Identity and Difference in Kind: The Metaphysics of Pleasure at the Beginning of Plato’s Philebus

The beginning of Plato's Philebus contains a puzzling argument: Socrates says that pleasures are different, and that this somehow supports the contention that not all pleasures are good (contrary to what he hedonist interlocutor, Protarchus, maintains). His argument has a bad reputation in the literature, and more to the point it is confusing. This paper sheds light on Socrates' argument by making use of principles from contemporary metaphysics. I argue that Socrates thinks of pleasure as exhibiting the structure that metaphysicians today associate with determinables and determinates. Specifically, he thinks that what makes each pleasure a pleasure is a unique profile, which simultaneously differentiates it from other pleasures. As a result, the kind, 'pleasure', is really a relational principle of coherence between the different kinds of pleasure. I argue that, based on this metaphysical picture, we can see why Socrates thinks that it is possible that some pleasures are bad, contrary to hedonism. Beyond making sense of the dialectic in the Philebus, my paper advances a growing literature on the interesting metaphysical views developed in this section of Plato's dialogue.