Note: This site is now Science Fiction & Fantasy. All speculative fiction, including alternate history, are considered on-topic.

Following up on:

  1. Should questions about "Is X science fiction" be off-topic?

  2. What is science fiction? How are we to discriminate between sci-fi and fantasy?

We should really come up with some criteria on what is and what isn't considered science fiction.

This would instantly answer all the question mentioned by [1] including one of my own and it would also be useful help when determining is a question offtopic or not.

  • 5
    This should be retaged as faq as soon as we get moderators. Jan 12, 2011 at 15:11
  • 1
    All the discord here is why we shouldn't make a big fuss over this. Let's wait until we find something that makes no sense to be here at face value, to decide. Like a question about "Moby Dick" or something.
    – DampeS8N
    Jan 13, 2011 at 13:32
  • There is also another question on meta on this topic: meta.scifi.stackexchange.com/questions/2/…
    – Iceag
    Jan 13, 2011 at 13:47

4 Answers 4


While this is a Frequently Asked Question, it is one where the community as a whole cannot—and should not be asked to—agree upon an answer.

For instance:

  • Is The Wizard of Oz SF?
    The immediate answer is "No," right?

    Are Heinlein's World as Myth books SF?
    It's generally agreed upon that they are.

    But if the "World as Myth" is SF, and the Oz books are part of the "World as Myth", how can we say that Oz is not SF?
    Note: this is a thought experiment, not my personal opinion.

  • Was Star Wars a Fantasy up until Lucas came up with the idea of midichlorians, and after that SF?
    My personal opinion on this one: SW was SF until Lucas came up with the idea of midichlorians, after which it was crap.

  • If a multi-book series starts off as Fantasy, and then later retcons in a slight scientific backstory, does that make the entire series SF?
    I'm looking at you here, Pern. And Darkover. And Wheel of Time. And any number of other worlds that fit this particular shoe.

    If a multi-year SF television series falls down a magical plot hole towards its end, does that make the whole thing Fantasy?
    Ah, BSG, we had such high hopes…

  • If a sufficiently advanced technology is indistinguishable from magic, then how can we say that any given fictional culture based on magic isn't actually based on advanced tech?

  • And so on, and so on…
    All lovely things to play with in your mind, but none of them help to achieve consensus.
    I don't expect that everyone will all come to the same conclusions when I can't even decide which ones I believe are SF two days running.

  • 3
    Easy: they're all SF. (As in speculative fiction, see my answer.)
    – user56
    Jan 13, 2011 at 19:11
  • @Dori: But my position is that “what is Science Fiction?” is not the right question, and that all SF is on-topic on this site.
    – user56
    Jan 15, 2011 at 15:20
  • @Dori so does this include or exclude Fantasy?
    – Ivo Flipse
    Jan 18, 2011 at 22:09
  • 1
    @Gilles, the term speculative fiction is damaging to the SF canon. Most fantasy readers don't read SF, they like the magic and the softness of fantasy. Even on Wikipedia, there is a speculative fiction portal (which is never seen by any SF fan (proportionally). I plan to create an SF portal in wikipedia. Jan 18, 2011 at 23:07
  • @Ivo: Does what include fantasy? There's a separate question for Is Fantasy in spec for this site?.
    – user56
    Jan 18, 2011 at 23:19
  • @scope_creep: The speculative fiction portal links to the science fiction portal in a very obvious way.
    – user56
    Jan 18, 2011 at 23:20
  • I hadn't seen that before I stumbled onto this one @Gilles
    – Ivo Flipse
    Jan 18, 2011 at 23:22
  • @Gilles, the sf is scrap compared to the standard or best. It's not being maintained and it off the speculative fiction branch, as a sub genre. Its a standalone older genre that fantasy, and needs to to reflect that. The first SF book was written I think 1740. Jan 20, 2011 at 4:33
  • Science fiction older than fantasy? The Historia Regum Britanniae was the first written account of the Arthurian legends, and was published in the 12th century. "Orlando Furioso" is poetic fantasy, and was written in the 1500s. And how can we forget " True Stories" (Ἀληθῆ διηγήματα), often also considered the first science fiction story? It contains manifestly fantastical elements (i.e. river of wine), which unlike, say, the Theogony, its author explicitly fabricated.
    – Adamant
    Mar 6, 2016 at 2:36

What if …?

The shortest definition of SF I know of is that it's any form of fiction that asks “what if?”. That's SF as in speculative fiction, not the more restrictive “science fiction” or “sci-fi”.

