Commentaria in Summam contra Gentiles, Liber II

After Saint Thomas has determined, in an absolute manner, the union of the intellectual soul to matter, he now begins to determine the mode of that union ¹. Concerning this he does two things: first he treats of the immediacy of the union; second, of its totality, in the following chapter.

I. As to the first point, three conclusions are set forth.

The first is: The soul is united to the body immediately in its being. For the explanation of this, it must be considered that, since nearly all philosophers have held that the intellect is in some way joined to the human body, there were some who, not attending to the condition of a form, held that the intellectual soul is not united to the body immediately, but that something mediates between it and the body, serving as a kind of bond and tie uniting it with the body: just as Averroes said that phantasms are the bond by which the intellect is united to man; others said that it is united to the body through its powers as intermediaries; some indeed held that a corporeal spirit mediates between soul and body; and still others said that light mediates, which they supposed to be a body.

Against these, therefore, from what has been shown—that the intellectual soul is the form of the body—Saint Thomas draws as a corollary that the soul must be united to the body immediately.

And it argues thus. Form is united to matter without a medium. But the intellective soul is the form of the body, as was shown in the preceding chapter. Therefore etc. The major premise is proved in two ways. First, by the authority of Aristotle in Book VIII of the Metaphysics, where he says that nothing makes one out of matter and form except an agent, which reduces potency to act. Second, because nothing makes one out of potency and act. But form is act of itself, not through something else. Therefore etc.

Note that the foundation of this argument is that form makes esse in act by itself, and not through any intermediary, since it is act through its own essence. Hence, when something is said to be one in the way it is a being, it must be that, just as the composite is a being immediately through form, so too it is one immediately through form; and thus form must be united to matter of itself and immediately, just as it gives esse of itself and immediately.

II. The second conclusion is: The soul, in moving, is united to the body mediately; that is, it moves the body of which it is called the soul, not immediately through its essence, but through some medium. It is proved: first, because it moves through its powers, just as it exercises all its other operations through its powers; second, because it moves the limbs by means of the spirit, and one organ by means of another.

It must be noted that the soul moves the body through apprehension and appetite, as is said in Questions on the Soul, a. 9, ad 6. And thus it is said to move through the powers whose operations are, namely, to apprehend and to desire. And because the sensitive appetite is founded in the heart, according to Aristotle, as is said in On Spiritual Creatures, a. 3, ad 4 ², therefore the heart is the first instrument through which it moves the other parts of the body: and this is what is said here, namely that it moves one member by means of another. But because it moves the grosser parts of the body through the subtler ones, therefore the first instrument of the motive power is the spirit, as is said by Aristotle in the Book On the Cause of the Movement of Animals ³.

But it must be understood that when the heart is said to be the first instrument of the motive power, and likewise the spirit, this is not in the same way: rather the heart is the first instrument joined to the motive power, as that in which is the appetite, which is the motive power; but the spirit is the first instrument separate, insofar as it is the first thing moved by the soul among those things that are separate.

III. The third conclusion is: In the way of generation, the dispositions of the body by which it becomes the proper recipient of such a form are intermediaries between soul and body; and thus the soul is united to the body through the mediation of these dispositions. It is proved: because the dispositions toward a form in the way of generation precede the form in matter, although they are posterior in being.

IV. Concerning this conclusion and its proof, a twofold doubt arises. First, because Saint Thomas, in the First Part, question 76, article 6, holds that it is impossible that any accidental disposition fall as something intermediate between body and soul, or between any substantial form whatever and its matter, and likewise that it is impossible for any accidental dispositions to pre-exist in matter before the substantial form. The opposite of this has been said here.

Second ⁴, because it does not seem possible that the dispositions along the way of generation precede the form in matter, and yet are posterior in being. For if they precede the form in matter, then they are in matter before the form. Therefore they precede in being. These consequences are evident, because in each of them the opposite of the consequent is incompatible with the antecedent.

V. For the clarification of the first doubt, two things must be noted. The first is that, since between the dispositions toward a form that remain together with the form, and the form itself, there is no order of duration, but they are introduced into matter simultaneously in the same instant, one must not seek between them a priority and posteriority of time—that is, which of them arrives in matter at an earlier time and which at a later—but one must investigate only the priority between them according to nature, and see which of them comes to the matter first by nature, as it were presupposed in the matter by the other.

