Social choice is concerned with the selection of an ideal (or social) option, which can be a so-called ‘social state’, or a social ‘utility’, or a social ‘preference’, or a social choice ‘set’, on the basis of individual utilities, or individual utility functions, or individual preferences, or individual choice sets, or individual choice functions. A number of scholars have outlined the limited aspect of the notion of utility, including, notably and pre-eminently, Amartya Sen and Martha C. Nussbaum. Although they did not put it in such a strong phrase, the basic idea is to replace the notion of utility by the notion of capability (leaving aside ‘happiness’, a notion which for many is hardly distinguishable from utility). As has been remarked by Mozaffar Qizilbash, the development of the capability approach has been focused on the capability of an individual; and the idea of amalgamating or aggregating individual data is consubstantial with social choice. The purpose of this text is to propose some preliminary ideas regarding the aggregation of individual capabilities.

This volume has its origins in a conference on “Justice, Political Liberalism, and Utilitarianism in Honour of John Harsanyi and John Rawls” that was held at the Université de Caen in June 1996. This conference received generous financial support from the Association pour le Développement de la Recherche en Économie et en Statistique, the Centre National de la Recherche Scientifique, the Centre de Recherche en Économie et Management (UMR-CNRS 6211), the Université de Caen, and the Ville de Caen.

We are grateful to the scholars who served as referees of the individual chapters, to Pascal Engel for his help in the organization of the Caen conference, and to Cathy Zebron who assisted with the preparation of the final manuscript. At Cambridge University Press, thanks are due to Patrick McCartan, who responded so favorably when this volume was first proposed to him, and to Scott Parris, who has been our editor from the outset. We are particularly grateful to our contributors and to Scott for their patience and encouragement during the inordinately long time it has taken to bring this project to fruition.

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.