He stood at the head of those who, regarding the universe as imperishable and existing from eternity, looked upon the chronic succession in the theory of Plato as a form in which to denote the relations of conceptual succession. He asserted that the soul was a self-moving member,—called Unity and Duality deities, considering the former as the first male existence, ruling in heaven, father and Jupiter; the latter as the female, as the mother of the Gods, and the soul of the universe, which reigns over the mutable world under heaven. He approximated to the Pythagoreans in considering Number as the principle of consciousness, and consequently of knowledge; supplying, however, what was deficient in the Pythagorean theory by the definition of Plato, that it is only in as far as number reconciles the opposition between the same and the different, and can raise itself to independent motion, that it is soul.
In his ethics he endeavoured to render the Platonic theory more complete, and to give it a more direct applicability to human life; admitting, besides the good and the bad, of something which is neither good nor bad, and some of these intermediate things, such as health, beauty, fame, good fortune, he would not admit to be absolutely worthless and indifferent. He maintained, however, in the most decided manner, that virtue is the only thing valuable in itself, and that the value of everything else is conditional, (see Cic. de Fin. iv. 18, de Leg. i. 21, Acad. i. 6, Tusc. Quæst. v. 10—18,) that happiness ought to coincide with the consciousness of virtue. He did not allow that mere intellectual scientific wisdom was the only true wisdom to be sought after as such by men: and in one point he came nearer the precepts of Christianity than any of the ancients, when he asserted the indispensableness of the morality of the thoughts to virtue, and declared it to be the same thing, whether a person cast longing eyes on the possessions of his neighbour, or attempted to possess himself of them by force.
Antisthenes was older than Plato; though the exact time of his birth is uncertain: but he fought at the battle of Tanagra, b.c. 420, though then very young. He became a
