Protagoras Through Plato and Aristotle: A Case for the Philosophical Significance of Ancient Relativism

In this contribution, I explore the treatment that Plato devotes to Protagoras’ relativism in the first section of the Theaetetus (151 E 1–186 E 12) where, among other things, the definition that knowledge is perception is put under scrutiny. What I aim to do is to understand the subtlety of Plato’s argument about Protagorean relativism and, at the same time, to assess its philosophical significance by revealing the inextric¬ability of ontological and epistemological aspects on which it is built (for this latter aspect, I refer to contemporary discussions of relativism, mainly to Margolis’ robust relativism). I then turn to Aristotle’s treatment of Protagoras’ relativism in Metaphysics Γ, sections 5 and 6, in order to show that Plato and Aristotle surprisingly share the same view as regards the philosophical content of Protagoras’ relativism (in doing so, I take position against the standard opinion among scholars that Plato and Aristotle understand Protagoras’ relativism in different, even incompatible, ways). What I ultimately aim to demonstrate is that Protagoras’ relativism, as understood by both Plato and Aristotle, is a coherent, even attractive, philosophical position.