You've recently been involved in a high-profile academic row over what drives the evolution of social traits such as altruism. Why should non-specialists care?

That is one of the main points of my new book. Scientific advances are now good enough for us to address coherently questions of where we came from and what we are. But to do so, we need to answer two more fundamental questions. The first is why advanced social life exists in the first place and has occurred so rarely. The second is what are the driving forces that brought it into existence.

Eusociality, where some individuals reduce their own reproductive potential to raise others' offspring, is what underpins the most advanced form of social organization and the dominance of social insects and humans. One of the key ideas to explain this has been kin selection theory or inclusive fitness, which argues that individuals cooperate according to how they are related. I have had doubts about it for quite a while. Standard natural selection is simpler and superior. Humans originated by multilevel selection—individual selection interacting with group selection, or tribe competing against tribe. We need to understand a great deal more about that.

How will a better understanding of multilevel selection help?

We should consider ourselves as a product of these two interacting and often competing levels of evolutionary selection. Individual versus group selection results in a mix of altruism and selfishness, of virtue and sin, among the members of a society. If we look at it that way, then we have what appears to be a pretty straightforward answer as to why conflicted emotions are at the very foundation of human existence. I think that also explains why we never seem to be able to work things out satisfactorily, particularly internationally.

So it comes down to a conflict between individual and group-selected traits?

Yes. And you can see this especially in the difficulty of harmonizing different religions. We ought to recognize that religious strife is not the consequence of differences among people. It's about conflicts between creation stories. We have bizarre creation myths and each is characterized by assuring believers that theirs is the correct story, and that therefore they are superior in every sense to people who belong to other religions. This feeds into our tribalistic tendencies to form groups, occupy territories and react fiercely to any intrusion or threat to ourselves, our tribe and our special creation story. Such intense instincts could arise in evolution only by group selection—tribe competing against tribe. For me, the peculiar qualities of faith are a logical outcome of this level of biological organization....