The Role of Information in Social Welfare Judgements.

This paper criticizes the claim that the Arrow Impossibility Theorem arises from an attempt to make social welfare judgments based on inadequate information. This paper shows how it is possible to modify conventio nal social choice to include those kinds of information the absence o f which is said to be responsible for the Arrow Theorem. However, a v ery similar impossibility theorem can be proved in the new framework. This suggests that there is a need to base welfare judgments on card inal utilities (or some similar kind of information). The author anal yzes the Liberal Paradox in terms of the framework proposed in the pa per. Copyright 1987 by Royal Economic Society.