I do not fear computers. I fear the lack of them.

The true delight is in the finding out rather than in the knowing.

Before another century is done it will be hard for people to imagine a time when humanity was confined to one world, and it will seem to them incredible that there was ever anybody who doubted the value of space and wanted to turn his or her back on the Universe.

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.

Saying something is 'too bad' is easy. You say you disapprove, which makes you a nice person, and then you can go about your business and not be interested anymore. It's a lot worse than 'too bad.' It's against everything decent and natural.

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]

There’s nothing to it. All you have to do is take a close look at yourself and you will understand everyone else. We’re in no way different ourselves... You show me someone who can’t understand people and I’ll show you someone who has built up a false image of himself.