Pyrrho

Pyrrho of Elis was the founder of Greek Scepticism in its radical form. He held that things are in themselves unknowable and indifferent, that for every claim an equal counter-claim can be found, and that the wise response is epochē — the suspension of judgment. From this suspension, he taught, follows ataraxia, the untroubled calm that is the goal of life.

He is said to have travelled east with the army of Alexander and met the 'naked sages' of India, and to have lived his doctrine with serene unconcern. He wrote nothing; his teaching survives through followers and, centuries later, the writings of Sextus Empiricus.