Humanity has the stars in its future, and that future is too important to be lost under the burden of juvenile folly and ignorant superstition.

In all the known history of Mankind, advances have been made primarily in physical technology; in the capacity of handling the inanimate world about Man. Control of self and society has been left to to chance or to the vague gropings of intuitive ethical systems based on inspiration and emotion. As a result no culture of greater stability than about fifty-five percent has ever existed, and these only as the result of great human misery.

Despite all that education and experience can do, I retain a certain level of unsophistication that I cannot eradicate and that my friends find amusing. In fact, I think I sometimes detect conspiratorial plottings among my friends to protect me against my own lack of sophistication. I don't mind. I suspect that I am never quite as unsophisticated as they think I am, but I don't mind.

Politically popular speech has always been protected: even the Jews were free to say ‘Heil Hitler.’

All of a sudden, space isn't friendly. All of a sudden, it's a place where people can die. . . . Many more people are going to die. But we can't explore space if the requirement is that there be no casualties; we can't do anything if the requirement is that there be no casualties.

When I feel difficulty coming on, I switch to another book I'm writing. When I get back to the problem, my unconscious has solved it.

I am not responsible for what other people think. I am responsible only for what I myself think, and I know what that is. No idea I've ever come up with has ever struck me as a divine revelation. Nothing I have ever observed leads me to think there is a God watching over me.