It's not so much that there's no difference between science fiction and fantasy as that SF is a more strictly delimited subset of fantasy (as opposed to so-called mimetic fiction, which is to say, fiction without the spec element.) But the line is very, very blurry. (Witness, say Roger Zelazny as a case in point.)
I personally kind of find attempts to strive for tight definitions of what are, essentially, marketing categories sort of a time-waster; it just doesn't interest me. On the other hand, the internets are full of people who find it a fulfilling hobby.
Inspiration is commonly found dissolved in ordinary tap water. Story ideas are highly soluble. This is also why exercise can bring them to the fore; the release of sweat and consumption of body fat can trigger "inspiration flashbacks," not unlike the sort more often linked to LSD.
We recommend vitamin B and a steady diet of whisky to counteract this.
Original comment-screened post here, if you want to ask something.