Objection 5: Further, it cannot be said that God concurs in sin. But if the rational soul be created by God, sometimes God concurs in the sin of adultery, since sometimes offspring is begotten of illicit intercourse. Therefore the rational soul is not created by God.
On the contrary, It is written in De Eccl. Dogmat. xiv that "the rational soul is not engendered by coition."
I answer that, It is impossible for an active power existing in matter to extend its action to the production of an immaterial effect. Now it is manifest that the intellectual principle in man transcends matter; for it has an operation in which the body takes no part whatever. It is therefore impossible for the seminal power to produce the intellectual principle.
Again, the seminal power acts by virtue of the soul of the begetter according as the soul of the begetter is the act of the body, making use of the body in its operation. Now the body has nothing whatever to do in the operation of the intellect. Therefore the power of the intellectual principle, as intellectual, cannot reach the semen. Hence the Philosopher says (De Gener. Animal. ii, 3): "It follows that the intellect alone comes from without."
Again, since the intellectual soul has an operation independent of the body, it is subsistent, as proved above (Q[75], A[2]): therefore to be and to be made are proper to it. Moreover, since it is an immaterial substance it cannot be caused through generation, but only through creation by God. Therefore to hold that the intellectual soul is caused by the begetter, is nothing else than to hold the soul to be non-subsistent and consequently to perish with the body. It is therefore heretical to say that the intellectual soul is transmitted with the semen.
Reply to Objection 1: In the passage quoted, the part is put instead of the whole, the soul for the whole man, by the figure of synecdoche.
Reply to Objection 2: Some say that the vital functions observed in the embryo are not from its soul, but from the soul of the mother; or from the formative power of the semen. Both of these explanations are false; for vital functions such as feeling, nourishment, and growth cannot be from an extrinsic principle. Consequently it must be said that the soul is in the embryo; the nutritive soul from the beginning, then the sensitive, lastly the intellectual soul.
Therefore some say that in addition to the vegetative soul which existed first, another, namely the sensitive, soul supervenes; and in addition to this, again another, namely the intellectual soul. Thus there would be in man three souls of which one would be in potentiality to another. This has been disproved above (Q[76], A[3]).
Therefore others say that the same soul which was at first merely vegetative, afterwards through the action of the seminal power, becomes a sensitive soul; and finally this same soul becomes intellectual, not indeed through the active seminal power, but by the power of a higher agent, namely God enlightening (the soul) from without. For this reason the Philosopher says that the intellect comes from without. But this will not hold. First, because no substantial form is susceptible of more or less; but addition of greater perfection constitutes another species, just as the addition of unity constitutes another species of number. Now it is not possible for the same identical form to belong to different species. Secondly, because it would follow that the generation of an animal would be a continuous movement, proceeding gradually from the imperfect to the perfect, as happens in alteration. Thirdly, because it would follow that the generation of a man or an animal is not generation simply, because the subject thereof would be a being in act. For if the vegetative soul is from the beginning in the matter of offspring, and is subsequently gradually brought to perfection; this will imply addition of further perfection without corruption of the preceding perfection. And this is contrary to the nature of generation properly so called. Fourthly, because either that which is caused by the action of God is something subsistent: and thus it must needs be essentially distinct from the pre-existing form, which was non-subsistent; and we shall then come back to the opinion of those who held the existence of several souls in the body---or else it is not subsistent, but a perfection of the pre-existing soul: and from this it follows of necessity that the intellectual soul perishes with the body, which cannot be admitted.
There is again another explanation, according to those who held that all men have but one intellect in common: but this has been disproved above (Q[76], A[2]).
We must therefore say that since the generation of one thing is the corruption of another, it follows of necessity that both in men and in other animals, when a more perfect form supervenes the previous form is corrupted: yet so that the supervening form contains the perfection of the previous form, and something in addition. It is in this way that through many generations and corruptions we arrive at the ultimate substantial form, both in man and other animals. This indeed is apparent to the senses in animals generated from putrefaction. We conclude therefore that the intellectual soul is created by God at the end of human generation, and this soul is at the same time sensitive and nutritive, the pre-existing forms being corrupted.
