Ethical egoism is the view that the pursuit of one’s own happiness is the highest moral value. Thus, people act morally when they pursue their own best interests. This view is the opposite of altruism which is the position that the highest aim of people should be to seek the welfare of others.
Ethical egoism does not necessarily call for rude or overtly selfish behavior, but with all things being equal, a person should look out for his own interests over those of others. Ethical egoism is sometimes viewed as being rooted in psychological egoism which is the view that people are psychologically-oriented toward seeking their own interests over the interests of others. Even if a person appears to act in the best interests of someone else, even that act is ultimately motivated by self interest.
Ethical egoism is found in the person of Glaucon in Plato’s Republic. Forms of ethical egoism can also be found in the writings of Aristotle, Thomas Hobbes, and Benedict Spinoza.