The person one loves never really exists, but is a projection focused through the lens of the mind onto whatever screen it fits with least distortion.

Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering.

The greatest tragedy in mankind's entire history may be the hijacking of morality by religion.

The best measure of a man's honesty isn't his income tax return. It's the zero adjust on his bathroom scale.

Sometimes when I'm in a bookstore or library, I am overwhelmed by all the things that I do not know. Then I am seized by a powerful desire to read all the books, one by one.

It is really quite amazing by what margins competent but conservative scientists and engineers can miss the mark, when they start with the preconceived idea that what they are investigating is impossible.

And because, in all the Galaxy, they had found nothing more precious than Mind, they encouraged its dawning everywhere. They became farmers in the fields of stars; they sowed, and sometimes they reaped. And sometimes, dispassionately, they had to weed.