09 Chapter 1724

THE ‘PROBLEM OF ALTRUISM’ has remained a thorn in the side of evolutionary biology since Darwin. In On the origin of species (1860), Darwin clearly recognized that the widespread existence of altruistic behavioural adaptations was a potential problem for his theory of natural selection. The general problem is that, if nature is ‘red in tooth and claw’ and natural selection produces adaptations by virtue of competitive elimination of the less fit, how could it produce the many examples of cooperation found in nature in which individuals sacrifice some degree of fitness for another? Since Darwin’s time, evolutionary biologists have tried to explain altruism within the natural selection framework. This has resulted in many different efforts to explain how altruism could be maintained under selection. These many theories all appear to successfully demonstrate ways that altruistic behaviours might be sustained against ‘invasion’ by non-altruistic alternatives. These are relevant to our approach, but only as post hoc adaptive consequences of the emergence of altruism. We will argue below that the standard natural selection approach does not do an adequate job of explaining the origins of such adaptations. The selection framework itself is an incomplete explanation for the evolution of altruism because it necessarily avoids answering the question of how altruistic behaviours initially arise in a non-altruistic context, and instead explains how they might be stabilized or modified with respect to alternatives in a given environment. This is because natural selection theory is intrinsically agnostic to how a given trait initially arises. Nevertheless, this does not mean that the question of how modification of traits is generated is entirely irrelevant. This agnosticism can lead to the expectation that random mutation, recombination and genetic drift are sufficient mechanisms to explain the creativity that is evident in evolution. It has been easy to avoid addressing the question of the source of variant forms in contexts where a new adaptation can be traced to prior