Plato was not the only philosopher to regard himself as the heir and successor of Socrates. This claim was also put forward for himself by Antisthenes. Slightly older than Plato, he was already living in Athens as a sophist before he met Socrates, but thereafter he became Socrates' ardent disciple. That aspect of Socrates which he most fervently admired, and which left its mark later on Antisthenes' own school of Cynics, was the strength and independence of his moral character. By comparison with this quality the Cynics deliberately disparaged all learning, all refinement, all civilization even; they set themselves to ignore, or even (in the case of Diogenes) openly to flout, the customary conventions and proprieties; they determined to reject as superfluous and dispensable worldly goods, worldly positions, even freedom in the ordinary sense — for slavery, they held, can be borne with perfect tranquillity, and leaves it open to the slave to maintain his integrity and virtue. They seem at first to have been inspired, as perhaps no other group of philosophers was, with an active missionary spirit. Instead of pursuing their debates in academic seclusion, they became wandering mendicants, preaching against the shams and corruption of the world, and in favor of a simple, supposedly "natural" life in which all should be equal, the whole of mankind one family. It is plain that we have here a foretaste of Stoicism; and in fact, as Stoicism developed, the Cynics languished. Much later, their doctrines were revived, but in a weakened form. The Hellenistic Cynics, instead of preaching opposition to the forms and conventions of life, favored rather an easy adaptability to them. While still insisting on their triviality as compared with the ways of "nature," still preaching the brotherhood of man, and still disparaging learning, they were ready to approve of an uncommitted acceptance of whatever the world might offer. Wealth, strictly, was worthless; but, if one happened to be rich, one might as well act out the proper part of a rich man. Since the doctrine had never had any great theoretical backing, the later writings of Cynicism tended to become less philosophical, less argumentative, more and more a blend of exhortation and satire. The diatribes of Teles, and the essays and fables of Menippus, contributed little if anything to philosophy; but they provided, apart from the lively satire of their contents, new literary forms that were later adopted by, among many others, Seneca and Lucian.
But later Stoics retained a high respect for the Cynic philosopher. We find in Epictetus the following words:
— And how is it possible for a man who has nothing, who is naked, without home or hearth, in squalor, without a slave, without a city, to live serenely? Behold, God has sent you the man who will show in practice that it is possible. "Look at me," he says, "I am without a home, without a city, without property, without a slave; I sleep on the ground; I have neither wife nor children, no miserable governor's mansion, but only earth, and sky, and one rough cloak. Yet what do I lack? Am I not free from pain and fear, am I not free? When has anyone among you seen me failing to get what I desire, or falling into what I would avoid? When have I ever found fault with either God or man? When have I ever blamed anyone? Has anyone among you seen me with a gloomy face? And how do I face those persons before whom you stand in fear and awe? Do I not face them as slaves? Who, when he lays eyes upon me, does not feel that he is seeing his king and his master?"
Lo, these are words that befit a Cynic, this is his character, and his plan of life.