mid-late 2nd century AD) was a Greek Pyrrhonist philosopher and Empiric school physician with Roman citizenship.

[2] The Suda, a 10th-century Byzantine encyclopedia, states that he was the same person as Sextus of Chaeronea,[3] as do other pre-modern sources, but this identification is commonly doubted.

Diogenes Laërtius[12] and the Suda[3] report that Sextus Empiricus wrote ten books on Pyrrhonism.

Sextus Empiricus's three surviving works are the Outlines of Pyrrhonism (Πυῤῥώνειοι ὑποτυπώσεις, Pyrrhōneioi hypotypōseis, thus commonly abbreviated PH), and two distinct works preserved under the same title, Adversus Mathematicos (Πρὸς μαθηματικούς, Pros mathematikous, commonly abbreviated "AM" or "M" and known as Against Those in the Disciplines, or Against the Mathematicians).

Adversus Mathematicos I–VI is sometimes distinguished from Adversus Mathematicos VII–XI by using another title, Against the Dogmatists (Πρὸς δογματικούς, Pros dogmatikous) and then the remaining books are numbered as I–II, III–IV, and V, despite the fact that it is commonly inferred that what we have is just part of a larger work whose beginning is missing and it is unknown how much of the total work has been lost.

Sextus's Outlines were widely read in Europe during the 16th, 17th and 18th centuries, and had a profound effect on Michel de Montaigne, David Hume and Georg Wilhelm Friedrich Hegel, among many others.

Since the Renaissance, French philosophy has been continuously influenced by Sextus: Montaigne in the 16th century, Descartes, Blaise Pascal, Pierre-Daniel Huet and François de La Mothe Le Vayer in the 17th century, many of the "Philosophes", and in recent times controversial figures such as Michel Onfray, in a direct line of filiation between Sextus' radical skepticism and secular or even radical atheism.