a thing is one, the more it is by nature prior.
Deinde cum dicit: quod autem secundum locum mutatio etc., ostendit per opiniones antiquorum philosophorum, quod motus localis sit primus motuum. Et dicit quod huic veritati attestantur dicta omnium philosophorum antiquorum, qui de motu fecerunt memoriam; quia principiis attribuunt quod moveant motu locali. 1139. Then at (899) he shows through the opinions of the early philosophers that local motion is the first of motions. And he says that the statements of all the ancient philosophers who discussed motion attest to this truth, for they declare that the principles of things move with local motion.
Et hoc primo ostendit per opinionem Empedoclis, qui posuit amicitiam et litem prima principia moventia; quorum amicitia congregat, lis vero disgregat: congregatio autem et disgregatio sunt motus locales. He refers first to the opinion of Empedocles, who posited friendship and strife as the first moving principles, the former gathering and the latter separating—and gathering and separating are local motions.
Secundo ostendit idem per opinionem Anaxagorae, qui posuit intellectum primam causam moventem; cuius opus, secundum ipsum, est disgregare commixta. Secondly, he shows the same thing through the opinion of Anaxagoras, who posited Intellect as the first moving cause, whose work, according to him, is to separate what is commingled.
Tertio ostendit idem per opinionem Democriti, qui non posuit causam moventem, sed dixit quod omnia moventur propter naturam vacui. Motus autem qui est propter vacuum, est loci mutatio, vel similis loci mutationi: quia vacuum et locus non differunt nisi ratione, ut in quarto dictum est. Et sic dum ponunt res primo moveri propter vacuum, ponunt motum localem naturaliter primum, et nullum aliorum motuum: sed alios motus opinantur consequi ad motum localem. Dicunt enim sequentes Democritum, quod augmentari et corrumpi et alterari contingit per quandam congregationem et disgregationem indivisibilium corporum. Thirdly, he shows the same thing through the opinion of Democritus, who did not posit a moving cause but said that all things are moved on account of the nature of the void. But a motion that is due to the void is a local motion or one similar to local motion, for void and place differ only in conception, as was said in Book IV. And so, by positing that things are first moved on account of the void, they posit local motion as naturally first and none of the other motions, but they believe that the other motions follow upon local motion. For those who follow Democritus declare that being increased and corrupted and altered occur by a certain assembling and separating of indivisible bodies.
Quarto ostendit idem per opiniones antiquorum naturalium, qui ponebant unam causam materialem tantum, vel aquam vel aerem vel ignem, vel aliquid medium. Ex illo enim uno materiali principio constituunt generationem et corruptionem rerum per condensationem et rarefactionem; quae per quandam congregationem et disgregationem complentur. Fourthly, he shows the same thing through the opinions of the ancient philosophers of nature who posited only one cause, a material cause, namely, water, or air, or fire, or some intermediate. For from that one material cause they explain the generation and ceasing-to-be of things through condensation and rarefaction, which are completed by a kind of assembling and separation.
Quinto ostendit idem per opinionem Platonis, qui posuit animam esse primam causam motus. Posuit enim Plato quod movens seipsum, quod est anima, est principium omnium eorum quae moventur. Movere autem seipsum convenit animali et omni animato, secundum eum qui est secundum locum autokinesim, idest per transmutationem localem. Fifthly, he shows the same through the opinion of Plato who posited soul as the first cause of motion. For Plato posited that that which moves itself, which is the soul, is the principle of all things that are moved. But self-movement belongs to animals and all animate things, according to autokinesis with respect to place, i.e., per se local transmutation.
Sexto autem ostendit idem per ea quae communiter et vulgariter loquentes dicunt. Illud enim solum proprie dicimus moveri, quod movetur secundum motum localem. Si autem aliquid quiescat in loco, sed moveatur motu augmenti aut decrementi aut alterationis, dicitur quod movetur quodammodo, sed non simpliciter. Sixthly, he shows the same thing through what is commonly and popularly held, For we only say that to be moved in the proper sense which is moved with respect to place. Whereas, if something is at rest in place, but is moved with the motion of growth or decrease or alteration, it is said to be moved in a certain sense but not absolutely.
Deinde cum dicit: quod quidem igitur semper motus erat etc., epilogat quae dixerat: scilicet quod motus semper fuerit et semper erit, et quod est aliquod primum principium motus perpetui, et quis sit primus motus, et quem motum contingat esse perpetuum, et quod primum movens sit immobile. Haec enim omnia in praecedentibus declarata sunt. 1140. Then at (900) he summarizes what he had said, namely, that motion always has been and always will be, and that there is some first principle of perpetual motions and what the first motion is, and which motion happens to be perpetual, and that the first mover is immobile. For all these things have been set forth in what has preceded.

Lectio 21
Limitations of a finite mover
Chapter 10
10 Ὅτι δὲ τοῦτ' ἀμερὲς ἀναγκαῖον εἶναι καὶ μηδὲν ἔχειν μέγεθος, νῦν λέγωμεν, πρῶτον περὶ τῶν προτέρων αὐτοῦ διορίσαντες. We have now to assert that the first movent must be without parts and without magnitude, beginning with the establishment of the premisses on which this conclusion depends.
τούτων δ' ἓν μέν ἐστιν ὅτι οὐχ οἷόν τε οὐδὲν πεπερασμένον κινεῖν ἄπειρον χρόνον. τρία γὰρ ἔστιν, τὸ κινοῦν, τὸ κινούμενον, τὸ ἐν ᾧ τρίτον, ὁ χρόνος. ταῦτα δὲ ἢ πάντα ἄπειρα ἢ πάντα πεπερασμένα ἢ ἔνια, οἷον τὰ δύο ἢ τὸ ἕν. ἔστω δὴ τὸ Α τὸ κινοῦν, τὸ δὲ κινούμενον Β, χρόνος ἄπειρος ἐφ' οὗ Γ. τὸ δὴ Δ τῆς Β κινείτω τι μέρος, τὸ ἐφ' οὗ Ε. οὐ δὴ ἐν ἴσῳ τῷ Γ· ἐν πλείονι γὰρ τὸ μεῖζον. ὥστ' οὐκ ἄπειρος ὁ χρόνος ὁ τὸ Ζ. οὕτω δὴ τῇ Δ προστιθεὶς καταναλώσω τὸ Α καὶ τῇ Ε τὸ Β· τὸν δὲ χρόνον οὐ καταναλώσω ἀεὶ ἀφαιρῶν ἴσον· ἄπειρος γάρ· ὥστε ἡ πᾶσα Α τὴν ὅλην Β κινήσει ἐν πεπερασμένῳ χρόνῳ τοῦ Γ. οὐκ ἄρα οἷόν τε ὑπὸ πεπερασμένου κινεῖσθαι οὐδὲν ἄπειρον κίνησιν. One of these premisses is that nothing finite can cause motion during an infinite time. We have three things, the movent, the moved, and thirdly that in which the motion takes place, namely the time: and these are either all infinite or all finite or partly—that is to say two of them or one of them—finite and partly infinite. Let A be the movement, B the moved, and G the infinite time. Now let us suppose that D moves E, a part of B. Then the time occupied by this motion cannot be equal to G: for the greater the amount moved, the longer the time occupied. It follows that the time Z is not infinite. Now we see that by continuing to add to D, I shall use up A and by continuing to add to E, I shall use up B: but I shall not use up the time by continually subtracting a corresponding amount from it, because it is infinite. Consequently the duration of the part of G which is occupied by all A in moving the whole of B, will be finite. Therefore a finite thing cannot impart to anything an infinite motion. It is clear, then, that it is impossible for the finite to cause motion during an infinite time.
ὅτι μὲν οὖν οὐκ ἐνδέχεται τὸ πεπερασμένον ἄπειρον κινεῖν χρόνον, φανερόν· ὅτι δ' ὅλως οὐκ ἐνδέχεται ἐν πεπερασμένῳ μεγέθει ἄπειρον εἶναι δύναμιν, ἐκ τῶνδε δῆλον. ἔστω γὰρ ἡ πλείων δύναμις ἀεὶ ἡ τὸ ἴσον ἐν ἐλάττονι χρόνῳ ποιοῦσα, οἷον θερμαίνουσα ἢ γλυκαίνουσα ἢ ῥιπτοῦσα καὶ ὅλως κινοῦσα. ἀνάγκη ἄρα καὶ ὑπὸ τοῦ πεπερασμένου μὲν ἄπειρον δ' ἔχοντος δύναμιν πάσχειν τι τὸ πάσχον, καὶ πλεῖον ἢ ὑπ' ἄλλου· πλείων γὰρ ἡ ἄπειρος. ἀλλὰ μὴν χρόνον γε οὐκ ἐνδέχεται εἶναι οὐδένα. εἰ γάρ ἐστιν ὁ ἐφ' οὗ Α χρόνος ἐν ᾧ ἡ ἄπειρος ἰσχὺς ἐθέρμανεν ἢ ἔωσεν, ἐν τῷ δὲ ΑΒ πεπερασμένη τις, πρὸς ταύτην (266b.) μείζω λαμβάνων ἀεὶ πεπερασμένην ἥξω ποτὲ εἰς τὸ ἐν τῷ Α χρόνῳ κεκινηκέναι· πρὸς πεπερασμένον γὰρ ἀεὶ προστιθεὶς ὑπερβαλῶ παντὸς ὡρισμένου, καὶ ἀφαιρῶν ἐλλείψω ὡσαύτως. ἐν ἴσῳ ἄρα χρόνῳ κινήσει τῇ ἀπείρῳ ἡ πεπερασμένη. τοῦτο δὲ ἀδύνατον· It has now to be shown that in no case is it possible for an infinite force to reside in a finite magnitude. This can be shown as follows: we take it for granted that the greater force is always that which in less time than another does an equal amount of work when engaged in any activity—in heating, for example, or sweetening or throwing; in fact, in causing any kind of motion. Then that on which the forces act must be affected to some extent by our supposed finite magnitude possessing an infinite force as well as by anything else, in fact to a greater extent than by anything else, since the infinite force is greater than any other. But then there cannot be any time in which its action could take place. Suppose that A is the time occupied by the infinite power in the performance of an act of heating or pushing, and that AB is the time occupied by a finite power in the performance of the same act: then by adding to the latter another finite power and continually increasing the magnitude of the power so added I shall at some time or other reach a point at which the finite power has completed the motive act in the time A: for by continual addition to a finite magnitude I must arrive at a magnitude that exceeds any assigned limit, and in the same way by continual subtraction I must arrive at one that falls short of any assigned limit. So we get the result that the finite force will occupy the same amount of time in performing the motive act as the infinite force. But this is impossible.
