In ethics egoism entails that the individual self is either the motivating moral force and is, or should, be the end of moral action.
Egoism divides into both a positive and normative ethic.
The positive ethic views egoism as a factual description of human affairs, that is people are motivated by their own interests and desires. The normative ethic is that they should be so motivated. In its strong form the theory asserts that people always act in their own interests, even though they may disguise their motivation with references to helping others or doing their duty. At this point psychological egoism's validity turns on the question of moral motivation. If psychological egoism is reduced to an assumption concerning human nature, then it follows that it is just as valid to hold a competing theory of human motivation, psychological altruism for example.