Pyrrho of Elis c. 360 BC – c. 270 BC

Pyrrho of Elis was an ancient Greek philosopher of the late fourth and early third centuries BC, the founder of the philosophical school of Skepticism that bears his name as Pyrrhonism. He left no writings of his own; his teachings survive in summaries by his student Timon of Phlius and in later sources, principally Diogenes Laertius and Sextus Empiricus. He is reported to have travelled with Alexander the Great's expedition as far as India, where he encountered the gymnosophists, naked sages whose practice may have shaped his doctrine of suspension of judgement. The Pyrrhonian aim was tranquillity (ataraxia) achieved by suspending assent to all dogmatic claims, recognising the equal force of competing arguments. His thought decisively shaped the later Skeptical tradition that culminated in Sextus Empiricus.