οὐδὲν ἄρα πεπερασμένον ἐνδέχε ται ἄπειρον δύναμιν ἔχειν. οὐ τοίνυν οὐδ' ἐν ἀπείρῳ πεπερασμένην· Therefore nothing finite can possess an infinite force. So it is also impossible for a finite force to reside in an infinite magnitude.
καίτοι ἐνδέχεται ἐν ἐλάττονι μεγέθει πλείω δύναμιν εἶναι· ἀλλ' ἔτι μᾶλλον ἐν μείζονι πλείω. It is true that a greater force can reside in a lesser magnitude: but the superiority of any such greater force can be still greater if the magnitude in which it resides is greater.
ἔστω δὴ τὸ ἐφ' οὗ ΑΒ ἄπειρον. τὸ δὴ ΒΓ ἔχει δύναμίν τινα, ἣ ἔν τινι χρόνῳ ἐκίνησεν τὴν Δ, ἐν τῷ χρόνῳ ἐφ' οὗ ΕΖ. ἂν δὴ τῆς ΒΓ διπλασίαν λαμβάνω, ἐν ἡμίσει χρόνῳ τοῦ ΕΖ (ἔστω γὰρ αὕτη ἡ ἀναλογία), ὥστε ἐν τῷ ΖΘ κινήσει. οὐκοῦν οὕτω λαμβάνων ἀεὶ τὴν μὲν ΑΒ οὐδέποτε διέξειμι, τοῦ χρόνου δὲ τοῦ δοθέντος αἰεὶ ἐλάττω λήψομαι. ἄπειρος ἄρα ἡ δύναμις ἔσται· πάσης γὰρ πεπερασμένης ὑπερβάλλει δυνάμεως, εἴ γε πάσης πεπερασμένης δυνάμεως ἀνάγκη πεπερασμένον εἶναι καὶ τὸν χρόνον (εἰ γὰρ ἔν τινι ἡ τοσηδί, ἡ μείζων ἐν ἐλάττονι μὲν ὡρισμένῳ δὲ χρόνῳ κινήσει, κατὰ τὴν ἀντιστροφὴν τῆς ἀναλογίας)· ἄπειρος δὲ πᾶσα δύναμις, ὥσπερ καὶ πλῆθος καὶ μέγεθος τὸ ὑπερβάλλον παντὸς ὡρισμένου. Now let AB be an infinite magnitude. Then BG possesses a certain force that occupies a certain time, let us say the time Z in moving D. Now if I take a magnitude twice as great at BG, the time occupied by this magnitude in moving D will be half of EZ (assuming this to be the proportion): so we may call this time ZH. That being so, by continually taking a greater magnitude in this way I shall never arrive at the full AB, whereas I shall always be getting a lesser fraction of the time given. Therefore the force must be infinite, since it exceeds any finite force. Moreover the time occupied by the action of any finite force must also be finite: for if a given force moves something in a certain time, a greater force will do so in a lesser time, but still a definite time, in inverse proportion. But a force must always be infinite—just as a number or a magnitude is—if it exceeds all definite limits.
ἔστιν δὲ καὶ ὧδε δεῖξαι τοῦτο· ληψόμεθα γάρ τινα δύναμιν τὴν αὐτὴν τῷ γένει τῇ ἐν τῷ ἀπείρῳ μεγέθει, ἐν πεπερασμένῳ μεγέθει οὖσαν, ἣ καταμετρήσει τὴν ἐν τῷ ἀπείρῳ πεπερασμένην δύναμιν. This point may also be proved in another way—by taking a finite magnitude in which there resides a force the same in kind as that which resides in the infinite magnitude, so that this force will be a measure of the finite force residing in the infinite magnitude. It is plain, then, from the foregoing arguments that it is impossible for an infinite force to reside in a finite magnitude or for a finite force to reside in an infinite magnitude.
Postquam philosophus ostendit qualis sit primus motus, hic ostendit quale sit primum movens. Et dividitur in partes duas: primo dicit de quo est intentio; secundo exequitur propositum, ibi: horum autem unum quidem et cetera. 1141. After describing the condition of the first motion, the Philosopher here describes the condition of the first mover. And it is divided into two parts: First he mentions his intention; Secondly, he carries out his proposal, at 1142.
Dicit autem primo, quod cum dictum sit supra quod primum movens est immobile, nunc dicendum est quod primum movens est indivisibile et nullam habens magnitudinem, sicut omnino incorporeum. Sed antequam hoc ostendamus, oportet praedeterminare quaedam quae exiguntur ad huius probationem. He says first (901), then, that since it was said above that the first mover is immobile, now we must assert that the first mover is indivisible and has no magnitude, as being wholly incorporeal. But before we show this, certain things necessary for this proof must be settled in advance.
Deinde cum dicit: horum autem unum quidem etc., exequitur propositum. 1142. Then at (902) he carries out his proposal:
Et primo praemittit quaedam quae sunt necessaria ad principalis propositi ostensionem; secundo ostendit principale propositum, ibi: determinatis autem his et cetera. First he premises things required for proving the main proposition; Secondly, he proves the main proposition, at the end of L. 23.
Circa primum tria facit: primo ostendit quod ad motum infinitum requiritur potentia infinita; secundo quod potentia infinita non potest esse in magnitudine finita, ibi: quod autem omnino in finita magnitudine etc.; tertio quod primum motorem oportet esse unum, qui moveat motum continuum et sempiternum, ibi: de his autem quae feruntur et cetera. About the first he does three things: First he shows that an infinite motion supposes an infinite power; Secondly, that an infinite power cannot exist in a magnitude, at 1146; Thirdly, that the first mover must be one which causes a continuous and undying motion, (L. 22).
Dicit ergo primo, quod inter ea quae praedeterminanda sunt ante principale propositum, unum est quod impossibile est aliquod finitum secundum potentiam, movere per tempus infinitum. Quod sic ostendit. He says therefore first (902) that among the things to be established before the main proposition, one is that it is impossible for anything of finite power to cause motion for an infinite time. This he now proves.
Tria sunt in quolibet motu: quorum unum est id quod movetur, aliud est ipsum movens, tertium autem est tempus in quo fit motus. There are three things in every motion: one of which is what is moved, another is the mover, and the third is the time in which the motion occurs.
Oportet autem quod aut omnia ista sint infinita, aut omnia sint finita, aut quod quaedam sint finita et quaedam infinita, vel duo tantum vel unum. But all three must be infinite, or all three finite, or some finite and some infinite, i.e., either two only or one.
Ponatur ergo primo quod a sit movens, et b sit mobile, et tempus infinitum sit c. Et ponatur quod aliqua pars ipsius a, quae est d, moveat aliquam partem b, quae est e. His ergo positionibus factis, concludi potest quod d movet e in tempore non aequali ipsi c, in quo a movebat b, sed in tempore minori. Suppose, therefore, that A is the mover, B the mobile, and C the infinite time. Then let D, a part of At move E, a part of B. Under these conditions, it could be concluded that D moves E in a time not equal to time C (in which A moved B) but in less time.
Probatum est enim in sexto quod totum mobile in maiori tempore pertransit aliquod signum, quam pars eius. Cum ergo tempus quod est c sit infinitum, relinquitur quod tempus in quo d movet e, non erit infinitum, sed finitum. Et sit illud tempus z; ut sicut a movet b in tempore c infinito, ita d moveat e in tempore z finito. Cum autem d sit pars ipsius a, si subtrahendo ab a addam ipsi d, totaliter ipsum a auferetur vel consumetur, cum sit finitum: omne enim finitum consumitur per subtractionem, si eadem quantitas semper sumatur, ut in tertio dictum est. For it has been proved in Book VI that the entire mobile requires more time to pass a certain point than it takes for a part of it. Therefore, since the time C is infinite, it follows that the time in which D moves E will not be infinite but finite. So let that time be Z, so that just as A moves B in the infinite time C, D moves E in the finite time Z. But since D is part of A, then if we add to D by subtracting from A, the A will eventually be entirely taken away or used up, since it is finite, and every finite is used up by subtraction, if the same quantity is continually taken away, as said in Book III.
Et similiter consumetur ipsum b, si continue subtrahatur aliquid ab ipso et apponatur ipsi e; quia b etiam ponebatur esse finitum. Sed quantumcumque auferam a tempore quod est c, etiam secundum eandem quantitatem auferendo, non consumetur totum c; quia ponitur esse infinitum. And likewise, B will be used up, if continual subtractions are made from it and added to E, because B is also finite. But no matter how much is taken from the time C—even if the same amount is continually taken away—all of C will not be used up, because it is infinite.
