Interpersonal Comparisons of the Extended Sympathy Type and the Possibility of Social Choice

Abstract

As is well-known, Arrow’s celebrated general possibility theorem is based on the view that ‘interpersonal comparison of utilities has no meaning and, in fact, that there is no meaning relevant to welfare comparisons in the measurability of individual utility’ (Arrow, 1963, p. 9). It deserves emphasis that the reason underlying his insistence on ordinal as well as interpersonally non-comparable utilities is ‘the application of Leibniz’s principle of the identity of indiscernibles’, according to which ‘only observed difference can be used as a basis for explanation’ (Arrow, 1963, p. 109). It was precisely because interpersonal comparison of utilities was considered not to be based on any observable choice behaviour that the Arrow social welfare function was to depend only on interpersonally non-comparable individual preference orderings over the set of alternative social states.