Social choice in a sequential environment

In a recent paper 2] we presented a model of societies. In the context of that model, we argued that in the field of social choice it is necessary to consider some type of cardinal utility indices if we want to develop a sensible analysis. The main purpose of the present article is to complete and extend an argument initiated in Section 5 of 2] by giving a rigorous formulation and proof of a theorem informally discussed there.To formulate rigorously our theorem a concept of impersonality is introduced that appears to be more general than those which have been used in the economic literature.Our arguments concerning the need to use cardinal utility indices in the field of social choice are shown to be similar to those used by the proponents of decentralization in the controversy regarding centralization and decentralization as alternative ways of organizing the economic activity of a society.An earlier version of this paper was presented at the Econometric Society Winter Meeting held in Toronto, Canada, December 1972.