Multi-Level Selection in Natural Selection: A Review of Okasha’s Ideas

As the inheritance of a trait which can be effective in the survival of an organism was the cornerstone of Darwin's argument for the abstraction of natural selection, each level of the biological hierarchy from genome to a community of entities can be regarded as the subject of natural selection. So the idea of abstracting natural selection at multiple levels would not be unreasonable, especially with respect to evidence of altruism in the social and biological groups. Based on this argument, in his famous book Evolution and the Levels of Selection, Samir Okasha tried to make a framework for the multi-level selection by using statistical methods, which could be applied independently in any level of biological world. By employing the Price equation, he tried to describe the concepts of group selection in mathematical terms, which leads to philosophical debates especially about the causal relationship between the traits and fitness. He proposed the contextual analysis to separate the causal relationship and byproducts. On the other hand, relying on the concepts raised by the discussions as to multi-level selection, Okasha tried to explain biological events as well as the major evolutionary transitions.