Optimal taxation theory and principles of fairness

The achievements and limitations of the classical theory of optimal labor-income taxation based on social welfare functions are now well known, although utilitarianism still dominates public economics. We review the recent interest that has arisen for broadening the normative approach and making room for fairness principles such as desert or responsibility. Fairness principles sometimes provide immediate recommendations about the relative weights to assign to various income ranges, but in general require a careful choice of utility representations embodying the relevant interpersonal comparisons. The main message of this paper is that the traditional tool of welfare economics, the social welfare function framework, is flexible enough to incorporate many approaches, from egalitarianism to libertarianism.