The easiest way to explain the spectrum of fantasy to science fiction is to just paint it on the wall.
• Science Fantasy, the usual place you find Space Opera and Planet Stories.
• Soft Science Fiction. Includes “non-magical fantasy,” and “hard fantasy.”
• Science Fiction.
• Hard Science Fiction.
Fantasy includes all kinds of things, and they really don’t spectrum — they’re just different settings or things to use as elements or mechanisms. It’s the science fiction folks who get fussy about how much science their stories have going.
Fantasy is any specfi with openly irrational elements. That’s magic, ghosts, the supernatural, reincarnation, and a lot of people would include stories with actually operational religious systems. Y’know, as if there really are deities and prayers really can change the world. Science fiction assumes an atheist’s universe.
Opposing it, hard science fiction contains only what the hard science fiction folks see as reality, along with highly probable speculations on science. None of those nanobots and wormhole transits: science that probably works, we just haven’t figured out exactly how to implement it. In my travels I ran across a crit group for hard science fiction only, and they wanted people exploring the future of society, technology, and life on Earth, because any form of space travel out of the solar system, especially FTL, was just too whiffly for them. If that’s what fascinates you, super! Hard science fiction does tend to like its science and tech explained, so you will absolutely need sections that, in any other sub-genre, would be called an info-dump. So choosing your genre changes your revision.
Science fiction in general is not as hard-line delimited. If you can imagine it in scientific terms, you can go with it. Imagine creatures evolved in or adapted to life in the atmosphere of a star. Too silly for hard science fiction, but fine for general speculation if you can work out something that looks to work even for a bit. General science fiction readers love having their minds expanded.
Soft science fiction is all the speculative stories lacking irrational elements, but focused away from mathematics, physics, chemistry and the other hard sciences, toward the soft sciences: biology, psychology, sociology. Re-imagine our world in the future, perhaps with no more technology and maybe less, but with changes in culture and politics, in relations and religion. That’s soft science fiction. Imagine a world that isn’t ours, but that has evolved a similar biosphere with human beings, and their own cultures and languages. That’s soft science fiction, and always has been (Gormenghast trilogy by Mervyn Peake). Having to now call it a kind of fantasy betrays the hand of the hard science fiction types trying to kick everything out of science fiction except their stuff, or people who have read so little outside hard science fiction that they don’t recognize soft science fiction.
Science fantasy is either science fiction by people who believe some things are real, or rationally speculative, that other people don’t, like psychic powers, or by those who just want to tell a rattling good tale in an imaginative future or other world without having to take a new college degree. Science fantasy unabashedly enjoys action, adventure, romance, and a huge sense of wonder, in dazzling places, whether gritty or gorgeous. They don’t want to put you in a magic mindset, even if they do fall through unidentified holes in space-time to worlds of adventure.
Most space opera (the Lensman books by E. E. “Doc” Smith) and planet stories (habitable planets in our solar system, and sometimes elsewhere, like the Planet of Adventure series by Jack Vance) fall into science fantasy. So do swords and science (A Princess of Mars by ERB; Sea-Kings of Mars/The Sword of Rhiannon by Leigh Bracket). One really has to throw into it anything with speculation that has big logical holes, like faster than light travel or time-travel by any means I’ve seen presented.
There are conventions of non-scientific science for science fantasy, that allow writers to have their fun, make their points, and dazzle us for a while with the modern equivalent of the Thousand and One Nights — tales of wonder that take us out of the here and now. These include things like FTL travel and communication, teleportation, assorted means of hand-held destruction under the generic names of ray-guns, blasters, and the like, space combat at noticeable portions of light speed, and so on. They have been the work of many good scientists, speculating how some real science might make something vaguely possible, if you don’t look at it too hard, and everyone’s inventions are more or less tossed into the toy chest for others to use. You get extra points if you come up with a new one, like when hyperspace jump got replaced with wormholes.
To be bald, much of science fantasy is, more or less, “used furniture” — stories that in other days, or genres, would be set in the Old West, or sword-wearing royal courts, an embattled Europe, or sailing the Caribbean. But for today, writers find it more flexible and exciting to invent their own worlds, where the readers can’t anticipate what lies around the next corner.
