Commerce, trade and exchange make other people more valuable alive than dead, and mean that people try to anticipate what the other guy needs and wants. It engages the mechanisms of reciprocal altruism, as the evolutionary biologists call it, as opposed to raw dominance.

When it comes to explaining human thought and behavior, the possibility that heredity plays any role at all still has the power to shock. To acknowledge human nature, many think, is to endorse racism, sexism, war, greed, genocide, nihilism, reactionary politics, and neglect of children and the disadvantaged. Any claim that the mind has an innate organization strikes people not as a hypothesis that might be incorrect but as a thought it is immoral to think.

The connections I draw between human nature and political systems in my new book, for example, were prefigured in the debates during the Enlightenment and during the framing of the American Constitution.

In societies no less than individuals, acknowledging our limitations may ultimately be more humane than denying them.

An ideology can provide a satisfying narrative that explains chaotic events and collective misfortunes in a way that flatters the virtue and competence of believers, while being vague or conspiratorial enough to withstand skeptical scrutiny.

The more you think about and interact with other people, the more you realize that it is untenable to privilege your interests over theirs, at least not if you want them to listen to you. You can’t say that my interests are special compared to yours any more than you can say that the particular spot that I am standing on is a unique part of the universe because I happen to be standing on it that very minute.

In the 1970s, many intellectuals had become political radicals. Marxism was correct, liberalism was for wimps, and Marx had pronounced that 'the ruling ideas of each age have ever been the ideas of its ruling class.'