skeptikos

Skeptikos (Greek: skeptikos) is a term used in ancient Greek philosophy to denote “skeptical” or “a skeptic.” It is also used to refer to adherents of the skeptical schools within Hellenistic philosophy. The word derives from skeptesthai, “to look, to consider,” and from skepsis, “examination” or “doubt.”

Two principal strands developed in the Hellenistic era. Pyrrhonian skepticism, founded by Pyrrho of Elis, urged epoché—the suspension of judgment about all topics—and sought ataraxia, or peace of mind, through withholding assent. Academic skepticism, associated with Arcesilaus and later Carneades, held that certainty is unattainable but argued that some beliefs can be more probable than others, allowing practical decision-making without dogmatic claims.

Sextus Empiricus, a later skeptic, compiled influential systematic presentations of skeptical arguments in works such as Outlines of Pyrrhonism and Against the Professors, shaping both late antiquity and medieval thought. Key themes of Skeptikos traditions include the practice of epoche, the aim of ataraxia, the distinction between appearances (phainomena) and things as they are, and the claim that most beliefs are uncertain.

Influence and legacy extend from ancient philosophy to later European thought and to modern critical inquiry. In contemporary usage, a skeptic is typically someone who questions claims and seeks evidence, and the modern scientific-skepticism movement applies rigorous standards of reasoning and evidence to extraordinary or controversial propositions. Skeptikos, as a philosophical identity, denotes a stance of doubt tempered by practical engagement with belief.