De operationibus occultis naturae ad quemdam militem ultramontanum


tr. by J. B. McAllister
Washington D.C.: Catholic University of America Press, 1939


Since in some natural bodies certain natural activities appear whose principles cannot be, understood, your honor has askted that I write what I think about them.

Statement of the problem

We see indeed that a body follows the movments of the elements governing it. A stone, for example, is moved towards the center (of the earth) according to the property of earth dominant in it. Metals also have the power of cooling according to the property of water. Therefore al actions and movements whatsoever of bodies colnposed of elements take place according to the property and power of the elements of which such bodies are made Now such actions and movements have a clear origin, about which there arises no doubt. But there are some workings of these bodies which cannot be caused by the powers of the elements: for example, the magnet attracts iron, and certain medicines purge particular humors in definite parts of the body. Actions of this sort, therefore, must Je traced to higher principles.

We must now consider that an agent of a lower rank acts or is moved according to the power of a superior agent in two ways: one way in so far as the action prcceeds from it according to a form and power imparted by a superior agent, as the moon illuminated through light received froa the sun. In another way it acts only through the power of the superior agent, without receiving a form for acting. It is moved only through the motion of the superior agent, as a carpenter uses a saw for cutting. The sawing is indeed primarily the work of the artisan but secondarily of the saw in so far as it is moved by the artisan—not because such an action follows upon some form and power which might stay in the saw after the artisan has used it. If, then, elementary bodies share in the actions or movements of superior agents, it ought to be in one or the other of the above mentioned ways; either the actions result from forns and powers implanted by superior agents in the elementary bodies, or the actions merely follow upon the movement of the elementary bodies by thesuperior agents.

Superior agents which exceed the nature of elements and elementary bodies are not only heavenly bodies, but also superior separated substances. Each of them produces in inferior bodies actions or movements which do not spring from a form implanted in the inferior 'bodies, .but which come solely from the movement of the superior agents. For the sea, in its ebb and flow, has this motion over and above the property of the element (water) from the power of the moon, not indeed thrcugh an implanted form, but through the moon's movement, which agitates the water. Then again necromantic images have effects which do not issue from form; they may have received, but from demons who are active in the images. And we think the same thing sometimes happens through the action of God or the good angels. For the fact, that sick people were cured at the shadow of Peter the Apostle or that some illness is dispelled upon contact with a saint's relics, is not attributable to a form implanted in these bodies, but only to the divine power which uses the bodies for these results.

It is clear that not all the workings of elementary bodies manifesting occult operations are like these. Firstly, the said workings, since they do not arise from some implanted form, are not found commonly in every individual of the same species: for not every bone nor all the relics of the saint heal upon touch, but those of some at some times. And so neither does every image have effects of this sort, nor does all water flow and ebb according to the movement of the moon. But certain secret workings are found in some bodies which are likewise found in all which are of the same species—for example, every magnet attracts iron. Whence it follows that these (latter) activities arise from an intrinsc principle common to things of the same species. Secondly, activities, which have been mentioned above, do not always proceed from habits of this sort. The evident proof for this is that they do not proceed from a power residing and permanent in them, but only from the motion of a superior agent—just as the saw does not always cut wood brought into contact with it, but only when it is moved for this purpose by an artisan. Certain occult workings, however, arise from inferior bodies, which whenever they are used, themselves being passive, produce the same effects, as rhubarb always purges a definite humor. And from this it is concluded that the action arises from some power residing and permanent in the body.


It remains now to consider wha: is that permanent intrinsic principle from which such activities proceed. Clearly this principle is some potency: for the interilal principle by which an agent acts or suffers action we call a potency. And indeed this potency according as it is referred to the limit of anything's possible activity receives the name and description of power. Now the power which is the principle of such actions and passions is shown to be derived especially from the specific form of a thing; for every accident which is proper to some species, is derived from the essential principles of that species. Hence it is that to explain the characteristic passions of their subjects we take for the cause a definition designating the essential principles of the thing. But the principle of essence and quidditas is a form existing in determinate matter. Therefore such povrers ought to proceed from forms of things according as they exist in their own matters.

Secondly, since the nature of a thing is termed its form and matter, if a power of a thing should not be derived from them, it will not be a power natural to the thing, and consequently no activity or passion proceeding from such a power will be natural. Now such activities which go beyond nature are not abiding—for example, that water when heated heats; but secret activities of which we are now speaking are always the same, or as often as possible. Hence the conclusion that powers which are the principles of these actions are essential and proceed from a form according as it exists in such matter.

The Platonists indeed were wont to attribute the principle of substantial forms to separated substances which they called species or ideas, the individual representations of which they said were natural forms implanted in matter. But this principle cannot be sufficient. First, the thing making ought to be like the thing made. Now that which comes about in natural things is not iorm, but a mixture of matter and form; for to this purpose something is made, that it be. Properly it is said to be the subsistent composite whereas the form is said to be that whereby something is. Therefore, that which comes to be is not rightly form but a composite, and that which makes natural things to be is not only form but the composite.

Secondly, forms existing apart from matter ought to be unmoved, because movement is an act of something in potency, which is the case with prime matter. And so these forms ought to be unchangeable. Now from a cause that is always the same proceed forms that are always the same. But this is not evident in the forms of inferior bodies, because of the coming-to-be and passing-away of these bodies. Therefore, of these corruptible bodies the principles ol their forms are heavenly bodies, which, being different according to their rise and fall, cause coming-to-be and passing-away in inferior bodies.

