ABSTRACT
In Kenneth Arrow’s seminal Social Choice and Individual Values (Arrow 1951), collective decision-making is viewed as a problem in preference aggregation: the objective is to determine a collective (social) ranking of a set of alternatives based on individual preferences. This procedure for aggregating preferences, a social welfare function, is designed before the preferences are known so that it will be applicable whatever these preferences turn out to be. In this respect, a social welfare function operates like the rules for conducting an election: the procedure for determining a winner based on the ballots cast is specified before the voting takes place.
