On intra- and interpersonal utility comparisons

In this paper, it is suggested to formulate assumptions on the comparability of individual utilities in terms of meaningful statements rather than using the usual way of defining such assumptions by means of certain sets of admissible transformations. Various assumptions involving intra- and interpersonal comparisons of utility levels and utility differences are introduced in terms of meaningful statements and compared to their “traditional” counterparts. It is shown that these two approaches are, in general, not equivalent. In a social choice framework, it is demonstrated that the difference between these approaches can be quite substantial: replacing the usual cardinal unit comparability assumption by a condition involving comparisons of utility differences which is similar in spirit turns a well-known characterization of the utilitarian social welfare functional into an impossibility theorem.