Philo's ethics, like the rest of his philosophy, exhibits the transfusion of Greek ideas with his Hebrew spirit. The Greek philosophers had evolved a rational plan of life, while the Jewish teachers were impregnated with burning ardor for the living God; and Philo brings the two things together, making ethics dependent on religion. The Stoics, who were the most powerful school of his day, regarded as the ideal of goodness life according to unbending reason and in complete independence of God or man. Philo understands God as a personal power making for righteousness, and man's excellence, accordingly, which is likeness to God, is piety and charity.[269] Above all he insists upon Faith ([Greek: pistis]) and he defines virtue as a condition of soul which fixes its hopes upon the truly Existent God. The Stoics also professed to honor faith or confidence above all things, but the virtue which they meant was reliance upon man's own powers. Philo's virtue is almost the converse of this. Man must feel completely dependent upon God, and his proper attitude is humility and resignation. So only can he receive within his soul the seed of goodness, and finally the Divine Logos.[270] Yet at the same time Philo remains loyal to the Jewish ideal of conduct: faith without works is empty, and, as he puts it, "The true-born goods are faith and consistency of word and action."[271] The attainment of the highest excellence demands severe discipline, save for those few blessed souls whom God perfects without any effort on their part. The rest can only secure self-realization by self-renunciation; they must avoid the bodily passions and bodily lusts.[272] At times the Divine enthusiasm causes Philo, like many a Jewish saint and like his master Plato, to scorn all bodily limitations and recommend "insensibility" ([Greek: apatheia])[273] by which he means that man should crush his physical desires and repress his feelings. Not that the good life seems to him to imply absence of pleasure. On the contrary, it is filled with the purest of joy, for when man rises to the love of God "in calm of mind, all passion spent," then and then alone has he tasted true joyousness. The symbol of this bliss is Isaac ([Hebrew: ytshk]), the laughter of the soul. It was noticed in the second chapter that Philo modified his ethical ideas during his life. In the earlier period he insists more strongly on the need of ascetic self-denial, and has almost a horror of the world. Maturer experience, however, taught him that man is made for this world, and that a wise use of its goods was a surer path to happiness and to God than flight from all temptations. In his later writings, therefore, he exhibits a striking moderation. He reproaches the ascetics for their "savage enthusiasm,"[274] probably hinting at the extreme sects of the Essenes and the Therapeutæ. "Those who follow a gentler wisdom seek after God, but at the same time do not despise human things."