Effective education may also require co-opting old faculties to deal with new demands. . . Because much of the content of education is not cognitively natural, the process of mastering it may not always be easy and pleasant, notwithstanding the mantra that learning is fun.

The typical imperative from biology is not "Thou shalt... ," but "If ... then ... else.

We often feel that a clever aphorism captures a truth that would require pages to defend in any other way.

Since violence is largely a male pastime, cultures that empower women tend to move away from the glorification of violence and are less likely to breed dangerous subcultures of rootless young men.

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.

If you give people literacy, bad ideas can be attacked and experiments tried, and lessons will accumulate.

For all the tribulations in our lives, for all the troubles that remain in the world, the decline of violence is an accomplishment that we can savor - and an impetus to cherish the forces of civilization and enlightenment that made it possible.