Instrumental Rationality in the Social Sciences

This paper draws some bold conclusions from modest premises. My topic is an old one, the Neohumean view of practical rationality. First, I show that this view consists of two independent claims, instrumentalism and subjectivism. Most critics run these together. Instrumentalism is entailed by many theories beyond Neohumeanism, viz., by any theory that says rational actions maximize something. Second, I give a new argument against instrumentalism, using simple counterexamples. This argument systematically undermines consequentialism and rational choice theory, I show, using detailed examples of their many social science applications. There is no obvious fix.