While reading another questions, I had to think about what is the relationship between fantasy and science fiction? Is science fiction just a sub-genre of fantasy? If they are considered different genres, what are the key characteristics that define them and keep them from being one genre and a sub-genre?

  • Why the close votes? This is perfectly reasonable and on-topic question. – Dima Sep 8 '11 at 14:15
  • 6
    @Dima - because it doesn't have a good "correct" answer - merely differing opinions that are all equally valid depending on ones point of view</yoda> – DVK-on-Ahch-To Sep 8 '11 at 16:00
  • 4
    I kinda disagree with the no "correct answer," I think Jeff gave a very good answer. He made it clear what the relationship is, and some characteristics that are in each. – Sydenam Sep 8 '11 at 16:38
  • @DVK I agree entirely with Sydenam. The answer given by Jeff gives great definitions of the two genres. While "Sci-fi" and "Fantasy" are fuzzy concepts, there is a general consensus of what they mean and what the distinction is. If all definitions were equally valid, the terms would be meaningless. – Dima Sep 8 '11 at 17:40
  • 2
    The close votes are because everyone and their two-headed dog has their own definition of fantasy and science fiction, and we could endlessly quibble about the precise boundaries, but this isn't the place for it, to the extent that we've identified questions about the definition of SF as off-topic in our faq. – user56 Apr 10 '12 at 22:27

Science Fiction and Fantasy are both considered sub-genres of Speculative Fiction.

The essential difference is that science fiction is supposed to be plausible at the time - it requires little or no suspension of disbelief. It is generally (but not always) set in the future, and involves advanced technology which allows certain breaks from current limits.

Fantasy is traditionally set in the past, or in an alternate universe which resembles certain times in our past. It generally requires more suspension of disbelief - magic and the supernatural play a much larger part.

These aren't hard and fast rules, of course.

| improve this answer | |
  • 1
    Pern is not fantasy. It is science fiction. The dragons' abilities are not magical, they are psionic. The planet Pern is colonized by humans from Earth in our far distant future. Otherwise, though, the answer is reasonably correct. – Donald.McLean Apr 9 '12 at 4:00
  • 3
    @Donald.McLean: Pern is fantasy. It just calls it's magic 'science'. Nothing about that series was even scientifically plausible at the time of writing. – Jeff Apr 9 '12 at 13:06
  • 3
    @Jeff: There is no requirement for something to be "scientifically plausible" in order for it to be science fiction. The only fantastical element in the stories are the abilities of the dragons and those fall well within the established boundaries of psionics. – Donald.McLean Apr 9 '12 at 13:19
  • 3
    @Jeff: Actually, no, there is no such requirement. Most people who actually study physics would argue that both time travel and travel between parallel universes are impossible. Are you saying those are fantasy too? Are you saying that Star Trek is fantasy as well? Many characters in the Star Trek universe exhibit psionic abilities that are far in advance of what appears in the Pern novels. – Donald.McLean Apr 10 '12 at 13:51
  • 2
    @Jeff Except that, by the rules in your answer Pern could still be classified as science fiction. It is set in the far future, the planet was colonized by humans who travelled there from Earth in starships (that technology has since been lost). And if you are ok with psionics in Star Trek then Pern is a slam dunk for the same label. – Donald.McLean Apr 10 '12 at 14:48

The technical definition of Science Fiction is as a subset of Fantasy.

Fantasy in common use, however, has become a term for settings that (any one or more of):

  • lack modern technology
  • have magic
  • make use of improbable† pasts as setting tropes (as with Conan and Kull)
  • have settings with altered physics‡

Generally, Science Fiction has come to mean settings that (any one or more of):

  • set in space or across space
  • have higher technology than modern
  • have a clear recent divergence point and alternate history
  • have one clear break in physics‡
  • have aliens
  • FTL travel

Sci-fi may include

  • limited magic in the form of psionics, especially telepathy and clairavoyance.
  • alternate timelines based upon clear divergence points/events.

Several settings are sci-fi, but have fantasy trappings, including McCaffrey's Pern setting... it's set on a world around the star Rukbat. Ironwood, by Bill Willingham, is a connected alternate universe, with a strogn fantasy feel, and imported Marlboro cigarettes...

† most would say impossible pasts, now, as almost no one seriously believes in prediluvian cultures any more

‡ I've read several short stories where the change was a change in physics and exploration of it. In fantasy, usually as means of having medieval settings without gunpowder, as the universe differs by gunpowder not generating a detonation. In science-fiction, it has been used as a means of exploring other elements of culture. In both, it straddles the borderline. Often called Science Fantasy.

| improve this answer | |
  • Psionics are not a form of magic, they are a type of meta-physics - an aspect of the universe which transcends the normal laws of physics. In Star Trek, for example, the Q Continuum and the Organians could not possibly exist within the perceivable limits of physics. Also, claiming that science fiction is a subset of fantasy is exactly backwards. – Donald.McLean Apr 9 '12 at 13:34
  • Phlogiston predates oxidation but that doesn't make it correct. Separating Science Fiction from Fantasy allows the more precise discussion of the genres and categorizing either as a subset of the other, while arguably accurate, is really an insult to both. Also, it is widely regarded as accepted practice that psionics in and of themselves, in the absence of any other fantastical elements, are regarded as a science fiction element. I would strongly argue that higher-order beings should also be included. – Donald.McLean Apr 10 '12 at 1:27
  • We'll just have to disagree on that because I see no reason why psionics should be classified as a type of magic. In fact, I disagree with your entire line of reasoning that anything that is not strictly within the bounds of our current understanding of physics could be classified as magic. – Donald.McLean Apr 10 '12 at 3:09
  • @Donald.McLean I deleted my responses: You should do likewise, and instead post a separate answer rather than attempting to get me to twist mine to your distorted views. – aramis Apr 11 '12 at 9:28

Simple and short, as stated by Prof. Farnsworth (or rather his alter ego The Great Wizard Greyfarn)

[..] instead of science, we believe in crazy hocus-pocus.

(from Bender's Game)

| improve this answer | |

Not the answer you're looking for? Browse other questions tagged or ask your own question.