Ex hoc concludit quod totum a movet totum b in tempore aliquo finito, quod est pars ipsius c. Quod quidem sic sequitur ex praemissis, quia secundum proportionem qua additur ad mobile et ad motorem, additur etiam ad tempus motus. Cum ergo subtrahendo a toto mobili et motore, et addendo ad partes ipsorum, consumatur quandoque totum mobile et totum movens, ita quod totum quod erat in toto addetur parti; sequetur quod proportionaliter addendo ad tempus, resultabit tempus finitum, in quo totum movens movebit totum mobile. Et sic oportet quod si movens est finitum et mobile finitum, quod tempus sit finitum. From this he concludes that the entire A moves the entire B in a finite time, which is part of C. And this does indeed follow from the premises, because additions are made to the time of the motion in the same ratio as they are made to the mobile and to the mover, Since, therefore, by subtracting from the entire mobile and mover and by adding to their parts, the whole mobile the whole mover are at length used up, so that all that was in the whole is added to the part, it will follow that by proportional additions being made to the time, there will result a finite time in which the whole mover will move the whole mobile. Thus, if the mover is finite and the mobile also finite, the time too must be finite.
Sic ergo non est possibile quod a finito movente moveatur aliquid motu infinito, scilicet secundum tempus infinitum. Et sic patet quod primo proponebatur, quod non contingit quod finitum movens moveat in tempore infinito. According to this, therefore, it is not possible that by a finite mover anything be moved with an infinite motion, namely, according to an infinite time. And so what was first proposed is now plain, namely, that it does not happen that a finite mover should cause motion for an infinite time.
Movet autem Avicenna dubitationem circa hanc Aristotelis demonstrationem. Videtur enim non esse universalis: est enim aliquod finitum movens et mobile, a quo non potest aliquid subtrahi vel auferri, sicut est corpus caeleste; quod tamen in hac demonstratione non excipitur. Unde videtur quod vel demonstratio sit particularis, vel procedat ex falsa suppositione. 1143. But Avicenna raises a difficulty about this demonstration of Aristotle. For it seems not to be universal, since there exists a finite mover and mobile from which nothing can be subtracted or taken away, such as a heavenly body, which nevertheless was not excluded from Aristotle’s proof. Hence it seems that the proof is either particular, or it proceeds from a false assumption.
Huic autem obiectioni respondet Averroes in commento, quod quamvis a caelo nihil posset subtrahi, haec tamen conditionalis est vera: si a caelo aliqua pars auferatur, pars illa movebit aut movebitur in minori tempore quam totum. Nihil enim prohibet conditionalem esse veram, cuius antecedens est impossibile; sicut patet in hac conditionali: si homo volat, habet alas. Quidquid autem tollit veritatem conditionalis verae, est falsum, licet antecedens conditionalis sit falsum. Veritas autem praedictae conditionalis non potest stare cum hoc quod finitum moveat tempore infinito, ut patet per deductionem Aristotelis. Sic igitur ex veritate praemissae conditionalis, concludit Aristoteles impossibile esse quod finitum moveat tempore infinito. To this objection Averroes in his Commentary answers that although nothing can be subtracted from the heavenly body, yet the conditional is true, that if a part be taken away from the body, that part will move or be moved in less time than the whole body. For there is nothing to prevent a conditional from being true, even if its antecedent be impossible, as is patent from this conditional: If a man flies, he has wings. But whatever takes away the truth of a true conditional is false, even though the antecedent of the conditional be false. Now the truth of the above conditional cannot stand with the statement that the finite moves for an infinite time, as is evident through Aristotle’s deduction, Thus, therefore, from the truth of the foregoing conditional Aristotle concludes that it is impossible for a finite thing to cause motion for an infinite time.
Potest autem brevius dici, quod Aristoteles quando in demonstrationibus suis utitur ablatione vel subtractione, non semper per ablationem intelligenda est solutio continuitatis, quam impossibile est esse in corpore caelesti; sed ablatio intelligi potest secundum quamcumque designationem. Sicut in ligno continuo manente possum designare vel tactu vel cogitatione aliquod punctum, quasi dividens totum; et per hunc modum auferre aliquam partem a toto, et dicere quod minor albedo est in parte quam in toto. Et per hunc etiam modum potest dici quod minor virtus est ad movendum in parte corporis caelestis per designationem ablata, quam in toto. However, it may be said more briefly that when Aristotle in his demonstrations speaks of removing or subtracting, it does not always have to be understood in the sense of destroying a thing’s continuity, which is impossible in a heavenly body; rather, subtraction can be understood in the sense of designating. For example, I can without disturbing the continuity of a piece of wood designate by touch or thought a certain point as though dividing the whole, and in this way I can remove a part from the whole and say that there is less whiteness in that part than in the whole. In like manner, it can be said that there is less power to move in a part of a heavenly body— a part removed by designating it—than in the whole.
Alia autem dubitatio est difficilior. Non enim videtur esse contra rationem moventis finiti, quod moveat tempore infinito: quia si illud finitum sit incorruptibile vel impassibile secundum suam naturam, et non recedens a sua natura, semper eodem modo se habet ad movendum; quia idem eodem modo se habens, semper facit idem. Unde non est magis ratio quare non possit movere post, quam ante. Et hoc sensibiliter apparet: videmus enim quod sol potest in infinito tempore movere corpora inferiora. 1144. But there is another and greater difficulty. For it does not seem to be against the prerogatives of a finite mover to cause motion for an infinite time, because if that finite thing is imperishable or impassible in its nature, and never loses its nature, it will maintain itself always in the same way with respect to causing motion, for a same thing, remaining in the same state, will always do the same. Hence, there would be no reason for its not being able to get later as it did before. This is evident to sense, for we observe that the sun can in an infinite time move lower bodies.
Ad huius autem dubitationis solutionem, investigandus est processus demonstrationis inductae. Certum enim debet esse, quod sic intelligenda est conclusio, quemadmodum sequitur ex praemissis. To settle this difficulty, we must investigate the sequence of demonstration set forth by Aristotle. For it should be certain that the conclusion is to be interpreted in the sense in which it follows from the premises.
Considerandum est igitur quod tempus motus potest accipi dupliciter, praecipue in motu locali: uno modo secundum partes mobilis; alio modo secundum partes magnitudinis supra quam transit motus. Manifestum est enim quod prius una pars mobilis pertransit aliquod signum magnitudinis, quam totum mobile: similiter etiam totum mobile prius pertransit unam partem magnitudinis, quam totam. Apparet autem manifeste ex processu Aristotelis, quod hic loquitur de tempore motus, secundum quod tempus motus accipitur secundum partes mobilis; et non secundum quod accipitur secundum partes magnitudinis. Accipit enim in sua demonstratione, quod pars moventis moveat partem mobilis in minori tempore quam totum moveat totum: quod non esset verum si acciperemus tempus motus secundum partes magnitudinis quae motu pertransitur. Eadem enim est proportio partis motoris ad partes mobilis, quae est proportio totius motoris ad totum mobile. Unde aequali velocitate semper pars movebit partem, qua totum movet totum: et sic in aequali tempore pertransibit pars mobilis aliquam magnitudinem, mota a parte motoris, et totum mobile motum a toto motore. We should consider, therefore, that the time of a motion may be taken in two senses, especially in local motion: in one sense, according to the parts of the mobile; in another sense, according to the parts of the magnitude along which the motion passes. For it is plain that one part of the mobile passes a designated point of the magnitude, before the whole does, and that the whole traverses part of the magnitude before it traverses all of it. Now, it is plainly clear from the procedure of Aristotle’s demonstration, that he is speaking of time of motion according to the parts of the mobile and not according to the parts of the magnitude. For in his demonstrations he assumes that part of the mover moves part of the mobile in less time than the whole moves the whole. But this could not be true, if we took time of motion according to the parts of the magnitude traversed by the motion; for the ratio of the part of the mover to the part of the mobile is the same as that of the whole mover to the whole mobile. Hence, a part will always move part with the same velocity as the whole moves the whole. Thus in an equal time part of the mobile moved by part of the mover will traverse some magnitude and the whole mobile moved by the whole mover will also.
Vel forte in minori tempore movebitur totum quam pars: quia potentia unita maior est quam potentia divisa, et quanto maior est potentia moventis, velocior est motus, et tempus minus. Oportet ergo quod hoc intelligatur secundum quod accipitur tempus motus secundum partes mobilis: quia una pars mobilis in minori tempore pertransit aliquod signum, quam totum mobile. Et secundum hoc est impossibile quod tempore infinito moveatur, nisi sit mobile infinitum. Impossibile est autem quod mobile infinitum moveatur a motore finito: quia semper virtus motoris est maior quam virtus mobilis. Unde necesse est quod mobile infinitum moveatur a motore infinito. Et sic, sicut impossibile sequitur ex hoc quod ponitur quod motor finitus moveat mobile finitum, motu qui sit infinitus secundum partes mobilis; ita, remoto hoc inconvenienti, oportet ulterius hoc concludere, quod motus infinitus sit mobilis infiniti a motore infinito. Or perhaps the whole will be moved in less time than the part, because a united force is greater than a divided force, and the greater the force of the mover, the swifter the motion and the less the time. Therefore, this must be understood in the sense that the time of motion is taken according to parts of the mobile, because one part of the mobile will pass a definite point in less time than the whole will. In this sense, it is impossible for anything but an infinite mobile to be moved for an infinite time. But an infinite mobile cannot be moved by a finite mover, since the power of the mover is always greater than the power of the mobile. Hence an infinite mobile must be moved by an infinite power. Consequently, just as an impossibility follows from the assumption that a finite mover moves a finite mobile with an infinite motion according to the parts of the mobile, so, this incompatibility once removed, one must further conclude that an infinite motion belongs to an infinite mobile from an infinite mover.
