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.

The world is being Americanized and technologized to its limits, and that makes it dull for some people. Reaching the Moon restores the frontier and gives us the lands beyond.

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.

Feminine intuition? Is that what you wanted the robot for? You men. Faced with a woman reaching a correct conclusion and unable to accept the fact that she is your equal or superior in intelligence, you invent something called feminine intuition.

Any book worth banning is a book worth reading.

When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together.

Tell me why the stars do shine, Tell me why the ivy twines, Tell me what makes skies so blue, And I'll tell you why I love you. Nuclear fusion makes stars to shine, Tropisms make the ivy twine, Raleigh scattering make skies so blue, Testicular hormones are why I love you.