Belief in the supernatural reflects a failure of the imagination.

By the age of eighteen, a human has acquired enough joy and heartache to provide the food of reflection for a century.

If you feel that you must suffer, then plan your suffering carefully -- as you choose your dreams, as you conceive your ancestors.

It may be true that there are no atheists in foxholes. But you don't find many Christians there, either. Or, about as many of one as the other.

We are preoccupied with time. If we could learn to love space as deeply as we are now obsessed with time, we might discover a new meaning in the phrase to live like men.

There is science, logic, reason; there is thought verified by experience. And then there is California.

Climbing K2 or floating the Grand Canyon in an inner tube; there are some things one would rather have done than do.