Sed contra hoc potest aliquis obiicere, quod Aristoteles supra non probavit motum esse infinitum secundum partes mobilis, sicut motus corporis infiniti dicitur infinitus: quia totum universum corporeum finitum est, ut probatum est in tertio huius, et probabitur in I de caelo. Unde non videtur esse demonstratio Aristotelis sic verificata ad propositum concludendum, ut scilicet primus motor qui movet motum infinitum, sit infinitus. 1145. But against this, someone could object that Aristotle did not prove above that motion is infinite according to the parts of the mobile in the way that the motion of an infinite body is said to be infinite, for the entire corporeal universe is finite, as was proved in Book III and will be proved in On the Heavens I. Hence the demonstration of Aristotle does not seem to be verified as concluding to his proposition, namely, that the first mover, which causes an infinite motion, is infinite.
Sed dicendum quod id quod est prima causa motus infiniti, oportet quod sit per se causa infinitatis motus: quia semper causa quae est per se, est prior ea quae est per aliud, ut supra dictum est. Virtus autem causae per se determinatur ad effectum per se, et non ad effectum per accidens: sic enim supra in secundo docuit Aristoteles comparare causas effectibus. Cum autem contingat motum esse infinitum dupliciter, sicut dictum est, scilicet secundum partes mobilis, et secundum partes longitudinis supra quam transit motus; per se infinitum est in motu ex partibus mobilis, per accidens autem secundum partes longitudinis: quia quantitas motus quae attenditur secundum partes mobilis, competit ei secundum proprium subiectum, et ita inest ei per se, quantitas autem motus quae accipitur secundum partes longitudinis, accipitur secundum reiterationem motus ipsius mobilis, prout scilicet mobile totum, quod complevit motum suum super unam partem longitudinis, iterato pertransit aliam. Illud ergo quod est prima causa infinitatis motus, habet virtutem super infinitatem motus quae est per se, ut scilicet possit movere mobile infinitum si contingat: et ideo necesse est quod sit infinitum. Et quamvis primum mobile sit finitum, tamen habet quandam similitudinem cum infinito, ut dictum est in tertio. Ad hoc autem quod aliquid sit causa motus infiniti per reiterationem motus (quod est per accidens), non oportet quod habeat virtutem infinitam, sed sufficit si habet virtutem immobilem finitam: quia semper manente eadem virtute, poterit reiterare eundem effectum; sicut sol habet virtutem finitam, et tamen posset movere inferiora elementa tempore infinito, si motus esset sempiternus, secundum positionem Aristotelis. Non enim est prima causa infinitatis motus, sed quasi ab alio mota ad movendum tempore infinito, secundum positionem praedictam. But it should be said that what is first cause of an infinite motion must be the per se cause of the infinity of the motion, because the cause which is per se is always prior to that which is so by virtue of something else, as has been said above. Now, the power of a per se cause is determined to a per se effect and not to a per accidens effect, for that is the way Aristotle taught causes are to be compared to their effects in Book II. But, because motion can be infinite in two ways, as has been said, namely, according to the parts of the mobile and according to the parts of the length along which the motion takes place, per se the infinite is in motion from the parts of the mobile, but per accidens according to the parts of the length—for the quantity of motion based on the parts of the mobile belongs to it by reason of its proper subject and so is present in it per se, whereas the quantity of motion based on the parts of the length is based on constant repetition of the mobile’s motion, in the sense that a whole mobile, having completed its entire motion upon one part of the length, now successively traverses another. The first cause, therefore, of the infinity of motion has power over the infinity of motion which is per se, in such a way, namely, as to enable it to move an infinite mobile, should there be such. Hence, it must be infinite. And even though the first mobile be finite, it has, nevertheless, a certain likeness to the infinite, as was said in Book III. But in order that something be the cause of a motion that is infinite through repetition (which is per accidens) infinite power is not required, but an immobile finite power is enough, because, so long as the power remains the same, it will be able to repeat the same effect, as the sun has a finite energy yet can move the lower elements in an infinite time, should motion be, as Aristotle posits, eternal. For it is not the first cause of the infinity of motion but is something as though moved by another to move in an infinite time, according to the position stated above.
Deinde cum dicit: quod autem omnino in finita etc., ostendit quod necesse est virtutem quae est in magnitudine, proportionari magnitudini in qua est. Et primo ostendit quod in magnitudine finita non potest esse potentia infinita, quod principalius intendit; secundo quod nec in magnitudine infinita potest esse potentia finita, ibi: nullum igitur finitum et cetera. 1146. Then at (903) he shows that the power in a magnitude must be proportional to the magnitude in which it exists. First he shows that in a finite magnitude there cannot be an infinite power—and this is what he chiefly intends; Secondly, that on the other hand, in an infinite magnitude there cannot be a finite power, at 1156.
Quod autem in magnitudine finita non contingat esse potentiam infinitam, probat, duas suppositiones praemittendo. Quarum prima est, quod maior potentia aequalem effectum perficit in minore tempore quam minor: sicut maior potentia calefactiva ad aequalem caliditatem perducit id in quo agit, in minori tempore; et simile est de potentia dulcorantis vel proiicientis, vel cuiuscumque moventis. That an infinite power cannot exist in a finite magnitude he proves at (903), but first he mentions two assumptions. The first is that a greater power produces an equal effect in less time than a lesser power, as a greater heating force raises a thing on which it acts to an equal temperature in less time, and the same is true of a sweetener, or a hurler, or any cause of motion.
Et ex hac suppositione concludit, quod cum potentia infinita sit maior quam potentia finita, necesse est quod si sit aliqua magnitudo finita habens potentiam infinitam, quod a tali agente sive unum patiens sive plura patiantur in eodem tempore maiorem mutationem, quam ab alio habente potentiam finitam: vel e converso quod aequalem mutationem patiens, ab eo patiatur in minori tempore. Utrumque enim potest intelligi in eo quod dicit et plus quam ab alio. And from this assumption he concludes that since an infinite power is greater than a finite power, then, necessarily, if there is a finite magnitude possessing an infinite power, one or a number of things will in the same time undergo from such an agent a greater change than from another having finite power, or, conversely, that which undergoes an equal change will do so from it in less time. Either interpretation suits what Aristotle says here, namely, “...to a greater extent than by anything else.”
Secunda suppositio est, quod cum omne quod movetur moveatur in tempore, ut in sexto probatum est, non potest esse quod patiens immutetur ab agente infinitae potentiae in non tempore. Immutatur ergo in tempore. The second assumption is that, since whatever is being moved is being moved in time, as was proved in Book VI, it cannot be that something undergoing is changed in no time by an agent of infinite power. Therefore, it is changed in time.
Ex hoc sic procedit. Sit tempus in quo virtus infinita movet calefaciendo vel impellendo, a; tempus autem in quo aliqua virtus finita movet, sit ab, quod est maius quam a. Qualibet autem potentia finita potest accipi alia maior. Si ergo accipiamus aliam maiorem potentiam finitam quam primam, quae movebat in tempore ab, sequetur quod haec secunda potentia movebit in tempore minori; et iterum tertia potentia finita maior in tempore adhuc minori. Et sic semper accipiendo finitam potentiam, veniam aliquando ad hoc quod aliqua potentia finita moveat in tempore a: cum enim semper fiat additio ad potentiam finitam, excedetur omnis determinata proportio. Simul autem additur ad potentiam motivam et subtrahitur a tempore motus; quia maior potentia in minori tempore movere potest. From this he proceeds in the following manner: Let A be the time in which an infinite power causes change by heating or throwing, and let the time in which a finite power is causing change be AB, which is longer than A. Now, no matter what a finite power may be, a still greater may be taken. If, therefore, we take another finite power greater than the first and which caused change in time AB, it will act in a shorter time. Again, a third and greater power will cause the change in still less time, And thus by always taking a finite power I will at length come to a finite power that will produce the change in time A, for when an addition is continually made to a finite power, any predetermined ratio will be exceeded. But as the power is increased, the time is decreased, because a greater power can cause a change in less time.
Sic ergo sequetur quod finita potentia perficiat motum in aequali tempore cum potentia infinita, quae ponebatur movere in a. Hoc autem est impossibile: ergo nulla magnitudo finita habet potentiam infinitam. In this way, therefore, it will follow that a finite power will produce a change in a time equal to that used by the infinite power, which was assumed as acting in time A. But this is impossible. Therefore, no finite magnitude has an infinite power.
Dubitatur autem circa hanc rationem multipliciter. Primo namque videtur quod haec ratio nullo modo concludat. Quod enim per se convenit alicui, per nullam potentiam potest ab eo removeri, quantumcumque sit magna: non enim est ex defectu potentiae, vel infinitati potentiae repugnat, si dicatur fieri non posse quod homo non sit animal. Esse autem in tempore per se convenit motui: ponitur enim motus in definitione temporis, ut supra in quarto habitum est. Ergo si ponatur etiam potentia infinita movens, non sequitur quod motus sit in non tempore, ut Aristoteles hic concludit. 1147. Now, there are many doubts about this argument. First, it seems not to conclude in any way. For what belongs per se to a thing cannot be taken from it by any power however great, for it is not due to any lack of power, nor does it conflict with infinity of power, if it be said that it is impossible for man not to be an animal. But to exist in time belongs per se to motion, for motion is found in the definition of time, as was had above in Book IV. Therefore, if an infinite moving power is conceded to exist, it does not follow that motion exists in non-time as Aristotle here concludes.
