Rational egoism (also called rational selfishness) is the principle that an action is rational if and only if it maximizes one's self-interest. As such, it is considered a normative form of egoism, though historically has been associated with both descriptive and normative forms. In its strong form, rational egoism holds that to not pursue one's own interest is unequivocally irrational. Its weaker form, however, holds that while it is rational to pursue self-interest, failing to pursue self-interest is not always irrational.
Rational egoism (Russian: ) emerged as the dominant social philosophy of the Russian nihilist movement, having developed in the works of nihilist philosophers Nikolay Chernyshevsky and Dmitry Pisarev. However, their terminology was largely obfuscated to avoid government censorship and the name rational egoism explicitly is unmentioned in the writings of both philosophers. Rational egoism was further embodied in Chernyshevsky's 1863 novel What Is to Be Done?, and was criticised in response by Fyodor Dostoyevsky in his 1864 work Notes from Underground. For Chernyshevsky, rational egoism served as the basis for the socialist development of human society.
English philosopher Henry Sidgwick discussed rational egoism in his book The Methods of Ethics, first published in 1872. A method of ethics is "any rational procedure by which we determine what individual human beings 'ought' - or what it is 'right' for them - to do, or seek to realize by voluntary action". Sidgwick considers three such procedures, namely, rational egoism, dogmatic intuitionism, and utilitarianism. Rational egoism is the view that, if rational, "an agent regards quantity of consequent pleasure and pain to himself alone important in choosing between alternatives of action; and seeks always the greatest attainable surplus of pleasure over pain".
Sidgwick found it difficult to find any persuasive reason for preferring rational egoism over utilitarianism. Although utilitarianism can be provided with a rational basis and reconciled with the morality of common sense, rational egoism appears to be an equally plausible doctrine regarding what we have most reason to do. Thus we must "admit an ultimate and fundamental contradiction in our apparent intuitions of what is Reasonable in conduct; and from this admission it would seem to follow that the apparently intuitive operation of Practical Reason, manifested in these contradictory judgments, is after all illusory".
The author and philosopher Ayn Rand also discusses a theory that she called 'rational egoism'. She holds that it is both irrational and immoral to act against one's self-interest. Thus, her view is a conjunction of both rational egoism (in the standard sense) and ethical egoism, because according to Objectivist philosophy, egoism cannot be properly justified without an epistemology based on reason.
Her book The Virtue of Selfishness (1964) explains the concept of rational egoism in depth. According to Rand, a rational man holds his own life as his highest value, rationality as his highest virtue, and his happiness as the final purpose of his life.
Conversely, Rand was sharply critical of the ethical doctrine of altruism:
Do not confuse altruism with kindness, good will or respect for the rights of others. These are not primaries, but consequences, which, in fact, altruism makes impossible. The irreducible primary of altruism, the basic absolute is self-sacrifice - which means self-immolation, self-abnegation, self-denial self-destruction - which means the self as a standard of evil, the selfless as a standard of the good. Do not hide behind such superficialities as whether you should or should not give a dime to a beggar. This is not the issue. The issue is whether you do or do not have the right to exist without giving him that dime. The issue is whether you must keep buying your life, dime by dime, from any beggar who might choose to approach you. The issue is whether the need of others is the first mortgage on your life and the moral purpose of your existence. The issue is whether man is to be regarded as a sacrificial animal. Any man of self-esteem will answer: No. Altruism says: Yes.
Two objections to rational egoism are given by the English philosopher Derek Parfit, who discusses the theory at length in Reasons and Persons (1984). First, from the rational egoist point of view, it is rational to contribute to a pension scheme now, even though this is detrimental to one's present interests (which are to spend the money now). But it seems equally reasonable to maximize one's interests now, given that one's reasons are not only relative to him, but to him as he is now (and not his future self, who is argued to be a "different" person). Parfit also argues that since the connections between the present mental state and the mental state of one's future self may decrease, it is not plausible to claim that one should be indifferent between one's present and future self.
The "selfish gene" model of evolution suggests that human (and animal) behaviors that seem altruistic are actually selfish, if viewed from the perspective of genes/phenotypes. People help each other "selflessly" because copies of their own genes also exist in others, so behaviors that help the genes survive are selected for, with the altruistic drive decreasing with genetic distance.