Theory Reduction

Philosophers use “theory reduction” as a term of art to denote the scientific practice whereby a more basic theory expresses or otherwise captures the facts and principles described by a less basic theory. The reducing theory thus preserves the ontology of the reduced theory, at least in ideal cases. Accordingly, theory reduction contrasts with “theory replacement” according to which a less basic theory and its ontology are rejected.

One important topic concerns the logic of reduction or how it is best conceived. Major ideas includes reduction as a derivation by bridge principles (Nagel 1961), the role of identities in bridge principles (Sklar 1967), approximate reduction (Schaffner 1967), an expanded continuum of strong to weak reduction that advertises no bridge laws (Churchland 1979; Bickle 1997), compositional or mechanistic reduction (Wimsatt 1976; Bechtel 2007), and functional reduction (Kim 1998). Other important topics concern the analysis of scientific cases (Kitcher 1984; Bickle 2005), the nature of theories as sentential items versus models (SUPPES 1957), issues of intralevel versus interlevel competition (McCauley 1986), how the co-evolution of theories might affect the prospects for or the interpretation of reduction (Churchland 1986; Endicott 1998), cases wherein a less basic and unreduced theory is retained rather than replaced (Fodor 1974; Rosenberg 2006), and the phenomenon of multiple realizability that underlies the non-reduced status of such theories (Bechtel 1999; Batterman 2000; Shapiro 2004; Aizawa & Gillett 2009).