Through the process of writing my novel, I've found that I really don't know where it fits in the written realm. I believe I should have a clear understanding to identify what genre my book belongs in.

Fantasy is about things that cannot occur and has no logical explanation; about alien planets and magic and monsters. Science fiction has logical explanations to all things occurring in the work and often takes place in a futuristic time setting.

Or, pulled straight from a dictionary:

Science fiction: Fiction based on imagined future scientific or technological advances and major social or environmental changes, frequently portraying space or time travel and alien life on other planets.

Fantasy: A genre of imaginative fiction involving magic and adventure, esp. in a setting other than the real world.

But for novels that are completely rooted in logic and playing out on different planets with inhabitants who greatly resemble humans and have no powers, what then? Is it filed in a completely different category than these two?

I really need a healthy dose of clarification on the matter.

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    Why are you asking? As per my answer, I am not convinced that rigid definitions are always helpful, so I am interested in why you want to identify these distinctions. Commented Jun 25, 2012 at 12:23
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    "Science fiction means what we point to when we say it," said Damon Knight. The general distinction is fairly clear, while the precise distinction is largely academic. Many many existing discussions on this. See: TV Tropes, Wikipedia, David Brin, Orson Scott Card (Amazon book).
    – Standback
    Commented Jun 25, 2012 at 16:26
  • @SchroedingersCat I am asking because, through the process of writing my novel, I've found that I really don't know where it fits in the written realm.I believe I should have a clear understanding to identify what genre my book belongs in. Commented Jun 25, 2012 at 19:00
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    @FearlessWriter I think, if I may be blunt, you should write a good novel first, and then worry about where it fits. Genre is a marketing distinction.
    – Patches
    Commented Jun 25, 2012 at 23:33
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    This question is basically prompting a whole bunch of extremely broad generalizations. Rather than asking about "the Difference between A and B," why don't you tell a little more about your work and why you feel it doesn't fit comfortably in either category, and ask specifically about your work? The difference between SF and F is an interesting discussion, but it doesn't work very well as a straightforward Q&A. (Best to open a new question, since the existing answers here are very open-ended and don't address your particular story.)
    – Standback
    Commented Jun 26, 2012 at 9:42

11 Answers 11


To me, the difference is not whether the story has a logical explanation, but whether it could have an explanation in this universe. Another way to say it: Fantasy may violate what we know to be true of the universe. Science fiction may not.

A monster, an alien planet, or "magic" could be either fantastical or science fictional, depending on whether it violates the known laws of the universe.

Now, even that line is fuzzy, because "known" is fuzzy and to some extent changeable. And different readers know different things. A quirk of physics that most readers would accept might violate the knowledge of a scientist who specializes in that aspect of physics.

And sometimes an explanation will make the difference. A given monster, planet, or magic might, with sufficient explanation, shift from fantasy to science fiction. What seems like magic may be "merely" technology sufficiently advanced.

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    A lot of major SF tropes are widely considered impossible in real-life. The Mundane SF movement is one attempt to restore some measure of plausibility to the genre. So it's not even about which explanation is plausible, and more about whether the explanation pretends plausibility.
    – Standback
    Commented Jun 26, 2012 at 9:28

To me, the science in science fiction is what differentiates the two. That is usually represented by devices of some sort. Nor does it necessarily need to be a silicon-based device, a carbon-based biological based device would equally foot the bill. But there is always some device that is what makes the special power of the world (be it a method of transportation, communication, etc.) There are also different levels of science fiction. A soft science fiction story probably wouldn't explain how an ansible works, as long as it does. In hard science fiction, the technology behind such a device would not only need to be described in glorious detail but it pretty much needs to actually work based upon the scientific principles that we know and understand today.

Fantasy novels, on the other hand, are almost always rooted some non-device based means of getting things done. It could be magic or runes or wishes, but it does not strictly depend upon a manufactured device being used to make things happen. As with science fiction, there are levels of fantasy, such as hard fantasy.

It should be noted that the vast majority of fantasy and sci fi is not strictly delineated. In fantasy fiction there are always "things" that contain the world's special power, but it doesn't actually create it. These would include such things as Frodo's ring or Harry's Nimbus 2000. Likewise, in science fiction there are often special powers of the mind (psi) that function as that genre's magic. Think of the Bene Gesserit abilities of Dune, for instance, or "the Force" in Star Wars.

And, of course, as Arthur C. Clarke has famously pointed out, [a]ny sufficiently advanced technology is indistinguishable from magic which implies that if you get far enough out in time, it all merges into the same thing.


I think Philip K. Dick said it best:

Fantasy involves that which general opinion regards as impossible; science fiction involves that which general opinion regards as possible under the right circumstances. This is in essence a judgement-call, since what is possible and what is not possible is not objectively known but is, rather, a subjective belief on the part of the author and of the reader.

