Sci-fi is often called the "fiction of ideas", and is all about exploring what the world would be like if X were true, and it has a particular set of tropes (starships, aliens, new technologies, etc.) that go along with that.
Whereas fantasy is about telling mythic tales about archetypes -- the trickster, the hero, the journey through the underworld, etc. -- and it has another set of tropes (dragons, magic, swords, etc.) that resonate with that kind of story.
Now, we have some stories (Star Wars being perhaps the best example) where the author uses the tropes of sci-fi to tell a mythic tale in the fantasy mode. The story doesn't explore the implications of space travel, it uses the spaceship as a substitute for the hero's trusty steed. These kinds of stories get called "science fantasy".
My question for you, dear reader, is what would you call the inverse of science fantasy? That is, a story that explores the implications of various speculative statements made involving fantasy tropes? A story that doesn't use the dragon as a symbol of greed and power, but inquires what are the consequences of dragons being top predators in a primarily thaumivorous ecology?
Because I think that's a lot of what I'm interested in writing.