Having the monstrous ego that I do, I’ve been watching the Rough Guide to Sci-Fi Movies Canon meme go through the blogosphere, and also reading comments people have been making about the selections for the Canon, and their own choices for addition to or subtraction from the Canon. One of the major complaints I see is the lack of the appearance of King Kong or of notice of any of special effect genius Ray Harryhausen’s films in the Canon itself (I will note Harryhausen is quite prominent in the book proper, in the "Icons of SF" chapter).
The reason for the lack of inclusion of these films, and several others that people feel passionate about, is simply that I don’t consider them to be science fiction films. One of the things I decided early on was to leave out films that were primarily fantasy films — and many of the films people are asking about are, to me, fantasy and not science fiction.
This naturally leads to the question of, well, what is "science fiction?" As it happens, I answer that on the first page of the first chapter of the book, when I map out three criteria for a film (or, indeed, any work) to be considered science fiction. I don’t think it compromises the book to share those with you here. So — Scalzi’s Three Criteria for Science Fiction are as follows:
1. The Work Takes Place in the Future — or what was the future when the work was completed. Alternate timelines may also qualify if they follow at least one of the other criteria.
2. The Work Uses Technology that Does Not Currently Exist — or (again) did not exist at the time the work was completed. Extrapolation from existing technology qualifies as well.
3. Events Are, By and Large, Rationally Based — I’ll quote myself here: "Though important events, situations and characters may in themselves be fantastical, science fiction assumes an explanation based on a logical universe. This is opposed to fantasy works, and some horror, in which such ideas are described through magic or the whims of the gods." This one gets stretchy, I’ll admit — there are plenty of science fiction films where the "rational" explanation for events is pretty damn stupid ("The creature was exposed to harmful Zeta Rays!!!"), but if those are the cards they want to play, you’ve got to play them.
One of these criteria is often sufficient to describe a work as SF, but it’s best when at least two of the criteria are in play. The Road Warrior, for example, takes place in future time and is rationally based, even if the technology in it is already known to us. Star Wars uses futuristic techonology and is largely rationally based, even if it takes place a long time ago in a galaxy far, far away. The Matrix is future time and futuristic tech, but the computer universe in which the events take place has a rationality that is best described as malleable.
Employing these criteria eliminates a number of films that seem at least cursorially SFnial. King Kong fails all three (present time, present tech, no rational explanation for a 50 ft gorilla), as do many of the classic monster flicks. Harryhausen’s most significant films were mythologically based, so they’re out, too.
This is not to say these films don’t share an important heritage with SF films, both in terms of audience and in terms of production (particularly relating to special effects); they clearly do, and I address much of the "backstage" stuff like that in the book. Be that as it may, these films aren’t science fiction, at least as I defined it.
Let me also note that these three criteria do leave plenty of room for judgement calls. For example, Superman is an SF film to me, largely due to The Man of Steel’s origin story (from another planet, which involved future tech to get here, and also a rational (if silly) explanation for his superpowers), but Batman isn’t — he’s just a guy with many cool gizmos and the need for lots of therapy. I wouldn’t classify most James Bond movies as SF, even though he employs some future tech with his gadgets, but on the other hand Moonraker is total SF, and there’s no getting around that. 28 Days Later… qualifies as SF for its "rage virus," but Night of the Living Dead is fantasical horror.
There are a lot of movies (not to mention books and other media) that are on the bubble in terms of being science fiction or something else. You can get pretty Talmudic parsing which films qualify as SF and which don’t, and naturally I had to do some of that. Generally I think I made good calls, but again I don’t assume everyone will agree, and indeed am having a blast reading examples of where people don’t. But at least now you all know where I’m coming from when I say that I didn’t consider some of your favorite science fiction-like films to be science fiction.