Is the being in an irreversible persistent vegetative state as the result of a horrible accident numerically identical to the human person, Lindsay, who existed before the accident? Many proponents of Thomistic metaphysics have argued that Aquinas’s answer to this question must be “yes.” In particular, it seems that Aquinas’s commitment to both Aristotelian hylomorphism and the unity of substantial form (viz., that each body/soul composite possesses one and only one substantial form) entails the position that the human person remains (...) alive as long as biological life persists. I argue, however, that although Aquinas does possess a deeply integrated account of human nature and is indeed committed to the claim that the person, Lindsay, exists as long as Lindsay’s body lives, there is good reason to suppose that he also holds that the body in the PVS is not Lindsay’s body in anything more than an equivocal sense. (shrink)