Not Just a Terminological Difference: Cartesian Substance Dualism vs Thomistic Hylomorphism

In Are We Bodies or Souls? Richard Swinburne presents an updated formulation and defense of his dualist theory of the human person. On this theory, human persons are compound substances, composed of both bodies and souls. The soul is the only essential component of the human person, however, and so each of us could, in principle, continue to exist without our bodies, composed of nothing more than our souls. As Swinburne himself points out, his theory of the human person shares many similarities with the hylomorphic theory of the human person espoused by Thomas Aquinas. Swinburne suggests at one point that the differences between the two theories are “almost entirely terminological,” pertaining chiefly to how each understands the term ‘substance’. In this essay, I aim to show that the differences between Swinburne’s Cartesian substance dualism and Thomistic hylomorphism are much more significant than that. I argue, moreover, that the distinctive claims of Thomistic hylomorphism allow it to successfully avoid some key concerns for Swinburne’s view.