Though knowledge itself increasingly ignores boundaries between fields, professors are apt to organize their pedagogy around the methods and history of their academic subculture rather than some coherent topic in the world.

What a dull universe it would be if everything in it conformed to our expectations, if it held nothing to surprise or baffle us or confound our common sense. A century ago no one foresaw the existence of black holes, an expanding universe, oceans on Jupiter's moons, or DNA. What could be more enriching than to know that we share a common origin with all living things, that we are kin to chimpanzees, redwoods and mollusks? And isn't it a source of wonder to realize that the iron in our blood and the calcium in our bones were created in the bellies of supernovas?

A...reason we are so-so scientists is that our brains were shaped for fitness, not for truth. Sometimes truth is adaptive, but sometimes it is not.

All of the violence that doesn't occur doesn't get reported on the news.

As technology accumulates and people in more parts of the planet become interdependent, the hatred between them tends to decrease, for the simple reason that you can't kill someone and trade with him too.

Many artists and scholars have pointed out that ultimately art depends on human nature.

Nature is a hanging judge," goes an old saying. Many tragedies come from our physical and cognitive makeup. Our bodies are extraordinarily improbable arrangements of matter, with many ways for things to go wrong and only a few ways for things to go right. We are certain to die, and smart enough to know it. Our minds are adapted to a world that no longer exists, prone to misunderstandings correctable only by arduous education, and condemned to perplexity about the deepest questions we can ascertain.