It is really quite amazing by what margins competent but conservative scientists and engineers can miss the mark, when they start with the preconceived idea that what they are investigating is impossible.

'The Devil in the Dark' impressed me because it presented the idea, unusual in science fiction then and now, that something weird, and even dangerous, need not be malevolent. That is a lesson that many of today's politicians have yet to learn.

You can't have it both ways. You can't have both free will and a benevolent higher power who protects you from yourself.

Attempting to define science fiction is an undertaking almost as difficult, though not so popular, as trying to define pornography... In both pornography and SF, the problem lies in knowing exactly where to draw the line.

Never attribute to malevolence what is merely due to incompetence

It is not easy to see how the more extreme forms of nationalism can long survive when men have seen the Earth in its true perspective as a single small globe against the stars.

Death focuses the mind on the things that really matter: why are we here, and what should we do?