Proceedings of the American Catholic Philosophical Association

Volume 75, 2001

Person, Soul, and Immortality

Aquinas on the Individuation of Non-Living Substances

One important part of Aquinas’s theory of the nature of corruptible corporeal substances is his account of the individuation of such entities. In this paper, I examine an aspect of Aquinas’s account of individuation that has not received as much attention as some others, namely, how Aquinas applies his account of individuation specifically to cases involving non-living corporeal substances. I first offer an interpretation of a key passage in Aquinas’s corpus where he explains his theory of individuation. Second, I examine a text where Aquinas applies his account of individuation to a case involving non-living substances. Finally, I raise a possible objection to what Aquinas says about the individuation of non-living substances and in answering the objection suggest that Aquinas holds the view that non-living substances enjoy a less perfect mode of individuality when compared to living substances.