CARNEADES (214-129 B.C.), Greek philosopher, founder of the Third or New Academy, was born at Cyrene. Little is known of his life. He learned dialectics under Diogenes the Stoic, and under Hegesinus, leader of the academy. The chief objects of his study, however, were the works of Chrysippus, op position to whose views is the mainspring of his philosophy. In 155, together with Diogenes the Stoic and Critolaus the Peri patetic, he was sent on an embassy to Rome to justify certain depredations committed by the Athenians in the territory of Oropus. On this occasion he delivered two speeches on successive days, one in favour of justice, the other against it. His powerful reasoning excited among the Roman youth an enthusiasm for philosophical speculations, and the elder Cato insisted on Car neades and his companions being dismissed from the city.
Carneades, practically a 5th-century sophist, is the most im portant of the ancient sceptics. Negatively, his philosophy is a polemic against the Stoic theory of knowledge in all its aspects. All our sensations are relative, and acquaint us, not with things as they are, but only with the impressions that things produce upon us; it is impossible to distinguish between false and true im pressions; therefore the Stoic Ovraala KaraXrl'rrLKii (see Sroics) must be given up. There is no criterion of truth. In answer to the Stoic doctrine of design in nature, he points to the existence of evil; and against the theory of a divine providence he argues that the world cannot be shown to be anything but the product of natural forces. While against Stoic theology he points out that individuality is not consonant with infinity, with Aristotle he ar gues that virtue, as relative, cannot be ascribed to God; and further that neither intelligence, corporeality nor incorporeality, nor in fact anything can be regarded as attributes of God; thus anticipating much in modern thought.
The positive side of his teaching resembles in all essentials that of Arcesilaus (q.v.). Knowledge being impossible, a wise man should practise broxii (suspension of judgment). He will not even be sure that he can be sure of nothing. Ideas or notions are never true, but only probable ; nevertheless, there are degrees of probability, and hence degrees of belief, leading to action, accord ing as the impression is merely probable in itself ; probable and uncontradicted; or probable, uncontradicted and confirmed by in vestigation. Carneades left no written works; his opinions seem to have been systematized by Clitomachus.
See A. Geffers, De Arcesilae Successoribus (1845) ; C. Gouraud, De Carneadis Vita et Placitis (1848) ; V. Brochard, Les Sceptiques grecs (1887) ; C. Martha, "Le PhiIosophe Carneade a Rome," in Revue des deux mondes, xxix. (1878) , and the histories of philosophy ; F. Alessio, Carneade (Mondovi, 189o), also ACADEMY, GREEK.