Introduction

Socrates' ad hominem challenge to Protagoras confronts this central contradiction in the sophist's thought: the egalitarianism of Protagoras' doctrine is at odds with the inegalitarian implication of his own expertise. Through this confrontation, which moves the argument toward the dialogue's central passage, Socrates shows that Protagoras' theory, his view of the character of knowledge, is instrumental to his notion of good. Protagoras expresses this notion in a particular understanding of advantage, of what's “good for” oneself. The heart of the dialogue faces the question as to whether Protagoras and his adherents, Theodorus and Theaetetus, have rightly understood human good. In particular, it explores whether advantage understood in Protagorean terms can be the good for him, or for any of us, insofar as we are beings capable of self-contradiction, beings whose heterogeneous nature generates such conflicts as that regarding equality, which are inherent in political life.

The “delivery” already made evident the connection between one's view of good, on the one hand, and what knowledge is taken to be, on the other. This connection makes the adequacy of Protagoras' understanding of good bear on the explicit theme of the dialogue. Doubts about the adequacy of that understanding raise the question as to whether, like Protagoras, we should regard the knowledge we seek as the most certain means to a universally accepted good.