The second is that, according to the teaching of Saint Thomas in the First Part, at the cited question and article, ad 1, and in De Spiritualibus, a. 3, ad 20, and in the Quaestio de Anima, a. 9: since a more perfect form contains in virtuality whatever belongs to the other, inferior forms, and each perfects matter according to distinct degrees of perfection, we understand beforehand that matter is first perfected according to the lower degree, and according to the accidents consequent upon that degree, before it is perfected according to the more perfect and higher degree. For example, because the soul gives corporeal esse and animate esse, we understand it first to give matter corporeal esse with the accidents of corporeity before it gives animate esse. Hence the soul can be considered in two ways: in one way, absolutely and with respect to its entire effect, namely that which befits it both insofar as it is a soul and insofar as it virtually contains the degrees of the inferior forms; in another way, with respect to only the further and more perfect effect, namely that which it produces insofar as it is a soul. If it is considered absolutely and with respect to its total effect, then nothing precedes the substantial form in matter: for matter must first be understood to be in act simply and absolutely, which comes about through the substantial form giving esse simply, before being in act such, which comes about through an accidental form. But if it is considered with respect to the further and more perfect effect, then the accidental dispositions consequent upon the lower degree precede the substantial form in matter in the order of generation: just as we understand the form to give first the less perfect degree before the more perfect, because nature proceeds from the imperfect to the perfect.

To the doubt, therefore, it is said that what Saint Thomas says in the First Part does not contradict what is said here. For there he speaks of the soul, and universally of substantial form, with respect to its total effect. Since matter in itself is in potency to corporeal substantial esse, and it is not necessary that it be disposed by other accidents toward corporeal substantial form or toward substantial esse, between matter and form, as he assigns it the lowest grade of being, it is not necessary for disposing accidents to mediate. — But here Saint Thomas speaks of the soul and substantial form insofar as it gives a further and more perfect grade. For if matter in itself is not disposed so as to be the proper perfectible of some form as such a form, but needs accidents appropriating it to that form, then according to the order of generation those accidents must be understood beforehand in matter before the form, as such a form, is understood to come to matter: since nature first disposes matter before introducing form. And thus, since matter needs accidental dispositions for the more perfect grade of the soul, the dispositions of the body must be understood beforehand in matter before the form, according to that grade, is understood to come to the body.

VI. For the clarification of the second doubt ⁵, one must understand what is meant by order according to the way of generation, and then the answer to the doubt will appear more plain and clear. It must be known, therefore, that since nature acts for an end, just as intellect does, as is said in Physics II ⁶, a twofold order can be considered in the works of nature: one according to nature's intention; the other according to the execution of what it intends. The first is called the order of the perfection and intention of nature; it is also called the order according to the account of the formal, final, or efficient cause, because the end, which is the first thing intended by nature, coincides in the same number with the form of the effect, but with the agent in the same species. The second order is called the order of generation, insofar as nature produces and generates its effects in a certain sequence; it is also called the order of time, because, since the natural agent acts in time, it produces one thing before another in time; and because this execution takes place insofar as something is brought from potency into act, and matter is first potency, therefore this order is called the order according to the account of the material cause.

According to this twofold order of nature, something is called prior and posterior in different ways. For since, with respect to each cause, that is prior which is closer to that cause, therefore in the way of the intention of nature, which is the order according to the account of the final, formal, and efficient cause, that is prior which is closer to the form and the end, and more like the agent. Hence according to this order, the agent itself is prior to its effect; the end itself is prior to those things that are for the sake of the end; form itself and act are prior to potency; and the more something approaches the likeness of the agent, or also draws nearer to the end and to the form that is the terminus of generation, the more prior it is. And since something is more perfect the more it approaches the end and the likeness of the agent, therefore according to this order the perfect is prior to the imperfect. — In the way of generation, however, which is the order according to the account of the material cause, potency is prior to act, and the imperfect is prior to the perfect: because the more imperfect something is, the more it approaches the conditions of matter.

It must be noted, however, that with Saint Thomas the order of generation is sometimes distinguished against the order of nature, as in Quaestiones de Malo, q. 4, a. 3; at other times it is contained under the order of nature, as in the First Part, q. 85, a. 3, ad 1. For the order of nature can be taken in two ways. In one way, as distinguished against an order according to the apprehension of the intellect alone: and thus it contains under itself the order of generation, since it is an order outside the intellect. In another way, as taken according to the account of formal cause: and thus it is divided against the order of generation. For since form is more nature than matter, act is said to be prior by nature than potency, as is stated in Quodlibet V, q. 10, a. 1 ⁷; and thus the order that is according to form retained for itself the name of order of nature, while the order that is according to matter received the name of order of generation and time.

2. To the doubt, therefore, it is said that by "order in being" Saint Thomas understands the order of nature according to the genus of efficient and formal cause absolutely: because esse belongs to the thing produced both on account of the form and on account of the efficient cause. And thus accidents, which are dispositions of matter toward the substantial form insofar as it gives a more perfect act, since they follow the esse of the form in matter absolutely—as accidents consequent upon the composite of matter and form giving esse according to a lower degree—are posterior in being to the substantial form itself. For they are related to the form as effect to cause; but an effect, as such, is posterior to its cause in being according to the order of nature and causality; for every effect presupposes its cause to be, even if it be simultaneous with it in time. — But according to the order in the way of generation, which is the order according to the account of material cause, the same accidents precede the form itself in matter insofar as it gives a further and more perfect degree. For since they are dispositions of matter as receptive of the form according to that further degree, they belong to the genus of material cause; and thus they precede the form, as potency precedes act and the imperfect precedes the perfect. Hence, although they are introduced into matter simultaneously with the form, they are nevertheless understood beforehand, as such, to inhere in matter prior to the form's being united to matter according to that degree for whose reception they are understood to dispose it.

