Theaetetus

A Platonic dialogue in which Socrates presses the young mathematician Theaetetus on a single question — what is knowledge? — and dismantles three answers in turn: that knowledge is perception, that it is true belief, and that it is true belief with an account. The dialogue ends in acknowledged failure, having cleared the ground rather than built on it, and it is the classical source for the puzzle of how a false belief is even possible. Composed in Greek in the fourth century BC; there is no meaningful single publication date, and the standard modern editions are translations.

Why it’s on the list: It sits in McCord’s opening section on Classical Greek Political Philosophy, the block of the curriculum that starts a builder on first principles — what can be known, and how an argument is tested — before any question of how to organise a society is raised.

Where I saw it: Brendan McCord’s Philosopher-Entrepreneur Reading List, in the Political Philosophy and the History of Ideas part, section Classical Greek Political Philosophy — a structured curriculum shared on X on March 9, 2026 and saved to Kyle’s Apple Note “Books To Read”. The full 211-entry transcription is on The Philosopher-Entrepreneur Reading List.

Connections

• Plato — the author; the dialogue is one of his late epistemological works.
• Socrates — the interlocutor who does the questioning here.
• Epistemology — the branch of philosophy this dialogue effectively founds.
• Knowledge — the dialogue’s single subject.
• The Philosopher-Entrepreneur Reading List — the curriculum this came from.