On the impossibility of complete Non-Interference in Paretian social judgements

We study a principle of ‘Non-Interference’ in social welfare judgements. Non-Interference captures aspects of liberal approaches (particularly a Millian approach) to social decision making. In its full generality, Non-Interference produces an impossibility result: together with Weak Pareto Optimality, it implies that a social welfare ordering must be dictatorial. However, interesting restricted versions of Non-Interference are compatible with standard social welfare orderings.