Readers often think of science fiction and fantasy as two separate but related genres. They both rely on creating unusual worlds and telling stories that explore them. Sci-fi and fantasy overlap - there are common tropes, archetypes, stories, etc - but most readers divide novels into one genre or the other. However the line between sci-fi and fantasy is blurry and there are some stories that cross over from one genre to the other. These are science fiction fantasy books.
China Miéville is an author whose work exists in this blurred territory. He has written urban fantasy novels like King Rat and science fiction like Embassytown, but some of his books, like The Scar, use both sci-fi and fantasy concepts. The Scar has magic (thaumaturgy in this universe) and vampires as characters, but there are also spaceships and aliens in the novel. Miéville’s writing borrows from the iconography of both genres, and he fits into neither.
In order to find out what exists between the two genres, we should look at the difference between them. The commonly accepted distinction is that science fiction should have some scientific explanation for the imaginative concepts that the author has invented for the story. For example, the novel the Andy Weir's novel The Martian is based on what is scientifically possible now and what might be possible in the future, where as there is no scientific explanation of the origin of the Discworld. These stories are easy to classify as one genre or the other.
Dr Who is a good example of a TV show that is both sci-fi and fantasy. Although a lot of Dr Who is based upon what we know about science, there are a lot of Dr Who stories that do not stand up to scientific analysis. Time travel is probably not possible; neither can a child crying on Christmas Day defeat a homicidal snowman. The Daleks and the Cybermen make sense when looked at from a scientific point of view, as they are imagined along the lines of possible developments in cybernetics, but when Amy wishes the Doctor back from the dead it is not scientific and neither are the means by which the Weeping Angels turn to stone when looked at. These devices can be used to tell emotionally engaging stories, but they do not stand up to scientific scrutiny, so Dr Who sits in the space between sci-fi and fantasy as it has elements of both.
A book can be in both genres not just by borrowing from both: a writer can approach non-scientific concepts in scientific way. For example, the time machine, from HG Wells’s novel, is a realistic (as was considered possible at the time) scientific explanation of what the future will be like told through a non-scientific means, i.e. time travel. Wells's vision of the future and the people in it makes sense but the science of the machine does not.
Rather than sitting across both genres, a story can move from one to the other. Anne McCaffrey's ‘Dragon Flight’ novels start off as fantasy but then become science fiction as the technology and science behind the setting is revealed. From the characters’ point of view it makes sense for them to explain their circumstances - mainly the existence of dragons - as magic based upon what they know, but their understanding changes as the story progresses across several novels.
The characters' perception of what is magic and what is science is key to the stories that sit on the blurred line between the sci-fi and fantasy genres. In some stories, the explanation is deliberately vague, which makes it harder to tell whether it is scientific or not because according to Clarke’s third law ‘any sufficiently advanced technology is indistinguishable from magic’.
In many of the stories the power of technology is shielded in mysticism. In Frank Herbert's novel Dune, the line between science and magic is blurred because of social factors. The Bene Gesserit Sisterhood and the Kwisatz Haderach are mystical and they have strange abilities, such as seeing through time and having ancestral memories, all of which is unscientific. The protagonist Paul's experience of the world of Dune is more like that of a fantasy novel (understanding strange things as magic) because that is how he sees the world. Paul does not seek scientific explanations to the strange things that he encounters, as we would, because of the different society he was raised in. The reader cannot judge if these concepts are scientific or magic because there is no reason for the characters to ask this question. The reader has to put this novel on the blurred line between sci-fi and fantasy because of how the characters see their world.
Characters see the world of Dune differently to our world because it is set in the far future and society has changed a lot in the intermediate millennia. Star Wars is another similar example where mysticism shields concepts such as the Force from scientific analysis and the characters do not question this. The technology behind the Death Star is based on projections from our science, but the Jedi and the Force is more difficult to explain. Like Dune, the characters do not question the unexplained nature of the Force, so the viewer can never know for sure. Star Wars is set ‘a long time ago in a galaxy far, far away’ and Dune is our distant future, so it makes sense that society’s views on what should be questioned and investigated are different.
There is no hard and fast rule about which genre stories fall into and which ones are in between genres. The further the story is removed from our world, the more difficult it is to classify story concepts as magic or science. The Martian is clearly science fiction, but the science behind a lot of the book is not fully explained. There is no scientific explanation as to how they transported something the size of the rovers to Mars so the reader must just accept this for the story to work, much as they must accept magic in a fantasy story. Whilst there is no scientific explanation to the origin of the Discworld, the ways in which magic works in Terry Pratchett’s novels follows set rules like science does and is investigated in a scientific way at Unseen University. Even these books which appear easy to classify as one genre or the other have elements of both.
Across all of literature, the lines between genres are blurring to tell interesting stories, not just sci-fi and fantasy. As the distinction between genres becomes more vague, it will get harder to classify stories into one genre or the other.