4-4
SUBSTANCECommentary on the Sentences I, d.8, q.4, a.2, ad 2
A substance is that which does not exist in a subject.
This is the meaning of substance insofar as it is a category according to Avicenna, namely, that it is something having an essence to which belongs existence in itself and not in another.
De potentia q.9, a.1
Substance may be taken in two ways. (1) In one sense it is the ultimate subject which is not predicated of another, and this is the individual in the genus of substance; (2) in another sense it is the form or nature of a subject.
The reason for this distinction is that several subjects may have a common nature; thus several men have in common the nature of man. Hence the need of distinguishing that which is one from that which is multiple: for the common nature is signified by the definition which indicates what a thing is: so that this common nature is called the essence or quiddity. Wherefore whatsoever a thing contains pertaining to the common nature is included in the signification of the essence, whereas this cannot be said of all that is contained in the individual substance.
For if whatsoever is in the individual substance were to belong to the common nature, there would be no possible distinction between individual substances of the same nature. Now that which is in the individual substance besides the common nature is individual matter which is the principle of individuation and consequently individual accidents which determine this same matter. Accordingly, the essence is compared to the individual substance as a formal part thereof, for instance, human nature in Socrates. Hence in things composed of matter and form, the essence is not quite the same as the subject, and consequently it is not predicated of the subject: for we do not say that Socrates is his human nature.
De potentia q.7, a.3, ad 4
The nature of substance, therefore, must be understood as follows. A substance is a thing to which it belongs to be not in a subject. The name thing takes its origin from the quiddity, just as the name being comes from to be.
In this way, the definition of substance is understood as that which has a quiddity to which it belongs to be not in another. Now, this is not appropriate to God, for He has no quiddity save His being. In no way, then, is God in the genus of substance. Thus He is in no genus, since we have shown that He is not in the genus of accident.
According to Avicenna (Metaph. 111, 8), substance is not rightly defined as (~) a self-subsistent being; for being cannot be the genus of a thing, as the Philosopher says (Metaph. 11, 3), because nothing can be added to being that has not a share of being, and a difference should not be a part of the genus.
If, however, substance can be defined notwithstanding that it is the most universal of genera, its definition will be a thing whose quiddity is competent to have being not in a subject. Hence the definition of substance cannot be applied to God, whose quiddity is not different from His being. Wherefore God is not contained in the genus of substance, but is above all substance.
C.G. I, 32, 7
What is predicated of some things according to priority and posteriority is certainly not predicated (~) univocally. For the prior is included in the definition of the posterior, as substance is included in the definition of accident according as an accident is a being. If, then, being were said univocally of substance and accident, substance would have to be included in the definition of being insofar as being is predicated of substance. But this is clearly impossible.
C.G. IV, ch.14, 12
Although, of course, one holds that there is a relation in God, it does not, for all that, follow that there is in God something which has a dependent being, for in us the relations have a dependent being because their being is other than the being of the substance. Hence, they have a proper mode of being in their proper essence, just as happens in the case of the other accidents. In view of the fact that all accidents are forms of a sort superadded to the substance and caused by the principles of the substance, it must be that their being is superadded to the being of the substance and dependent on that being.
S.T. I, q.3, a.5, ad 1
The name substance signifies not only what is being of itself - for being cannot of itself be a genus - but it also signifies an essence to which it belongs in this way, namely, of itself, which being (i.e., existence) however is not its essence.
Substance, Quiddity, Essence, Suppositum, and Subsistence
Commentary on the Sentences I, d.23, q.1, a.1
It is clear that existence is something common and does not determine any particular mode of being. Subsistence, however, designates a determinate mode of being, namely, that something exists in itself and not in another as do accidents. . . . Therefore, it is clear that to be designates something common to all beings, while to subsist and to support others is proper to the first category of being.
C.G. I, 21, 4
Forms that are not predicated of subsisting things, whether these be considered universally or each is taken singly, are forms that do not subsist through themselves as singulars individuated in themselves. We do not say that Socrates, or man, or animal is whiteness, because whiteness does not subsist as a singular through itself but is individuated through its subsisting subjects. In the same way, also, natural forms do not subsist as singulars through themselves but are individuated in their proper matters. This is why we do not say that this fire, or fire, is its own form. The very essences or >quiddities of genera and species are individuated through the designated matter of this or that individual, even though the quiddity of the genus or the species should include common form and matter. That is why we do not say that Socrates or man is humanity.
Quodlibetalia IX, q.2, a.2
Of the names that signify individuality, some are found in all classes of being such as the names singular, particular, and individual. Thus a designated whiteness is singular, particular, and individual... Other names signify the individual only in the genus of substance, such as the name hypostasis which signifies an individual substance of a rational nature, or the name >supposite, or a "thing of nature," none of which can be predicated of the designated whiteness even though the whiteness is individual.
