1. Antiquity

Skepticism (from Gk. skeptomai, “examine”) is a principle of thought, constantly modified in the history of philosophy, whereby doubt is cast on everything. It originated with the founder of the third post-Aristotelian school, Pyrrho of Elis (ca. 360–ca. 272 b.c.). Pyrrho’s teachings were handed down by Sextus Empiricus (fl. early 3d cent. a.d.), ¶ which gave rise to the traditional equating of Pyrrhonism and skepticism. Pyrrho established the possibi…