To understand the ethical egoism theory we must first know certain principles behind it. Ethical egoism is a normative theory, which means it prescribes how we should think, behave, and act. Shaver presents three features of ethical egoism as individual, personal and universal. He states that individual ethical egoism is notion that all persons should serve self-interest. Personal ethical egoism is the belief that one should act from the motive of self-interest (Shaver). Universal ethical egoism is the doctrine that all persons should pursue their own interests exclusively (Shaver).
The foundation of a coherent theory of ethics is in truth, consistency, and completeness. 'In truth' means that a statement of action is either true or false and not both. Consistency means that there should be no contradictions or incompatible statements. Completeness means that there should be no moral truth, which is not provable from the basic moral principles of the theory (Moseley).