A response to:

Date: Sun, 17 Sep1995
From: Frances Rosenbluth

>Along with Meg, I'd like to add a response to Prof. Hashimori's assertion that
rational choice political scientists make more assumptions about aggregate
utility functions than economists do. This, in general, is not true.

It is statements like these that concern me when I read what political
scientists are doing with rational choice modeling techniques. Maybe it is only
a semantic discrepany, maybe it is not. If it is the former, than please except
my apology for my intention is not to be trite. If it is the latter, than
perhaps I will have given food for additional thought.

Neither should economists, nor political scientists aggregate across utility
functions. Aggregation in an economic sense means addition, and individual
utility can neither be measured, nor added. In economics we aggregate across
individual demand functions, which are DERIVED from individual utility
functions. We DO NOT AGGREGATE across utility functions.

When in economics we use representative agents, we assume that everyone has the
same, or similar (homothetic) utility function -- i.e. everyone is subject to
the same set of choices with identical inclinations toward each. It is this
notion of identical inclinations which is the hardest to swallow empircally. It
is one thing to be confronted with the same set of choices, it is quite another
to assume, that one's proclivity to choose one alternative over the other is
identical with everyone elses. That assumes A WHOLE LOT of prior conditioning.

John Thies's recent entry explained very well, what "ratchers" are up to in
political science, and your own new insights seem to coincide with his. Once
again, however, the political arena in which people seek to coordinate
collectively supported agendas, is very different from the market place, where
the individual must reach into his pocket each time he confronts a new or the
same cashier.

When we use representative agents in International Trade Theory we assume the
existence of social indifference curves, which amounts to something like a
national personality.

Have you heard any good Belgian jokes lately?

Hashimori, Iwato