Plato’s Theaetetus

Perception, memory, truth, and knowledge all play major roles in this
dialogue. What is remarkable about Plato’s treatment of those ideas is how
contemporary are both the questions and the answers he puts in the mouths of
his characters. Socrates is adamant in asserting that he does not know the
answers but that his function is simply to help formulate and critically
examine the doctrines presented by others. While he was still alive, the great
sophist Protagoras was a friend of Theodorus who has subsequently given up
abstract philosophical inquiry and now teaches mathematics, astronomy, and
logic to young people such as Theaetetus, the most gifted student he has ever
encountered. Socrates examines young Theaetetus to determine whether or not
what he has learned from Theodorus provides wisdom and truth. The analogies
and metaphors that emerge during their conversation foreshadow the theories of
mind favored by contemporary cognitive scientists, but Plato’s dialogue also
raises serious doubts about the cogency of those explanations.