 (b) A characteristic difference between theory reduction and explanatory reduction stems from the fact that the former—focusing on the epistemic notion of logical deduction—does not incorporate the historically ubiquitous ontological idea that a reduction explains the whole in terms of its parts (see, e.g., Winther 2011). Models of explanatory reduction typically assume that reductive explanation is  causal explanation,  where a higher level feature is explained by the interaction of constituent parts. Stuart Kauffman (1971) gave an early expression of the idea that the search for explanations in experimental biology proceeds by decomposing an overall system into interacting parts. Wimsatt (1976b) also recognized that this mapped more naturally onto the language of biologists, especially the practice of discovering and elucidating mechanisms (see also Bechtel and Richardson 1993). Mechanism approaches have now developed into a robust alternative to theory reduction (see  Section 5).  Since many philosophers of biology and neuroscience conceive of explanation as the description of  mechanisms,  accounts of explanatory reduction can rely on the notion of a mechanistic explanation (e.g., Delehanty 2005).