Commentaria in Summam contra Gentiles, Liber II

After St. Thomas had determined the question of the soul's duration, he now begins to determine the question of its production ¹. In regard to this he does three things principally: first, he shows that the soul is not transmitted with the seed; second, that it is produced by creation ²; third, he brings forward arguments to the contrary and resolves them ³.

I. As to the first point, it must be known from the doctrine of St. Thomas, II Sent., d. XVIII ⁴, that traduction imports two things, namely origin and decision (separation). For something to be said to be traduced from another, it is required that it originate from it through the decision and separation of some substance. Hence, if wood is divided into several parts, one part is not said to be traduced from another: because, although there is a decision there, there is not an origination of the one from the other. Similarly, fire generated is not said to be properly traduced from the generating fire: because, although it has its origin from it, this is not by the separation of some substance from the generating fire. But in the generation of animals, traduction is properly said to occur, where one thing originates from another through the decision of seed. Therefore, for the soul to be traduced with the seed is for it to be produced by the generating man through the decision of the seed.

And Saint Thomas also hints at this meaning at the beginning of the chapter, where he says that the human soul is not transmitted with the seed, as if sown through intercourse.

It is proved, however, first as follows. The operation of the intellective soul does not occur through a bodily organ, but the operation of the nutritive and sensitive souls does occur through one. Therefore these do not begin to be through the transmission of seed, but those do. — The consequence is proved. Because for those things whose principles' operations are without body, their generation is not through the generation of a body; but for those whose operations cannot be without body, neither can their beginning be without body—that is, their being begins and is generated through the generation of a body; for a thing has being in the manner in which it operates. Now the transmission of seed is ordered to the generation of a body.

To make this argument evident, it must be considered that a form which has no operation without a bodily organ is not a subsistent form, but only a form by which something is. And because it befits each thing to come to be in the same way as it befits it to be, such a form, since it does not have subsistent esse of itself, cannot be produced of itself either, so as to be that which is produced, but is only that by which the composite is produced. For this reason, it is produced by no other production than that by which the body and the composite are produced. But a form which has an operation without a bodily organ is subsistent of itself. Therefore it is produced by its own proper operation, and not by that by which the body is generated. And this is the foundation of that proposition assumed for the proof of the consequence. St. Thomas touched upon this foundation in his proof of that proposition, assigning as its cause that a thing operates just as it has esse: for if it does not operate of itself, it does not have subsistent esse of itself; but if it operates of itself, it has subsistent esse of itself.

II. Second ⁵. If it begins to be through the transmission of seed, either this is because it is in the seed in act, as divided from the generating soul only accidentally, just as the seed is divided from the body, as we see in annulose animals, which live when cut in pieces; or because there is in the seed a power productive of it.

Not in the first place. Then, because the intellective soul is the most perfect of forms and of the greatest power, and it requires as its proper perfectible a body having great diversity of parts, and consequently cannot be actually in the semen emitted: just as neither are the souls of the more perfect brute animals multiplied by emission. — Then, because intellect is not the act of any body, so that it could be divided per accidens with the division of the body.

Not even according to this, for three reasons. First ⁶, because it would follow that the soul has its esse dependent on the body. But the contrary of this was shown above. Therefore, etc. — The consequence is proved. Because the active power which is in the seed acts toward the generation of the animal by transmuting the body. But every form which begins to be through a transmutation of matter has an esse dependent on matter: since the transmutation of matter is terminated at the esse in act of matter, which comes about through the union of the form; and consequently, if by this the form begins to be simpliciter, the esse of the form is nothing other than its being united to matter.

III. For the clarification of this argument, two things must be noted. The first is that the first mode of the soul's transmission rejected here, namely that the soul would be in act in the seed, is to be understood as follows. It proceeds as if the soul were extended along with the extension of the body, so that one part would be in the generating body and another part in the seed, and that upon the seed's separation from the body a part of the soul would also be separated from another part, as if the soul were one in act and many in potency: just as whiteness is extended to the extension of the body, and according to one part it is in one part of the body, while according to another part it is in another part of the body; and just as one part of the body is separated from another, so too is one part of the whiteness separated from another; so that the whiteness which was one in act and two in potency becomes two whitenesses in act.

2. The second point is that, when Saint Thomas says, Hence, if by this the form begins to be simply to be a form, it will not be a form except in this: that it is united to matter, the word simply can be construed in two ways: either as going with what precedes, punctuating thus, Hence, if by this the form begins to be simply a form; or as going with what follows, punctuating thus, Hence, if by this the form begins to be a form, to be a form will not consist in anything except in being united to matter.

If it is taken in the first way, it seems to determine that word, begins. Hence the sense is that, if by the fact that form is united to matter it begins to be absolutely or altogether to have esse as form—just as matter begins to be in act through the fact that form is united to it—then the esse of form will not exist except in union with matter: just as being in act belongs to matter only in union with form. And then the word simply is posited to exclude the beginning of form in matter. For if form simply and absolutely begins to be from the fact that it is united to matter, then it cannot be except in union with matter; but if it begins to be only in this respect, and does not simply begin to be from the fact that it is united to matter, it need not follow that it cannot be except in union with matter.

But if it is taken in the second way, then it determines that word, non erit. And the sense is that the esse of the form will not be, speaking absolutely, except in union with matter. And this is said by contrast with that mode in which, in a qualified sense and with something added, the esse of the soul is not except in the union of form to matter—namely, as it is the form of this thing existing in this thing. For it is false, speaking absolutely, that the soul does not have esse except in union with matter; yet it is true that the soul, insofar as it is the form of this man existing in him, does not have esse except through union with matter, as was shown above at ⁷

Both senses have truth. Nevertheless, the first sense, and the first punctuation, seems to be intended here, because it is more absolute, and more fitting to be had.

