John Harsanyi

Hungarian-American economist and philosopher who provided game-theoretic foundations for utilitarianism and defended rule utilitarianism independently of Rawls's veil of ignorance argument.

Preference aggregation: behind a veil of ignorance, a rational agent would choose to maximize aggregate expected utility — providing a game-theoretic derivation of utilitarianism. The Aggregation Theorem: individual utility functions can be aggregated into a social welfare function under certain conditions. Nobel Prize in Economics 1994 (shared with Nash and Selten).