Skepticism
The tradition of suspending judgment where evidence does not settle a question — Pyrrhonism seeking tranquillity through balanced arguments, Academic skepticism arguing that nothing can be known.
Skepticism as a tradition is the practice of suspending judgment where the evidence does not settle a question. It produced two distinct ancient schools and a method that outlived both.
Pyrrhonism
Pyrrho of Elis (c. 360–270 BC) gave the movement its name. Sextus Empiricus systematized it around 200 AD in the Outlines of Pyrrhonism, the main surviving source.
The method is opposition. For any claim, the Pyrrhonist produces a counter-claim of equal weight, leaving the mind in balance with no ground to prefer either. Judgment is suspended — epoche — and the reported result is ataraxia, freedom from disturbance, arriving unsought once the struggle to settle the question is abandoned.
The Pyrrhonists were careful not to assert that knowledge is impossible, since that is itself a claim to knowledge. They described themselves as still inquiring, and treated their own arguments as medicines to be discarded once they had worked.
Academic skepticism
Plato's Academy took a skeptical turn under Arcesilaus in the third century BC and argued the stronger thesis that nothing can be known. Carneades developed an account of the plausible to allow action without assent. Cicero preserved much of this material, and its transmission shaped early modern philosophy directly.
Afterwards
Sextus was translated into Latin in the sixteenth century and unsettled European philosophy. Montaigne absorbed it; Descartes took the skeptical arguments seriously enough to build his method around answering them; Hume reached skeptical conclusions about causation and the self by empiricist means, then argued that nature prevents us from living by them.
The tradition survives less as a position than as an instrument: the standing demand that a claim state what would count against it. See also the concept of skepticism.
Questions
What is philosophical skepticism?
The practice of suspending judgment where evidence is insufficient. Ancient Pyrrhonists opposed every argument with an equal counter-argument to reach suspension of judgment and freedom from disturbance.
What is epoche?
The Greek term for suspension of judgment. Pyrrhonists used it to describe the state reached when opposing arguments balance and no ground remains for preferring either.
How did skepticism influence modern philosophy?
The rediscovery of Sextus Empiricus in the sixteenth century shaped Montaigne and set the problem Descartes designed his method to answer. Hume later reached skeptical conclusions by empiricist reasoning.