Frank Herbert
Science fiction represents the modern heresy and the cutting edge of speculative imagination as it grapples with Mysterious Time---linear or non-linear time.
Our motto is Nothing Secret, Nothing Sacred.
Damon Knight
What we get from science fiction---what keeps us reading it, in spite of our doubts and occasional disgust---is not different from the thing that makes mainstream stories rewarding, but only expressed differently. We live on a minute island of known things. Our undiminished wonder at the mystery which surrounds us is what makes us human. In science fiction we can approach that mystery, not in small, everyday symbols, but in bigger ones of space and time.
Sam J. Lundwall
A simplified definition would be that the author of a "straight" science fiction story proceeds from (or alleges to proceed from) known facts, developed in a credible way...
Sam Moskowitz
Science fiction is a branch of fantasy identifiable by the fact that it eases the "willing suspension of disbelief" on the part of its readers by utilizing an atmosphere of scientific credibility for its imaginative speculations in physical science, space, time, social science, and philosophy.
Alexei Panshin
Facts and a concern with change are the stuff that science fiction is made of; science fiction that ignores facts and change can be made less frightening and more popular, but inasmuch as it is superficial, stupid, false-to-fact, timid foolish or dull, it is minor in another and more important way, and it is certainly bad as science fiction.
... its [science fiction's]attraction lies ... in the unique opportunity it offers for placing familiar things in unfamiliar contexts, and unfamiliar things in familiar contexts, thereby yielding fresh insights and perspective.
Frederik Pohl
The future depicted in a good SF story ought to be in fact possible, or at least plausible. That means that the writer should be able to convince the reader (and himself) that the wonders he is describing really can come true...and that gets tricky when you take a good, hard look at the world around you.
-- The Shape of Things to Come and Why It Is Bad, SFC, December 1991
If anyone were to force me to make a thumbnail description of the differences between SF and fantasy, I think I would say that SF looks towards an imaginary future, while fantasy, by and large, looks towards an imaginary past. Both can be entertaining. Both can possibly be, perhaps sometimes actually are, even inspiring. But as we can't change the past, and can't avoid changing the future, only one of them can be real.
-- Pohlemic, SFC, May 1992
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.
-- Pohlemic, SFC, May 1992
Does the story tell me something worth knowing, that I had not known before, about the relationship between man and technology? Does it enlighten me on some area of science where I had been in the dark? Does it open a new horizon for my thinking? Does it lead me to think new kinds of thoughts, that I would not otherwise perhaps have thought at all? Does it suggest possibilities about the alternative possible future courses my world can take? Does it illuminate events and trends of today, by showing me where they may lead tomorrow? Does it give me a fresh and objective point of view on my own world and culture, perhaps by letting me see it through the eyes of a different kind of creature entirely, from a planet light-years away?
These qualities are not only among those which make science fiction good, they are what make it unique. Be it never so beautifully written, a story is not a good science fiction story unless it rates high in these aspects. The content of the story is as valid a criterion as the style.
-- Introduction--SF:Contemporary Mythologies (New York, 1978)
Eric S. Rabkin
A work belongs in the genre of science fiction if its narrative world is at least somewhat different from our own, and if that difference is apparent against the background of an organized body of knowledge.
-- The Fantastic In Literature (Princeton University Press, 1976)
Dick Riley
At its best, science fiction has no peer in creating another universe of experience, in showing us what we look like in the mirror of technological society or through the eyes of a non-human.
-- Critical Encounters (New York, 1978)
Thomas N. Scortia
... [science fiction has]the humanistic assumption that the laws of nature are amenable to the interpretation of human logic and, more than this, amenable to logical extrapolation.
Tom Shippey
A revealing way of describing science fiction is to say that it is part of a literary mode which one may call "fabril" "Fabril" is the opposite of "Pastoral". But while "the pastoral" is an established and much-discussed literary mode, recognized as such since early antiquity, its dark opposite has not yet been accepted, or even named, by the law-givers of literature. Yet the opposition is a clear one. Pastoral literature is rural, nostalgic, conservative. It idealizes the past and tends to convert complexities into simplicity; its central image is the shepherd. Fabril literature (of which science fiction is now by far the most prominent genre) is overwhelmingly urban, disruptive, future-oriented, eager for novelty; its central images is the "faber", the smith or blacksmith in older usage, but now extended in science fiction to mean the creator of artefacts in general--metallic, crystalline, genetic, or even social.
-- Introduction, The Oxford Book of Science Fiction, (Oxford, 1992)
