Impartiality and relative utilitarianism

A novel axiomatization of relative utilitarianism is provided using the single-profile setting used in Harsanyi’s Social Aggregation Theorem. Harsanyi’s axioms are supplemented with an impartiality axiom that requires social alternative lotteries p and q to be socially indifferent when (i) two individuals have conflicting preferences for them and everybody else is indifferent and (ii) the concerned individuals’ strengths of preference for p over q have the same magnitude. This axiomatization shows that equality of the social weights can be obtained in a single-profile setting and that no interprofile condition is needed to obtain profile-independent weights in a multi-profile setting.