From a letter, May 1981; as quoted on p.28 of "The Twisted Worlds of Philip K. Dick" by Umberto Rossi


Whenever this question comes up I always say that the clue is in the name. It's SCIENCE fiction. That means that the story must absolutely rely on science in order to be told and if it doesn't, it's probably fantasy. Now that doesn't mean that the science in the story has to be real, neither does it have to make sense (except within the logical parameters of its own world) and it doesn't have to be set in the future so I'm not necessarily talking about robots or spacecraft or "phasers on stun", but the science does have to be one of the major driving forces of the story. Without the science, the story could not be told.

A great example of this is Back To The Future. In the film Doc Brown has to deliver 1.21 gigawatts of electricity, directly into the Flux Capacitor, at the exact moment that the car hits 88mph to travel through time. Later on when Marty McFly is trapped in 1955 the only way to get back is to rig up the DeLorean with a conducting rod so that, as long as Marty hits his mark at exactly the right moment, while doing exactly 88mph, the lightning will send 1.21 gigawatts of electricity directly into the Flux Capacitor, sending Marty back to the future.

This is classic science fiction. The story absolutely relies on the science to work, without the science, the story could not be told. The fact that the science is utter nonsense is neither here nor there but what does matter is that the science is utterly consistent within the confines of the film and in both time periods. The physics(!) dictates 1.21 gigawatts of power into the Flux Capacitor at 88mph and the same is true in both 1985 and in 1955, the challenge is in harnessing that kind of power in 1955 to get Marty home and that is what makes Back to the Future such a terrific film.

Remember though, ultimately very few people care about the science. What they want to know is "Will Marty's parents get together? Will he get back to 1985 before he ceases to exist?" because like all great science fiction, the science drives the story but it's the people we care about.


Real difference:

Science fiction pretends to be possible. It says We haven't managed to pull this off yet, but we still might someday! Or else, it says We never pulled this off, but if history had gone a little differently, we could have!

Fantasy flat out says This shit is impossible, but it's happening anywayyyy!!!!

Secondary difference which is a thematic generalization, not always true:

Fantasy uses unrealistic aspects to allow characters to explore themselves and their own potential in more inventive ways.

Science fiction uses unrealistic aspects to explore society and humanity in more inventive ways.


Each of the three genres discussed here (science fiction, fantasy, and horror) lends itself to different aspects of the human experience.

Horror is the easiest to categorize: Horror is about being powerless in the face of evil. Whether this evil is supernatural (the movie Poltergeist), ostensibly scientific (the Alien franchise) or social (as in the Killing Fields), when the protagonist's only manner of survival is avoidance/escape, the story can be characterized as horror.

Science fiction best lends itself to explorations of social issues, and fantasy best lends itself to exploration of moral issues. This is why Star Wars is best seen as a fantasy series, and why 1984, in spite of taking place in a setting that is scientifically regressing, is arguably a work in the science fiction genre.

  • I really like this answer, particularly on horror. The sci fi and fantasy I'll have to think about, particularly the sci fi.
    – Patches
    Commented Nov 20, 2017 at 16:17
  • Horror doesn't have to be about evil. In most of the Lovecraft mythos, the horror in assorted stories comes not from the assorted cosmic entities and whatever being evil, but because humanity doesn't even register to them as something significant enough to notice and for morality to come into play. They think about their effects on us about as much as we concern ourselves over the fate of dust mites that could be crushed due to human actions that have nothing to do with them. The mite regards my foot coming down to their inevitable doom as horror; I'm just walking somewhere. Commented Aug 27, 2018 at 19:27
  • From our perspective many of the malignant entities in the Cthulhu Mythos are evil; they knowingly pursue the destruction, enslavement, corruption, or consumption of humanity. Some of this is planned and some of it is opportunistic. While humanity is beneath the notice of some of the major entities, at those times that humanity or specific humans have come to their attention, the response has been hostile. There are races that aren't malignant towards us (nightgaunts, Yith, etc.), but those aren't the creatures we're scared of.
    – EvilSnack
    Commented Aug 29, 2018 at 3:35

To come from the other side, I think fantasy will usually have characters with some form of "mystical" power - however it is described or explained - which is core to the story. The power is not something created - which would imply that everyone could have it - but something which is indigenous to the character or characters.

In SF there is often no sense of the mystical. Where there is, it is not something that empowers people beyond an inner strength that they may get from their mysticism. In the end, the story is driven by scientific progress or regress, and by application of science.

However, classification is always difficult, and not always helpful. Blurring boundaries often makes for a fun story, and one that challenges the reader. Some of the best stories fail to fit into a clear category - Audrey Niffeneggers "The Time Travellers Wife" is probably romantic fiction, but there is a definite SF element in it.

