I always hear people interchanging the terms and confusing them so here’s a definition of each: a scifi story happens in the future and it’s remotely possible and fantasy is a thing happening in the past or in a “parallel” time and it didn’t or will not happen. But there’s an issue there: if in the fantasy story they mention a time in the past it’s 100% fantasy but if they don’t mention the date it might be some time in the future. So in theory scifi and fantasy are the same if the date is not mentioned in the story. Since we constantly have more and more control of nature; what’s going to stop some people in the future from making dragons and castles and stuff like that? Or maybe more likely they can just have some kind of huge computer like in The Matrix where they can live in The Lord of the Rings world for example. Here or course I’m assuming that if you can’t distinguish it from reality then it’s also a reality (physics-wise). All fantasy stories told today could be used. But who wants to do that? Who wants to settle with dragons and medieval buildings when they are going to have technology “Indistinguishable from Magic” as Robert Forward’s book is titled? Oh wait … those 8 million War of Warcraft users … So yeah: all fantasy is science fiction.