Obviously, all fiction is fantasy when you come down to it - fantasy is anything that isn't real - but that would be a bit of a glib answer.
I have read so little fantasy / SF (esp SF, due to early bad experiences with some poor-quality, overly-macho works) that I hardly feel qualified to comment on the fantasy / SF division compared to the other, much wiser people on your flist.
Thinking about this, though, I guess it must be hard to write good SF because you do always have to judge where you can stretch the science a bit in favour of a good story (or come up with something scientifically plausible which helps your plot)
But also it must be hard to write good fantasy without it all getting a little bit silly / ironic / over the top.
It's probably all about pretending you are writing credible, consistent, cool SF while actually writing fantasy and hoping nobody will notice :-)
Veering off topic
I have read so little fantasy / SF (esp SF, due to early bad experiences with some poor-quality, overly-macho works) that I hardly feel qualified to comment on the fantasy / SF division compared to the other, much wiser people on your flist.
Thinking about this, though, I guess it must be hard to write good SF because you do always have to judge where you can stretch the science a bit in favour of a good story (or come up with something scientifically plausible which helps your plot)
But also it must be hard to write good fantasy without it all getting a little bit silly / ironic / over the top.
It's probably all about pretending you are writing credible, consistent, cool SF while actually writing fantasy and hoping nobody will notice :-)