The reason for this is that those names signify something subsistent but accidents do not subsist. Likewise with regard to the parts of substances, although they are of the nature of subsistent things, they do not subsist of themselves but are in something else. Therefore, the above-mentioned ,names are not predicated of the parts as substances, for we do not say that this hand is a hypostasis, a person, or supposite, or a "thing of nature" even though one can say that it is something individual, particular, or singular, names that can be applied to accidents.
S.T. I, q.29, a.1
Although universal and particular exists in every genus [that is, in all the categories and even in things that do not fit into the categories such as motion, aggregates, or works or art] nevertheless, in a special way the individual belongs to the genus of substance. For substance is individuated through itself, whereas the accidents are individuated by the subject, which is the substance. For this particular whiteness is called this because it exists in this particular subject. And so it is reasonable that the individuals of the genus substance should have a special name of their own; for they are called hypostases or first substances.
Further still, in a more special and perfect way, the particular and the individual are found in rational substances, which have dominion over their own actions, and which are not only made to act, as are others, but act of themselves; for actions belong to singulars. Therefore, individuals of a rational nature even have a special name among other substances; and this name is person.
Definition of Person
St. Thomas, Summa Theologiae, I, q. 29, art. 1
We proceed thus to the First Article:
Objection 1. It would seem that the definition of person given by Boethius is insufficient-that is, a person is an individual substance of a rational nature. For nothing singular can be subject to definition. But person signifies something singular. Therefore person is improperly defined.
Obj. 2. Further, substance, as placed above in the definition of person, is either first substance or second substance. If it is the former, the word individual is superfluous, because first substance is individual substance; if it stands for second substance, the added word individual is false, for there is a contradiction in terms, since second substances are called genera or species. Therefore this definition is incorrect.
Obj. 3. Further, a term of intention must not be included in the definition of a thing. For to define a man as a species of animal would not be a correct definition, since man is the name of a thing, and species is a name of an intention. Therefore, since person is the name of a thing (for it signifies a substance of a rational nature), the word individual which is an intentional name comes improperly into the definition.
Obj. 4. Further, Nature is the principle of motion and rest, in those things in which it is essentially, and not accidentally, as Aristotle says. But person is found in immovable things, as in God, and in the angels. Therefore the Word nature ought not to enter into the definition of person, but the word should rather be essence.
Obj. 5. Further, the separated soul is an individual substance of a rational nature; but it is not a person. Therefore person is not properly defined as above.
I answer that, although universal and particular exist in every genus, nevertheless, in a certain special way the individual belongs to the genus of substance. For substance is individuated through itself, whereas the accidents are individuated by the subject, which is the substance. For this particular whiteness is called this because it exists in this particular subject. And so it is reasonable that the individuals of the genus substance should have a special name of their own; for they are called hypostases, or first substances.
Further still, in a more special and perfect way, the particular and the individual are found in rational substances, which have dominion over their own actions, and which are not only made to act, as are others, but act of themselves; for actions belong to singulars. Therefore, individuals of a rational nature even have a special name among other substances; and this name is person.
Thus the term individual substance is placed in the definition of person, as signifying the singular in the genus of substance; and the term rational nature is added, as signifying the singular in the class of rational substances.
Reply Obj. 1. Although this or that singular may not be definable, yet what belongs to the general idea of singular can be defined; and so the Philosopher gives a definition of first substance .4 This is also the way in which Boethius defines person.
Reply Obj. 2. In the opinion of some, the term substance in the definition of person stands for first substance, which is the hypostasis; nor is the term individual superfluously added, inasmuch as by the name of hypostasis or first substance the idea of universality and of part is excluded. For we do not say that man-in-general is an hypostasis, nor that the hand is, since it is only a part. But when individual is added, the idea of assumptibility is excluded from person; for the human nature in Christ is not a person, since it is assumed by a greater -that is, by the Word of God. It is, however, better to say that substance is here taken in a general sense, as divided into first and second, and that when individual is added, it is restricted to first substance.
Reply Obj. 3. Since substantial differences are unknown to us, or at least unnamed by us, it is sometimes necessary to use accidental differences in their place; as, for example, we may say that fire is a simple, hot, and dry body: for proper accidents are the effects of substantial forms, and make them known. Likewise, terms expressive of intention can be used in defining realities if used to signify things which are unnamed. And so the term individual is placed in the definition of person to signify the mode of subsistence which belongs to particular substances.
Reply Obj. 4. According to the Philosopher, the term nature was first used to signify the generation of living things, which is called nativity. And because this kind of generation comes from an intrinsic principle, this term is extended to signify the intrinsic principle of any kind of movement. In this sense be defines nature., And since this kind of principle is either formal or material, both matter and form are commonly called nature. And as the essence of anything is completed by the form, for this reason the essence of anything, signified by the definition, is commonly called nature. And here nature is taken in that sense. Hence Boethius says that nature is the specific difference giving its form to each thing; for the specific difference completes the definition, and is derived from the proper form of a thing. So in the definition of person, which means the singular in a determined genus, it was more correct for Boethius to use the term nature than essence, because the latter is taken from being, which is most common.