Item si consideretur processus philosophi, ex hoc concludit quod motus sit in non tempore, quia potentia movens est infinita; sed potentia infinita movens potest etiam non esse in corpore; ergo eadem ratione sequitur quod talis potentia, si sit infinita, movebit in non tempore. Non ergo per hoc quod est impossibile moveri in non tempore, potest concludi quod nulla virtus infinita est in magnitudine, sed quod simpliciter nulla virtus movens sit infinita. Likewise, if the sequence of the argument of the Philosopher is considered, it will be seen that his conclusion that motion exists in non-time is inferred from the fact that the moving power is infinite; but an infinite moving power can also not be in a body. Therefore, for the same reason, it follows that such a power, if it is infinite, will move in non-time. Hence, from the impossibility of being moved in non-time it cannot be inferred that no infinite power exists in a magnitude, but absolutely that no moving power at all is infinite.
Item, ad magnitudinem potentiae duo pertinere videntur, scilicet velocitas motus et diuturnitas ipsius; et secundum excessum potentiae videmus fieri excessum in utroque dictorum. Sed secundum excessum potentiae infinitae, supra ostendit quod motus perpetuus est ab aliqua potentia infinita, non autem quod aliqua potentia infinita non sit in magnitudine. Ergo similiter et hic, secundum excessum in velocitate non debet concludere quod nulla virtus infinita sit in magnitudine, sed quod virtus quae movet tempore infinito, propter sui infinitatem moveat etiam in non tempore. Again, two things seem to pertain to the magnitude of a power, namely, the swiftness of motion and its diuturnity; and any superabundance in the power causes a corresponding superabundance in each of these two things. But with respect to the superabundance of an infinite power, he showed above that a perpetual motion depends on an infinite power, but not that an infinite power does not exist in a magnitude. Therefore, here too, with respect to excess of swiftness, he ought not to conclude that no infinite power exists in a magnitude, but that the power which moves in an infinite time would, on account of its infinity, also move in non-time.
Item videtur conclusio esse falsa. Quanto enim est maior virtus alicuius corporis, tanto diutius potest conservari in esse: si ergo nullius corporis potentia esset infinita, nullum corpus posset in infinitum durare. Quod patet esse falsum tam secundum opinionem ipsius, quam secundum sententiam fidei Christianae, quae ponit substantiam mundi in infinitum duraturam. Again, the conclusion seems to be false. For the greater the power of a body, the longer it can endure. If, therefore, the power of no body were infinite, no body could endure ad infinitum. Now this is plainly false, both according to his own opinion and according to the tenets of the Christian faith, which posits that the substance of the world will endure ad infinitum.
Posset etiam moveri obiectio de divisione et additione quibus utitur, quae non conveniunt rerum naturae; sed quia de hoc superius satis dictum est, praetermittatur ad praesens. It could also be objected that the division and addition which he uses have no correspondence in reality, but since this was sufficiently discussed previously, it can be passed over at the present time.
His ergo dubitationibus per ordinem respondentes, dicendum est ad primam, quod philosophus non intendit hic facere demonstrationem ostensivam, sed demonstrationem ad impossibile ducentem; in qua, quia ex aliquo dato aliquid sequitur quod est impossibile, concluditur primum datum impossibile esse. Non autem est verum quod primum datum simul cum conclusione esse sit possibile; sicut si daretur quod esset aliqua potentia quae posset removere genus a specie, sequeretur quod illa potentia posset facere quod homo non esset animal: sed quia hoc est impossibile, impossibile est et primum; non autem ex hoc potest concludi esse possibile, quod sit aliqua potentia quae faciat hominem non esse animal. Ita ex hoc quod est aliquam potentiam infinitam esse in magnitudine, ex necessitate sequitur motum esse in non tempore: sed quia hoc est impossibile, impossibile est infinitam potentiam esse in magnitudine; nec potest ex hoc concludi esse possibile quod potentia infinita moveat in non tempore. 1148. Answering, therefore, these doubts in order, it must be said with respect to the first one, that the Philosopher in this place does not intend an ostensive demonstration but one that leads to an impossibility, in which, since from something given an impossibility follows, that which was given is concluded to be impossible. For it is not true that the first supposition can possibly co-exist with the conclusion. Thus the supposition that there was some power which could remove the genus from a species, would allow us to conclude that that power could make man not be animal; but because this is impossible, the supposition too is impossible. From this, then, it cannot be concluded that it is possible for a power to exist that could make man not be animal. So, too, from the fact that an infinite power exists in a magnitude, it follows of necessity that motion exists in non-time; but since this is impossible, it is impossible for an infinite power to exist in a magnitude; nor can it be concluded from this that it is possible for an infinite power to move in non-time.
Ad secundam autem dubitationem respondet Averroes in commento huius loci, dicens quod ratio Aristotelis hic procedit de potentia, ratione suae infinitatis. Finitum autem et infinitum convenit quantitati, ut supra in primo habitum est: unde potentiae quae non est in magnitudine, non proprie competit quod sit finita vel infinita. 1149. To the second doubt Averroes responds in his Commentary at this place that the argument of Aristotle here proceeds from power under the aspect of its infinity. But “finite” and “infinite” belong to quantity, as was proved in Book I. Hence, finite and infinite do not properly belong to a power that is not in a magnitude.
Sed haec responsio est et contra intentionem Aristotelis, et contra veritatem. Contra intentionem quidem Aristotelis est, quia Aristoteles in praecedenti demonstratione probavit quod potentia movens tempore infinito sit infinita: et ex hoc infra concludit quod potentia movens caelum non est potentia in magnitudine. But this answer is contrary both to the intention of Aristotle, and to the truth. It is contrary to Aristotle’s intention, because in the preceding demonstration Aristotle proved that a power which causes motion for an infinite time is infinite, and from this he later concludes that the power moving the heavens is not a power existing in a magnitude.
Est etiam contra veritatem: quia cum omnis potentia activa sit secundum aliquam formam, eo modo convenit magnitudo potentiae, et per consequens finitum et infinitum, sicut convenit formae. Formae autem convenit magnitudo et per se, et per accidens: per se quidem, secundum perfectionem ipsius formae, sicut dicitur magna albedo etiam parvae nivis, secundum perfectionem propriae rationis; per accidens autem secundum quod aliqua forma habet extensionem in subiecto, sicut dicitur magna albedo propter magnitudinem superficiei. It is also against the truth: for since every active power is according to some form, magnitude, and consequently its finiteness and infinity, belong to a power in the way it belongs to form. But magnitude belongs to form both per se and per accidens: it belongs per se, according to the perfection of the form, as a whiteness is called “great” even in a small amount of snow, according to the perfection of its proper notion; it belongs per accidens, according to the extension that a form has in a subject, as a whiteness can be called “great” on account of the size of its surface.
Haec autem secunda magnitudo non potest competere potentiae quae non est in magnitudine: sed prima magnitudo maxime ei competit, quia potentiae immateriales, quanto sunt minus contractae per applicationem ad materiam, tanto sunt perfectiores et universaliores. Now, this second magnitude cannot belong to a power not in a magnitude, but the first magnitude most truly does, because non-material powers, the less they are restricted through union with matter, the more perfect and more universal they are.
Velocitas autem motus non consequitur magnitudinem virtutis quae est per accidens, per extensionem ad magnitudinem subiecti, sed magis eam quae est per se, secundum propriam perfectionem: quia quanto aliquod ens actu est perfectius, tanto est vehementius activum. Unde non potest dici quod potentia quae non est in magnitudine, quia non est infinita infinitate magnitudinis quae est ex magnitudine subiecti, propter hoc non causet augmentum velocitatis in infinitum, quod est movere in non tempore. But swiftness of motion does not follow upon a magnitude of power which is per accidens, by extension with the magnitude of the subject; rather, it follows one that is per se, according to its proper perfection, because the more perfect a thing is in act, the more vehemently is it active. Hence it cannot be said that a power which does not exist in a magnitude, because it is not infinite with the infinity of magnitude which depends on the magnitude of the subject, therefore cannot cause an increase of swiftness ad infinitum, i.e., move in non-time.
Unde et idem Commentator hanc dubitationem aliter solvit in XI Metaphys., ubi dicit quod corpus caeleste movetur a duplici motore, scilicet a motore coniuncto, qui est anima caeli, et a motore separato, qui non movetur neque per se neque per accidens. Et quia ille motor separatus est infinitae virtutis, motus caeli acquirit ab eo perpetuam durationem: quia vero motor coniunctus est finitae virtutis, ideo motus caeli acquirit ab eo velocitatem determinatam. Hence the same Commentator solves this same difficulty in another way in Metaphysics XI, where he says that a heavenly body is moved by a two-fold mover, i.e., by a conjoined mover, which is the soul of the heavens, and by a separated mover, which is not moved either per se or per accidens. And because that separated mover has infinite power, the movement of the heaven acquires from it a perpetual duration; but because the conjoined mover has finite power, the movement of the heaven acquires from it a determinate swiftness.
