The phrase “speculative fiction” is one I’m not particularly fond of. Its official definition, according to Merriam-Webster, is “a broad literary genre encompassing any fiction with supernatural, fantastical, or futuristic elements.” Speculative fiction covers a few different genres, and each of them are doing different things. The three main genres under the overarching label of speculative fiction are: science fiction, fantasy, and horror. These three are further divided into different subgenres. While there can be a lot of overlap between these genres, they are very different in terms of overarching themes and types of conflicts they cover. This is generally why I don’t like the phrase – not to mention that taken literally, speculative fiction is redundant in and of itself. Fiction is speculative by its very nature. In my experience, it’s a phrase most often used by condescending “literary” writers – and even some of the more pretentious science fiction writers – who don’t have a full understanding of what the purpose of each genre is.
When most people think of speculative fiction, they think of science fiction. That is because the term was coined at a time when science fiction was extremely popular. Science fiction does contain imagined elements that don’t exist in the real world (thus the “speculative” part of the term), but so do fantasy and a lot of horror subgenres. What makes sci-fi stand out from the others is that sci-fi often deals with themes involving scientific and technological advancements.
Fantasy, on the other hand, is not limited by scientific fact. Escapism is the primary purpose of fantasy, and many fantasy authors take that literally. Fantasies often take place in entirely different worlds; sometimes they take place in a world that looks like ours with magical elements. Good vs. Evil are often major conflicts, and many fantasy authors use their worlds as allegories to make sense of complicated, real-world issues.
Horror is a little different from science fiction and fantasy. Where setting and theme tend to be the defining aspects of the other two genres, horror has a bigger emphasis on mood and atmosphere. The unknown – and the fear of it – is largely utilized in horror. Because mood is more important to horror than setting and theme, it’s easy to combine it with other genres. Dark fantasy combines fantasy with horror, and dystopias or apocalyptic fiction often combine science fiction with horror. Horror is a versatile genre that can tackle religion, politics, technology, and societal mores.
There can be a lot of overlap between these three genres and their subgenres, but all three are distinct, separate genres that fulfill distinct and separate needs in a reader. Lumping them all under the same umbrella category does a disservice to those who read those genres, as well as those who write them.