Aristippus in Harpers Dictionary of Classical Antiquities

（Ἀρίστιππος). A Greek philosopher, a native of Cyrené and a pupil of Socrates, after whose death in B.C. 399 he travelled about the Greek cities, imparting instruction for money. He was founder of the Cyrenaic School, or the system of Hedonism (from ἡδονή, pleasure). His doctrine was that as a basis for human knowledge the only things real and true are our sensations, and not the external objects that produce them; that the aim of life is what all living things strive after, pleasure; and that virtue is only so far a good thing as it tends to the production of pleasure. The wise man shows his wisdom in governing his desires; mental training, indeed, being the only thing which can qualify us for real enjoyment. In pleasure there is no difference of kind, only of degree and duration. Aristippus's writings seem to have disappeared early; five letters, in the Doric dialect, which have come down under his name are undoubtedly spurious. See Ueberweg, Hist. of Philosophy, pp. 59-98, Eng. trans. (N. Y. 1872); his life by Diogenes Laertius; and the articles Cyrenaici; Epicurus; Philosophia.