Abstract
Utilitarianism holds that morally right actions are those that maximize aggregate welfare. One might therefore expect a society that adopts utilitarianism as its guiding moral code to flourish. However, across five preregistered studies (plus one preregistered supplemental study; total N = 2,626), we find that laypeople view utilitarianism as being self-defeating. Participants expect a society that adopts a welfare-maximizing moral code to contain less happiness and more suffering than a society that adopts a moral code based on fixed rules or duties. While individuals endorse welfare maximization as a societal aim and believe that promoting moderate versions of utilitarianism’s implications—especially greater impartiality and personal self-sacrifice—would advance this aim, they view utilitarianism as promoting these implications to an extreme and ultimately self-defeating degree. This yields a fundamental paradox in lay moral reasoning: the moral philosophy explicitly designed to maximize welfare is expected to fail to do so at scale.