Q1143Doubt is the origin of wisdom.
Not Descartes's wording, though it fairly labels his method. In the Meditations (1641) and the Discourse on Method (1637), Descartes systematically doubted everything that could be doubted — senses, mathematics, the world itself — until he hit the one indubitable fact: doubting is thinking, and thinking proves a thinker. Doubt, used as an instrument rather than a mood, became modern philosophy's founding tool.

