For one thing, before the 20th century, there were plenty of genocides. We tend to forget about them, partly because they weren't as well documented and partly because, until recently, people didn't care. We used euphemisms like 'sackings' and 'sieges' instead of calling them 'genocides.'

Morality is not just any old topic in psychology but close to our conception of the meaning of life. Moral goodness is what gives each of us the sense that we are worthy human beings.

You could think of an ecosystem as a bunch of antagonistic arms races, almost: Everything that an animal depends upon for food is the body part of some other animal or plant who would just as soon keep that body part for itself.

The rules of friendship are tacit, unconscious; they are not rational. In business, though, you have to think rationally.

The Rights Revolutions too have given us ideals that educated people today take for granted but that are virtually unprecedented in human history, such as that people of all races and creeds have equal rights, that women should be free from all forms of coercion, that children should never, ever be spanked, that students should be protected from bullying, and that there’s nothing wrong with being gay. I don’t find it at all implausible that these are gifts, in part, of a refined and widening application of reason.

By exploring the political and moral colorings of discoveries about what makes us tick, we can have a more honest science and a less fearful intellectual milieu.

The brain is not a bag of traits. It's startlingly complex. There are few or no single genes with a consistent effect on the mind.