Definitions of Science Fiction

Many definitions for Science Fiction have been offered by authors, editors, academics and fans. Some in the field are content with the timeless definition by Damon Knight, who went on record with “Science Fiction is what we point at when we say it.”, but not everyone is that charitable, hence the page that follows.

A few caveats. This is an old list, I compiled it in what feels like a lifetime ago, when we had no flashy www interfaces and google–I am sure some of it was from the Lysator gopher server, and I doubt the majority of the visitors to this site would even know what a gopher server is without googling it. Thus, some of the definitions do not have proper attribution. I am planning on rectifying that oversight as best as I can, and add more definitions as I come across them, so please accept this page for what it is, an enthusiasts work-in-progress.

That said, if you do have information about the origins/sources of the definitions lacking them, or if you come across any definitions with sources, I would be more than happy to include them in the page.

If you are one of the people I have quoted (or, as the case might be, mis-quoted) please let me know if you are fine with me including (and in the case of misquotes, fixing) your definition. If your definition is on this page and you would like me to link your name line to your own website, I would be glad to do that as well.
–Genk Gökçe



Aldiss, Brian W.
Science fiction is the search for definition of man and his status in the universe which will stand in our advanced but confused state of knowledge (science), and is characteristically cast in the Gothic or post-Gothic mould.
Trillion Year Spree: the History of Science Fiction (London, 1986)

Allen, Dick
Is it any wonder that a new generation has rediscovered science fiction, rediscovered a form of literature that argues through its intuitive force that the individual can shape and change and influence and triumph; that man can eliminate both war and poverty; that miracles are possible; that love, if given a chance, can become the main driving force of human relationships?

Amis, Kingsley
Science Fiction is that class of prose narrative treating of a situation that could not arise in the world we know, but which is hypothesized on the basis of some innovation in science or technology, or pseudo-technology, whether human or extra-terresial in origin.
New Maps Of Hell (London, 1960)

Appel, Benjamin
Science fiction reflects scientific thought; a fiction of things-to-come based on things-on-hand.
The Fantastic Mirror-SF Across The Ages (Panthenon 1969)

Asimov, Isaac
Modern science fiction is the only form of literature that consistently considers the nature of the changes that face us, the possible consequences, and the possible solutions.

That branch of literature which is concerned with the impact of scientific advance upon human beings.



Bailey, James O.
The touchstone for scientific fiction, then, is that it describes an imaginary invention or discovery in the natural sciences. The most serious pieces of this fiction arise from speculation about what may happen if science makes an extraordinary discovery. The romance is an attempt to anticipate this discovery and its impact upon society, and to foresee how mankind may adjust to the new condition.
Pilgrims Through Space and Time (New York, 1947)

Benford, Gregory
SF is a controlled way to think and dream about the future. An integration of the mood and attitude of science (the objective universe) with the fears and hopes that spring from the unconscious. Anything that turns you and your social context, the social you, inside out. Nightmares and visions, always outlined by the barely possible.

Bilker, Harvey L. & Audrey L.
Science fiction deals with some aspect of technology or science, whether or not that particular technology or science exists at present or is an extrapolation or theory logically presented. It also includes the methodical and systematic investigation and/or study of an object, whether or not investigation of that subject actually exists. … Science fiction does not predict the future. It imaginatively extrapolates from what is known or theorized. … As much as science fiction is set in the future, it does not predict it/ The ideas in science fiction are far ahead of reality.
Writing Science Fiction That Sells (Chicago, 1982)

Bradbury, Ray
Science fiction is really sociological studies of the future, things that the writer believes are going to happen by putting two and two together.

de Bono, Edward
Science fiction creates a provocative hypothesis which allows us to look at things in a new way–for our enjoyment or even insight. Because science fiction moves ahead into the future rather than back into the past, it has total freedom of provation. The interesting thing about the provocation is that it has to be related semi-logically to the existing state of affairs, otherwise it becomes pure gibberish which has an annoyance, rather than a provocative value. … In science fiction a single change in a particular concept is often followed through to all its implications.
Lateral Thinking and Science Fiction, in Science Fiction At Large (Victor Gollancz, London, 1976)

Boyd, John
Science fiction is story-telling, usually imaginative as distinct from realistic fiction, which poses the effects of current or extrapolated scientific discoveries, or a single discovery, on the behavior of individuals of society.
Mainstream fiction gives imaginative reality to probable events within a framework of the historical past or present; science fiction gives reality to possible events, usually in the future, extrapolated from present scientific knowledge or existing cultural and social trends. Both genres ordinarily observe the unities and adhere to a cause-and-effect schema.

