The Role of the Digression on the Man of the Law Courts and the Philosopher (172b-177c) in the Argument of _Theaetetus_

Near the end of his examination of whether perception can be knowledge, Socrates gives a long digression about the ‘man of the law courts’ and the ‘philosopher’. Interpreters have mostly judged that this digression plays no role in the dialogue’s main argument. I will argue that, on the contrary, it supplies an important step in the refutation of Protagoras’ thesis of the relativism of opinions.