Nevertheless, such forms are derived from separated substances as first principles, which, through the power and movement of heavenly bodies, impress upon corporeal matter forms which they can understand in themselves. And, since we have shown that activities and powers of natural things are caused by their specific forms, it follows that they may be traced back further, namely to higher principles, to heavenly bodies or to the powers of heavenly bodies, and still further to separated intellectual substances.

A trace of both of these princples is evident in the very workings of natural things; for the fact, that the activities of Nature take place with a certain change and according to a definite interval of time, is due to a heavenly body upon whose movement the reckoning of time is based. But due to separated intellectual substances one finds in the operations of Nature that they proceed along fixed paths to determined ends, with order and in a most fitting way, like those things which are made by human skill; so that the whole work of Nature seems to be the achievement of a wise agent. Thus Nature is said to act with wisdom. Now the work of a wise man ought be well-ordered; for we say rightly that this is characteristic of the sage, that he disposes of all things harmoniously.

Therefore, because the forms of inferior things arise from the wisdom of separated substances through the intermedary of the power and movement of heavenly bodies, some order ought to be found among these forms of inferior bodies, and in such a way, namely, that some are less perfect and closer to natter, while others, however are more perfect and closer to superior agents. The most imperfect forms, though, and especially close to matter, are the forms of elements, of which the inferior bodies are composed as regards their matter. And these (inferior bodies) are indeed the nore noble (the more) that, being removed from a contrariety of elements, they approach uniformity of composition, and thus become in some way or other like to havenly bodies, which are free of all contrariety. Now that which is composed of contraries is neither of the contraries in act but cnly in potency. And therefore the greater the uniformity of mixture which such bodies approach, so much the more noble a form do they receive froin God. Such is the human body, which, enjoying a most uniform composition, as the excellence of touch in men indicates, has a most noble form, namely a rational soul.

Powers and activities ought to be in proportion to the forms from which they proceed. And thus it is that the forms of elements which are for the most part material give rise to active and passive qualities, for example, heat and cold, moisture and dryness and other similar things which regard the distribution of matter. But the forms of mixtures, namely of inanimate bodies like stones, metals, minerals, in addition ls to the powers and activities which they share with the elements of which they are composed, have certain other more noble virtues and activities arising from specific forms—for instance, gold gladdens the heart and the sapphire stops bleeding. Thus, always in an ascending order, the more noble the specific forms, so much the more excellent are the powers and operations which come from them, till that most noble form, the rational soul, is reached, which has intellectual power and activities which not only surpass the power and activity of the elements but also every corporeal power and activity.

Now from the forms at either end of the scale we ought to pass judgment on the forms in between. For as the power of heating and cooling is in fire and water as a result of their special forms, and as man's intellectual power and activity arise from his rational soul, so all powers and activities of things in between which exceed the virtues of the elements, arise from their proper forms, and are traced back to higher principles, to the powers of heavenly bodies, and still further to separated substances. For from these principles the forms of inferior bodies are derived, the rational sod alone excepted, which so proceeds from an immaterial cause, that is, from God, that it is in no way the product of the power of heavenly bodies. Otherwise it could not have intellectual power and activity wholly free of the body.

Therefore, because such powers and workings are derived from a specific form which is common to all the individuals of the same species, it is impossible for an individual of a species to have some kind of power or activity beyond the otker individuals of the same species, just because it came into being under a definite configuration of heavenly bodies. Yet it is possible that in an individual of the same species the power and activity arising from the species should be found more or less intense according to a diverse distriburion of matter and the different configuration of the heavenly botlies at the coming into being of this or that individual.

From this it is further evident that artificial forms are certain accidents which do not arise from the species. For it is impossible that an artificial product can have or share in a heavenly body's operation and virtue, in order that, through some endowed power, it might effect natural results transcending the virtue of the elements. If there were any such powers in artificial things they would not arise from a form (impressed) by heavenly bodies, since the form produced) by the artisan is nothing other than order, composition and shape, from which such powers and activities cannot come Clearly, then, if artificial things evidence some such powers—for example, should serpents die at the sight of some sculpture or animals be paralyzed in their tracks or suffer injury—it does not come from same impressed and permanent virtue but from the power of an external agent, which uses these things as instruments for its own results.

Nor can it be said tha: such activities result from the power of heavenly bodies, becausc they act only in a natural way on those inferior things. And that a body has such and such a shape does not make it either more or less suitable for receiving the impression of a natural agent. Thus it is impossible, that images or sculptures which are nade for producing extraordinary effects should have their efficacy from heavenly bodies, although they seem to be made under certain constellation. They have it only from superior agents which work through inages and sculptures.

Just as images are made from natural matter, but get their form through human skill, so also human words have indeed their matter, that is, the sounds produced by the mouth of man, but they have their meaning and as it were their form from the intellect expressing its concepts through such sounds. And so, for a like reason, human words do not have any efficacy for changing a natural body through the power of some natural cause, but only through some spiritual substance.


For these works which are effected through such words, or through any kind of image or sculpture, or any such things, are not natural, because they do not spring froin an iutrinsic but only froin an extrinsic virtue. Rather they are to be classed as superstition. The activities, however, which we have said above arise from the forms of things are natural, because they proceed from internal principles.

And so let what has been said about occult workings and activities suffice for the present.