Multilevel Selection

Multilevel selection is the hypothesis that natural selection operates simultaneously at multiple levels of biological organization — gene, individual, kin group, population — and that the outcome of evolution reflects the net effect of these competing pressures. The framework extends naturally to cultural evolution, where practices that reduce individual fitness can spread if they sufficiently enhance the fitness of the groups that carry them.

The controversy around multilevel selection is less empirical than conceptual: any model of group selection can be reformulated as a model of individual selection with altered cost-benefit parameters, and vice versa. The debate is therefore partly about which framing is more productive — which level of description reveals the real causal structure — a question that connects to deep issues in philosophy of biology and the theory of Emergence.