In ordinary speech, selfishness (also called ‘egotism’, a word never used in philosophy).
As a philosophical doctrine egoism is either psychological egoism (for which see hedonism), or ethical egoism, which contrasts with universalism and altruism. Like them it is a form of consequentialism, and prescribes that everyone should always act so as to maximize his own happiness or welfare.
Egoism must be distinguished from the absurd doctrine, which has no name, that everyone should maximize the speaker’s happiness – but this very distinction leads to an objection to egoism: can I consistently prescribe egoism to you, since I shall be encouraging you to act in your interest and not in mine? Also seeking my own happiness may not be the best way of achieving it.
However, sometimes ‘enlightened egoism’ is advocated as a means rather than an end, on the grounds that for everyone to pursue their own interest will maximize the general prosperity.
H Sidgwick, The Methods of Ethics, book 2 (1874; 7th and final edn 1901)
Egoism is the philosophy concerned with the role of the self, or ego, as the motivation and goal of one’s own action. Different theories on egoism encompass a range of disparate ideas and can generally be categorized into descriptive or normative forms. That is, they may be interested in either describing that people do act in self-interest or prescribing that they should. Other definitions of egoism may instead emphasise action according to one’s will rather than one’s self-interest, and furthermore posit that this is a truer sense of egoism.
The New Catholic Encyclopedia states of egoism that it “incorporates in itself certain basic truths: it is natural for man to love himself; he should moreover do so, since each one is ultimately responsible for himself; pleasure, the development of one’s potentialities, and the acquisition of power are normally desirable.” The moral censure of self-interest is a common subject of critique in egoist philosophy, with such judgments being examined as means of control and the result of power relations. Egoism may also reject that insight into one’s internal motivation can arrive extrinsically, such as from psychology or sociology, though, for example, this is not present in the philosophy of Friedrich Nietzsche.