The struggle for life and adaptation by natural selection

Abstract

While the struggle for life played an important role in the process of natural selection as it was conceived by Darwin, natural selection is commonly characterized today as a process which does not necessarily involve struggle. Nevertheless, there have been some attempts to show the importance of struggle to the process of natural selection. The present paper aims to continue these attempts and clarify the precise evolutionary role of struggle. The paper focuses on a recent dispute regarding the role of struggle between Peter Godfrey-Smith and Tim Lewens. Godfrey-Smith argues that struggle makes populations into "paradigm cases of Darwinian populations", meaning that struggle leads natural selection to produce adaptations. Lewens, in contrast, argues that Godfrey-Smith's argument fails to show that struggle plays such a role. I argue that Godfrey-Smith's argument that struggle leads selection to produce adaptations can be understood in two different ways. Lewens interprets Godfrey-Smith's argument in one of these ways, and rightly argues that thus understood, this argument fails to show that struggle leads selection to produce adaptations. However, I show that understood in a second way, Godfrey-Smith's argument does show that struggle plays such a role. Still, I show that there is an additional problem with Godfrey-Smith's argument that struggle makes populations into "paradigm cases of Darwinian populations". It does not capture the precise role played by struggle in the relation between selection and adaptation. Thus, the present paper clarifies the unique role that struggle plays in the relation between selection and adaptation in evolutionary theory.