Skepticism, Descartes' Doubt, and the Cogito

Skepticism is the view, or the challenge, that we lack knowledge, either about some domain or about almost everything. It is one of the most powerful engines in epistemology, because responding to it forces us to clarify what knowledge requires. Distinguishing kinds of skepticism, examining Descartes' famous method of doubt, and surveying the main responses gives us a map of the terrain.

Local and global skepticism

Local skepticism targets a specific domain: one might be skeptical about knowledge of the future, of other minds, of morality, or of the past, while accepting knowledge in other areas. Global skepticism is far more radical, claiming that we cannot know anything at all, or at least nothing about the external world. Global skepticism is usually driven by skeptical scenarios, imagi