a Greek philosopher, and founder of the sect of the Cynics, who flourished about 380 B.C. He was born at Athens, and passed the early part of his life as a soldier. He was first a pupil of the sophist Gorgias, but afterwards became a zealous disciple and friend of Socrates, whom he faithfully attended till his death. The exhortations of his master to temperance and simplicity of life were carried by him into practice with a strictness bordering on fanaticism. Permitting his beard to grow, he went about the streets in a thread-bare coat, scarcely to be distinguished from a common beggar; an affectation of severity that called forth the satirical remark of Socrates, "that the pride of Antisthenes peeped out through the holes of his cloak." He prided himself upon the most rigid virtue, and thought it his duty to attack the vicious wherever he found them. This gave him some reputation in the city; but it may be supposed that, in the luxurious city of Athens, he had more enemies than disciples. His philosophy was exclusively practical; despising speculative science, he held the nature of things to be undefinable, and all opinions to be identical. Virtue, which he held to be the supreme good, consisted, with him, in temperance, and freedom from the dominion of the passions, by means of which the wise man becomes independent of all external circumstances, and possesses in himself all the sources of felicity and perfection. Virtue is the only beauty; vice the only deformity; all things else are indifferent (ἀδιάφορα) and unworthy of pursuit. Regarding the Deity, as Cicero (De Nat. Deor. i. 13) informs us, he held "that the gods of the people were many, but that the true God was One." Notwithstanding the repulsive austerity of his manners, the elevated ethical teaching of Antisthenes drew around him a numerous body of disciples (see CRUCES), of whom the most celebrated was Diogenes of Sinope; and by his twofold influence, positive and negative, he may be regarded as the parent of Stoicism on the one hand, and of Pyrrhonism on the other.

The works of Antisthenes formed, according to Diogenes Laërtius, ten books; of these there are now extant only two discourses entitled Ajax and Ulysses; and some letters. The collected fragments were published by Winckelmann. Turici, 1842.