Harsanyi's utilitarian theorem states that the social welfare function is the weighted sum of individuals' utility functions if: (i) society maximizes expected social welfare; (ii) individuals maximize expected utility; (iii) society is indifferent between two probability distributions over social states whenever all individuals are. After giving a simpler proof, an alternative axiomatic foundation for Vickrey-Harsanyi utilitarianism is provided. By making using an extended version of Harsanyi's concept of a player's "type" in the theory of games with incomplete information, the problem of forming social objectives when there is incomplete information can also be resolved, at least in principle.