 The other major form of critique of genic pluralism is based on arguments concerning the causal structure of selective episodes. The idea here is that while genic pluralism gets the “genetic book-keeping” (i.e., the input/output relations) correct, it does not accurately reflect the causal processes that bring about the result in question (Wimsatt 1980a,b). Some examples of this approach used against the genic pluralists (including Sober 1990; Sober &amp; Wilson 1994, 1998) also appeal to aspects of the manifestor-of-adaptations and beneficiary questions to establish the failure of genic pluralism to represent certain selective events correctly. Causal concerns are also raised in some other work (Shanahan 1997, Van der Steen and Van den Berg 1999, Stanford 2001, and Glennan 2002), though without the focus on other units questions. The weakness of this line of criticism is its inability to isolate a notion of cause that is both plausible and plausibly true of hierarchical but not genic level models. This feature—that the genic and hierarchical models are so similar as to be indistinguishable—which appears as an insurmountable problem in the context of debates about differing causal structure, turns out to be the locus of critical response to genic pluralism, which denies that the genic selectionists have any distinct and coherent genic level causes at all (Lloyd 2005; Lloyd et al. 2005).