[Teresa Edgerton]

Well, it makes perfect sense to me -- it doesn't go far enough, and it needs a bit of qualifying, but as a capsule description I feel it works very well.

Of course as JD says there is a broad middle ground where the two halves of the genre meet, but I think it's a pretty servicable definition for stories that fall outside of that area.

But I can see how the definition would be confusing to -- for instance -- anyone who doesn't believe as I do that SF is simply a subset of Fantasy.