Aristippus, the founder of the Cyrenaic school of philosophy among the Greeks, was a native of Cyrene, in Africa. Having come into contact with Socrates on a visit to Athens, he became one of his pupils, and remained with the master almost up to his death, 399 B.C. He taught philosophy both at Athens and Ægina, and was the first of the pupils of Socrates to take money for his instruction. Aristippus passed a considerable part of his life in Syracuse, at the court of Dionysius, the tyrant, where he acquired the reputation of an elegant philosophic voluptuary. Plato says Aristippus was the only man he knew who could wear with equal grace both fine clothes and rags. Diogenes Laertius records a number of his sayings, which reveal a sharp, lively, and self-complacent nature. He lived some time at Corinth, in intimacy with the famous Lais, but towards the close of his life he is supposed to have retired to Cyrene. He taught his leading doctrines to his daughter Arete, by whom they were communicated to her son Aristippus the Younger. The latter is supposed first to have systematised them, as it is more than probable that Aristippus published nothing during his life. He prided himself more upon spending his days in what he conceived to be a philosophical manner, than in elaborating a philosophical system for the benefit of mankind.
The Cyrenaic school, who carried out the doctrines of Aristippus to their legitimate conclusions, professed a great contempt for speculative philosophy and for physical and mathematical knowledge. They confined their investigations to morals, and formed an ethical system completely in harmony with the gay, self-possessed, worldly, and sceptical character of their master. Its chief points were: (1) that all human sensations are either pleasurable or painful, and that pleasure and pain are the only criterions of good and evil; (2) that pleasure consists in a gentle, and pain in a violent motion of the soul; (3) that happiness is simply the result of a continuous series of pleasurable sensations; (4) that actions are in themselves morally indifferent, and that men are concerned only with their results. The great philosophic sensualist stood out in strong relief against the gloom and austerity of Antisthenes and the Cynic school. The doctrine that makes pleasure the chief good is often called Hedonism (from Gr. hêdonē, 'pleasure').