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.

Journalists say that when a dog bites a man, that is not news, but when a man bites a dog, that is news ... Thanks to the mathematics of combinatorics, we will never run out of news.

Climate change could produce a lot of misery and waste without necessarily leading to large-scale armed conflict, which depends more on ideology and bad governance than on resource scarcity.

Most wars are not fought over shortages of resources such as food and water, but rather over conquest, revenge, and ideology.

The reason the United States is not so likely to invade Iran is precisely because of the lessons learned from Iraq. And conversely, the Iranian push towards nuclear capability is calculated to deter invasions like the kind deposing Saddam Husain.

We can shape events in each other's brains with exquisite precision.

Evolution is an indispensable component of any satisfying explanation of our psychology.