On interpersonal utility comparisons

This paper argues that interpersonal comparisons of utility levels are difficult in principle and that interpersonal comparisons of utility differences can also hardly be defined based solely on individual choice behavior.The author is indebted to Professor M. Wooders for detailed comments on an earlier draft and to Professor R. Selten, M. Shubik, Y. Ito, K. Kamiyama and H. Atsumi for helpful discussions. He also thanks Professors L. Gevers, Y. K. Ng and a referee of this journal for valuable comments on earlier drafts.