Sed nec ista responsio sufficiens est. Cum enim utrumque videatur consequi potentiam infinitam, scilicet quod moveat tempore infinito, ut praecedens demonstratio conclusit, et quod moveat in non tempore, ut videtur concludere haec demonstratio: iterum restat dubitatio quare anima caeli, quae movet in virtute motoris separati infiniti, magis ab eo sortiatur ut possit movere tempore infinito, quam ut moveat velocitate infinita, idest in non tempore. But even this answer is not sufficient. For since both seem to follow upon an infinite power, namely, that it act for an infinite time, as the preceding demonstration concluded, and that it act in non-time, as this demonstration seems to conclude, the doubt still remains why the soul of the heaven which acts in virtue of an infinite separated mover obtains from it the ability to act for an infinite time rather than the ability to act with infinite swiftness, i.e., in non-time.
Ad hanc igitur dubitationem dicendum est, quod omnis potentia quae non est in magnitudine, movet per intellectum: sic enim philosophus probat caelum moveri a suo motore, in XI Metaphys. Nulla autem potentia quae est in magnitudine, movet quasi intelligens: probatum est enim in III de anima, quod intellectus non est virtus alicuius corporis. 1150. In answer to this doubt it must be said that every power not in a magnitude acts through intellect, for so the Philosopher proves in Metaphysics XI that the heaven is moved by its mover. But no power in a magnitude acts as though through intellect, for it was proved in On the Soul III that the intellect is not a power of any body.
Haec autem est differentia inter agens per intellectum et agens materiale, quia actio agentis materialis proportionatur naturae agentis; tanta enim procedit calefactio quantus est calor: sed actio agentis per intellectum, non proportionatur naturae ipsius, sed formae apprehensae; non enim aedificator tantum aedificat quantum potest, sed quantum exigit ratio formae conceptae. Now this is the difference between an agent that acts through intellect and a material agent: the action of the material agent is proportioned to the nature of the agent, for a heating process proceeds in proportion to the heat, but the action of an intellectual agent is not proportioned to its nature but to the form apprehended, for a builder does not build as much as he can, but as much as the notion of the conceived form requires.
Sic igitur si aliqua esset virtus infinita in magnitudine, sequeretur quod motus ab ipsa procedens esset secundum proportionem eius: et ita procedit demonstratio praesens. Si autem sit virtus infinita non in magnitudine, motus ab ipsa non procedit secundum proportionem virtutis, sed secundum rationem formae apprehensae, idest secundum quod convenit fini et naturae subiecti. Consequently, if an infinite power existed in a magnitude, it would follow that the motion produced by it would be in proportion, to it, as the present demonstration shows. But if an infinite power is not in a magnitude, a motion does not proceed from that power in proportion to its power but according to the notion of the thing apprehended, i.e., according as it fits the end and nature of the subject.
Est etiam aliud attendendum, quod sicut probatum est in sexto huius, nihil movetur nisi magnitudinem habens: unde velocitas motus est effectus receptus a movente in aliquo habente magnitudinem. Manifestum est autem, quod nihil habens magnitudinem potest recipere effectum aequalem proportionaliter potentiae quae non est in magnitudine; quia omnis natura corporea comparatur ad naturam incorpoream sicut quoddam particulare ad absolutum et universale. Unde non potest concludi, si virtus infinita non sit in magnitudine, quod ex ea consequatur in aliquo corpore infinita velocitas, quae est effectus proportionatus tali potentiae, ut dictum est. Another point that should be noted is that, as was proved in Book VII only things having magnitude are moved; wherefore, the swiftness of motion is an effect received from the mover into something having magnitude. But it is plain that nothing having magnitude can receive an effect equal proportionately to the power which is not in a magnitude, because every corporeal nature is related to the incorporeal as a certain particular to what is absolute and universal, Hence, it cannot be concluded, if an infinite power is not in a magnitude, that from it there results in a body an infinite swiftness, which is the effect proportionate to such a power, as has been said.
Sed nihil prohibet in aliqua magnitudine recipi effectum virtutis quae est in magnitudine, quia causa proportionatur effectui. Unde si poneretur quod aliqua virtus infinita esset in magnitudine, sequeretur quod effectus correspondens esset in magnitudine, scilicet velocitas infinita. Et hoc est impossibile: ergo et primum. But there is nothing to prevent a magnitude from receiving the effect of a power existing in a magnitude, because the cause is proportioned to the effect. Hence if it were supposed that an infinite power existed in a magnitude, it would follow that a corresponding effect would exist in a magnitude, namely, an infinite swiftness. But this is impossible; therefore, the first too is impossible.
Ex his autem patet solutio tertiae dubitationis. Nam moveri tempore infinito non repugnat rationi magnitudinis motae: convenit enim magnitudini circulari, ut supra ostensum est. Sed moveri velocitate infinita, idest in non tempore, contrariatur rationi magnitudinis, ut in sexto probatum est. Unde a primo movente infinitae virtutis, secundum Aristotelem, causatur motus diuturnitatis infinitae; non autem motus velocitatis infinitae. 1151. From this the resolution of the third doubt is clear. For to be moved for an infinite time is not repugnant to the notion of a moved magnitude, for it befits a circular magnitude, as was shown above. But to be moved with an infinite speed, i.e., in non-time, is contrary to the notion of a magnitude, as was proved in Book VI. Hence the first mover, possessing infinite power, is, according to Aristotle, the cause of a motion that lasts an infinite time, but not one that has infinite speed.
Ad quartam vero dubitationem, solvit Alexander, ut Averroes dicit hic in commento, quod corpus caeleste acquirit aeternitatem a motore separato, quod est infinitae virtutis, sicut et perpetuitatem motus. Unde sicut non est ex infinitate caelestis corporis quod in perpetuum moveatur, ita non est ex infinitate corporis caelestis quod in perpetuum duret; sed utrumque est ex infinitate motoris separati. 1152. The fourth doubt is, according to Averroes in his Commentary, answered by Alexander’s saying that a heavenly body acquires eternity from a separated mover having infinite power, as well as perpetuity of motion. Hence, just as it is not from the infinity of a heavenly body that it is perpetually moved, so, too, it is not from the infinity of the heavenly body that it endures forever. Both are from the infinity of the separated mover.
Hanc autem responsionem Averroes improbare nititur et hic in commento, et in XI Metaphys., dicens quod impossibile est quod aliquid acquirat perpetuitatem essendi ab alio; quia sequeretur quod id quod in se est corruptibile, fieret aeternum. Sed perpetuitatem motus potest aliquid acquirere ab altero: eo quod motus est actus mobilis a movente. Dicit ergo quod in corpore caelesti, quantum est de se, non est aliqua potentia ad non esse, quia eius substantiae non est aliquid contrarium: sed in ipso est aliqua potentia ad quietem, quia motui eius contrariatur quies. Et inde est quod non indiget acquirere perpetuitatem essendi ab alio: sed perpetuitatem motus ab alio acquirere indiget. Now Averroes tries to refute this answer, both in his Commentary on this passage and in Metaphysics XI, and says that it is impossible for something to acquire perpetuity of existence from another, because it would follow that something in se perishable could be eternal. Yet something can acquire perpetuity of motion from another, for motion is an act existing in a mobile but caused by a mover. He says therefore that in a heavenly body considered in itself there is no potency to non-existence, because its substance has no contrary, but there is a potency to rest, because rest is contrary to its motion. And that is why it does not have to acquire perpetuity of existence from another, but must acquire perpetuity of motion from another.
Quod autem in corpore caelesti non sit aliqua potentia ad non esse, ex hoc contingere dicit, quod corpus caeleste dicit non esse compositum ex materia et forma quasi ex potentia et actu; sed dicit ipsum esse materiam actu existentem, et formam eius dicit animam ipsius; ita tamen quod non constituatur in esse per formam, sed solum in moveri. Et sic dicit in eo esse, non potentiam ad esse, sed solum ad ubi, sicut philosophus dicit in XI Metaphys. That a heavenly body has no potency to non-existence happens, he says, because a heavenly body is not composed of matter and form as though of potency and act. Rather, says he, such a body is matter existing in act, while its form is its soul, in such a way that it is not constituted in being through the form, but only in motion. Consequently, says he, there is present in it not a potency to existence, but solely a potency to “where” (place), as the Philosopher says in Metaphysics XI.
Sed haec solutio et veritati repugnat, et intentioni Aristotelis. Veritati quidem repugnat multipliciter: et primo quia dicit quod corpus caeleste non componitur ex materia et forma: hoc enim est omnino impossibile. Manifestum est enim corpus caeleste esse aliquid actu; alioquin non moveretur: quod enim est in potentia tantum, non est subiectum motus, ut in sexto habitum est. Oportet autem omne quod est actu, vel esse formam subsistentem, sicut substantiae separatae; vel habere formam in alio, quod quidem se habet ad formam sicut materia, et sicut potentia ad actum. Non autem potest dici quod corpus caeleste sit forma subsistens: quia sic esset intellectum in actu, non cadens sub sensu neque sub quantitate. Relinquitur ergo quod est compositum ex materia et forma, et ex potentia et actu; et sic est in ipso quodammodo potentia ad non esse. 1153. But this solution conforms neither to the truth nor to the intention of Aristotle. It is not in conformity with truth on a number of counts: First, because he says that a heavenly body is not composed of matter and form—which is utterly impossible. For it is plain that a heavenly body is something actual, otherwise it would not be in motion—something that is in potency only is not a subject of motion, as was proved in Book VI. But, whatever is actual is either a subsisting form, as are the separated substances, or has form in something else, which is related to the form as matter, and as potency to act. Now, it cannot be said that a heavenly body is a subsistent form, because then it would be understood in act and neither sensible nor existing under quantity. Therefore, it must be a composite of matter and form, and of potency and act. Consequently, there is in it in some sense a potency to non-existence.
