Measurement scales and welfarist social choice

- A generalization of a social welfare functional is proposed.
- Real well-being changes are distinguished from those due to measurement scale changes.
- Scale-dependent welfarism is axiomatized.
- Scale-dependent welfarism allows for ethically attractive functionals that would otherwise be excluded.

The social welfare functional approach to social choice theory fails to distinguish a genuine change in individual well-beings from a merely representational change due to the use of different measurement scales. A generalization of the concept of a social welfare functional is introduced that explicitly takes account of the scales that are used to measure well-beings so as to distinguish between these two kinds of changes. This generalization of the standard theoretical framework results in a more satisfactory formulation of welfarism, the doctrine that social alternatives are evaluated and socially ranked solely in terms of the well-beings of the relevant individuals. This scale-dependent form of welfarism is axiomatized using this framework. The implications of this approach for characterizing classes of social welfare orderings are also considered.