Science Fiction

undefined> I see a lot of overlap between urban fantasy fans and science fiction fans.

This makes a certain amount of sense, I think: to me, the defining line between science and magic is that, at core, scientific phenomena have an explanation, while magic ones don't. You may not understand how Star Trek phasers work, but the premise is that in-universe, there's a good explanation that someone understands. Whereas the reason Harry Potter can wave his wand and make an object levitate is Just Because. There's no ultimate explanation.

I'm simplifying to make the distinction clear, but of course human literature is vast and varied. And urban fantasy, in particular, tends to straddle the line between SF and fantasy: the action doesn't take place in A Land Far, Far Away, where the rules are different; it's London, or Chicago, or Mogadishu, where guns and cars obey Boyle's law, and carpets don't just hover in the air without a really good reason.

I'm not familiar with all of the worlds you cite, but in The Dresden Files, for instance, magic obeys certain rules, so that if you know how a spell works, but you don't have all the components, you can figure out a substitution. Or in The Laundry Files, you start with the premise that there are Lovecraftian horrors out there and work out the consequences, in the finest tradition of SF, and come to the conclusion that there will be paperwork.