Sed dato quod corpus caeleste non sit compositum ex materia et forma, adhuc oportet in ipso ponere aliquo modo potentiam essendi. Necesse est enim quod omnis substantia simplex subsistens, vel ipsa sit suum esse, vel participet esse. Substantia autem simplex quae est ipsum esse subsistens, non potest esse nisi una, sicut nec albedo, si esset subsistens, posset esse nisi una. Omnis ergo substantia quae est post primam substantiam simplicem, participat esse. Omne autem participans componitur ex participante et participato, et participans est in potentia ad participatum. In omni ergo substantia quantumcumque simplici, post primam substantiam simplicem, est potentia essendi. But even if a heavenly body were not a composite of matter and form, it would still be necessary to place in it, in some sense, a potency in respect of existence. For every simple self-subsisting substance is necessarily either its own existence or it shares in existence. But a simple substance which is self-subsistent existence itself cannot be but one, just as whiteness, if whiteness were a subsistent being, could be but one. Consequently, every substance after the first simple substance participates existence. But every participant is composed of the participant and what it participates, and the participant is in potency to what it participates. Therefore, in every substance, however simple, other than the first simple substance, there is a potency to existence.
Deceptus autem fuit per aequivocationem potentiae. Nam potentia quandoque dicitur quod se habet ad opposita. Et hoc excluditur a corpore caelesti, et a substantiis simplicibus separatis: quia non est in eis potentia ad non esse, secundum intentionem Aristotelis; eo quod substantiae simplices sunt formae tantum, formae autem per se convenit esse; materia autem corporis caelestis non est in potentia ad aliam formam. Sicut enim corpus caeleste comparatur ad suam figuram, cuius est subiectum, ut potentia ad actum, et tamen non potest non habere talem figuram: ita materia corporis caelestis comparatur ad talem formam ut potentia ad actum, et tamen non est in potentia ad privationem huius formae, vel ad non esse. Non enim omnis potentia est oppositorum: alioquin possibile non sequeretur ad necesse, sicut dicitur in II perihermeneias. Now he was deceived by the equivocation in “potency.” For potency sometimes refers to what is open to opposites. In this sense, potency is excluded from a heavenly body and from separated simple substances, because, in Aristotle’s opinion, they have no potency to non-existence, for simple substances are forms only, and it belongs per se to a form that it exist, while the matter of a heavenly body is not in potency to another form. For just as a heavenly body is related to its figure, of which it is the subject, as potency to act, and yet cannot not have such a figure, so the matter of the heavenly body is related to its form as potency to act, and yet it is not in potency to being deprived of this form or to non-being. For not every potency is open to opposites; otherwise possibility would not follow upon necessity, as is said in Perihermeneias II.
Est etiam eius positio contra intentionem Aristotelis, qui in I de caelo in quadam demonstratione utitur quod corpus caeleste habeat potentiam vel virtutem ad hoc quod sit semper. Non potest ergo evadere inconveniens per hoc quod dicit quod in corpore caelesti non est potentia essendi: hoc enim est manifeste falsum, et contra intentionem Aristotelis. His position is also contrary to the intention of Aristotle, who in On the Heavens I, in a certain demonstration, uses the fact that a heavenly body has the potency or the virtue to exist always. Therefore, he cannot avoid the incompatibility by saying that in a heavenly body there is no potency to existing: for this is evidently false and contrary to the intention of Aristotle.
Videamus ergo utrum convenienter impugnet solutionem Alexandri, qui dicit quod corpus caeleste acquirit aeternitatem ab alio. Esset siquidem conveniens eius improbatio, si Alexander posuisset quod corpus caeleste de se haberet potentiam ad esse et non esse, et acquireret ab alio esse semper. Et hoc dico supposita intentione ipsius, ut non excludamus omnipotentiam Dei, per quam corruptibile hoc potest induere incorruptionem: quod nunc discutere ad propositum non pertinet. Sed tamen Averroes, etiam sua intentione supposita, non potest concludere contra Alexandrum, qui non posuit quod corpus caeleste acquirat aeternitatem ab alio, quasi de se habens potentiam ad esse et non esse, sed quasi non habens a se esse. Omne enim quod non est suum esse, participat esse a causa prima, quae est suum esse. Unde et ipsemet confitetur in libro de substantia orbis, quod Deus est causa caeli non solum quantum ad motum eius, sed etiam quantum ad substantiam ipsius: quod non est nisi quia ab eo habet esse. Non autem habet ab eo esse nisi perpetuum: habet ergo perpetuitatem ab alio. 1154. Therefore, let us see whether he adequately refuted the solution of Alexander who says that a heavenly body acquires its perpetuity from something else. His refutation would indeed be good, if Alexander had posited that a heavenly body had of itself a potency to existence and non-existence, and that it acquired from something else its perpetual existence. This I say while keeping in mind his intention, and not excluding the omnipotence of God, by which “this corruptible can put on incorruptibility”—to discuss which now does not pertain to the present question. Still Averroes, even supposing his intention, cannot conclude against Alexander, who did not posit that the heavenly body acquires its perpetuity from something else, as though it had a potency to existence and non-existence, but as though not having its existence from itself. For whatever is not its own existence participates existence from the first cause that is its own existence. Hence, he himself professes in his book, On the Substance of the Orb, that God is the cause of the heavens not only with respect to its motion, but with respect to its substance as well, which would not be true unless it has its existence from something else. But the only existence it has from another is a perpetual one; consequently, its perpetuity is from another.
Et in hoc etiam consonant dicta Aristotelis, qui dicit in V Metaphys., et supra in principio huius octavi, quod quaedam sunt necessaria quae habent causam suae necessitatis. Hoc ergo supposito, plana est solutio secundum intentionem Alexandri, quod sicut corpus caeleste habet moveri ab alio, ita et esse. Unde sicut motus perpetuus demonstrat infinitam virtutem motoris, non autem ipsius mobilis; ita et perpetua eius duratio demonstrat infinitam virtutem causae a qua habet esse. And this is in agreement with the teachings of Aristotle who, in Metaphysics V and in the beginning of this Book VIII of the Physics, says that there a some necessary things that have a cause of their necessity. In the light of this, the solution according to the intention of Alexander is plain, namely, that just as a heavenly body derives its motion elsewhere, so too its existence. Hence, just as a perpetual motion demonstrates the infinite power of the mover but not of the mobile, so too its perpetual duration demonstrates the infinite power of the cause from which it derives its existence.
Non tamen omnino eodem modo se habet potentia corporis caelestis ad esse et ad moveri perpetuo. Non quidem secundum differentiam quam ipse assignat, quod in corpore caelesti sit quantum ad moveri potentia ad opposita, quae sunt quies et motus: sed ad opposita quae sunt diversa ubi. 1155. But the potency of a heavenly body to existence is not exactly the same as its potency to perpetual motion. However, the difference is not the one he assigns, namely, that in a heavenly body there is with respect to motion a potency to opposites, these being rest and motion; rather it is to opposites which are different “where’s” (places).
Sed differunt quantum ad aliud. Nam motus secundum se cadit in tempore: esse vero non cadit secundum se in tempore, sed solum secundum quod subiacet motui. Si ergo sit aliquod esse quod non subiacet motui, illud esse nullo modo cadit sub tempore. Potentia ergo quae est ad moveri in tempore infinito, respicit infinitatem temporis directe et per se. Sed potentia quae est ad esse tempore infinito, si quidem illud esse sit transmutabile, respicit quantitatem temporis: et ideo maior virtus vel potentia requiritur ad hoc quod aliquid duret in esse transmutabili maiori tempore. Sed potentia quae est respectu esse intransmutabilis, nullo modo respicit quantitatem temporis. Unde magnitudo vel infinitas temporis nihil facit ad magnitudinem vel infinitatem potentiae respectu talis esse. Dato ergo per impossibile quod corpus caeleste non haberet esse ab alio, adhuc non posset ex perpetuitate ipsius concludi, quod in eo esset virtus infinita. But they differ in respect of something else. For motion according to itself falls under time, whereas existence according to itself does not fall under time, but only according as it is subject to motion, Therefore, if there is an existence not subject to motion, it in no wise falls under time. Hence, the potency to be moved for an infinite time regards the infinity of time directly and per se. But a potency to exist for an infinite time, if that existence is transmutable, regards a quantity of time and, therefore, a greater power is required for something to endure in transmutable existence for a longer time, But a potency in respect to intransmutable existence has no relationship to a quantity of time. Hence the magnitude or infinity of time has nothing to do with the magnitude or infinity of the power in respect to such existence. Therefore, granting the impossible assumption that a heavenly body did not derive its existence elsewhere, its perpetuity would not be grounds for concluding that an infinite power exists in it.
Deinde cum dicit: nullum itaque finitum etc., probat quod in magnitudine infinita non potest esse potentia finita. Et hoc duabus rationibus: circa quarum primam tria facit. 1156. Then at (904) he proves that in an infinite magnitude there cannot exist a finite power, And this he does with two arguments, with respect to the first of which he does three things:
Primo ponit conclusionem intentam, dicens quod sicut in magnitudine finita non potest esse potentia infinita, ita nec in aliquo quanto infinito potest esse potentia finita secundum totum (nam pars infiniti si accipiatur finita, habebit potentiam finitam). Hoc autem inducit non quasi necessarium ad principale propositum ostendendum, sed quasi cohaerens et affine conclusioni prius demonstratae. First he mentions the conclusion intended, namely, that just as there cannot be an infinite power in a finite magnitude, so neither can there be a finite power in an infinite quantity taken as a whole (for if a finite part of the infinite be taken, it will have a finite power). He mentions this conclusion not as though it were needed for proving his principal conclusion but as cohering with, and akin to, the conclusion previously demonstrated.
