I actually haven’t read much Science-Fiction, or at least not for a while. My early culture in this genre comes exclusively from my father, who wasn’t much a reader. To me, S-F was first and foremost video games, movies, and comics. And I think it’s safe to claim that 19th century literary works and games like StarCraft II don’t share a common purpose or structure and barely share an aesthetic guideline. So then, how could we justify this common label of “Science-Fiction”?

Well, first thing that comes to mind: they all introduce the reader to one or more products of a fictitious science, or fictitious products of an existing science, and then it kind of extrapolates on that. I had previously encountered the concept of novum presented by Darko Suvin, and it seems really relevant to me. Most science-fiction works elaborate on some kind of premisse: “let’s say we can genetically engeneer people” (Gattaca), “let’s say there are replicants” (Blade Runner), “let’s say there are these two alien species, and humans wear mecanical suits to carry bigger guns” (StarCraft). But then the question that comes to my mind is: does this novum have to be exclusively technical or scientific? Is the Force an SF novum? Or is it a structural device proper to fantasy invading an otherwise aesthetically SF space?

These question have to be left unaswered in such a short essay. But though I obviously can’t define what SF is here, I could think of reasons why people actually use the term “Science-fiction”. And for this, like for any other genre, our best option would be the wittgensteinian concept of “family resemblance”. There’s a set of thematic and aesthetic criteria that’s spread across all of Science-Fiction, but no one criterium can claim to be the one. Space travel, machines, alien lifeforms, A.I., androids, etc, all of these are themes widely known as “Science-Fiction themes”. It’s not the themes that make the genre, it’s the genre that makes its themes (I think of time travel and uchronias, for example). And sometimes, an author can even make use of these themes outside of the canonically defined genre (like in the super-hero genre).

As Freedman argues: Science-Fiction is not a category but a tendency, and there can theoretically be no perfect SF work. But of course these themes and this tendancy are also subject to change as the genre evolves and as actual science evolves too: what was Science-Fiction in Destination Moon! is regarded as merely historical in First Man.