Abstract
A careful reading of the initial posing of the issue to be debated with Protagoras and of its subsequent restatement when the debate resumes after a break will show that Socrates employs three distinct formulae, only the first of which answers at all closely to the term "Unity of the Virtues" which has been commonly used in the scholarly literature as a label for the position which Socrates upholds in the debate. The other two formulae, perfectly distinguishable from the first, I shall call the "Similarity" and "Biconditionality" Theses. I shall discuss the three Theses seriatim. But let me emphasize from the start that they are not treated in the text as logically disjoint tenets, but as successive moments in the elucidation of a single doctrine. That is how Protagoras himself understands them. At no point does he try to drive a wedge between them or play off one against another. He accepts them as complementary expressions of a theory which he rejects and combats as a whole.
