  This view has been extensively challenged by philosophers of biology on both methodological and conceptual grounds, though there are, among philosophers, enthusiastic supporters (cf. Dennett 1995). In all the give and take, it is seldom noticed that defenders of this view claim to be carrying the Darwinian flag (Gayon 1998 and Gould 2003 are exceptions). Yet it is certainly not a position that Darwin would recognize--and not merely because he lacked a coherent theory of the units of inheritance. It is not a Darwinian view because for Darwin it was differences in the abilities of organisms at various stages of development to respond to the challenges of life that had causal primacy in the explanation of evolutionary change. Among evolutionary biologists from the ‘neo-Darwinian synthesis’ on, it is those who stress the role of organisms in populations interacting differentially to ever-variable ecological conditions in causing changes in the gene pools of those populations who are the card-carrying Darwinians. 