All too often people point at the trappings of a fiction and claim that they identify it. Book A contains spaceships and robots, therefore it must be science fiction. Book B has dragons and castles, so it must be fantasy. But as a means of defining a fiction, it’s imprecise, often inaccurate and very much open to abuse. For every book which can be definitively identified by its tropes, there are countless others that can’t, or that require the trope itself to be re-defined. Tropes do not identify a genre: if you paint a car yellow, it does not make it a banana.

To date, the one definition of science fiction that has generated the least argument is Damon Knight’s 1952 comment, science fiction “means what we point to when we say it”. It makes the definition purely personal and subjective. Which makes it completely bloody useless as a tool. And I think it’s important to know what science fiction is you’re going to write it or write about it. Having said that, most of the definitions of sf in Wikipedia – see here – are by sf writers. And most of those definitions are completely ineffective.

A useful definition has to describe something intrinsic to the text, not something extra-textual. We don’t, for example, assume every book with a robot on the cover is science fiction – though many sf novels have robots on the cover, and many books with robots on the cover are sf. And to assume that every book which features a robot in the story is science fiction is identification by trope, which is also wrong. A bildungsroman novel set in a car factory, for example, would feature robots.

I’ve been thinking about agency in fiction and how it can be used to differentiate between fantasy and science fiction. In fantasy, objects which do not have agency in the real world are given it by authorial fiat. In science fiction, the agency is applied systemically by the natural world – the laws of physics, cosmology, biology, etc. Just like it is in mimetic fiction. Things happen in mimetic fiction as the real world dictates they happen – planes fly because their wings generate lift, boats float because they displace water equal to their weight, apples fall from trees because of the law of gravity, and so on. The same holds true in science fiction, though some of the elements of the natural world may be invented, such as that allowing FTL travel.

Also important in science fiction is wonder, which is the bit that fills your imagination up to the brim and then spills over. It is the chief reason people read science fiction in the first place. But wonder also applies to fantasy – dragons are objects of wonder, for example. I have in the past had a go at defining wonder – see here – and even managed to turn it into a (slightly tongue-in-cheek) equation.

Then it occurred to me that if I used both agency and wonder, it gave me a handy way to categorise fiction:

Works can, of course, straddle borders, which can lead to interesting effects. But as means of distinguishing between various genres, the above chart doesn’t rely on tropes – in fact, it completely ignores them. A story can, for example, feature dragons, defined as cryptozoologic reptiles, and be science fiction. A fantasy novel can feature spaceships which fly between worlds because some person in a cloak waves their hands and mutters gibberish.

Now, of course, someone is sure to think of examples where my definition doesn’t fit…