It's just science fiction so it's allowed to be silly, and childish, and stupid. It's just science fiction, so it doesn't have to make sense. It's just science fiction, so you must ask nothing more of it than loud noises and flashing lights.

Of course there are worlds. Millions of them! Every star you see has worlds, and most of those you don't see.

... you just can't differentiate between a robot and the very best of humans.

University President: Why is it that you physicists always require so much expensive equipment? Now the Department of Mathematics requires nothing but money for paper, pencils, and erasers . . . and the Department of Philosophy is better still. It doesn't even ask for erasers.

The Three Laws of Robotics: 1: A robot may not injure a human being or, through inaction, allow a human being to come to harm; 2: A robot must obey the orders given it by human beings except where such orders would conflict with the First Law; 3: A robot must protect its own existence as long as such protection does not conflict with the First or Second Law; The Zeroth Law: A robot may not harm humanity, or, by inaction, allow humanity to come to harm.

Every religion seems like a fantasy to outsiders, but as holy truth to those of the faith.

No one can possibly have lived through the Great Depression without being scarred by it. No amount of experience since the depression can convince someone who has lived through it that the world is safe economically.