function is, to be the form of the human body; and this it is, even in its intellectual operations. All human souls are of the same species. But we learned in case of the angels that immaterial substances can have no individuation within any one species. How then are the immaterial souls of men, intellectual entities as they are, preserved from flowing together into one intellectual soul? The answer is: They are first individuated by the bodies to which they are joined. In Thomas’s words: “Although the intellectual soul has no matter from which it is constituted, just as an angel has none, yet it is form of a certain matter, as an angel is not. And so, according to the division of the matter, there are many souls of one species, whereas there cannot be many angels of one species” (Q. LXXVI, Art. II).
Hereupon, however, one would suppose that this diversity of the souls of the one human species would cease with their separation from the body. This, of course, Thomas denies. His reason is, that since the soul is, secundum suum esse, or naturally, joined to a body, and since the multiplicity of any type of entities depends upon their esse, the accident of the separation of soul and body between death and judgment cannot destroy the essential individuality of the separated souls. An inclinatio to an individuated body exists in the separated soul, and individuates the latter. In sum, then, the human individual is such, first of all, by the fact that his soul is naturally the form of this individual body, and Socrates, for instance, is defined, in this aspect, as the being who possesses “this flesh and these bones.” On the other hand, in
