 While etiological theories dominate the discussion of normative functions in philosophy of biology, the etiological theory is not uncontroversial. Some question whether teleology can be naturalized (e.g., Bedau 1991). Others support other theories for other reasons. Perhaps the systemic theory is the most popular alternative (see esp. Cummins 1975). Systemic theories of function emphasize the role of function ascriptions in functional analyses of systems. Functional analyses of systems conceptually decompose complex activities of whole systems into the activities of their contributing parts. The function of a part is its contribution to the complex activity of the system that is under analysis. Proponents of the etiological theory have no objection to the idea that biologists give functional analyses of systems but contend that the systemic analysis, on its own, fails to naturalize the normativity of functions or to do so successfully (i.e. it fails to provide an adequate account of   malfunctioning).[4]   Some who support a systemic theory argue that biology has no need for a naturalistic notion of malfunction (e.g., Davies 2001), while others argue that abnormal functioning is statistically atypical (Boorse 2002, Craver 2001,  Lewens 2004).[5] 