Rights, Games and Social Choice

Abstract

It has been argued by Amartya Sen that two of the most fundamental principles in evaluating social states-the Pareto principle and the libertarian claim-conflict with each other.' The Pareto principle demands that if everyone prefers a certain social state to another, then the former state is better for the society than the latter. The libertarian claim is that everyone has a right to determine certain decisions by himself, no matter what others think. Sen's proof of the impossibility of a Paretian liberal has provoked an extensive debate among economists, political scientists and philosophers. A fundamental assumption in Sen's argument is that, for any set of individual preference orderings, a collective choice rule determines a social preference ordering of the possible social states. Both the Pareto principle and the condition of minimal liberalism are formulated as constraints on social preference relations. A consequence of this approach is that an individual right, in its most elementary form, is conceived of as a possibility of determining the social ordering of a pair of social states. In all technical discussions that have followed Sen's original result, this view of individual rights has hardly been questioned.2 I believe, however, that it is nr1isleading. An alternative approach to individual rights, suggested by Robert Nozick, is that such rights, if exercised, put constraints on the set of alternatives open to social choice. ([ 13]: 165-66.) Nozick sees no conflict between social welfare and liberalism-for him rights take precedence over welfare. In this paper, I will present a simple framework for rights and the exercising of rights in which Nozick's suggestion is incorporated. A system of individual and collectivistic rights will be put into a gametheoretical setting where the choices of strategies by individuals or coalitions correspond to the exercising of different rights. This approach is fundamentally different from Sen's and I believe that rights,