Lives and Opinions of Eminent Philosophers

​Of the philosophers, some were named after cities, as the Elians, Megarians, Eretrians, and Cyrenaics; others after localities, as the Academics and Stoics. Still others were named after accidental occurrences, as the Peripatetics; and after gibes, as the Cynics; others after their dispositions, as the Eudaemonists; some after their conceits, as the Truth-lovers, Elenctics, and Analogetics; and some after their teachers, as the Socratics, Epicureans, and the like. Again, some were called physicists from their inquiry into nature; others ethicists from their concern with morals; and dialecticians are as many as engage in the subtleties of arguments.

​The parts of philosophy are three: physics, ethics, and dialectic. Physics is concerned with the cosmos and the things in it; ethics with life and what pertains to us; while dialectic champions the arguments of both. And down to Archelaus the physical species prevailed; but from Socrates, as has been said, the ethical; and from Zeno of Elea the dialectical. Of the ethical branch there have been ten schools: Academic, Cyrenaic, Elian, Megarian, Cynic, Eretrian, Dialectic, Peripatetic, Stoic, and Epicurean.

​Now, of the Academic school, Plato presided over the Old, Arcesilaus over the Middle, and Lacydes over the New; Aristippus of Cyrene over the Cyrenaic; Phaedo of Elis over the Elian; Euclides of Megara over the Megarian; Antisthenes of Athens over the Cynic; Menedemus of Eretria over the Eretrian; Clitomachus of Carthage over the Dialectic; Aristotle of Stagira over the Peripatetic; Zeno of Citium over the Stoic; while the Epicurean was named after Epicurus himself. Hippobotus, however, in his On Schools, says that there are nine schools and persuasions: first the Megarian, second the Eretrian, third the Cyrenaic, fourth the Epicurean, fifth the Annicerean, sixth the Theodorean, seventh the Zenonian, which is also the Stoic, eighth the Old Academic, and ninth the Peripatetic;

​he includes neither the Cynic, nor the Elian, nor the Dialectic. For most do not even acknowledge the Pyrrhonean because of its obscurity; some say it is a school in one sense, but in another sense not. It seems, however, to be a school. For we call a school that which follows or seems to follow some rational account in accordance with appearances; on which basis we might reasonably call the Skeptical school a school. But if we understand by school an inclination toward doctrines that have a coherence, it could no longer be called a school; for it has no doctrines. Such, then, are the beginnings, successions, and so many parts, and this number of schools of philosophy.

​Moreover, a short time ago an Eclectic school was introduced by Potamo of Alexandria, who selected what pleased him from each of the schools. He holds, as he says in his Elements, that there are criteria of truth: one being that by which judgment is made, that is, the governing principle; the other that through which, such as the most accurate impression. He also holds as principles of all things matter and the efficient cause, quality and place; for they correspond to that out of which, that by which, in what quality, and in which. And the end to which all things are referred is a life perfect according to every virtue, not without the natural things of the body and external goods. We must now speak of the men themselves, and first of Thales.