Commentaria in Summam contra Gentiles, Liber II

The truth concerning the union of a spiritual substance with matter having been shown, Saint Thomas, in the fourth place, resolves the arguments brought forward above against the determinate truth, in chapter LVI¹. In this matter he does two things: first he resolves the arguments of others; secondly, the arguments of Averroes².

I. To the first, therefore, he says of the others that it is false that a spiritual substance and a body are two substances actually existing; rather, from them there comes to be one substance actually existing. But if it were argued that, when the soul is separated from the body, each remains apart on its own: it is said that the body is not the same with the soul present and with it absent, but the soul makes it be in act.

For the declaration of this response, it must be considered, as is had from Qu. de Anima, art. 2, ad 11, that Saint Thomas understands by a substance actually existing, in this place, a substance having its own esse distinct from the esse of another, and perfect in its species and nature. Now thus, if the body were constituted by another form than the soul, the body and the soul would be two substances actually existing: because, since actual esse follows upon the substantial form, just as there would be two forms, so there would be two eses, and consequently the body and the soul would be two substances existing in act. But now, because the body, which is a part of the composite of soul and body, is not a body by another form than the soul, therefore the esse of the body and of the soul is one; and so the body and the soul are not two substances actually existing. When the soul, however, is separated from the body, the same body does not remain: since the same form does not remain in the matter. Therefore then out of that body and the soul one thing could not be made: because they are two substances actually existing.

II. To the second it is answered that an intellectual substance and a body, if they existed separately, would be of different genera. But as they are united, they are of one genus as principles: in the way in which matter and form are understood to be contained in the same genus.

For the clarification of this answer, it must be noted, as can be drawn from the doctrine of Saint Thomas in On Spiritual Creatures, art. 2, ad 16, and On the Soul, art. 1, ad 13, and art. 2, ad 10, that body and intellectual substance, if taken as two species, are then properly in a genus, and cannot be of the same genus, at least according to natural consideration: because the corruptible and the incorruptible have a different mode of being, and the ratio of potency is different in each. If, however, they are taken as each is a part of human nature, then it does not belong to them to be in a genus or species, since they do not signify anything complete in species, but rather the composite. Nevertheless, they are reduced to the genus and species of their composite as its principles, and thus they are of the same genus and species, namely reductively. And therefore, when Saint Thomas says that body and intellectual substance, existing separately, are species of different genera, he understands them as existing separately in such a way that each of them is a species per se: for thus they would be species of different genera. But if they are taken as united, as parts constituting human substance, then they are of the same genus reductively.

III. To the third it is answered by denying the consequence. For a form is not called material because it has esse in matter, but because it is immersed in matter, or wholly comprehended by matter. This does not befit a spiritual substance, even though it have esse in matter: as was shown in the preceding chapter.

Note that, if we wished to extend the name of material form to every form having esse in matter, it could be granted that the intellectual soul and a spiritual substance are a material form. But because common usage has it that by the name of material form is understood only a form depending on matter with respect to its esse, therefore it is absolutely denied that the intellectual soul is a material form.

To the fourth, it is answered that the philosophers understood this of the intellect, which is a power of the soul, and not of the essence and intellectual substance. For the intellectual soul, according to its essence, gives esse to such a body; but its intellectual power is not the act of any organ, as its other powers are, because its action is not completed through a bodily organ, as is the act of the other powers.

To the fifth it is answered by denying the consequence. And it is said that, although the soul is the form of matter, it is not such a form as is immersed in matter; rather, it is raised above matter more than all other forms. And therefore it can have an operation without the body, as not depending on the body in operating: for neither does it depend on the body in its esse. And likewise it can have a power that is not the act of any body.

IV. But it must be noted that Saint Thomas gives a similar reply in the First Part, q. 76, art. 1, ad 4, saying that, because the soul, on account of its perfection, is not immersed in matter and wholly comprehended by it, nothing prevents some power of the soul from not being the act of a body, even though the soul according to its essence is the form of the body.

But some Thomists adapt this response to the argument³ in such a way that the fallacy of figure of speech is committed in the argument, by changing a "how" into a "more," that is, by changing the mode of abstraction into a greater degree of abstraction. Hence, on the basis of this response they concede that the intellect does indeed have some mode of abstraction which the soul does not have, but they deny that it is more abstracted; rather, the soul has a mode of abstraction by which it is abstracted from the body to a greater degree, namely, by having a substantial esse not dependent on matter.

