Explanation, Unification, and Mechanisms

Abstract

This paper presents a new account of unifying explanation, which differs from Kitcher’s explanatory unification in a number of ways. Kitcher’s account preserves much of the covering-law model, identifying explanation with subsumption of many diverse phenomena under a general argument pattern. Many scientific explanations, however, fit neither the unification nor covering-law accounts. An important variety of these, mechanistic explanations in biology, has received considerable philosophical attention. I argue that important examples of mechanistic explanation in biology are also unifying explanations – in a sense different than Kitcher’s. Using the example of the operon, a seminal explanation of molecular biology, I show that some mechanistic models describe combining relations that unify lower-level parts in the sense of connecting them into a new, complex whole (commonsense unification). In describing how lower-level components are unified in this commonsense way, models like the operon thereby unify higher- and lower-level descriptions of the phenomenon to be explained (perspectival unification). The last sections discuss how unifying multi-level explanations can yield understanding, in an epistemically interesting sense, and show that this new account helps resolve recent debates about explanation in Systems Biology.