 Many contemporary accounts of explanatory reduction focus on  mechanisms  and the study of  model organisms.  One reply to the multiple realization objection from this perspective argues explicitly for token-token reduction, discussing how the causal description of a token mechanism explains (Delehanty 2005). Weber (2005) acknowledges that higher level features are multiply realizable but notes that this does not hamper the reducibility of token systems or individual organisms: “the fact that chemotactic behavior is multiply realizable does not affect the reductionistic explanation of this organism’s behavioral biology” (48). However, this stratagem ignores the key point of contention because token-token reduction is uncontroversial. The focus on token phenomena or individual organisms fails to address an important epistemological feature of scientific knowledge: explanations often cover types of phenomena. In many biological contexts, such as  developmental biology,  the intellectual aim is to explain phenomena instantiated in many organisms and the use of model organisms is predicated on this  aim.[13]  Any version of epistemic reductionism has to address this feature of scientific explanation to be adequate. Explaining development—as understood by many developmental biologists—means to have an account of ontogeny exhibited by individual organisms belonging to a larger group (e.g., understanding the developmental principles that govern vertebrate or amphibian development). As the same morphological structure may develop in different species by means of different processes and based on the action of different genes, multiple realization obtains and is relevant for such explanations (Laubichler and Wagner 2001).