Stoics (Gr. στоά, porch), or philosophers of the porch, one of the speculative schools of antiquity, so called from the place at Athens (στоά ποικίλη) in which their founder Zeno gave his instructions (about 300 13. C). Of their earlier representatives, besides the founder, the most prominent were Ariston of Chios, Clean-thes, Chrysippus, Zeno of Tarsus, Persaeus, Herillus of Carthage, Sphaerus, Diogenes the Babylonian, Antipater of Tarsus, and Posido-nius and Panrotius of Rhodes (about 130 B. G); of their later, Seneca (died A. D. 65), Epictetus, Annaeus Cornutus, Persius Flaccus, Musonius Rufus, Arrian, Marcus Aurelius, and many of the most distinguished Roman citizens. Originally treating the three departments of logic, physics, and ethics, they are chiefly known as moralists, since they con-nected philosophy intimately with the duties of practical life. In logic, they found the criterion of knowledge in sensuous impressions, which furnish the materials fashioned by reason, and combated skepticism by affirming that every representation of an object implies the existence of the object itself.

In physics, they regarded God and the world as power and its manifestation, matter being a passive ground in which dwells the divine energy. Their ethics was a protest against moral indifference, and to live in harmony with nature, conformably to reason and the demands of universal good, and in the utmost indifference to pleasure, pain, and all external good or evil, was their fundamental maxim. (See Moral Philosophy, vol. xi., p. 809.) An attempt to revive the stoic philosophy was made by Justus Lipsius (1547-1606), especially in his Mannductio ad Stoicam Philosophiam and Physiologia Stoicorum. - See Tiedemann, System der stoischen Moral (1776).; Dourif, Du Stolcisme et du Christianisme (Paris, 1863); O. Reichel, "The Stoics, Epicureans, and Skeptics" (translated from Zeller's Philosophic der Griechen, London, 1869); Weygoldt, Zeno von Citium und seine Lehre (Jena, 1872); and Wellmann, Die Philosophic des Stoikers Zenon (Leipsic, 1873).