Bretnor, Reginald
Science Fiction: fiction based on rational speculation regarding the human experience of science and its resultant technologies.

Brians, Paul
[Science Fiction is:] a subdivision of fantastic literature which employs science or rationalism to create an appearance of plausibility
Posted to the mailing list SF-LIT, May 16, 1996

Brunner, John
As its best, SF is the medium in which our miserable certainty that tomorrow will be different from today in ways we can’t predict, can be transmuted to a sense of excitement and anticipation, occasionally evolving into awe. Poised between intransigent scepticism and uncritical credulity, it is par excellence the literature of the open mind.
Science Fiction and the Larger Lunacy, in Science Fiction at Large (Victor Gollancz, London, 1976)



Campbell, John W. Jr.

The major distinction between fantasy and science fiction is, simply, that science fiction uses one, or a very, very few new postulates, and develops the rigidly consistent logical consequences of these limited postulates. Fantasy makes its rules as it goes along…The basic nature of fantasy is “The only rule is, make up a new rule any time you need one!” The basic rule of science fiction is “Set up a basic proposition–then develop its consistent, logical consequences.”
Introduction, Analog 6, Garden City, New York, 1966

On the archetypal SF story: I want the kind of story that could be published in a magazine of the year two thousand A.D. as a contemporary adventure story. No gee-whiz, just take the technology for granted.
quoted by Frederik Pohl, in The Way The Future Was, Ballantine, New York, 1978

Carr, Terry
Science Fiction is literature about the future, telling stories of the marvels we hope to see–or for our descendants to see–tomorrow, in the next century, or in the limitless duration of time.
Introduction, Dream’s Edge, Sierre Club Books, San Fransisco, 1980

Conklin, Groff
The best definition of science fiction is that it consists of stories in which one or more definitely scientific notion or theory or actual discovery is extrapolated, played with, embroided on, in a non-logical, or fictional sense, and thus carried beyond the realm of the immediately possible in an effort to see how much fun the author and reader can have exploring the imaginary outer reaches of a given idea’s potentialities.

Crispin, Edmund
A science fiction story is one which presupposes a technology, or an effect of technology, or a disturbance in the natural order, such as humanity, upto the time of writing, has not in actual fact experienced.
Best Science Fiction Stories (London, 1955)

de Camp, L. Sprague
Therefore, no matter how the world makes out in the next few centuries, a large class of readers at least will not be too surprised at anything. They will have been through it all before in fictional form, and will not be too paralyzed with astonishment to try to cope with contingencies as they arise.


Del Rey, Lester
… science fiction “is the myth-making principle of human nature today.”

Dickson, Gordon R.
In short, the straw of a manufactured realism with which the sf writer makes his particular literary bricks must be entirely convincing to the reader in it own right, or the whole story will lose its power to convince.



Franklin, Bruce
We talk a lot about science fiction as extrapolation, but in fact most science fiction does not extrapolate seriously. Instead it takes a willful, often whimsical, leap into a world spun out of the fantasy of the author….

Franklin, Bruce H.
In fact, one good working definition of science fiction may be the literature which, growing with science and technology, evaluates it and relates it meaningfully to the rest of human existence.

Frye, Northrop
Science fiction frequently tries to imagine what life would be like on a plane as far above us as we are above savagery; its setting is often of a kind that appears to us technologically miraculous. It is thus a mode of romance with a strong tendency to myth.


Gaddis, Vincent H.
Science fiction expressses the dreams that, varied and modified, later becomes the visions and then the realities in scientific progress. Unlike fantasy they present probabilities in their basic structure and create a reservoir of imaginative thought that sometimes can inspire more practical thinking.

