 Models of explanatory reduction avoid several problems facing theory reduction (see  Section 3.1).  Since explanatory reduction is not committed to the relata of an explanation being theories involving laws, it can defend the possibility of reduction without formally reconstructing a clearly delineated theory of molecular biology or classical genetics. Its focus on reduction as explanation of a whole in terms of its parts captures a feature of actual molecular explanations. Whereas accounts of theory reduction have to acknowledge that reduction (in this sense) has not yet been achieved and must appeal to its “in principle” possibility, accounts of explanatory reduction comport well with the piecemeal nature of actual scientific research. Experimental and molecular biology can offer reductive explanations even if many facts remain unexplained and existing explanations still require more details to be filled in. Current biology effectively explains individual facts and generalities of smaller scope, and the explanans can be a mere fragment of a theory (see, e.g., Schaffner 2006 on “patchy and fragmentary” reductions). Finally, given that mechanistic explanations in experimental biology are preceded by and closely tied to the discovery of mechanisms (Craver and Darden 2013), explanatory reduction provides an account of reduction that can be related to scientific discovery, while approaches of theory reduction have to separate the context of justification (reduction and explanation) from the context of discovery.