Revisiting Fodor’s Argument Against the Unity of Science

Abstract The article offers an internal critique of Fodor’s original argument against the unity of science, claiming that multiple realization in special sciences blocks reduction to physical science and secures their autonomy. Fodor’s argument has been a cornerstone of the argument against reductionism in the philosophy of mind. In this article, we aim to show that it fails even when Fodor’s own presuppositions and his own understandings of key terms are considered. In this sense, the article probes the original argument for its internal consistency. Firstly, we provide an overview of multiple realization, along with the main motivation for it, i.e., the rejection of psychophysical reductionism, and a detailed discussion of Fodor’s claims and key terminology. This is followed by examining Fodor’s argument against psychophysical reductionism using his key example of multiple realization, Gresham’s law in economics. We argue that the law is either not multiply realized or basic sciences are also multiply realized, both options being problematic for Fodor. Turning to the apparent impossibility of reducing ceteris paribus special science laws via exceptionless bridge laws to exceptionless physical laws, we argue that the problem lies in the notion of “proper law”: if understood as an exceptionless law, the argument rests on a contradiction, and if understood as a “not gerrymandered” (not arbitrary) law, the key assumption of the argument, i.e., that special science kinds are natural, is simply false. The original argument, therefore, fails to establish the autonomy of special sciences even if Fodor’s own understanding of key terms is adopted, which leaves him, contrary to his opinion, empty-handed in the battle against psychophysical reductionism.