A brief post yesterday at The OF Blog has set off a number of other bloggers. What's the difference between SF and fantasy? The post doesn't really speculate, just brings up the topic in an "I've been thinking about this lately" kind of way, but a few other bloggers have followed up with more in-depth thoughts.
Spiral Galaxy responded with a post arguing that in fantasy, certain special people are "born with the power." That is, only certain people can wield magic, while anyone can use technology. There's a follow-up at Smith Orbit that agrees and goes a little further, stating that fantasy contains a "romantic notion of authenticity"--that is, in fantasy, certain things or places are more pure or sacred or special and therefore contain power, while in SF, places and things are subject only to natural forces, which do not include "specialness."
Me, I'm inclined to follow Orson Scott Card's advice that SF contains rivets and fantasy doesn't, a short-hand way of differentiating between technology-driven SF and non-technological fantasy. But that's a bit simplistic too. Not all SF is about spaceships. Not all fantasy is about magic. When I shelved the fantasy section at a used bookstore years ago, I used to argue with our fiction director about where Anne McCaffrey's Pern books belonged. I wanted them in SF because the dragons were bioengineered creatures on another planet, the dragons' teleporting abilities were explained (in a handwavy way) as using natural processes, and while the people on the planet Pern had mostly forgotten about their past and had reverted to a much less technologically advanced society, they had originally arrived by spaceship. The fiction director wanted the Pern books in fantasy because, well, they had dragons on the covers. We were both right.
I don't really agree with the bloggers I linked to earlier, since I think they're using fantasy in a very narrow way. As I say, not all fantasy has magic. (Think of Ellen Kushner's Swordspoint). Giving fantasy all the people with special abilities ignores the varied abilities of real world people. For example, some people are tone deaf and literally cannot hear music as music, which doesn't make the rest of us special for hearing music where others hear cacophany. Likewise, ascribing specialness to things and places that are not actually any different from similar things and places is a human attribute and shows up in all kinds of fiction (the lucky penny, the sacred grove, the Indian burial ground, the magic sword, the holy book).
If this post is coming across as disjointed, that's because I've been working on it on and off for about two hours now. Basically, everyone draws the line between SF and F in a different place. Sometimes you don't even need rivets.