Rational egoism (also called rational selfishness) is the principle that an action is rational if and only if it maximizes one’s self-interest.[1][2] As such, it is considered a normative form of egoism,[3] though historically has been associated with both positive and normative forms.[4] 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.[5]

Originally an element of nihilist philosophy in Russia, it was later popularised in English-speaking countries by Russian-American author Ayn Rand.