3. But then a doubt arises concerning the first sense itself. For although the soul does not depend on matter simply speaking, its individuation, as was shown above ⁸ according to the mind of St. Thomas in I Sent., d. VIII, q. v, a. 2, ad 6, depends on the body with respect to its principle, though not with respect to its end. From this it seems that the following conditional is not true: If by being united to matter a form begins to be absolutely, there will not be esse of the form except in its being united to matter. For, from the words of St. Thomas, it holds at once both that the form begins to be through union with the body and that afterwards it is without the body.

It is answered that the statement that a form begins to be through its union with matter can be understood in two ways: in one way, that its union with matter is of itself the cause of the form's esse; in another way, that it is the cause without which the form does not begin to be, namely because it does not begin to be except with such a union. In the first way, to begin to be through union with matter implies that the form cannot be without such a union: for a proper effect cannot be without its proper and per se cause. But in the second way, that a form begins to be through such a union does not imply that it cannot be except in union with matter.

Saint Thomas takes the first sense in this passage. This is evident because he speaks of the form by way of its likeness to matter: from what he had said, that transmutation is determined ⁹ to the actual esse of matter, which comes about through union, he infers: Hence, if by this also, that is, if by the same reason by which matter begins to be in act, namely through the union of the form, the form were to begin to be simpliciter, the esse of the form would be nothing other than its being united to matter: just as, namely, the actual esse of matter is nothing other than its being united to the form. But it is clear that matter begins to be in act through the form in such a way that the form is per se the cause of the actual esse of matter itself. Therefore the antecedent of that conditional must be understood in a like manner: that the form begins to be simpliciter through its union with matter, in such a way that matter and such a union are the per se cause of the esse of the form. — He takes the second sense, however, in Book I of the Sentences.

IV. Second, to the same point ¹⁰. The intellective soul cannot be educed from the potency of matter, as was shown above. Therefore it is not produced by a power existing in the seed. — The consequence is proved: because every form that is educed into esse through the transmutation of matter, as is the case with a form produced by the power of the seed, is a form educed from the potency of matter.

Third, to the same point. Every action of a virtue that is in the seed is through a bodily power: for that power acts by means of the heat of fire, of the heavens, and of the soul. Therefore the soul cannot be produced by the power of the seed. — The consequence is proved. Because no active power acts beyond its genus. But the intellective soul exceeds the whole genus of bodies.

But this argument seems not to conclude. For someone might say that, although no principal active power acts beyond its genus, an instrumental power nevertheless can act beyond its genus by the power of the principal agent: just as heat produces flesh by the power of the soul, which exceeds the genus of the element. Similarly, the sacraments cause grace in the soul, which is something spiritual, according to the doctrine of Saint Thomas ¹¹. So it will likewise be said that the power of the seed, and the heats by which it operates, although they cannot produce the intellectual soul by their own power, can nevertheless produce it by the power of the generating soul.

It is answered, according to the doctrine of Saint Thomas, Prima Pars, q. 118, a. 2, that neither can semen act by the power of the soul so as to produce the intellective soul itself. For although the body, as the instrument of an immaterial substance insofar as it is immaterial, can act upon something immaterial—just as the phantasm, by the power of the agent intellect, produces in the possible intellect the intelligible species, which is altogether immaterial—nevertheless the body, as the instrument of an immaterial substance insofar as it is the act of the body, cannot act upon something immaterial, because an immaterial substance, as the act of a body, does not belong to the order of immaterial things but to the order of material things. Now semen does not act by the power of the intellective soul insofar as it is altogether immaterial, but insofar as it is the act of the body, since the generative power, through which generation is brought about, is the act of the body. Therefore, neither can it, insofar as it is the instrument of the generating soul, produce the soul. But it can indeed, because the soul, according to its essence, is intellectual and immaterial—although it does not act insofar as it is altogether immaterial but insofar as it is the act of the body—act by its power so as to produce dispositions toward the intellective soul, and thus cause its union with matter, which is to cause the soul insofar as it is the act of the body, just as it acts by its power insofar as it is the act of the body.

The proposition of St. Thomas, namely, No active power acts beyond its genus, is also true of the instrumental agent not acting in virtue of a principal agent of a higher order insofar as it is of a higher order, but as it pertains to the lower order. And thus St. Thomas understood it. But if it acts in virtue of an agent of a higher order as that agent is of a higher order, then it can act beyond its own genus: just as heat acts in virtue of the soul insofar as the soul is such, and a sacrament acts by divine power insofar as it exceeds bodily things. Hence the objections brought forward are not against the intended argument.

V. Third, it is argued principally ¹². The soul is an intellectual substance. Therefore etc. — The consequence is proved. For it is ridiculous to say that an intellectual substance is either divided by the division of a body or produced by any corporeal power: since by one or other of these modes something can be understood to be produced through the transmission of seed.

Fourth. The corruption of the body is not the cause of the soul's ceasing to be. Therefore neither is the generation of the body the cause of its beginning to be. But the transmission of seed is the proper cause of the generation of the body. Therefore, and so on.

It must be noted that "body" names the proper object perfectible by the soul. And this must first be constituted and organized by the power of the seed, as is evident in the embryo, so that at the last instant of an organization sufficient and necessary, the intellective soul may be introduced. On this account Saint Thomas says that the transmission of the seed is the proper cause of the generation of the body: not because the very separation of the seed from the generator, and its introduction into the womb, is the proper cause of generation, since these name a negation and a relation; but because the seed, once cut off and introduced, is the proper cause, while the cutting off and the introduction is a condition of the cause without which the generation of the body would not take place.

Finally, Saint Thomas says that by this the error of Apollinaris and his followers is destroyed, who held that, just as bodies are generated from bodies, so souls are generated from souls.