Proceedings of the American Catholic Philosophical Association

Volume 75, 2001

Person, Soul, and Immortality

A Solution to the Problem of Personal Identity in the Metaphysics of Thomas Aquinas

This paper presents a solution to the problem of personal identity over time in Thomas’s metaphysics. I argue that Professor Gracia’s solution to the problem of personal identity, existence, and Professor Stump’s solution, form or the human soul, are not only compatible but also necessarily interdependent on one another. This argument rests on (1) the special nature of the human soul, and (2) the metaphysical claim that for Thomas the human soul and existence are inseparable. First, I refine the problem of personal identity and briefly clarify some important distinctions. Second, I present Gracia’s arguments for the principle of existence (esse) being the criterion of personal identity over time in Thomas’s metaphysics. Third, I explain Stump’s arguments for form being the principle of personal identity over time in Thomas’s metaphysics, and show how Stump’s solution can answer some of the objections that Gracia presents. Finally, I argue that, according to Thomas, the soul of an individual human person and that person’s existence embrace one another with the strength of self-identity, and that it is correct and not inconsistent to say that both the human soul and existence are the cause and principle of personal identity over time in the metaphysics of Thomas.