Sextus Empiricus

Philosophy

As a skeptic, Sextus Empiricus raised concerns which applied to all types of knowledge. He doubted the validity of induction long before its best known critic, David Hume, and raised the regress argument against all forms of reasoning:

Those who claim for themselves to judge the truth are bound to possess a criterion of truth. This criterion, then, either is without a judge's approval or has been approved. But if it is without approval, whence comes it that it is trustworthy? For no matter of dispute is to be trusted without judging. And, if it has been approved, that which approves it, in turn, either has been approved or has not been approved, and so on ad infinitum.

This view is known as Pyrrhonian skepticism, which Sextus differentiated from Academic skepticism as practiced by Carneades which, according to Sextus, denies the possibility of knowledge altogether, something that Sextus criticized as being an affirmative belief. Instead, Sextus advocates simply giving up belief; in other words, suspending judgment (epoché) about whether or not anything is knowable. Only by suspending judgment can we attain a state of ataraxia (roughly, 'peace of mind').

There is some debate as to the extent to which Sextus advocated the suspension of judgement. According to Myles Burnyeat, Jonathan Barnes, and Benson Mates, Sextus advises that we should suspend judgment about virtually all beliefs; that is to say, we should neither affirm any belief as true nor deny any belief as false, since we may live without any beliefs, acting by habit. Michael Frede, however, defends a different interpretation, according to Sextus, beliefs are permissible so long as they are not grounded in reason, philosophy, or speculation; a skeptic may, for instance, accept commonly held views within their society. The key distinction between the skeptic and the dogmatist lies in the source of belief: the skeptic does not arrive at beliefs through rigorous philosophical inquiry.

Writings

Diogenes Laërtius and the Suda report that Sextus Empiricus wrote ten books on Pyrrhonism; the Suda also records a work titled Ethica. The three works of Sextus that survive in Greek are the Outlines of Pyrrhonism (Πυῤῥώνειοι ὑποτυπώσεις, Pyrrhōneioi hypotypōseis, commonly abbreviated PH) and two collections preserved under the common title Adversus Mathematicos (Πρὸς μαθηματικούς, Pros mathematikous, commonly abbreviated AM or M).

The surviving portion of Adversus Mathematicos is fragmentary and evidently incomplete: the text itself refers to parts that are missing and to other works of Sextus that do not survive, including Medical Commentaries (AM I 202), Empirical Commentaries (AM I 62), and Commentaries on the Soul (AM IV 284; AM VI 55).

The portion of AM that is securely preserved in the manuscripts corresponds to six books (often printed and discussed together as AM I–VI). These six books are traditionally titled and are commonly referred to in English collectively as "Against the Professors" (though only the heading Pros mathematikous and the title of the Outlines appear in the manuscripts themselves).

Beyond these six books, a further set of books preserved in some manuscript traditions has been transmitted under the same overall heading Adversus Mathematicos and in modern scholarship is frequently distinguished from AM I–VI. These later books (often numbered VII–XI in printed editions) are sometimes grouped under the separate title Against the Dogmatists (Πρὸς δογματικούς, Pros dogmatikous) or treated as parts of a larger, now‑partially lost collection often called Skeptical Treatises (Σκεπτικὰ Ὑπομνήματα, Skeptika Hypomnēmata). It is generally accepted that what survives of these later books is fragmentary and that their original relationship to the first six books and to the lost portions cannot be securely reconstructed.

In short: AM I–VI are the core books commonly printed and cited as Adversus Mathematicos (often called "Against the Professors"); the additional books transmitted as AM VII–XI are preserved in a more fragmentary state, are frequently treated as a separate or later section (sometimes titled Against the Dogmatists), and their original completeness and relation to the first six books remain uncertain.

Legacy

An influential Latin translation of Sextus's Outlines was published by Henricus Stephanus in Geneva in 1562, and this was followed by a complete Latin Sextus with Gentian Hervet as translator in 1569. Petrus and Jacobus Chouet published the Greek text for the first time in 1621. Stephanus did not publish it with his Latin translation either in 1562 or in 1569, nor was it published in the reprint of the latter in 1619.

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. Another source for the circulation of Sextus's ideas was Pierre Bayle's Dictionary. 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.