Pyrrhonism

Pyrrhonism is a school of ancient Greek skepticism founded by Pyrrho of Elis (c. 360–270 BCE). It holds that certainty about most beliefs is unattainable, and that one should suspend judgment (epoché) regarding non-evident propositions in order to achieve mental calm (ataraxia).

Its method rests on equipollence, the balancing of opposing arguments. For any issue, the reasons pro and con are often equally persuasive, so the honest response is to suspend assent rather than adopt a dogmatic view. Pyrrhonists emphasize ongoing inquiry rather than positive theses.

Practically, Pyrrhonists do not deny appearances or deny that we experience the world; rather, they deny that appearances justify definite beliefs about the underlying nature of reality or knowledge. They advocate withholding assent to non-evident claims while living according to appearances, and they seek tranquility through freedom from dogmatic commitment.

Key figures include Aenesidemus, who formulated the ten modes of skepticism to challenge dogmatic systems; later thinkers such as Agrippa and, most influentially, Sextus Empiricus, who systematized Pyrrhonian skepticism in works like Against the Physicists, Against the Logicians, and the Outlines of Pyrrhonism. The tradition contrasts with Academic Skepticism, which also questioned knowledge but did not necessarily demand the same method of perpetual inquiry.

Influence of Pyrrhonism extended beyond its era, shaping later skeptical attitudes in the Hellenistic world and resonating in medieval and modern thought. It contributed to the development of a method-based form of skepticism that emphasizes suspension of judgment as a route to tranquility rather than the assertion of positive beliefs.