Pyrrhonian

Pyrrhonian refers to the philosophical tradition of Pyrrhonism, a school of ancient Greek skepticism founded by Pyrrho of Elis in the 4th century BCE. Pyrrhonists aim to suspend judgment (epoché) about non-evident propositions and thereby attain ataraxia, or tranquil indifference. They do not claim to know the truth of appearances; instead they seek to avoid dogmatic beliefs by presenting opposing arguments as equally plausible, a method often described as equipollence. In practice, Pyrrhonists pursue a form of continuous inquiry that ends in suspension rather than assertion.

Historically, Pyrrhonian skepticism was developed and systematized by later philosophers such as Aenesidemus and Agrippa the Skeptic, who articulated tropes or modes that undercut secure knowledge claims. The most important source for Pyrrhonian thought is Sextus Empiricus (late 2nd to early 3rd century CE), whose writings, including the Outlines of Pyrrhonism, preserve the method and arguments of the school. The tradition emphasizes practical tranquility achieved through suspension, contrasting with dogmatic assertions about knowledge.

The term Pyrrhonian is used today to describe adherents or interpretations of Pyrrhonism. The school influenced later skeptical and epistemological traditions and is studied as a foundational form of ancient philosophical skepticism. It is often contrasted with Academic skepticism, which admitted the possibility of probabilistic knowledge, whereas Pyrrhonians maintained suspension of judgment as their method and goal.