"We are all connected to the cosmos, and it is a wonderful thing."

"I wouldn't compare it to sex, but it lasts longer."

"It is a matter of common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something."

"In the proof stage, I nearly cut that last sentence of the book. Had I done so, the sales might have been halved."

"I think that the human race has a great future ahead of it, if we can just learn to cooperate."