Utilitarian aggregation of beliefs and tastes

Harsanyi's utilitarianism is extended here to Savage's framework. We formulate a Pareto condition that implies that both society's utility function and its probability measure are linear combinations of those of the individuals. An indiscriminate Pareto condition has been shown to contradict linear aggregation of beliefs and tastes. We argue that such a condition is not compelling: Society should not necessarily endorse a unanimous choice when it is based on contradictory beliefs. Our Pareto condition is restricted to choices that involve identical beliefs only.