Chapter 118 - The Production of Man's Soul

The sensitive soul, not being a simple or self-subsisting substance, does not exist by direct creation. Its being is like that of other corporeal forms without independent being, which are said to exist as other composite beings exist through them, and hence it is dependent on the co7npositum. As the generator is like the thing generated, the sensitive soul and other forms must be produced by corporeal agents making a change in the matter from potentiality to act by its corporeal power. The more powerful an agent is, the wider is the sphere of its action. Thus non-living [inorganic] bodies are lower in the natural order, and beget their likeness not mediately but immediately, as fire begets fire; whereas living bodies, with greater power, beget both immediately and mediately, in nutrition as regards the first way, when flesh begets flesh, and the second in the act of generation chiefly by the soul of the generator. As the sensitive soul is therefore not a self-subsisting, nor a self-operative being, it cannot be made such; but it is dependent on the composition to which it belongs. The intellectual soul is otherwise produced; forasmuch as material force cannot produce an immaterial effect like intelligence, which is independent of the body. The intellect is produced by an external force, and is self-subsisting; and hence it has independent existence by separate creation.

Rational souls were not created together at the beginning of the world, as some have thought; for if it were so, the union of body and soul in man would be an accidental thing, and hence man would be man only accidentally, or the soul alone would be man. Neither was the soul created with the angels, for their mode of existence is different, as we see when we consider that if the soul's nature is to be in a body (as it is), to be without a body is unnatural, for the soul would not then enjoy its natural perfection. It does not become us to imagine that God should begin His work from imperfect things; He has not made man without hand and foot, which are natural parts of man, and much less would He have made him without a body; therefore He made the soul and body together. If it be said that it is not natural for a soul to be united to a body, we must ask for the reason why it was so united; and if it be said that it was by His Will only, then this would appear irrational, as the soul would not require the body. Nor would there be any reason why, if souls were created at the beginning of the world, they should be confined to one body for so long a time. And further, the union of the soul to a body would then be a thing of chance, as two wills would be required, the will of the soul and the will of the generator. So if the union of the soul with the body were against its will, it would be violent and penal. Hence we must hold that souls are created when they are introduced into their bodies.