Reply to Objection 3: This argument holds in the case of diverse agents not ordered to one another. But where there are many agents ordered to one another, nothing hinders the power of the higher agent from reaching to the ultimate form; while the powers of the inferior agents extend only to some disposition of matter: thus in the generation of an animal, the seminal power disposes the matter, but the power of the soul gives the form. Now it is manifest from what has been said above (Q[105], A[5]; Q[110], A[1]) that the whole of corporeal nature acts as the instrument of a spiritual power, especially of God. Therefore nothing hinders the formation of the body from being due to a corporeal power, while the intellectual soul is from God alone.
Reply to Objection 4: Man begets his like, forasmuch as by his seminal power the matter is disposed for the reception of a certain species of form.
Reply to Objection 5: In the action of the adulterer, what is of nature is good; in this God concurs. But what there is of inordinate lust is evil; in this God does not concur.
Whether human souls were created together at the beginning of the world?
Objection 1: It would seem that human souls were created together at the beginning of the world. For it is written ( Gn. 2:2 ): "God rested Him from all His work which He had done." This would not be true if He created new souls every day. Therefore all souls were created at the same time.
Objection 2: Further, spiritual substances before all others belong to the perfection of the universe. If therefore souls were created with the bodies, every day innumerable spiritual substances would be added to the perfection of the universe: consequently at the beginning the universe would have been imperfect. This is contrary to Gn. 2:2, where it is said that "God ended" all "His work."
Objection 3: Further, the end of a thing corresponds to its beginning. But the intellectual soul remains, when the body perishes. Therefore it began to exist before the body.
On the contrary, It is said (De Eccl. Dogmat. xiv, xviii) that "the soul is created together with the body."
I answer that, Some have maintained that it is accidental to the intellectual soul to be united to the body, asserting that the soul is of the same nature as those spiritual substances which are not united to a body. These, therefore, stated that the souls of men were created together with the angels at the beginning. But this statement is false. Firstly, in the very principle on which it is based. For if it were accidental to the soul to be united to the body, it would follow that man who results from this union is a being by accident; or that the soul is a man, which is false, as proved above (Q[75], A[4]). Moreover, that the human soul is not of the same nature as the angels, is proved from the different mode of understanding, as shown above (Q[55], A[2]; Q[85], A[1] ): for man understands through receiving from the senses, and turning to phantasms, as stated above (Q[84], AA[6],7; Q[85], A[1]). For this reason the soul needs to be united to the body, which is necessary to it for the operation of the sensitive part: whereas this cannot be said of an angel.
Secondly, this statement can be proved to be false in itself. For if it is natural to the soul to be united to the body, it is unnatural to it to be without a body, and as long as it is without a body it is deprived of its natural perfection. Now it was not fitting that God should begin His work with things imperfect and unnatural, for He did not make man without a hand or a foot, which are natural parts of a man. Much less, therefore, did He make the soul without a body.
But if someone say that it is not natural to the soul to be united to the body, he must give the reason why it is united to a body. And the reason must be either because the soul so willed, or for some other reason. If because the soul willed it---this seems incongruous. First, because it would be unreasonable of the soul to wish to be united to the body, if it did not need the body: for if it did need it, it would be natural for it to be united to it, since "nature does not fail in what is necessary." Secondly, because there would be no reason why, having been created from the beginning of the world, the soul should, after such a long time, come to wish to be united to the body. For a spiritual substance is above time, and superior to the heavenly revolutions. Thirdly, because it would seem that this body was united to this soul by chance: since for this union to take place two wills would have to concur---to wit, that of the incoming soul, and that of the begetter. If, however, this union be neither voluntary nor natural on the part of the soul, then it must be the result of some violent cause, and to the soul would have something of a penal and afflicting nature. This is in keeping with the opinion of Origen, who held that souls were embodies in punishment of sin. Since, therefore, all these opinions are unreasonable, we must simply confess that souls were not created before bodies, but are created at the same time as they are infused into them.
Reply to Objection 1: God is said to have rested on the seventh day, not from all work, since we read ( Jn. 5:17 ): "My Father worketh until now"; but from the creation of any new genera and species, which may not have already existed in the first works. For in this sense, the souls which are created now, existed already, as to the likeness of the species, in the first works, which included the creation of Adam's soul.
Reply to Objection 2: Something can be added every day to the perfection of the universe, as to the number of individuals, but not as to the number of species.
Reply to Objection 3: That the soul remains without the body is due to the corruption of the body, which was a result of sin. Consequently it was not fitting that God should make the soul without the body from the beginning: for as it is written ( Wis. 1:13 , 16 ): "God made not death . . . but the wicked with works and words have called it to them."