But it seems to me that this response does not reach the mind of St. Thomas, nor the intention of the argument. For the argument does not proceed from the perfection of the intellect to show that the soul cannot be the form of the body, but from the very mode of abstraction that belongs to the intellect. For if the intellect, which is a power of the soul, is abstracted from the body in such a way that it is not the act of a body, it seems that the soul likewise is not the act of the body, since the intellect is its power; otherwise the power would be more abstract than that whose power it is. Nor is any sophism committed in the argument. For from the fact that the intellect is abstracted from the body because it is not the act of any body, it is also abstracted with respect to independence from matter. And therefore it follows most fittingly that the soul will be more abstract and simpler if the soul is posited as the form of the body, because it will be abstracted only with respect to independence from matter, but not with respect to separation from it: for it is evident that the abstraction which is according to independence and separation from matter is greater than abstraction according to independence alone. Hence what this opinion says is false, namely, that the soul abstracts more from the body than the intellect does, on the ground that it subsists in its own esse, or does not depend on matter. It is indeed true that the soul thus abstracted is more perfect than the intellect, which is not a substance subsisting per se: yet it is not more abstract, if it subsists in such a way that it is nevertheless united to the body in esse.

For this reason it seems to me, with all due deference to a better judgment, that Saint Thomas in that response would be willing to grant that the intellect is more abstract and simpler than the soul: nor, on his view, would it be unfitting that from the form of matter—which nonetheless does not depend on matter—there flow not only corporeal and material power, but also a power which is not the act of anything and which is itself the soul, more abstract and simpler in this respect, that it is not united to matter. For this does not argue that that power is nobler than the soul except in a certain respect, as is said in Book IV, d. 11, q. 2, a. 1 ⁴, ad 1—namely, that simplicity of itself is not the cause of nobility, but perfection—but rather argues for the perfection of the soul, which, although it is the act of matter, is nevertheless raised so far above the condition of matter that from it there can flow a power which is not the act of any organ. For the origin of this abstraction of the intellect is the dignity and perfection of the soul, which so exceeds matter that it cannot be wholly comprehended by it.

It is clear, moreover, that this is the mind of St. Thomas from the reply he gives to the same argument in the Treatise On the Unity of the Intellect against the Averroists, ⁵ For after he had proposed, "But if it be objected against this that a power of the soul cannot be more immaterial or simpler than its essence," he adds that this would proceed most excellently if the essence of the human soul were so much the form of matter that it would not have esse through itself but through the esse of the composite, as is the case with other forms, which in themselves have neither esse nor operation apart from the communication of matter. But because the human soul is a form which matter indeed communicates to in some way, yet is not wholly comprehended by it on account of its dignity, nothing prevents it from having some operation or power which matter does not reach. From these words it is plainly evident that he wishes to say that nothing prevents a power of the soul not immersed in matter from being simpler than the essence of the soul insofar as it is not united to matter, just as, on account of its elevation above matter, it can have an operation in which matter does not share. It would, however, be unfitting for the power of a material form to be simpler than the form itself, since an operation in which matter does not share cannot belong to such a form.

Hence, responding to this argument in Questions on the Soul, article 2, ad 4, he says that because the intellect is not the act of any organ, it does not altogether exceed the essence of the soul; rather it is the highest thing within it, since it follows upon the soul insofar as it is raised above matter: as if to say that, although the intellect exceeds the soul in that it is more abstract and simpler, and thus is in a certain respect more exalted than it, nevertheless this does not detract from the dignity of the soul; for on this account it does not altogether exceed the essence of the soul, but remains simply and absolutely, according to its essence, more worthy than the intellect.

V. In the second place ⁶, the arguments by which Averroes strives to confirm his position, which were set forth above in chapter LIX, are answered. In this matter Saint Thomas does two things: first he resolves those arguments themselves; second, because those arguments have their foundation in the words of Aristotle, it is shown that this same truth which we have stated and defended holds also according to the mind and opinion of Aristotle ⁷.

To the first, therefore, it is answered that Aristotle's words are verified of the intellective power, which is not the act of any organ; but they are not said of the intellectual substance itself, as though it were not a form giving esse to the body.

To the second it is answered, and first it is said that Aristotle's demonstration declares that the words assumed in the first argument must be understood of the intellective power, as they were expounded, and not of the substance of the soul. For since, from the intellectual operation by which the soul ⁸ understands, he shows that intellect is unmixed and separate; while operation pertains to the power as to its principle, namely its proximate one: it is clear that by "intellect" he means that very power. For if we posit that the soul is the form of the body, but that intellect is the act of no body, it does not follow that intellect has some determinate sensible nature: since it is not posited to be a harmony, or a ratio and proportion of any organ, as sense is.

It is said second, from what is stated at the end of the first book On the Soul against those who claim that the soul has diverse parts of itself in diverse parts of the body, where it is said that it seems impossible for any part of the body to contain a part of the soul, and that it is difficult to imagine what sort of part the intellect contains or how it contains it, that when he says the intellect is unmixed or separate, he does not intend to exclude its being a part or power of the soul, which is the form of the whole body.

To the third objection, and to the fourth deduced from it, a single reply is given by denying the consequence. For although the operation of the intellect is entirely without a bodily organ, just as the intellect itself is, it does not follow that its reception is the reception of prime matter.

To the fifth it is answered that the infinite power of the intellect is not thereby removed: for power is not posited in magnitude, but in that which is grounded in an intellectual substance.