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.)

Arthur Clarke says that I am first in science and second in science fiction in accordance with an agreement we have made. I say he is first in science fiction and second in science.

Any teacher that can be replaced by a computer should be replaced by a computer.

I have never, in all my life, not for one moment, been tempted toward religion of any kind. The fact is that I feel no spiritual void. I have my philosophy of life, which does not include any aspect of the supernatural and which I find totally satisfying. I am, in short, a rationalist and believe only that which reason tells me is so.

A robot must obey the orders given it by human beings except where such orders would conflict with the First Law. [The Second Law of Robotics]

It takes more than capital to swing business. You've got to have the A. I. D. degree to get by - Advertising, Initiative, and Dynamics.