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.'

Look at almost any passage, and you'll find that a paragraph has five or six metaphors in it. It's not that the speaker is trying to be poetic, it's just that that's the way language works.

Mother Teresa was the very embodiment of saintliness: white-clad, sad-eyed, ascetic and often photographed with the wretched of the earth.

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?'

You could think of an ecosystem as a bunch of antagonistic arms races, almost: Everything that an animal depends upon for food is the body part of some other animal or plant who would just as soon keep that body part for itself.

I think that communism was a major force for violence for more than 100 years, because it was built into its ideology - that progress comes through class struggle, often violent.

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