1. All stories set in the future, because the future can’t be known. This includes all stories speculating about future technologies, which is, for some people, the only thing that science fiction is good for. Ironically, many stories written in the 1940s and 1950s that were set in what was then the future—the 1960s, 1970s and 1980s—are no longer “futuristic.” Yet they aren’t “false,” either, because few science fiction writers pretend to be writing what will happen. Rather, they write what might happen. So those out-of-date futures, like that depicted in the novel 1984, simply shift from the “future” category to:
2. All stories set in the historical past that contradict known facts of history. Within the field of science fiction, these are called “alternate world” stories. For instance, what if the Cuban Missile Crisis had led to nuclear war? What if Hitler had died in 1939? In the real world, of course, these events did not happen—so stories that take place in such false pasts are the purview of sci-fi and fantasy.
3. All stories set in other worlds, because we’ve never gone there. Whether “future humans” take part in the story or not, if it isn’t Earth, it belongs
to this genre.
4. All stories supposedly set on Earth, but before recorded history and contradicting the known archaeological record—stories about visits from ancient aliens, or ancient civilizations that left no trace, or “lost kingdoms” surviving into modern times.
5. All stories that contradict some known or supposed law of nature. Obviously, fantasy that uses magic falls into this category, but so does much sci-fi: time travel stories, for instance, or invisible man stories.
(From and article in Writer's Digest)
So, my friends, do you have any other thoughts and ideas about Science Fantasy? Are there even more divisions and sub-divisions? Leave your thoughts and comments, and have a FANTASTIC week!