What Is Sci-Fi?

Which Stories are in the Genre and Which Aren't?

Mark Hamill takes off his storm trooper helmet in a scene from the film 'Star Wars', 1977.
Mark Hamill takes off his storm trooper helmet in a scene from the film 'Star Wars', 1977. 20th Century-Fox/Getty Images

What is sci-fi? Science fiction's dirty little secret is that sci-fi is in the eye of the beholder. That said, there are certain guidelines that will help anyone genuinely interested in determining whether a work of fiction is science-y enough to qualify as science fiction. So, some guidelines:

Sci-Fi vs. Fantasy

Science fiction and fantasy both answer the question, "What if?" Works of fantasy imagine worlds and situations that could not possibly occur.

"The Lord of the Rings" is a classic example of fantasy literature and movies. Maybe hobbits and dragons could some day be genetically engineered…but Gandalf’s magic isn’t based on science. If it’s magic, it’s fantasy. And, generally, if it’s magic, that means it’s not sci-fi.

Some works, like the comic book "Saga," combine elements of both. The same is true of "The Avengers," which features a high-tech robotic combat suit and a Norse god. Generally, such works are considered to employ sci-fi elements, but some critics won’t consider them works of pure, straight-up science fiction. So, what is?

Science fiction takes our current understanding of how the universe works and imagines worlds, ideas, and technologies that we haven't seen yet, but still could fit within that understanding. It's fiction that expands on what we know about science, and scientific potential, operating within known or hypothesized scientific principles.

Space flight, for example, is something that exists today. Once upon a time, any work that included space flight qualified as sci-fi. Today, it’s less clear.

Some works of science fiction imagine new ways of crossing the universe that may seem impossible to us now, but still operate according to scientific principles extended from what we know now.

Others imagine the discovery of scientific principles currently unimagined. "Jurassic Park" is science fiction because we don’t currently have the technology to produce genetically modified dinosaurs. But that technology is a lot closer and more imaginable than building a Death Star. And if we ever do acquire that technology, "Jurassic Park" may not feel like science fiction anymore. For an example in the more familiar milieu of space, consider "Gravity." Is that sci-fi the same way "Interstellar" is? How far removed must the technology be from our own to qualify? Your light-year mileage may vary.

Take "Star Wars." The Force seems a lot like magic. But the Force eventually got a pseudo-scientific fig leaf with the introduction of midichlorians (don’t ask). This cemented "Star Wars" as a purely sci-fi work — if the rabid love of millions of sci-fi fans hadn’t already (the gravitational pull of "Star Wars" fandom is literally sufficient to change the sci-fi genre’s orbit). Of course, explanatory patchworks like midichlorians may end up making the difference between good or even classic sci-fi…and hokey sci-fi.

What Films are Considered Sci-Fi?

Sci-FiNot Sci-FiMaybe?
Star WarsLord of the RingsAvengers
Star TrekHarry PotterSaga
AlienTwilightGhostbusters
Jurassic ParkGame of ThronesiZombie

Kinds of Sci-Fi

As you might imagine, in a fictional genre this broad, there are lots of sub-genres. We’re perhaps most familiar with space operas like "Star Wars," but that’s by no means the only sub-genres. Here’s a partial list of sci-fi’s still-changing sub-genres:

Sci-Fi Sub-Genres

  • Post-apocalyptic
  • Alien invasion
  • Hard/soft sci-fi
  • Cyberpunk
  • Comedic Sci-Fi
  • Military Sci-Fi
  • Time travel
  • Feminist sci-fi
  • New wave
  • Superhero sci-fi
  • Alternate history

Good Sci-Fi vs. Bad Sci-Fi

It was science-fiction writer Ted Sturgeon who famously defended his native genre with what’s come to be known as Sturgeon’s Law, which says, simply, “Ninety percent of everything is crap.” His point was that critics who derided sci-fi as juvenile and unsophisticated had missed the fact that most works in every genre are pretty lousy.

But there’s nothing inherent in sci-fi that disqualifies its top ten percent from rivaling the greatest works in any other genre.

Kurt Vonnegut? Margaret Atwood? Science-fiction writers. "2001: A Space Odyssey"? Science-fiction movie. Sci-fi doesn’t tell you whether a work is trashy or classy, serious or funny, juvenile or adult. It can be any or all of those things.

Ultimately the point of the best science fiction is not the technologies or inventions. Like all drama, science fiction explores the human condition, but it can look at it from unexpected angles. It can even utilize comedy (e.g., "The Hitchhikers Guide to the Galaxy") to do so. Science fiction imagines strange challenges and opportunities for us in order to delve deep into human nature. That's why some of the most provocative science fiction starts with men and women very similar to us. What these people do when faced with unusual crises speaks directly to who we are in our everyday lives.

"Modern science fiction," wrote one of its masters, Isaac Asimov, in 1952, "is the only form of literature that consistently considers the nature of the changes that face us, the possible consequences, and the possible solutions. ... [It is] that branch of literature which is concerned with the impact of scientific advance upon human beings." That’s one aspect that usually lies at the root of the best science fiction -- the impact on human beings is what is explored by true science fiction.

Some sci-fi, however, uses technology to explore the nature of humanity. That’s what the classic sci-fi movie, "Blade Runner" did, imagining the creation of synthetic human beings to make us consider what criteria we use to define the line between human and not-human.

Ultimately, the best of sci-fi shares the same concern as works of art in any other genre: The nature of humanity. (And the worst of sci-fi shares the same concerns as the worst of other genres.) What sets sci-fi apart, then, is not the quality or the medium, but the use of concepts that we can not rule out as impossible in this world, the real world; concepts that necessarily apply to and affect everyone in it.