Philosophy, according to Zeno and other Stoics, was intimately connected with the duties of practical life. The contemplation, meditation, and thought recommended by Plato and Aristotle seemed only a covert recommendation of selfish enjoyment. The wisdom which it should be the aim of life to attain is virtue; and virtue is to live harmoniously with Nature. To live harmoniously with Nature is to exclude all personal ends; hence pleasure is to be disregarded, and pain is to be despised. And as all moral action must be in harmony with Nature the law of destiny is supreme, and all things move according to immutable fate. With the predominant tendency to the universal which characterized their system, the Stoics taught that the sage ought to regard himself as a citizen of the world rather than of any particular city or state. They made four things to be indispensable to virtue,--a knowledge of _good_ and _evil_, which is the province of the reason; _temperance_, a knowledge of the due regulation of the sensual passions; _fortitude_, a conviction that it is good to suffer what is necessary; and _justice_, or acquaintance with what ought to be to every individual. They made _perfection_ necessary to virtue; hence the severity of their system. The perfect sage, according to them, is raised above all influence of external events; he submits to the law of destiny; he is exempt from desire and fear, joy or sorrow; he is not governed even by what he is exposed to necessarily, like sorrow and pain; he is free from the restraints of passion; he is like a god in his mental placidity. Nor must the sage live only for himself, but for others also; he is a member of the whole body of mankind. He ought to marry, and to take part in public affairs; but he is to attack error and vice with uncompromising sternness, and will never weakly give way to compassion or forgiveness. Yet with this ideal the Stoics were forced to admit that virtue, like true knowledge, although theoretically attainable is practically beyond the reach of man. They were discontented with themselves and with all around them, and looked upon all institutions as corrupt. They had a profound contempt for their age, and for what modern society calls "success in life;" but it cannot be denied that they practised a lofty and stern virtue in their degenerate times. Their God was made subject to Fate; and he was a material god, synonymous with Nature. Thus their system was pantheistic. But they maintained the dignity of reason, and sought to attain to virtues which it is not in the power of man fully to reach.