(Ἀρίστων), son of Miltiades, born in the island of Chios, a Stoic and disciple of Zeno, flourished about B. C. 260, and was therefore contemporary with Epicurus, Aratus, Antigonus Gonatas, and with the first Punic war. Though he professed himself a Stoic, yet he differed from Zeno in several points; and indeed Diogenes Laertius (7.160, &c.) tells us, that he quitted the school of Zeno for that of Polemo the Platonist. He is said to have displeased the former by his loquacity,--a quality which others prized so highly, that he acquired the surname of Siren, as a master of persuasive eloquence. He was also called Phalancus, from his baldness. He rejected all branches of philosophy but ethics, considering physiology as beyond man's powers, and logic as unsuited to them. Even with regard to ethics, Seneca (Ep. 89) complains, that he deprived them of all their practical side, a subject which he said belonged to the schoolmaster rather than to the philosopher. The sole object, therefore, of ethics was to shew wherein the supreme good consists, and this he made to be ἀδιαφορία, i. e. entire indifference to everything except virtue and vice. (Cic. Ac. 2.42.) All external things therefore were in his view perfectly indifferent; so that he entirely rejected Zeno's distinction between the good and the preferable (τὰ προηγμένα), i. e. whatever excites desire in the individual mind of any rational being, without being in itself desirable or good, and of which the pure Stoical doctrine permitted an account to be taken in the conduct of human life. (Cic. Fin. 4.25.) But this notion of προηγμένα was so utterly rejected by Ariston, that he held it to be quite indifferent whether we are in perfect health, or afflicted by the severest sickness (Cic. Fin. 2.13); whereas of virtue he declared his wish that even beasts could understand words which would excite them to it. (Plut. Maximo c. Princip. Philosopho esse diss. § 1.) It is, however, obvious that those who adopt this theory of the absolute indifference of everything but virtue and vice, in fact take away all materials for virtue to act upon, and confine it in a state of mere abstraction. This part of Ariston's system is purely cynical, and perhaps he wished to shew his admiration for that philosophy, by opening his school at Athens in the Cynosarges, where Antisthenes had taught. [ANTISTHENES.] He also differed with Zeno as to the plurality of virtues, allowing of one only, which he called the health of the soul (ὑγείαν ὠνόμαζε, Plut. Virt. Mor. 2). This appears to follow from the cynical parts of his system, for by taking away all the objects of virtue, he of course deprives it of variety; and so he based all morality on a well-ordered mind. Connected with this is his paradox, Sapiens non opinatur--the philosopher is free from all opinions (since they would be liable to disturb his unruffled equanimity); and this doctrine seems to disclose a latent tendency to scepticism, which Cicero appears to have suspected, by often coupling him. with Pyrrho. In conformity with this view, he despised Zeno's physical speculations, and doubted whether God is or is not a living Being. (Cic. Nat. Deor. 1.14.) But this apparently atheistic dogma perhaps only referred to the Stoical conception of God, as of a subtle fire dwelling in the sky and ditlusing itself through the universe. [ZENO.] He may have meant merely to demonstrate his position, that physiology is above the human intellect, by shewing the impossibility of certainly attributing to this pantheistic essence, form, senses, or life. (Brucker, Hist. Crit. Phil. 2.2, 9; Ritter, Geschichte der Phil. 11.5, 1.)

Ariston is the founder of a small school, opposed to that of Herillus, and of which Diogenes Laertius mentions Diphilus and Miltiades as members. We learn from Athenaeus (vii. p. 281), on the authority of Eratosthenes and Apollophanes, two of his pupils, that in his old age he abandoned himself to pleasure. He is said to have died of a coup de soleil.