In the context of the discussion of psychological egoism and its opposition to psychological altruism, one distinguishes between selfishness and self-interest. These two terms differ due to the placing of oneself over others without regarding others’ interests, which is inherent to selfishness but not self-interest. In addition to these concepts, one should consider such terms as voluntary action and ethical egoism.
A voluntary action is a deed committed by a person out of their own will without outside persuasion. This is essential to understand when analyzing different situations for the role of psychological egoism in them. Furthermore, it is relevant to define ethical egoism, which asserts that it is morally right to act in one’s self-interest regardless of others. This concept is different from psychological egoism, which acknowledges the fact that people are motivated by their self-interest.