A second-century doctor doubted induction centuries before David Hume did
Almost nothing is known about Sextus Empiricus except that he practised medicine and wrote the fullest surviving case for ancient Pyrrhonist scepticism. His advice was radical: stop trying to settle whether anything can be known, suspend judgement, and peace of mind follows. Renaissance printers revived him, and Montaigne and Hume took notice.
Sextus flourished in the middle to late 2nd century CE and probably lived in Alexandria, Rome or Athens. His first name suggests Roman citizenship. The 10th-century Byzantine encyclopedia called the Suda equated him with Sextus of Chaeronea, an identification many now doubt. Tradition puts him in the Empiric school of medicine, where Pyrrhonism was popular, though twice in his writing he seems to lean towards the rival Methodic school.
His most famous weapon is the regress argument. Anyone who claims to judge truth needs a standard for doing so; that standard is either unapproved, in which case why trust it, or approved by something else, which then needs approval itself, without end. He also questioned inductive reasoning. Sextus separated his position from the Academic scepticism of Carneades, which he thought overreached by flatly denying that knowledge is possible, since that denial is itself a belief. The Pyrrhonist instead withholds assent, a stance called epoché, and reaches ataraxia, a calm freedom from disturbance.
How far that suspension goes is argued over. Myles Burnyeat, Jonathan Barnes and Benson Mates read him as urging us to drop nearly every belief and live by habit. Michael Frede argued that he allowed ordinary beliefs, such as the common views of one's society, provided they were not reached through philosophical theorising.
Three works survive in Greek: the Outlines of Pyrrhonism and two collections gathered under the title Adversus Mathematicos, whose first six books are known in English as Against the Professors; later, more fragmentary books are sometimes called Against the Dogmatists. The text mentions lost medical commentaries and a work on the soul. Henricus Stephanus printed a Latin version of the Outlines in Geneva in 1562, a complete Latin Sextus followed in 1569, and the Greek appeared in 1621. From Montaigne through Descartes and Pascal to Hegel, European thinkers kept returning to him.
Source: Sextus Empiricus
