It seems that Lysis, foreseeing the wrong inductions that would be drawn from what he had said, and as if he had a presentiment that one would not fail to generalize the influence of Necessity upon the actions of men, may have wished beforehand to oppose himself to the destructive dogma of fatality, by establishing the empire of the Will over the passions. This is in the doctrine of Pythagoras the real foundation of the liberty of man: for, according to this philosopher, no one is free, only he who knows how to master himself,[315] and the yoke of the passions is much heavier and more difficult to throw off than that of the most cruel tyrants. Pythagoras, however, did not, according to Hierocles, prescribe destroying the passions, as the Stoics taught in late times; but only to watch over them and repress excess in them, because all excess is vicious.[316] He regarded the passions as useful to man, and although produced in principle by Necessity, and given by an irresistible destiny, as nevertheless submissive in their use to the free power of the Will. Plato had well realized this truth and had forcibly indicated it in many passages of his works: one finds it chiefly in the second dialogue of Hippias, where this philosopher shows, evidently without seeming to have the design, that man good or bad, virtuous or criminal, truthful or false, is only such by the power of his will, and that the passion which carries him to virtue or to vice, to truth or falsehood, is nothing in itself; so that no man is bad, only by the faculty which he has of being good; nor good, only by the faculty which he has of being bad.