Abstract

In this dissertation, I aim to accomplish two goals. The first goal is to draw contemporary moral philosophers' attention to the need for a principal approach to virtue individuation. When we individuate virtues, we answer questions about the number of human virtues that exist and the ways in which they differ from one another. Most contemporary moral philosophers answer these questions in a haphazard way -- a practice that is in no small way responsible for the chaotic and cacophonous state of contemporary virtue ethics. I spend the second chapter developing a case for a principled approach to virtue individuation and laying out the desiderata for such a principle. I suggest that whatever criterion of individuation we adopt, it should be flexible yet parsimonious, so as to respect and preserve the diversity within the virtues. Moreover, our criterion must connect to our foundational beliefs about human nature and the nature of virtues in a non-trivial way. Having established the desiderata for a criterion of virtue individuation, I move to my second goal. This goal is to articulate Aquinas's approach to virtue individuation as a model for the way in which one might go about articulating one's own criterion. I argue that Aquinas individuates virtues based on their subject, their object, and their mode, and that this approach is an organic product of Aquinas's metaphysics of human nature. Accordingly, I dedicate the third chapter to sketching the relevant aspects of Aquinas's moral psychology and to situating Aquinas's account of habitus -- which is commonly translated into English as "habit" or "disposition" and of which virtue is a species -- within his moral psychology. The fourth chapter lays out Aquinas's account of virtues, paying special attention to the questions of virtue's subject, object, and mode. It also maps out the conceptual space -- the taxonomy of virtues -- that individual virtues may inhabit. With the conceptual apparatus thus established, in chapter five I explicated the Thomistic principle of virtue individuation. I demonstrate and test Aquinas's method by examining the virtues of generosity and magnificence, infused and acquired temperance, and, finally, a contemporary case of anger-regulating virtues.