 It is worth emphasizing that the sense in which decomposition is reductionistic is very different from that involved in more traditional philosophical accounts of theory reduction, which involves the derivation of one theory from another (Nagel 1961; see the entries on  scientific reduction  and  reductionism in biology).  Researchers pursue decomposition without assuming the existence of full theories at either level or that a theory at one level can be derived from one at a lower level. Moreover, in pursuing decomposition researchers typically do not assume that knowledge of the lower-level components is sufficient for explaining the phenomena—at a minimum, they recognize that how the components are organized is also important. The association of a cell process with a specific enzyme is not the end of the explanatory process—the activity of enzymes is often affected by the context in which the enzyme exists, for example, in a membrane. For this reason, researchers value in vitro reconstitution experiments in establishing that they have correctly accounted for a phenomenon.