Gernsback, Hugo
By “scientification,”… I mean the Jules Verne, H. G. Wells, and Edgar Allan Poe type of story—a charming romance intermingled with scientific fact and prosphetic vision.

Goswami, Amit
Science Fiction is that class of fiction which contains the currents of change in science and society. It concerns itself with the critique, extension, revision, and conspiracy of revolution, all directed against static scientific paradigms. Its goal is to prompt a paradigm shift to a new view that will be more responsive and true to nature.
The Cosmic Dancers (New York, 1983)

Garner, Alan
‘Science Fiction’ has the sound of a botched-up job, but what is describes is an aspect of the most important function of literature, the one to which we turn in our greater stress; that is, the flow of myth.
Man is an animal that tests boundaries. He is a ‘mearc-stapa’, ‘boundary strider’, and the nature of myth is to help him to understand those boundaries, to cross them and to comrehend the new; so that when Man reaches out, it is myth that supports him with a truth that is constant, although names and shapes may change. From within us, from our past, we find the future answered and the boundary met. … What I want to state for the moment is my view that the phrase ‘science fiction’ is a shoddy neologism, not a new branch of story. Whether we call it the Jungian archetype, or the manifestation of certain human behavioural characteristics, I find in ‘science fiction’ the record of Man’s boundary-treadings. And there will always be boundaries.
Inner Time, in Science Fiction at Large, London, Victor Gollancz, 1976

le Guin, Ursula K.
And what is science fiction at its best but just … a new tool …, a crazy, protean, left-handed monkey-wrench, which can be put to any use the craftsman has in mind–satire, extrapolation, prediction, absurdity, exactitude, exaggeration, warning, message-carrying, tale-telling, whatever you like–an infinitely expandable metaphor exactly suited to our expanding universe, a broken mirror, broken into numberless fragments, any one of which is capable of reflecting, for a moment, the left eye and the nose of the reader, and also the farthest stars shining in the depths of the remotest galaxy?
If science fiction is this, or is capable of being this, a true metaphor to our strange times, then surely it is rather stupid and reactionary to try to enclose it in the old limits of an old art–like trying to turn a nuclear reactor into a steam-engine.
Science Fiction and Mrs. Brown, in Science Fiction at Large, London, Victor Gollancz, 1976

Gunn, James E.
Science Fiction is the branch of literature that deals with the effects of change on people in the real world as it can be projected into the past, the future, or to distant places. It often concerns itself with scientific or technological change, and it usually involves matters whose importance is greater than the individual or the community; often civilization or the race itself is in danger.
Introduction, The Road To Science Fiction, Vol 1, NEL, New York 1977

Heard, Gerald
Science fiction in the hand of character-draughtsman can create a new contemporary tension-of-choice, new moral decisions, and so indicate how they may be faced or flunked.
In its [science fiction’s] aim it is bound, by its extrapolation of science and its use of dramatic plot, to view man and his machines and his environment as a three-fold whole, the machine being the hyphen. It also views man’s psyche, man’s physique and the entire life process as also a threefold interacting unit. Science fiction is the prophetic … the apocalyptic literature of our particular culminating epoch of crisis.


Heinlein, Robert A.
A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method.
To make this definition cover all science fiction (instead of “almost all”) it is necessary only to strike out the word “future.”
from: Science Fiction: its nature, faults and virtues, in The Science Fiction Novel, Advent, Chicago:1969
Science Fiction is speculative fiction in which the author takes as his first postulate the real worldas we know it, including all established facts and natural laws. The result can be extremely fantastic in content, but it is not fantasy; it is legitimate–and often very tightly reasoned–speculation about the possibilities of the real world. This category excludes rocket ships that make U-turns, serpent men of Neptune that lust after human maidens, and stories by authors who flunked their Boy Scout merit badge tests in descriptive astronomy.
Ray Guns And Spaceships, Expanded Universe, Ace, 1981

Herbert, Frank
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.


Knight, Damon
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.



Lundwall, Sam J.
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…



Moskowitz, Sam
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.



