Pyrrho of Elis · Philosophy
Pyrrho left no writings, but his way of thinking was systematised five centuries later by Sextus Empiricus, whose surviving works carried Pyrrhonism into the modern world - igniting the skeptical crisis of the Renaissance, shaping Montaigne, providing the doubt Descartes set out to defeat, and feeding the mitigated skepticism of Hume.
Pyrrho’s most remarkable achievement may be that his philosophy survived at all. He wrote nothing; he founded no formal institution; his teaching passed first by word of mouth to his pupil Timon, and might have faded entirely. Instead, the skeptical impulse he embodied was taken up, debated, and developed over the following centuries - revived by Aenesidemus in the first century BC, who organised the Ten Modes, and finally gathered into a complete, written system by the physician and philosopher Sextus Empiricus, who lived around the second century AD, some five hundred years after Pyrrho himself. Sextus’ works - above all the Outlines of Pyrrhonism and the larger Against the Mathematicians (better translated ‘against the dogmatists of the various disciplines’) - are the only substantial skeptical texts to survive from antiquity intact, and through them Pyrrho speaks to us still.
Sextus did for skepticism what no one had done before: he wrote it all down, systematically and accessibly, defining its terms, cataloguing its arguments, and answering its critics. He was an ‘empiric’ physician - a member of a medical school that distrusted hidden theoretical causes and trusted observed regularities - and this medical, anti-theoretical temperament suffused his philosophy: skepticism, for Sextus, was the intellectual analogue of treating the patient by what is observed rather than by speculative doctrine. His treatises are calm, orderly, and comprehensive, marching through the dogmatists of logic, physics, and ethics and meeting each with the apparatus of opposition and suspension. It is almost entirely through Sextus that the later world knew Pyrrhonism - and so the history of skepticism’s vast influence is really the history of what happened when Sextus’ books were read.
For most of the Middle Ages, Sextus’ skeptical texts lay almost unread in the Latin West. Their dramatic re-entry into European thought came in the sixteenth century, when Sextus’ Outlines were printed in Latin translation (Henri Estienne’s edition of 1562) and circulated widely. The timing could hardly have been more explosive. Europe was convulsed by the Reformation, and at the heart of that conflict lay a question that was, at bottom, skeptical: by what criterion do we know religious truth? Catholics appealed to the authority of the Church and tradition; Protestants appealed to Scripture and individual conscience; and each side could show that the other’s criterion was unproven, circular, or question-begging. Into this furnace the rediscovered Pyrrhonism poured its ancient arsenal - the modes, the regress of the criterion, the equipollence of opposed positions - and the result was what historians have called the ‘skeptical crisis’ of early modern thought.
The crisis was profound because Sextus’ arguments seemed to threaten not just this or that doctrine but the very possibility of rational certainty about anything - religion, knowledge of nature, morality. If, as the skeptics argued, every proof requires a criterion, and every criterion requires a proof, then no belief can be finally grounded, and the confident edifice of dogmatic philosophy and theology trembles. Some thinkers wielded Pyrrhonism as a weapon for faith - arguing that since reason can prove nothing, we should humbly accept religious authority on trust (a stance called ‘fideism’). Others were driven by the skeptical challenge to seek some new, skeptic-proof foundation for knowledge. Either way, the rediscovery of Sextus did not leave European thought as it found it: an ancient philosopher who had written nothing, transmitted by a physician five centuries his junior, became, two thousand years on, one of the great destabilising forces in the birth of modern philosophy.
It is no exaggeration to say that Pyrrhonian skepticism, transmitted through Sextus and detonated in the Renaissance, helped set the agenda for the whole of modern philosophy. The defining question of modern epistemology - how, if at all, can we attain certain knowledge, and what are its foundations? - is the skeptical question, and the great modern systems are, in large part, answers to it. Descartes sought an indubitable foundation in the thinking self; the empiricists Locke, Berkeley, and Hume traced knowledge to experience and grappled with how far experience can take us; Kant’s entire critical philosophy was, by his own account, an attempt to secure knowledge against the skeptic by showing what the mind must contribute to experience. Behind each of these stands the figure of the skeptic, posing the challenge that had to be met.
This is the deepest measure of Pyrrho’s importance: not that many people became thoroughgoing Pyrrhonists (few did), but that his challenge proved impossible to ignore. A philosophy is sometimes most influential through the responses it forces, and skepticism is the supreme example - the permanent gadfly of the dogmatic mind, the question that every confident system must answer or be embarrassed by. Even today, the skeptic’s demand - by what criterion do you know that? and how do you justify the criterion? - remains the test that any theory of knowledge must pass. Pyrrho gave philosophy its most durable problem. The man who wrote nothing, who claimed to know nothing, who founded no school, set in motion a question that has driven the discipline for two and a half thousand years and shows no sign of being finally answered. To study Pyrrho is to meet the doubt at the root of the modern mind.
This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.
You learned that Pyrrho founded a way of thinking that was systematised by Sextus Empiricus (c. 2nd century AD), whose Outlines of Pyrrhonism survived and was rediscovered in the Renaissance. This sparked a skeptical crisis that shaped Montaigne (‘What do I know?’), gave Descartes the radical doubt he tried to overcom…
Leads to David Hume.
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