The opposition between utilitarianism and liberal egalitarianism has triggered the most important developments in political philosophy in the twentieth century and has had a considerable effect on other subjects as well, such as law and economics. The turn of the new century has witnessed the death of two prominent scholars in these debates, John Harsanyi and John Rawls. Harsanyi and Rawls have undoubtedly been the leading figures in each of these schools of thought in recent decades. Building on the work of classical utilitarians such as Jeremy Bentham and John Stuart Mill, Harsanyi has provided decision-theoretic foundations for utilitarianism that have served as the touchstone for Rawls's own critique of utilitarianism. Rawls believes that utilitarianism fails to satisfy Immanuel Kant's maxim that individuals should be treated as ends in and of themselves, not just as means for promoting the social good. Drawing inspiration from the writings of social contract theorists such as John Locke and Jean-Jacques Rousseau, Rawls has fashioned a modern statement of liberal egalitarian principles for the design of the basic institutions of society that respect Kant's maxim.

The writings of Harsanyi and Rawls offer vigorous defenses of their theories, which their lively exchanges have done much to illuminate. Their theories draw on and provide support for widely shared values. Their contributions have been, and will continue to be, inspirational for scholars and others who seek to understand what social justice and ethical behavior require. The voluminous literature that has responded to Harsanyi's and Rawls'swritings has drawnoutmany of the implications of their theories, has clarified and refined their most convincing arguments, and has pointed out ambiguities and weaknesses in their reasoning.