 There is an explanation for why utilitarianism seems so much less determinate in its policy (including structural) recommendations and it points to what is the greatest challenge to utilitarianism as a guiding distributive principle. Other distributive principles can rule out, relatively quickly, various policies on the grounds that they clearly violate the guiding principle, but utilitarians must examine, in great detail, all the policies on offer. For each policy, they must determine the distribution of goods and services yielded by the policy and at least three other factors: the identity of each person in the distribution (if individuals’ utility functions differ); the utility of each person from the goods and services distributed to them; the utility of each person from the policy itself. They must then aggregate these utilities across all individuals. The size of the information requirements make this task impossible. Hence, broad assumptions must be made and each different set of assumptions will yield a different answer, and so the answers range across the full set of policies on offer. Moreover, there is no obvious way to arbitrate between the different sets of assumptions. For instance, suppose three utilitarians agree on the same utilitarian distributive principle. Utilitarian 1, for example, may assert that the population’s utility function conforms to function A (e.g. people’s marginal utility is diminishing at rate R) and is maximized by Policy 1; Utilitarian 2, however, asserts that half the population’s utility function conforms to function A and half to function B (e.g. people’s marginal utility is diminishing at rate 2R) and is maximized by Policy 2; Utilitarian 3 asserts Utilitarian 2 is correct about the utility functions of the population but claims that Policy 3 is the one that will maximize utility. The challenge for contemporary utilitarians is to explain, given the massive informational requirements of utilitarianism and our apparent human inability to meet those requirements, how the population, and its experts, can plausibly arbitrate between conflicting policy and institutional recommendations coming from utilitarian theorists who share the same underlying normative principle.