  • +1 Appreciating the use of "The Time Traveller's Wife" as a reference. A rewatch worthy, I believe.
    – storbror
    Commented Apr 28, 2017 at 10:11
  • @storbror The movie was good but the book is very much worth reading. As is usual with movies, they left a lot out.
    – Cyn
    Commented Feb 23, 2019 at 16:13

I read the following breakdown of speculative fiction in some writing article or book, and I can't remember were or who wrote it, so unfortunately I can't attribute it. But, it's been really useful for my thinking, so here goes:

Science Fiction is fiction of the mind, Fantasy is fiction of the heart, and Horror is fiction of the senses.

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    Not sure I agree. Good SF has me yearning for the wolds being described, and good writing of any sort has me feeling the emotions of the characters. Commented Jun 26, 2012 at 7:56
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    I'm... not sure that answer has much practical utility.
    – Standback
    Commented Jun 26, 2012 at 9:23
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    Despite that I agree with the other commenters, I do very much like your quote and do indeed understand what it suggests. Commented Jul 1, 2012 at 18:58
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    "So if science fiction is the genre of the mind, and fantasy is the genre of the heart, what might horror be? ... Horror is the genre of the senses." --- Edo Van Belkom, Writing Horror (2000), page 12.
    – Gaultheria
    Commented Nov 2, 2017 at 4:23

An even simpler answer:

If the world of the novel purports that proper application of the scientific method in OUR WORLD could explain what's going on, it's sci-fi.

Otherwise, fantasy.

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    Example: Question. How does a giant eye of writhing flame float in the air above a stone tower? Research. There is no information available on this subject. Hypothesis. There must be something holding it up. Test hypothesis by doing an experiment. We take away the top layer of stone beneath the eye and replace it with linoleum flooring. The eye continues to float. Analyze your data and draw a conclusion. There is absolutely nothing holding this eye up. Bam. Fantasy. Commented Jul 1, 2012 at 18:56

Here is what I hope is a sufficient short answer:

Science Fiction and Fantasy both change or add some aspect to our world. The general difference is that, in Science Fiction, the new aspect (like interstellar space travel or aliens) could exist, following the laws of the world we live in. It also usually has a technological theme/tone. Fantasy usually invents something that requires new laws and/or does not fit in or follow the laws of our universe (like magic). Fantasy usually has a more magical/mystical tone.

But there is also a little choice involved. Something that breaks the laws of the universe but it achieved through the press of a button or through a machine might be considered science fiction. Likewise, something that does not violate the laws of our universe but is accomplished with the swish of a wand might be considered fantasy.

Really, the line between science fiction and fantasy is not a line at all. It's more like a gradient.

I'd say if it's tech, like warping between space, you're probably in science fiction. If you're magic, like Harry Potter, you're probably on the Fantasy side.


The difference is thematic.

Fantasy deals with destiny, family lineage and dynasty, purity of purpose, and typically things of the past. Fantasy looks back to a "simpler" age with polarized b&w morality (reductive), to examine character journeys about becoming legendary archetypes and paragons – combine family lineage with paragon characters and we get Chosen One stories, sometimes "accidental chosen ones" who did not know the true nature of their lineage until they pass a purity test and the story eventually distills them into paragons. Characters get punished for defying their destiny – an unconscious signal of a setting that looks like the past is that destiny has already been written and cannot be altered.

The themes in Science Fiction are invention and evolution – the opposite of a pre-determined destiny. Characters evolve their way into and out of trouble. Typically this evolution is already underway, perhaps science is evolving faster than society (progressive), or one group of characters has an evolutionary advantage over another. Conflict is solved not through a purity test but by unconventional thinking and the confluence of ideas. The unconscious signal of setting stories in the future is that fate has not yet been decided, and can be altered. Grey morality means that Science Fiction often deals with the unexpected consequences of invention or evolution. There is no "destiny" in the Fantasy sense because the future is unwritten and anyone can evolve.

Themes are stronger than tropes

Despite the gonzo trappings of deliberately anachronistic tropes: telepathy druids, raygun princesses, future primitives, a theme about bloodline purity and pre-destiny is (for the most part) mutually exclusive to a theme about invention and evolution. Star Wars is Fantasy, period. There is not a single invention or scientist in the entire SW universe, and zero problems are solved through innovation or intelligence. In contrast, a story set in the historical past might feature an anachronistic inventor who builds a robot out of coconuts – the fact that the reader knows these inventions already, doesn't change the idea that the character is "winning" through invention and evolution.

In a nod to EvilSnack's answer, the 3rd genre in the trifecta is Horror which has its own themes about loss of personal agency and de-evolution of humanity, confrontation with the paranormal which goes unexplained, and no-win scenarios which the characters cannot completely overcome.


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