A welfarist critique of social choice theory

Abstract

This paper reconsiders the discussion on ordinal utilities versus preference intensities in voting theory. It is shown by way of an example that arguments concerning observability and risk-attitudes that have been presented in favour of Arrow’s Independence of Irrelevant Alternatives (IIA), and against utilitarian evaluation, fail due to strategic voting. The failure of these two arguments is then used to justify utilitarian evaluation of outcomes in voting. Given a utilitarian viewpoint, it is then argued that strategy-proofness is not normatively acceptable. Social choice theory is criticised not just by showing that some of its most important conditions are not normatively acceptable, but also by showing that the very idea of imposing condition on social choice function under the assumption of sincere behaviour does not make much sense because satisfying a condition does not quarantee that a voting rule actually has the properties that the condition confers to it under sincere behaviour. IIA, the binary intensity IIA, and monotonicity are used as illustrations of this phenomenon.