摘要：Nehring (2004) proposes an interesting methodology to extend the utilitarian criteriondefined under complete information to an interim social welfare ordering allowing to com-pare acts. The first axiom defining his approach, called "State Independence," requiresthe interim social welfare ordering to be consistent with ex-post utilitarian comparisons:if it is commonly known that the act f selects in each state an outcome that is sociallyprefererred according to the utilitarian criterion to the lottery selected by an alternativeact g, then f should be interim socially preferred to g. The second axiom is a classicalcondition of consistency with respect to interim Pareto comparisons: if an act f interimPareto dominates and act g, then f should be interim socially preferred to g. Nehringproves that 1) these two axioms are incompatible if there is no common prior, and 2)that the unique interim social welfare ordering that satisfies these two axioms when thereis a common prior is the ex-ante utilitarian criterion