Nicholls, Peter
First, [science fiction] is the great modern literature of metaphor. Conventional literature has a limit, set by everyday realism, to the juxtapositions of imagery it can allow itself. Science fiction, which can create its own worlds, has access to new juxtapositions. …
The second special strength of science fiction is related to the first. It is able to incorporate intellectually shocking material, partly because it is so pre-eminently the literature of change, as opposed to mainstream literature, which is the literature of human continuity. …
Third, science fiction is the literature of the outsider, in the extreme sense. Traditional realist fiction observes its action from the viewpoint of a partaker. It shares the illusions of the society which produces it. So does all fiction, but it is science fiction which makes the conscious effort, sometimes quite successful, to stand outside, to give us the Martian eye view of affairs. …
Fourth, science fiction allows us to escape, but gives us the choice of escaping into a world where all is not easy. It offers us as many hells as heavens, and in this respect its reputation for escapism needs to be modified.
Fifth, the freedom of imagery available to the science-fiction writer allows him to derive a potency of effect, whether consciously or unconsciously, from his own hopes and fears, which, in the way of archetypes, are likely to be ours too. The collapsing star, the monstrous embrace, the brilliant child misunderstood by his parents, the dying tribe, the animal which is a machin/e, and the machine which is an animal–these and many other familiar images of science fiction all have the obsessive power of the myth. In other words, even the inexperienced SF writer is working with materials that often cut very deep. This is why, in my view, it is pre-eminently the modern literature not of physics, but of metaphysics. It is in science fiction that we are now asking the deepest questions of meaning and causation.
Science Fiction: The Monsters and The Critics, in Science Fiction at Large, London, Victor Gollancz, 1976



Panshin, Alexei
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.

Pohl, Frederik
The future depicted in a good SF story ought to be in fact possible, or at least plausable. 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 illumunate 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)



Rabkin, Eric S.
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)

Riley, Dick
At its best, science fiction has no peer in creating another universe of experience, in showing us what we look like in the mirrorof technological society or throught the eyes of a non-human.
Critical Encounters (New York, 1978)



Scortia, Thomas N.
… [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.

Sheckley, Robert
I believe that people read science fiction for a sense of participation in the wonders to come. The quest for non-ordinary reality is something more than curiosity and wishful thinking. We are too crowded in our everyday lives by replicas of ourselves and by the repetitious artifacts of our days and nights. But we do not quite believe in this prosaic world. Continually we are reminded of the strangeness of birth and death, the vastness of time and space, the unknowability of ourselves. One would like to live differently, more significantly. One would like to participate in events more meaningful than is our daily round, feel sensations more exquisite than is our sensual lot. One reads science fiction in order momentarily to transcend the dull quality of everyday life. … Science fiction, with its meretricious air, gives some of us hope. We have come to suspect anything that speaks of the Truth. We suspect that we are being lulled to sleep by these marvellous truths, always inapplicable to ourselves. An instinct tells us that the truth is to be stumbled upon in unlikely places. And what more unlikely place than in science fiction, which claims many things but does not claim to be literally true?
The Search for the Marvellous, in Science Fiction at Large, London, Victor Gollancz, 1976

Shippey, Tom
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, distruptive, 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)

Stableford, Brian
True science fiction [is] fiction which attempts to build logically coherent imaginary worlds based on premises licensed by the world-view of contemporary science.
(edited from his GOH speech, ConFuse 91)

Science fiction is essentially a kind of fiction in which people learn more about how to live in the real world, visiting imaginary worlds unlike our own, in order to investigate by way of pleasurable thought-experiments how things might be done differently.
(from his GOH speech, ConFuse 91)

What is authentic about genuine science fiction, is that the science fiction writer should not stop with just saying: Well, the plot needs this to happen, therefore I’ll just do it and I’ll invent an excuse for it being able to be done. Proper science fiction ought to require people to begin to explore the consequences of what they’ve invented. And thus, I think that science fiction is, in a real sense, capable of being scientific. Not in the sense that it can foresee the future of science, but it can adopt a kind of variation of the scientific method itself, it does feel compelled to explore the consequences of hypotheses and the way things fit together.
(from an interview on Science in SF, ConFuse 91)