Reply Obj. 5. The soul is a part of the human species; and so, although it may exist in a separate state, yet since it retains its capacity for union, it cannot be called an individual substance, which is the hypostasis or first substance, as neither can the hand, nor any other part of man. Hence neither the definition nor the name of person belongs to it.
St. Thomas Aquinas, Summa Theologiae I, a. 29, art. 2.
We proceed thus to the Second Article:
Objection 1. It would seem that person is the same as hypostasis, subsistence, and essence. For Boethius says that the Greeks called the individual substance of a rational nature by the name hypostasis." But this with us signifies person. Therefore person is altogether the same as hypostasis.
Obj. 2. Further, as we say there are three persons in God, so we say there are three subsistences in God; which implies that person and subsistence have the same meaning. Therefore person and subsistence mean the same.
Obj. 3. Further, Boethius says that οὐσία which means essence, signifies a being composed of matter and form. Now, that which is composed of matter and form is the individual substance and is called hypostasis and person. Therefore all the aforesaid names seem to have the same meaning.
Obj. 4. On the contrary, Boethius says that genera and species only subsist; whereas individuals not only subsist, but also substand. But subsistences are so called from subsisting, as substance or hypostasis is so called from substanding. Therefore, since genera and species are not hypostases or persons, these are not the same as subsistences.
Obj. 5. Further, Boethius says that matter is called hypostasis, and form is called οὐσιώσις - that is, subsistence. But neither form nor matter can be called person. Therefore person differs from the others.
According to the Philosopher, substance is twofold. (1) In one sense, it means the quiddity of a thing, signified by the definition, and thus we say that the definition signifies the substance of a thing; in which sense substance is called by the Greeks ousia, which we may call essence. (2) In another sense, substance means a subject or suppositum, which subsists in the genus of substance. To this, taken in a general sense, can be applied a name expressive of an intention; and thus it is called the >suppositum.
It is also called by three names signifying a reality -that is, (1) a thing of nature, (2) subsistent being, and (3) hypostasis, according to a threefold consideration of the substance thus named.
For, (2) as it exists in itself and not in another, it is called subsistent being, for we say that those things subsist which exist in themselves and not in another. (1) As it underlies some common nature, it is called a thing of nature... (3) As it underlies the accidents, it is called hypostasis or substance.
What these three names signify in common in the whole genus of substances, this name person signifies in the genus of rational substances.
Reply Obj. 1. Among the Greeks, the term hypostasis, taken in the strict interpretation of the term, signifies any individual of the genus substance; but in the usual way of speaking, it means the individual of a rational nature, by reason of the excellence of that nature.
Reply Obj. 2. As we speak in the plural of three persons in God, and three subsistences, so the Greeks say three hypostases. But because the word substance, which, properly speaking, corresponds in meaning to hypostasis, is used among us in an equivocal sense (since it sometimes means the essence, and sometimes the hypostasis), in order to avoid any occasion of error, it was thought preferable to use subsistence for hypostasis, rather than substance.
Reply Obj. 3. Strictly speaking, the essence is what is expressed by the definition. Now, the definition comprises the principles of the species, but not the individual principles. Hence in things composed of matter and form, the essence signifies not only the form, nor only the matter, but what is composed of matter and the common form, as the principles of the species. But what is composed of this matter and this form has the nature of hypostasis and person. For soul, flesh, and bone belong to the nature of this man. Therefore hypostasis and person add the individual principles to the notion of essence; nor are these identified with the essence in things composed of matter and form, as we said above when considering the divine simplicity.
Reply Obj. 4. Boethius says that genera and species subsist, inasmuch as it belongs to some individual things to subsist; for which the reason is that they belong to genera and species comprised in the predicament of substance, and not because' species and genera themselves subsist, except in the opinion of Plato, who asserted that the species of things subsisted separately from singular things. To substand, however, belongs to the same individual things in relation to accidents, which are outside the essence of genera and species.
Reply Obj. 5. The individual composed of matter and form substands in relation to accident from the very nature of matter. Hence Boethius says: A simple form cannot be a subject. Its self-subsistence, however, is derived from the nature of its form, which does not enter an already subsisting thing, but gives actual existence to the matter, and so enables the individual to subsist. On this account, therefore, he ascribes hypostasis to matter, and οὐσιώσις or subsistence, to the form, because the matter is the principle of >substanding, and the form is the principle of subsisting.
S.T., I, q.29, a.3
Person signifies what is most perfect in all nature - that is, a subsistent individual of a rational nature. Hence, since everything that is perfect must be attributed to God, inasmuch as His essence contains every perfection, this name person is fittingly applied to God; not, however, as it is applied to creatures, but in a more excellent way.