Abstract
We examine the "Theaetetus" in the light of its juxtaposition of philosophical, mathematical and sophistical approaches to knowledge, which we show to be a prominent feature of the drama. We suggest that clarifying the nature of philosophy supersedes the question of knowledge as the main ambition of the "Theaetetus". Socrates shows Theaetetus that philosophy is not a demonstrative science, like geometry, but it is also not mere word-play, like sophistry. The nature of philosophy is revealed in Socrates' activity of examination and his refusal to deny his ignorance about knowledge