What qualifies a story as sf is that it is set in a world which is deliberately altered. Sometimes the alteration in question happens while the story is in progress, so that the narrative begins in a mundane setting which is then transformed by a new discovery in science or by some kind of catastrophe.
The Way To Write Science Fiction, Elm Tree Books, London, England, 1989

Sturgeon, Theodore
A science fiction story is a story built around human beings, with a human problem and a human solution, which would not have happened at all without its scientific content.
Definition given by: William Atheling Jr., (James Blish) in The issue at Hand: Studies in Contemporary Magazine Fiction (Chicago, 1964)

Suvin, Darko
It [science fiction] should be defined as a fictional tale determined by the hegemonic literary device of a locus and/or dramatis personae that (1) are radically or at least significantly different from empirical times, places, and characters of “mimetic” or “naturalist” fiction, but (2) are nonetheless–to the extent that SF differs from other “fantastic” genres, that is, ensembles of fictional tales without empirical validation–simultaneously perceived as not impossible within the cognitive (cosmological and anthropological) norms of the author’s epoch.
Preface, Metamorphoses Of Science Fiction, (Yale University Press, New Haven, 1979)

SF is, then, a literary genre whose necessary and sufficent conditions are the presence and interaction of estrangement and cognition, and whose main formal device is an imaginative framework alternative to the author’s empirical environment.
Chapter 1, Metamorphoses Of Science Fiction, (Yale University Press, New Haven, 1979)



Taylor, John
I consider science fiction to be the art of making a scientific ‘if’ interesting, a scientific ‘if’ being a postulate or a proposition of scientific form. For example it might be ‘if’ the wizards of the past were truly effective, or ‘if’ anti-gravity has been discovered. Such cases can usually be expressed as ‘if gravity (or whatever) were different from our present understanding of it’. The ‘if’ may not in fact be involved with mainstream science. It may have been from science in antiquity, it may be from science of 100 years hence, but it’s still a question of making the ‘if’ interesting. One could call science fiction S.IF, not SF. That is emphasising the ‘if’ aspect of the work, and of course, one has to assume that there’s a possibility of the ‘if’ actually happening.
Scientific Thought in Fiction and in Fact, in Science Fiction At Large, Victor Gollancz, London, 1976

Toffler, Alvin
By challenging anthropocentricism and temporal provincialism, science fiction throws open the whole of civilization and its premises to constructive criticism. Nothing is more necessary in a revolutionary moment. By dealing with possibilities not ordinarily considered–alternate worlds, alternate visions–it widens our repertoire of possible responses to change. It helps us to see the world as system, as a whole. It helps us think of history in very large sweeps, rather than puny slices. It also provides us with what psychologists call ‘no-trial learning’, that is, permits us, as does literature in general, to test out the consequences of certain forms of behavior, certain actions, without actually having to take those actions and the risks they entail. In societies, moreover, that do a very poor job of thinking through the second-, third-, or fourth-order consequences of technology, it helps to appraise future technologies before they arrive, rather than after the fact, when it may already be too late to cope with them. At an even deeper level, science fiction tries out new epistemologies, new notions of causality, non-linear time, language and communication, and, simply by encouraging a new time-bias (a greater future-consciousness), it leads to a kind of anticipatory adaptability by the culture.
Science Fiction and Change, in Science Fiction at Large, Victor Gollancz, London, 1976


Williamson, Jack
“Hard” science fiction … probes alternative possible futures by means of reasoned extrapolations in much the same way that good historical fiction reconstructs the probable past. Even far-out fantasy can present a significant test of human values exposed to a new environment. Deriving its most cogent ideas from the tension between permanence and change, science fiction combines the diversions of novelty with its pertinent kind of realism.

Wolleheim, Donald A.
Science fiction is that branch of fantasy, which, while not true to present-day knowledge, is rendered plausible by the reader’s recognition of the scientific possibilities of it being possible at some future date or at some uncertain point in the past.
“The Universe Makers”index


If you have a definition of Science Fiction you would like to see here, you can send it to me using the form below, preferably accompanied by a proper attribution/source. If you notice errors/misquotes in the already existing ones, or if you are able to provide proper attributions to those I have not yet been able to verify, you are welcome to fill the following form to contact me as well.

* indicates required field