 Perhaps the inconsistency that would most disconcert an economist arises between the Pareto criterion and the demand for aggregate rationality under uncertainty. Consider again our society of n individuals. Assume now, though, that society must choose among a number of policies, the consequences of which will depend on the underlying but unknown state of the world. Each individual has preferences over these policies that satisfy the axioms of subjective expected utility theory. Consequently, one may represent each individual’s preference over actions by a set of preferences over consequences and a set of beliefs (that satisfy the probability axioms) over states of the world; moreover, the individual prefers policy p to policy q if and only if the expected utility from policy p exceeds the expected utility from policy q. 