The Science of Good and Evil by Michael Shermer is an investigation of the evolution of morality that is “a paragon of popularised science and philosophy”. A century and a half after Darwin first proposed his “evolutionary ethics”, science has begun to tackle the roots of morality. Just as evolutionary biologists study why we are hungry (to motivate us to eat) or why sex is enjoyable (to motivate us to procreate), they are now researching the reasons for the very nature of humanity. The source of morality is the topic under discussion in Shermer’s latest book to uphold rationalism. Disposing off religion’s rival, moral relativism, the author says his thesis, labelled “provisional morality,” makes more sense.

What that means is that ethical rules are accepted conditionally and are as falsifiable as any scientific theory. He takes this precept into the realm of evolutionary psychology, drawing applied ethics from drastically different sources. He explores how humans evolved from social primates to moral primates, how and why morality motivates the human animal, and how the foundation of moral principles can be built upon empirical evidence.

Shermer also explains the implications of scientific findings for fate and free will, the existence of pure good and pure evil, and the development of early moral sentiments.