On the informational basis of social choice with the evaluation of opportunity sets

This paper examines the informational basis of social choice in a broader conceptual framework. Formal welfarism is a social evaluation in which any information other than the well-being of individuals is excluded, where the notion of individual well-being can be conceived in various ways. We propose a notion of individual well-being defined over pairs of outcomes and opportunity sets from which they are chosen. The concept of consequentialism and non-consequentialism is naturally introduced by restricting individual evaluation functions over the pairs of outcomes and opportunity sets. The two formal welfarism theorems provide axiomatic characterizations of formal welfarism in the extended framework. We show that the presence of a consequentialist or a non-consequentialist affects the validity of the two formal welfarism theorems in the extended framework.