Sextus Empiricus

Quick Facts

• Name: Sextus Empiricus
• Lived: probably in the 2nd or 3rd century CE
• Place: uncertain; Greek-speaking Roman world
• Role: philosopher and physician
• Tradition: Pyrrhonian skepticism, named after Pyrrho
• Main works: Outlines of Pyrrhonism and the books usually called Against the Mathematicians or Against the Professors
• Known for: suspension of judgment, equal opposing arguments, living by appearances, and tranquility

The Big Question

How should you live when every large claim about reality, knowledge, truth, causes, or goodness seems to meet a serious opposing argument?

Sextus's answer is not "believe nothing" as a new doctrine. It is: keep investigating, notice when the arguments balance, and withhold judgment when you cannot honestly see which side wins.

In One Minute

Sextus Empiricus is our main source for ancient Pyrrhonian skepticism. He did not argue that nothing is true. That would be another dogma. His point was more careful: when philosophers make big claims about reality, knowledge, causes, ethics, or logic, equally strong arguments often appear on the other side.

The skeptic responds by suspending judgment. Sextus calls this epoche: holding back from saying "this is true" or "this is false" when the case has not been settled. The skeptic then lives by appearances: what shows up in experience, bodily feeling, custom, law, and practical skill.

The surprising result, Sextus says, is ataraxia, or tranquility. The person who stops trying to force certainty out of unsettled questions becomes less disturbed by them.

What They Taught

Sextus taught skepticism as a practice of inquiry, not as a theory that says knowledge is impossible. Dogmatists claim to have discovered the truth. Academic skeptics, as he presents them, claim that truth cannot be discovered. Pyrrhonian skeptics keep looking without claiming that no answer can ever be found.

The central move is suspension of judgment. When a claim and its opposite seem equally forceful, the skeptic does not assent to either. Sextus calls this balance equipollence. It is the habit of asking whether a confident theory has really earned more trust than its rival.

This does not mean the skeptic stops living. Sextus separates appearances from beliefs about hidden reality. If honey tastes sweet, the skeptic can say, "It appears sweet to me." What the skeptic avoids is the stronger claim, "Honey is sweet by nature, in itself, in a way philosophy has proven."

Sextus says the skeptic follows appearances in four ordinary ways: nature, bodily feelings, customs and laws, and skills or arts. Hunger leads us to eat. Local law shapes conduct. A physician can treat a fever by learned practice without claiming to know the hidden ultimate nature of fever.

The emotional result is ataraxia, usually translated as tranquility or freedom from disturbance. Sextus describes people who wanted the truth so they could finally rest. Instead, they found serious arguments on both sides. When they stopped forcing a verdict, calm followed.

Sextus also gives the skeptic tools, often called modes or tropes. A mode is a pattern of argument that brings a claim into question. The Ten Modes collect ways appearances differ by situation, condition, amount, habit, custom, and relation. The Five Modes press a claim through disagreement, infinite regress, relativity, unsupported assumption, and circular proof.

This is why Sextus attacks the criterion of truth. A criterion is a standard for deciding which beliefs or impressions are true. Stoicism trusted a special kind of clear impression. Epicureanism trusted sensation more directly. Sextus asks how we know that any proposed standard is reliable. If another standard must test it, the problem starts again. If it proves itself, the argument is circular.

Key Ideas With Examples

• Suspension of judgment: holding back from a final yes or no. If one philosopher argues for pleasure and another for virtue as the highest good, the skeptic asks whether either side has really won.
• Equipollence: equal persuasive force on both sides. If two serious explanations fit the evidence, the skeptic does not pretend the tie is broken.
• Appearance: how something shows up before we add a theory about what it really is. A medicine may taste bitter. The skeptic can report that bitterness without claiming to know the medicine's real nature.
• Ataraxia: calm that comes when unresolved questions stop feeling like emergencies. The skeptic may still feel pain or hunger, but not the extra anxiety caused by dogma.
• Dogmatism: claiming to have settled a disputed or hidden truth. For Sextus, a dogmatist is anyone who says a philosophical theory has discovered how things really are.
• Modes or tropes: repeatable skeptical argument patterns. One mode asks for a proof of the proof, leading to infinite regress. Another points out circularity.
• Criterion of truth: the rule or test that tells us which impressions are true. Sextus presses the problem that the test itself needs a test, unless we simply assume it works.
• Living by appearances: acting without pretending to have final metaphysical knowledge. You can eat when hungry, obey local law, use a craft, and follow ordinary language.

Major Works

Outlines of Pyrrhonism is the best short map of Sextus's skepticism. Book I explains Pyrrhonism as a skill of setting opposed appearances and arguments against each other until suspension of judgment follows. It covers epoche, ataraxia, skeptical phrases, the modes, and rival schools. Books II and III apply the arguments to logic, physics, and ethics.

Against the Mathematicians is the traditional title for a larger set of books. "Mathematicians" here means learned specialists or professors, not only modern mathematicians. The first six books attack the theoretical claims of grammarians, rhetoricians, geometers, arithmeticians, astrologers, and musicians. The point is not that no one can use grammar or music. The point is that expert disciplines often claim more certainty than they can defend.

Against the Logicians, Against the Physicists, and Against the Ethicists are often grouped with Against the Mathematicians. These books expand the attack on philosophy itself: proof, signs, causes, gods, nature, good and bad, and the goal of life.

Why It Matters

Sextus preserved the fullest surviving account of ancient Pyrrhonian skepticism. Without him, Pyrrho would be much harder to understand.

He also gives later philosophy one of its hardest problems: how do we justify our standards of justification? If reason or the senses are the standard, why trust them? If you offer a proof, what justifies the proof?

His work separates skepticism from simple negativity. Sextus is not saying, "Everything is false." He is showing how inquiry can continue without premature certainty.

Proponents, Critics, and Opponents

Sextus presents himself as preserving the Pyrrhonian path associated with Pyrrho. He also draws on later skeptical tools linked with Aenesidemus and Agrippa.

His main opponents are dogmatic schools. He presses Stoicism on its claim that some impressions can certify their own truth. He presses Epicureanism on its confidence in sensation and atomist explanation.

The classic objection is practical: can anyone really live without beliefs? Sextus answers that the skeptic can live by appearances, feelings, customs, laws, and skills. Critics reply that this may rename ordinary beliefs instead of avoiding them.

Sextus became newly important in Renaissance and early modern Europe when his writings returned to wider circulation. His arguments helped shape the skeptical background for Michel de Montaigne, Rene Descartes, and David Hume.

Related Pages

• Pyrrho
• Skepticism
• Stoicism
• Epicureanism
• Rene Descartes
• David Hume