Secundo ibi: et tamen contingit etc., ponit quoddam per quod alicui videri posset quod in magnitudine infinita sit potentia finita: videmus enim quod aliqua minor magnitudo habet maiorem virtutem quam maior magnitudo, sicut parvus ignis habet maiorem virtutem activam quam multus aer. Sed per hoc non potest haberi quod quantum infinitum habeat potentiam finitam: quia si accipiatur aliqua adhuc magis excedens magnitudo, habebit maiorem virtutem; sicut si aer maior secundum aliquam quantitatem habet minus de virtute quam parvus ignis, si multum augeatur aeris quantitas, habebit maiorem virtutem quam parvus ignis. 1157. Secondly, at (905) he mentions something that could lead someone to suppose that there is a finite power in an infinite magnitude. For we see some lesser magnitude that has greater energy than a larger magnitude, as a small amount of fire has more active power than a large amount of air. But that does not permit us to conclude that an infinite quantity has a finite power, because if a still greater magnitude is taken, it will have greater power; for example, even though a greater quantity of air has less power than a small fire, yet if the quantity of air be much increased, it will have more power than the small fire.
Tertio ibi: sit igitur in quo est ab etc., ponit demonstrationem intentam: quae talis est. Sit quantum infinitum ab; et sit bc magnitudo finita alterius generis, quae habet quandam potentiam finitam; et sit quoddam mobile d, quod moveatur a magnitudine bc, in tempore quod est ez. Et quia bc est magnitudo finita, poterit accipi maior magnitudo: accipiatur ergo maior secundum duplam proportionem. 1158. Thirdly, at (906) he presents his intended demonstration: Let AB be an infinite quantity, and BC a finite magnitude of another kind, having a finite power; let D be a mobile that is being moved by the magnitude BC in time EZ. But because BC is a finite magnitude, it is possible to take a larger magnitude; let us therefore take one which is in double proportion.
Quanto autem est maior potentia moventis, tanto in minori tempore movet, ut habitum est in septimo: ergo duplum ipsius bc movebit idem mobile, scilicet d, in medio tempore, quod sit zt, ita quod intelligatur tempus ez dividi per medium in puncto t. Semper autem sic addendo ad bc, minuetur tempus motus: sed quantumcumque addatur ad bc, nunquam potest transire ab, quod improportionaliter excedit bc, sicut infinitum finitum. Et cum ab habeat potentiam finitam, movet in tempore finito d: et sic semper diminuendo de tempore quo movebat bc, perveniemus ad aliquod tempus minus quam sit tempus in quo movebat ab, quia omne finitum transcenditur per divisionem. Sequetur ergo quod minor potentia moveat in minori tempore; quod est impossibile. Relinquitur ergo quod in magnitudine infinita erat potentia infinita, quia scilicet potentia magnitudinis infinitae excedit omnem potentiam finitam. Now, the greater the power of a moving cause, the more it moves in less time, as was proved in Book VII. Therefore, the double of BC will move the same mobile, namely, D in one-half the time, namely, ZT, so that the time EZ is bisected by the point T. By continually adding to BC, the time of the motion will be decreased, yet no matter how much is added to BC, it can never traverse AB, which exceeds BC beyond any proportion, as the infinite exceeds the finite. And since AB has finite power, it moves D in a finite time. Consequently, by continually lessening the time BC consumes in moving, we shall reach a time less than the time consumed by AB in its action of moving, because every finite is surpassed by dividing. It will follow, therefore, that the lesser power will move in less time, and this is impossible. What remains, therefore, is that there was an infinite power in the infinite magnitude, for the power of the infinite magnitude exceeded every finite power.
Et hoc probatum est per subtractionem temporis: quia omnis potentiae finitae necesse est ponere quoddam determinatum tempus in quo movet. Quod ex hoc apparet: quia si tanta potentia movet in tanto tempore, maior movebit in minori tempore, sed tamen determinato, idest finito, secundum conversam proportionem; ut scilicet quantum additur ad potentiam, tantum diminuatur de tempore. Et sic quantumcumque addas ad potentiam finitam, dummodo remaneat potentia finita, semper habebit tempus finitum: quia erit accipere aliquod tempus quod erit tanto minus tempore prius dato, quanto potentia superexcrescens ex additione, est maior potentia prius data. This has been proved by subtracting time, because every finite power must have some determinate time in which it causes motion. This is clear from the following consideration: If so much power acts in so much time, a greater power will move in a time smaller but yet definite, i.e., finite, according to an inverse proportion, such that, by as much as is added to the power, by so much is the time decreased. Consequently, no matter how much is added to a finite power, so long as the power remains finite, so will the time always remain finite, for a time will be reached that will be as much less than a previously given time as the power growing by addition is greater than a power previously given.
Sed potentia infinita excellit in movendo omne determinatum tempus, sicut in omnibus aliis infinitis contingit: quia omne infinitum, sicut multitudo et magnitudo, excedit omne determinatum sui generis. Et sic manifestum est quod potentia infinita excedit omnem potentiam finitam, ex quo excessus potentiae super potentiam est sicut minoratio temporis a tempore, ut dictum est. Unde patet quod conclusio praedicta, scilicet quod magnitudinis infinitae sit potentia infinita, ex necessitate sequitur ex praemissis. But an infinite power in causing motion surpasses every determinate time, just as happens in all other cases involving the infinite—for every infinite, such as that of number and magnitude, exceeds everything determinate in its genus. Thus it is plain that an infinite power exceeds every finite power, because the excess of power over power corresponds to the decrease of time from time, as has been said. Hence, it is evident that the above-stated conclusion, namely, that the power of an infinite magnitude is infinite, follows of necessity from the premises.
Deinde cum dicit: est autem hoc demonstrare etc., ponit ad idem aliam demonstrationem, quae non differt a prima nisi in hoc, quod prima concludebat accipiendo potentiam finitam existentem in magnitudine finita alterius generis, haec autem secunda demonstratio procedit accipiendo quandam aliam potentiam finitam, existentem in alia magnitudine finita eiusdem generis, cuius est magnitudo infinita: puta si sit aer magnitudinis infinitae, habens potentiam finitam, accipiemus quandam potentiam finitam existentem in aliqua magnitudine finita alterius aeris. Hac positione facta, manifestum est quod potentia finita magnitudinis finitae aliquoties multiplicata, mensurabit potentiam finitam, quae est in magnitudine infinita; quia omne finitum mensuratur ab aliquo finito minori aliquoties sumpto, vel etiam exceditur. Cum ergo in magnitudine eiusdem generis oporteat quod maior magnitudo habeat maiorem potentiam, sicut maior aer habet maiorem potentiam quam minor; necesse erit quod illa magnitudo finita quae habebit eandem proportionem ad magnitudinem finitam prius acceptam, quam habet potentia finita infinitae magnitudinis ad potentiam magnitudinis finitae prius acceptae, habeat aequalem potentiam potentiae magnitudinis infinitae. Sicut si potentia finita magnitudinis infinitae erit centupla potentiae finitae cuiusdam magnitudinis finitae datae, oportebit quod magnitudo quae est centupla illius magnitudinis finitae, habeat aequalem potentiam magnitudini infinitae; ex quo proportionaliter in re eiusdem generis augetur magnitudo et potentia. 1159. Then at (907) he cites for the same another proof, which differs from the first merely in this, that the first proceeds on the assumption of a finite power existing in a finite magnitude of another kind; but this second proof proceeds on the assumption of a certain other finite power, in another finite magnitude of the same genus as the infinite magnitude. For example, if air is the infinite magnitude having a finite power, we will assume a finite power existing in some finite magnitude of another specimen of air. On these grounds, it is clear that the finite power of the finite magnitude will, if sufficiently multiplied, measure the finite power in the infinite magnitude, because a finite thing is measured or even exceeded by a smaller finite thing taken a certain number of times. Since, therefore, in a magnitude of the same kind, the greater must have more power, as a greater amount of air has more power than a smaller amount, it will be necessary that that finite magnitude which will have the same proportion to the finite magnitude previously taken, as the finite power of the infinite magnitude has to the power of the finite magnitude previously taken, have a power equal to the power of the infinite magnitude. For example, if the finite power of an infinite magnitude were to be 100 times the finite power of a given finite magnitude, then the magnitude 100 times the size of that finite magnitude has a power equal to the power of the infinite magnitude, for in a thing of the same genus the magnitude and the power increase in proportion.
Hoc autem est impossibile quod conclusum est; quia oporteret quod vel magnitudo finita esset aequalis infinitae, vel quod minor magnitudo eiusdem generis habeat aequalem potentiam maiori. Est ergo impossibile et primum ex quo sequitur, scilicet quod magnitudo infinita habeat potentiam finitam. However, the conclusion we have reached is impossible, because either the finite magnitude would have to be equal to an infinite ones or a smaller magnitude of the same genus would have a power equal to a larger magnitude of the same genus. Therefore, the assumption from which this conclusion followed is also impossible, namely, that an infinite magnitude may have a finite power.
Sic ergo epilogando concludit duas conclusiones demonstrativas, scilicet quod in magnitudine finita non possit esse potentia infinita, et quod in magnitudine infinita non possit esse potentia finita. In summary, therefore, he concludes to two demonstrated conclusions, namely, that in a finite magnitude there cannot be infinite power, and that in an infinite magnitude there cannot be finite power.