=55.= In the opposite direction ARISTIPPUS of Cyrene shared the sympathetic tone of Socrates, but could not adopt his moral earnestness or his zeal for the good of others. He refused altogether the earnest appeal of Socrates that he should take part in politics. ‘It seems to me,’ he says, ‘to show much folly that a man who has quite enough to do to find the necessities of life for himself, should not be satisfied with this, but should take upon himself to provide his fellow-citizens with all that they want, and to answer for his action in the courts if he is not successful.’ Aristippus revolted altogether from the ascetic form in which the Cynics represented his master’s teaching, and held that the wise man, by self-restraint and liberal training, attained to the truest pleasure, and that such pleasure was the end of life. The Cyrenaics (as his followers were called) were the precursors in ethics of the school of Epicurus; and the bitter opposition which was later on to rage between Stoics and Epicureans was anticipated by the conflict between the Cynics and the Cyrenaics. [Sidenote: The Megarians.] =56.= The school of EUCLIDES of Megara swerved suddenly from these ethical interests and devoted itself mainly to the problems of dialectic. From the Socratic practice of classification it arrived at the doctrine of the One being, which alone it held to be truly existent, and which it identified with the One God proclaimed by Xenophanes and his followers of the Eleatic school. To the Megaric school we are therefore chiefly indebted for the assertion of the philosophical principle of monism; the same school drew the necessary logical consequence, that evil is not in any real sense existent. From the Eleatics the Megarians further derived an interest in logical speculation of all kinds, and they were greatly occupied with the solution of fallacies: amongst the followers of this school we first meet with the puzzles of ‘the heap’ (_Sorites_), ‘the liar’ (_Pseudomenos_), and others upon which in later times Chrysippus and other Stoics sharpened their wits[89]. DIODORUS the Megarian set out certain propositions with regard to the relation of the possible and the necessary which are of critical importance in connexion with the problem of free-will[90]. Finally STILPO, who taught in Athens about 320 B.C., and who made a violent attack upon Plato’s theory of ideas, adopted an ethical standpoint not unlike that of the Cynics[91], and counted amongst his pupils the future founder of Stoicism. Stilpo enjoyed amongst his contemporaries a boundless reputation; princes and peoples vied in doing him honour[92]; but we have scarcely any record of his teaching, and know him almost exclusively as one who contributed to form the mind of Zeno. [Sidenote: Advance of Philosophy.]