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Sextus Empiricus

Hellenistic · Europe · 160 to 210

Ancient physician and writer whose surviving books set out the sceptic habit of suspending judgement to reach peace of mind.

What it is

Sextus Empiricus was a Greek physician and philosopher who lived probably in the second or third century CE. His writings, above all the Outlines of Pyrrhonism, are the fullest account we have of Pyrrhonian scepticism, the school named after Pyrrho.

The Pyrrhonian sceptic tries to find, for every argument, an equal argument on the other side, so that judgment is suspended on questions of theory. The result, he says, is not despair but a quiet mind. Very little is known of his own life.

The main ideas

  • Suspend judgment. When arguments on both sides seem equally strong, the sensible response is to hold back from deciding. None of the schools of philosophy offered a satisfying answer, so no school's claims are accepted.
  • Calm of mind. The aim of this suspension is tranquillity. It is meant to come as a by-product, not to be chased directly.
  • Live by how things appear. A sceptic can still act in everyday life by following appearances, customs and needs, without holding theories about what is ultimately true.
  • Against the dogmatists. He argues against the schools that claim to have found the truth about the world, which he calls dogmatists.

What it looks like in practice

Picture someone asked by two friends to decide which of two heated opinions is right, who finds the best arguments on each side about equal. Instead of forcing a verdict, they hold off, notice the relief, and carry on with what the day needs. The point is not that the question is unimportant, but that the person no longer needs an answer in order to act well and feel at ease. This is an illustration of the approach, not a report of Sextus.

Books and moments

  • Outlines of Pyrrhonism is the short, systematic account of the sceptical way.
  • Against the Mathematicians is a longer set of arguments against the learned arts and the dogmatic schools.

Questions and criticism

  • Can anyone live with no beliefs? He says a sceptic follows appearances, but critics ask whether suspending all judgment is really possible.
  • Is scepticism self-defeating? If every claim can be answered, so can the claim that every claim can be answered. How Sextus handles this is still discussed.
  • Is peace of mind a good reason to doubt? Some readers think the claim that suspension leads to calm is itself a belief about the world.

Close neighbours

Modern thinkers such as Montaigne, Descartes and Hume were influenced by his works. The pages on Hume and Descartes show how that scepticism returned.

Written by epchē in our own words, and checked against independent sources on 9 October 2026. The sources are listed below.

Philosophies they belong to or are close to

Who they connect to

Influenced

  • David Hume · Hume's mitigated scepticism echoes the ancient sceptics, whom he knew through Bayle. (scholars disagree about this link)
  • Michel de Montaigne · He read and took up the ancient sceptic arguments, and had a motto from them carved on his ceiling.
  • René Descartes · Renewed reading of Sextus in the sixteenth century set the sceptical problems Descartes tried to answer.

Influenced by

  • Pyrrho of Elis · The later sceptic school took Pyrrho as its founding figure.

Other Hellenistic thinkers

Sources we used

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