"For one thing, it is gratuitous to advise any human being to look out for himself. You can be sure that he will. It is far more difficult to persuade him to help his neighbor to build a dam or to defend a town or to give food he has accumulated to the victims of a famine. But since we must live together, dependent upon one another for many things and services, altruism is necessary to survival. To get people to do needed things is the perennial hard task of government, not to mention of religion and philosophy."