To test a perfect theory with imperfect instruments did not impress the Greek philosophers as a valid way to gain knowledge.

The world of A.D. 2014 will have few routine jobs that cannot be done better by some machine than by any human being. Mankind will therefore have become largely a race of machine tenders.

Theories are not so much wrong as incomplete

It seems to me that God is a convenient invention of the human mind

If my doctor told me I had only six minutes to live, I wouldn't brood. I'd type a little faster.

If I had felt then as I feel now, or as I felt a few years after I had married her, nothing could possibly have persuaded me to marry a woman who smoked. Dates, yes. Sexual adventures, yes. But to pin myself permanently inside closed quarters with a smoker? Never. Never. Never. Beauty wouldn't count, sweetness wouldn't count, suitability in every other respect wouldn't count.

Naturally, since [the Sumerians] didn't know what caused the flood anymore than we do, they blamed the gods. (That's the advantage of religion. You're never short an explanation for anything.)