Abstract

This essay is intended to support a certain picture of the relationship between metaphysics and ethics in Plato's thought. According to that picture, Plato's moral theory remained the same with respect to its central tenets throughout the dialogues, while his metaphysical theory grew more complex, partly as a result of his attempt to provide a strong theoretical foundation for his moral theory. The particular moral views that I use as an example to illustrate this thesis are related to Plato's treatment of pleasure. ;I begin by describing the relationship between Plato's treatment of pleasure, and the doctrine that no one does wrong willingly, which I take to be a fundamental tenet of his moral theory. I go on to discuss the role that moderation and measure play in Plato's treatment of pleasure, and suggest the broader significance that the concept of measure might have for Plato's metaphysical and moral theories. Next, I demonstrate that the Republic is not fully equal to the task of providing a theoretical foundation for Plato's treatment of pleasure. I then argue that some of the features by means of which the metaphysics of the Philebus differs from that of the Republic are features that make it possible to give a theoretical foundation to Plato's treatment of pleasure. Finally, I show that the discussion of pleasure in the Philebus does rely on those changes in Plato's metaphysics