Cognitive psychology has shown that the mind best understands facts when they are woven into a conceptual fabric, such as a narrative, mental map, or intuitive theory. Disconnected facts in the mind are like unlinked pages on the Web: They might as well not exist.

There's a common criticism of evolutionary psychology that it's fatalistic and it dooms us to eternal strife, 'Why even try to work toward peace if we're just bloody killer apes and violence is in our genes?'

Reason is non-negotiable. Try to argue against it, or to exclude it from some realm of knowledge, and you've already lost the argument, because you're using reason to make your case. ... We don't "believe" in reason.

I think that metaphor really is a key to explaining thought and language. The human mind comes equipped with an ability to penetrate the cladding of sensory appearance and discern the abstract construction underneath - not always on demand, and not infallibly, but often enough and insightfully enough to shape the human condition. Our powers of analogy allow us to apply ancient neural structures to newfound subject matter, to discover hidden laws and systems in nature, and not least, to amplify the expressive power of language itself.

Some people believe that the nuclear bomb should be awarded the Nobel Peace Prize, since it scared the major powers away from war by equating it with doomsday.

Pre-state societies were far more violent than our own.

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.'