Commentaria in Summam contra Gentiles, Liber II

As to the second point, the following conclusion is set down: God alone produced the human soul into esse ¹.

1. It is proved first as follows. The soul begins to be with the body, as was shown above. And not because it is generated per se, since it is not composed of matter and form. Nor because it is generated per accidens through the generation of the body by the power of the seed, as was also shown. Therefore it comes to be through creation. Therefore it is brought into being by God alone, to whom alone it belongs to create.

2. Second. The human soul has an active cause of its esse, since it is not its own esse. And it has this property among other forms, that it is subsistent in its esse. Therefore it has its coming-to-be of itself, beyond the manner of the other forms, which come to be per accidens through the composites being made. Therefore it either comes to be from something as from matter, or from nothing by creation. Not from matter: for it does not have matter as a part of itself. Therefore it comes to be by creation. Therefore it is created by God alone immediately.

It must be noted that, since matter is that from which something comes into existence, as is clear in Metaphysics V ², it is necessary that what is not only made in some matter but also made of matter per se have matter as a part of itself and be a composite. Therefore Saint Thomas proves excellently that the soul is not made from matter, because it does not have matter as a part of itself. Other forms, however, are not made per se, just as they do not have esse per se, but are made only through something else being made, namely the composite, as is said here. Therefore, although they do not have matter as a part of themselves, they can nevertheless be said, though improperly, to be made from matter, insofar as they are educed from the potency of matter.

3. Third. The soul is of the genus of intellectual substances, which cannot be understood to come into esse except by way of creation. Therefore etc. — The consequence is evident. Because things of one genus, that is, of one order of things, have the same mode of coming into esse.

It must be noted that Saint Thomas understands, by this same mode of coming into being, that same genus of production by which the thing produced is attained immediately; he does not, however, understand the accidents of that genus of production. I say this because other spiritual substances are not produced in matter, nor do they presuppose any material disposition through a natural agent, just as the soul is introduced into matter through a naturally disposed agent. For this happens to the production of the soul, which is a creation, insofar as the soul, although it is an intellectual substance, is nevertheless the form of a body.

4. Fourth. The soul cannot be brought into being in such a way that some principle of esse is acquired for itself, as happens in composite things, since it is a simple substance. Therefore it is brought into being by an agent in such a way that it receives esse from him absolutely. Therefore it is brought into being by the first and universal agent, who is God, because esse itself is the proper effect of the first and universal agent.

Note here that Saint Thomas posits one way in which esse is said to be the proper effect of God. For other agents, although they give esse, nevertheless give it only by imprinting the likenesses of their forms upon the things they make, and this likeness is the principle of being for the thing made. God, however, gives esse not only by giving a formal principle of being, but also by giving esse to a thing absolutely, without giving it any other formal principle of being. From this it is clear that esse, considered absolutely and in itself, and not as the formal effect of a form introduced into the produced thing, is produced by God alone. And thus esse, absolutely and in itself, is the proper effect of God, while that of other agents is an effect only as joined to a form produced in another.

5. Fifth. The end of the human soul, and its perfection, is that through knowledge and love it transcend the whole order of creatures and reach the first principle, which is God. Therefore it has from God the principle of its own origin: for the end of a thing corresponds to its principle.

Take care not to err in this: Saint Thomas does not say that the end of the soul is love and knowledge of God as though both belonged essentially to beatitude, but because knowledge is essentially beatitude, while love inseparably accompanies it.

It is confirmed lastly, because this is intimated in Genesis 1, where Scripture, attributing the souls of other animals to other causes—for instance, saying: Let the waters bring forth the creeping thing having a living soul, and similarly of the others—says of the soul of man ³: He breathed into his face the breath of life, attributing the creation of the human soul, namely, to God.

By this, says Saint Thomas, the error of those who posit that souls are created by angels is excluded.

Note that Saint Thomas, in the Prima, q. 118 ⁴, and in De Potentia, q. 3, a. 9, holds not only that it is false that the soul is transmitted with the seed, but also that this is heretical: because from this it follows that the subsistent soul is not a being, and consequently that it is corruptible along with the body.