Thus, therefore, it is clear that there is no contradiction in the words of St. Thomas, when he says that those dispositions precede the form in the way of generation, and yet are posterior in esse.

3. When it is objected that there is a contradiction, because, if the dispositions along the way of generation precede the form in matter, it follows that they are prior in matter, and thus prior in being — the answer is given, from what we have already said, that these dispositions can be compared to the form itself in two ways. In one way, both being taken absolutely. And thus they are posterior in being: because, as was said in the reply to the first doubt ⁸, no accidental form comes to matter unless it exists in act through substantial esse; and thus the substantial form must, speaking absolutely, be prior in matter to the accidental form. And in this way this Saint Thomas intends that the dispositions are posterior to the substantial form in being. — In another way we can compare the dispositions to the form itself as giving a further and more perfect grade, toward which they are understood to dispose. And thus they are prior to the form itself in being: for we understand matter to have dispositions toward a form before the form gives to matter the esse of that thing to which matter is proportioned through such dispositions.

The reason for this diversity is that, when these accidents are compared to the form absolutely, they are compared to it as effects to a cause: for they are in truth its effects, resulting from the union of the form with matter. But when they are compared to the form as conferring a further degree of perfection, they are considered not as effects of the form, since they do not follow upon the form as conferring that further degree of perfection, but rather as introduced into matter by an agent that first disposes the matter through these accidents before the form introduces that further degree. For it was said that, by the way of generation, the imperfect is prior to the perfect, and potency is prior to act: and thus an agent drawing something from potency into act first introduces into matter the imperfect form before the perfect form. Hence Saint Thomas says in the Qu. de Anima, art. 9, that these dispositions are presupposed to the form as introduced into matter by the agent. Therefore those dispositions are posterior in being, speaking simply: but they are prior in being by the way of generation, considered as dispositions to a further degree.

VII. But a doubt arises concerning this reply. For, as St. Thomas says in VII Metaph., lect. 13, everything that is prior in generation is prior in time, but not conversely. Now what is prior in time to another thing is prior to it simply in being. Therefore, if the dispositions toward the form precede the form in matter by way of generation, it follows that they are prior to the form itself simply in being. And thus the reply amounts to nothing.

2. For the resolution of this doubt two distinctions are needed. The first is that, since time is twofold, namely real and imaginary, something can be said to be prior in time in two ways: either because it is in the prior real time, or because it is understood to be in the prior imaginary time. — The second is that something can be said to be prior to another in generation in two ways. In one way, because it is ordered to the generation of the other, and its own generation precedes the other's generation: as in the generation of man, a living thing is generated before animal, and animal before man; hence it is said in that order that a living thing is prior in generation to animal, and animal to man. In another way, merely from the fact that it is ordered to the generation of another: as the parts are said to be prior to the whole in generation on this ground alone, that they are ordered to the generation of the whole.

It is said, therefore, that everything prior in generation in the first way is also prior in time in the first way. But for what is prior in generation in the second way, it suffices that it be prior in time in the second way: insofar as, if the intellect considers those things so ordered by nature to be produced successively, it considers that which is ordered to the generation of another to be generated and produced at an earlier time. And thus it would be true in fact that, if nature were to produce them separately, it would produce the prior one before that to whose generation it is ordered. Therefore, when Saint Thomas says, in the passages cited, that everything prior in generation is also prior in time, he takes "prior in generation" and "prior in time" universally and indistinctly, because everything prior in generation in either of those modes is prior in time in either of those modes; but he does not take "prior in time" only in the first mode. This is evident because he gives the example of the parts from which something is constituted with respect to the whole, saying that they are prior in time and in generation: yet it is clear that the form itself is not brought into being before the composite, since it comes to be only in the composite, such that it could be said to be in an earlier real time; rather, it is said to be prior in time because, if we imagine the form to be produced separately and the composite separately, we would imagine the form to be produced before the composite, since the composite presupposes the parts from which it is composed. — The dispositions, therefore, of which we speak, which accompany the form in matter, are not really prior in time, but only imaginarily.

It must be noted, however, that although the form does not simply precede those dispositions in time, since they are introduced into matter in the same instant, the form is nevertheless said to be prior in being to those dispositions, if all things are considered absolutely, but not conversely. For we do not say here that one thing is prior to another in being as though one had its being before the other in duration; but because one really depends upon the other according to its esse, and the other is for it the real cause of being. Now, the form is the real cause of being for such accidents; but accidents are not the real cause of being for the form itself, since they follow upon the esse of the form in matter absolutely, and only according to our manner of considering—inasmuch as we divide by our consideration the diverse perfections that the soul gives to matter, which are really one—and we understand accidents to mediate between the first and second perfection. Hence such accidents are really posterior to the form itself in being; yet they precede it in being according to some mode of our consideration.