In contrast with these other ethical perspectives, egoism is concerned with an action's real-life implications for the welfare of the acting human being. The specific principles recognized by egoism all derive their justification from their consequences in reality—that is, from the long-run internal and external benefits that they bring to the life of the individual who practices them. Our discussion of virtues in a later subsection, for instance, will include demonstrations of those practical benefits. Egoism flatly rejects the idea, inherited by Kant and later altruists from the ancient Stoics, that "virtue is its own reward."

The epistemological clash between egoism and other moral viewpoints explains why many people have initial difficulty in grasping the concept of selfishness. Accustomed to viewing moral issues in terms of consciousness rather than reality, they falsely assume it to mean the pursuit of the whims of one's consciousness—i. e., "do your own thing"—without regard to real-life consequences. In practice, they associate the term with an incongruous admixture of egoistic, egotistic, and hedonistic behaviors. In this course, the concept of selfishness is applied only to the pursuit of those values that sustain and promote one's own life. Like other valid concepts, it is thus based on a specific, observable difference in kind among units of reality.