Epictetus (mid-1st to 2nd cent. ce), Stoic philosopher from Hierapolis in Phrygia; in early life a slave of Epaphroditus (1) in Rome. Eventually freed by his master, he studied with Musonius Rufus. Epictetus taught in Rome until Domitian banished the philosophers in ce 89. He set up a school at Nicopolis (3) in Epirus, where his reputation attracted a following which included many upper-class Romans. Arrian published the oral teachings (Discourses, Διατριβαί‎) of Epictetus. Four books of these survive, along with a summary of key teachings known as the Manual (Ἐγχειρίδιον‎). These writings and his personal reputation made an impact on the emperor Marcus Aurelius; the Manual has been an important inspirational book in both ancient and modern times.

Epictetus' teaching took two forms. He taught basic works of Stoicism, especially those of Chrysippus, and shows considerable familiarity with technical matters. In the Discourses, however, great emphasis is placed on the need to put philosophical sophistication to work in reforming moral character; learning is of little value for its own sake.

Epictetus' philosophy was largely consistent with earlier Stoicism, although its idiom differs markedly. A major doctrinal innovation was his commitment to the innate character of moral beliefs; for earlier Stoics, such ideas were natural but not innate. Another novelty is in the organization of his teaching: Epictetus divided it into three ‘themes’ (τόποι‎), concerning (1) the control of desires and passions, (2) actions, and (3) assent. Other leading ideas include: (a) a contrast between what is in the power of the agent and what is not; beliefs, desires, plans, reactions, and interpretations of experience are ‘up to us’, while events which happen to us are not. This leads him to emphasize the use we make of our presentations in contrast to their mere reception. (b) An intense focus on προαίρεσις‎, the power of individual moral choice. (c) The Socratic claim that all men act according to what they believe to be good for them; hence, the proper response to moral error is an effort at education and not anger. (d) A powerful belief in divine providence. He interprets the rational, cosmic deity of Stoicism in a more personal sense with an emphasis on the need to harmonize one's will with that of the deity.