“There's no real objection to escapism, in the right places... We all want to escape occasionally. But science fiction is often very far from escapism, in fact you might say that science fiction is escape into reality... It's a fiction which does concern itself with real issues: the origin of man; our future. In fact I can't think of any form of literature which is more concerned with real issues, reality.”

“Much blood has also been spilled on the carpet in attempts to distinguish between science fiction and fantasy. I have suggested an operational definition: science fiction is something that COULD happen - but usually you wouldn't want it to. Fantasy is something that COULDN'T happen - though often you only wish that it could.”

“...science fiction is something that could happen - but usually you wouldn't want it to. Fantasy is something that couldn't happen - though often you only wish that it could.”

“Politicians should read science fiction, not westerns and detective stories.”

“That's really what SF is all about, you know: the big reality that pervades the real world we live in: the reality of change. Science fiction is the very literature of change. In fact, it is the only such literature we have.”

“It is a good principle in science not to believe any 'fact'---however well attested---until it fits into some accepted frame of reference. Occasionally, of course, an observation can shatter the frame and force the construction of a new one, but that is extremely rare. Galileos and Einsteins seldom appear more than once per century, which is just as well for the equanimity of mankind.”

“["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.”