The ISFDB policy seems like a good start, though I wouldn't be too strict with borderline cases such as technothrillers. (And of course this site isn't limited to written works.)

I don't see any mileage in refusing certain parts of SF such as alternate history or fantasy. This is too likely to generate fight upon fight about where the boundaries are. And there isn't really a science fiction community the way there is an sf community.

Be careful when using the terms “science-fiction” or “sci-fi” or “sf”, because people have different definitions. Science-fiction is usually about what might be, alternate history about what might have been, and fantasy about what can't be, but people disagree strongly on where to draw the line (is Star Wars science-fiction? Is anything with faster-than-light travel science-fiction? Is technology so advanced that it's indistinguishable from magic science-fiction?)

I especially warn against “sci-fi”, because many people who define themselves as “sf” aficionados use it in a somewhat disparaging way, limiting it to B-grade science-fiction.

  • While refusing to subdivide the genre into little fragments is an admirable principle, one of the purposes of this question is to enable us to provide an immediate and definitive answer to questions that are asked by people who want to know which of those little fragments a particular work belongs to. You can't answer the question "Is <work X> science fiction?" without a consensus definition of science fiction that you can point to, and what we're being asked to do in this question is to provide that definition.
    – Mike Scott
    Jan 13, 2011 at 8:14
  • 3
    @Mike: My answer to “what's on-topic here?” is “anything that asks ‘what if?’”.
    – user56
    Jan 13, 2011 at 8:21
  • 1
    This looks like a good rule of the thumb. Also, ISFDB link is very useful, we might copy and modify to include non-written works. And for any borderline case we can decide on the fly, and update our list accordingly. Jan 13, 2011 at 17:33

There's a pretty good list of definitions on Wikipedia. Of those, my favourite is the most recent, by Jeff Prucher: "A genre (of literature, film, etc.) in which the setting differs from our own world (e.g. by the invention of new technology, through contact with aliens, by having a different history, etc.), and in which the difference is based on extrapolations made from one or more changes or suppositions; hence, such a genre in which the difference is explained (explicitly or implicitly) in scientific or rational, as opposed to supernatural, terms."

But that definition doesn't work when the nature of the difference (is it supernatural or rational?) is not made clear -- for example, Robert Jordan's Wheel of Time series looked like fantasy in the first few volumes and it only became clear that it was SF after we had more information about the background and history of his world. I don't believe there is any feasible definition of science fiction that would let you categorise the first volume of the series as science fiction without reference to the later volumes.

  • What? Wheel of Time is SF? I've been considering reading it for a while, but now I'm way to intrigued to skip it. Jan 12, 2011 at 23:41
  • @Martinho Fernandes Skip it. The first couple of books are good enough to instill the makings of a really good disappointment that the rest are crap
    – johnc
    Feb 13, 2011 at 1:17

Wikipedia is a good source to decide whether or not something is Science Fiction, and we can surely take some information to specify some subgenres or unclear Questions.

For me there is a definition like the following most matching:

Definition of Science Fiction

There is a 3 Step definition:

  1. Science fiction is a genre of fiction in which the stories often tell about science and technology of the future. It is important to note that science fiction has a relationship with the principles of science—these stories involve partially true-partially fictitious laws or theories of science. It should not be completely unbelievable, because it then ventures into the genre fantasy.

  2. Science Fiction is a genre of fiction in which the plot creates situations different from those of both the present day and the known past. Science fiction texts also include a human element, explaining what effect new discoveries, happenings and scientific developments will have on us in this different future (or a different past).

  3. Science fiction is a genre of fiction in which texts are often set in the future, in space, on a different world, or in a different universe, dimension or an alternative timeline.

One of these criteria needs to be fit, to define whether something is Science Ficiton or not.

  • 1
    You've eliminated alternative histories, Star Wars (set a "long time ago", and therefore not in the future), prehistoric SF, and so on. You can't use "the future" as part of your definition.
    – Mike Scott
    Jan 12, 2011 at 17:36
  • but i wrote "the plot creates different from those of both present day and the known past" -> so star wars fits in within this definition. My Science Fiction definition consists of three parts, and only one of them needs to be given to define sth as SciFi. But i will edit it so that it becomes more obvious - thanks for the critic
    – Iceag
    Jan 12, 2011 at 22:44
  • By your definition, Star Wars is still excluded (“relationship with the principles of science”).
    – user56
    Jan 12, 2011 at 23:06

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