An idea · Nineteenth Century · first attested 1861
The Principle of Utility
The right action is the one that maximizes the happiness of those affected.
Bentham's foundational principle, refined by Mill: actions are right insofar as they tend to produce pleasure, wrong insofar as they produce pain — counting everyone's pleasure equally. Utilitarianism is the most influential consequentialist ethics and continues to shape welfare economics, public policy, and applied ethics.