Theaetetus

Plato's longest sustained treatment of epistemology. Socrates examines three definitions of knowledge with the young geometer Theaetetus: knowledge as perception, as true belief, and as true belief with an account. The dialogue ends in aporia, but along the way Plato gives us Protagoras' relativism, the famous 'digression' on the philosopher's nature, and one of antiquity's most patient pieces of philosophical investigation.