Abstract
In this paper I argue that Socrates’s evocation of Protagoras’s ghost in Theaetetus foregrounds and assaults the sophist’s humanity in its physical and mental manifestations: his ghostliness renders him unfit to evaluate a doctrine that makes human beings the measure of all things, while his haste to return to the Underworld prevents him from partaking in dialectic and exhibiting his rationality. I also show the contextual relevance of the episode by suggesting that the passage is the last act of a three-act parody of Protagoras’s humanity, which aims to refute the man-as-measure doctrine. The first act is the so-called Protagoras’s Apology (165e8-168c1), the second act is the self-refutation argument (170a6-171c7), and the third act is the sophist’s ghostly appearance (171c10-d3).
