A coherentist conception of ad hoc hypotheses Samuel Schindler
[email protected] forthcoming in Studies in History and Philosophy of Science Abstract What does it mean for a hypothesis to be ad hoc? One prominent account has it that ad hoc hypotheses have no independent empirical support. Others have viewed ad hoc judgements as subjective. Here I critically review both of these views and defend my own Coherentist Conception of Ad hocness by working out its conceptual and descriptive attractions. Keywords: ad hoc; confirmation; independent support; novel success; coherence 1 Introduction It is widely agreed—amongst scientists and philosophers alike—that a good hypothesis ought not to be ad hoc. Consequently, a theory that requires ad hoc hypotheses in order to overcome empirical tests ought to be less acceptable for a rational agent than a theory that does without (or with fewer) ad hoc amendments. But what precisely does it mean for a hypothesis to be ad hoc? This is what this paper is about. Concept clarification is one of the central tasks of philosophy. Usually, it involves an explicandum and an explicatum, viz. a pre-analytic concept that is to be explicated and a concept which explicates this concept, respectively (Carnap 1950). For example, the concept TEMPERATURE explicates our pre- analytic concepts of WARM and COLD, and allows us to be much more precise and clear in the way we communicate with each other. In the case of ad hocness, the pre-analytic concept is something along the lines of “was introduced for the sole purpose of ‘saving’ a theory which faces observational anomalies”.