Method of Doubt

The method of doubt is the philosophical procedure introduced by Descartes in the Meditations on First Philosophy (1641) of systematically doubting all beliefs that admit of any doubt, in order to identify those that survive the most radical skeptical challenges and can serve as secure foundations for knowledge. The method is not ordinary doubt but hyperbolical doubt: entertaining even the possibility of a deceiving demon, a dream, or a malicious god who systematically distorts perception and thought. What survives this radical doubt — the cogito (the thinking subject's existence), clear and distinct ideas, and ultimately God's existence and benevolence as guarantors of reliable cognition — forms the foundation on which Descartes attempts to reconstruct knowledge. The method of doubt is methodological rather than genuine: Descartes never believed he was dreaming or deceived by a demon; he used the possibility as a logical test for certainty. It established the framework of modern epistemology — the isolated subject seeking foundations for knowledge against a background of possible deception — that dominated philosophy from Descartes through Kant and beyond, and that still structures contemporary epistemology debates about external world skepticism and the justification of knowledge.