Evolutionary theory is one of the most wide-ranging and inspiring of scientific ideas. It offers a battery of methods that can be used to interpret human behaviour. But the legitimacy of this exercise is at the centre of a heated controversy that has raged for over a century. Many evolutionary biologists, anthropologists and psychologists are optimistic that evolutionary principles can be applied to human behaviour, and have offered evolutionary explanations for a wide range of human characteristics, such as homicide, religion and sex differences in behaviour. Others are sceptical of these...