Anyone who values truth should stop worshipping reason.

The extreme self-sacrifice characteristic of group-selected species such as ants and bees can often be found among soldiers.

There are a couple of watersheds in human evolution. Most people are comfortable thinking about tool use and language use as watersheds. But the ability to play non-zero-sum games was another watershed.

If you get something for nothing, part of you may be pleased, but part of you moves your hand to give something back.

Human rationality depends critically on sophisticated emotionality. It is only because our emotional brain works so well that our reasoning can work at all.

Almost everything we do is automatic, yet we're not aware of that. We feel like there's a circle of light. We're like the drunk who lost his keys and is looking under the streetlight, and the cop says, "Where'd you lose your keys?" You say, "Back in the alley, but the light's so much better over here." The divided self refers to the fact that we are basically animals with animal brains. These animal brains run our lives. They're very good at it.

Reciprocity is a deep instinct; it is the basic currency of social life.