In 1637, René Descartes published a short book that would change the course of Western philosophy. It was called Discourse on the Method, and it began with one of the most radical acts in the history of thought: a decision to doubt everything. Every belief. Every memory. Every sense-perception. Even the existence of the physical world.

What remained, after all that demolition, was a single point of certainty: I think, therefore I am.

This episode traces the arc of Descartes' intellectual autobiography—from the collapse of his education, through the famous "stove-heated room" where the method was born, to the discovery of the cogito and the strange, provisional moral code that allowed him to live while doubting everything. It's a story about what happens when you pull the foundation out from under your own mi ...