In defense of unrealistic assumptions

I argue that a theory's assumptions always are and ought to be unrealistic. Further we should attempt to make them more unrealistic in order to increa se a theory's fruitfulness. Many sociologists believe that a theory's assum ptions ought to be empirically realistic. I contend that this criticism pro bably stems from the confusion of a theory's assumptions with its scope con ditions. While Friedman's (1953) similar prescription is associated with th e instrumentalist philosophy of science, I maintain that it is also consist ent with the realist view if "unrealistic" is taken to mean "incomplete" ra ther than "untrue." I discuss a recent theory of the value of children by F riedman, Hechter and Kanazawa (1994) to point out how assumptions differ fr om scope renditions and how empirically plausible and realistic hypotheses can be logically deduced from highly unrealistic assumptions. I then discus s Kollock's (1993a, 1993b) revision of Axelrod's (1984) Cooperation Theory as an example of when assumptions need to be revised.