Cyberpunk was a style or attitude of science fiction that grew to prominence in the 1980s, but nowadays we see most new works called post-cyberpunk, if the term is referenced at all. It featured characters who did not create cybernetic technology, only bought or stole it, and used it primarily for illegal or questionable ends. It could be called a moribund style, too embedded in its time, like, say, the voyage imaginaire. In many cases, the kind of stories have evolved into transhuman stories.
Both science fiction and fantasy, as you can see, are not a matter of plot or theme, but world-building: the one that includes the speculative elements that need to be integral to the story. As a result, you can build it into a world of the past as well as the future, or into the present. A lot of science fiction starts with “Here’s my new invention/discovery: let’s see it totally foul up my life/the world/the time line.” That’s one of the earliest specfi templates, Science Bites.
You can have science fiction or fantasy mysteries (Jack Vance wrote a shelf of science fantasy mysteries).
You can also use either science fantasy or magic for your time-travel stories. Get crazy with intersections and go for a time-travel mystery.
Sometimes it is quite enough to whip someone forward or backward through time, just the once, a hiccup of the universe or a circuit, and the whole story will proceed off that one person or one village being misplaced into an alien milieu. The “true” time-travel template story, though, requires some control on travel as the person tries to fix or at least change what has or will happen, or find out what did happen.
Now, let’s step back to fantasy past the borderland of science fantasy. I have seen people who can’t imagine science fiction that doesn’t involve ray-guns and spaceships, and equally those who think all fantasy is clones of TLOTR. The variations of kind of story and kind of setting is limitless.
Not all fantasy is a quest, though this is a popular mechanism simply to get people out and around to show off the world. Some stories are domestic dramas with very oddly empowered characters.
Still, the best known sub-genre for producing huge volumes, often in trios and trios of trios, is that of heroic fantasy or high fantasy. It still may not require a quest, but winning a war (The Well of the Unicorn by Fletcher Pratt, so low in magic it almost qualifies for soft science fiction), withstanding an invasion, solving a riddle with desperate stakes, or other low-mileage heroisms.
For a while in the 1970s the primary form of high fantasy was called swords and sorcery, S&S for short we used it so much, so that you can find anthologies with that or similar titles, like Swordsmen and Sorcerers. If this differed from other high fantasy in a way to form a sub-sub-genre, it was the lone hero or pair of heroes coming into a strange place and defeating a supernatural foe with, wait for it, weapons and/or magic.
This became significant for creating the mindset that created Dungeons and Dragons. D&D fiction can be defined, not just as anything written for TSR’s several series of novels but anything that reeks too strongly of having started as someone’s dungeon adventure. (If you don’t know, you’re immune to writing one, probably, so don’t worry. If you always transcribe your gaming sessions — no, my friend, they have only a microscopic probability to make a great novel because characters are limited and stereotyped, all the monsters are predictable, and dungeons are dull places to read about. Andre Norton could barely pull off a D&D novel, Quag Keep, and you aren’t in her class. Don’t brush off my opinion as an outsider’s: I used to publish in The Dragon/Dragon Magazine. I’m not hostile, I’m just realistic.)
Fantasy also holds two opposing sub-sub-genres, the gentle fantasy and the gritty fantasy, which could be summed up as rainbows’n’unicorns vs. magicpunk.
Gritty fantasy strips away the romance and glamour, though not the sense of wonder. In gritty fantasy your barbarians aren’t noble free savages but swinging between gluttony and famine, only bathe when they fall off their horses at a ford, and have high infant mortality, while enduring a plethora of constrictive customs. Being a warrior is hard filthy work with high employee turn-over, lousy chow, and no retirement fund. The adventure the character gets hauled into may be the only glory they ever get, if it even is glorious.
It can also be urban fantasy with unglamorous characters — the welfare mother who isn’t terribly bright but rescues a sick goblin. Fantasy set in the writer’s here and now used to be the norm. Urban fantasy has developed as a genre for stories set in cities, not off in the isolated countryside, now that most Americans are urban, not rural (The War for the Oaks by Emma Bull), and it tends to be dark and gritty (Our Lady of Darkness and a pile of others by Fritz Leiber).
The gentle fantasy, interestingly, is often set in a culture not at all medievalesque. The brown-skinned people of the village live kind and mindful lives, until something comes to menace them, that must be defeated without violence — so they’d better find the old forgotten magic. Or the lonely child has to bring kindness and magic back into the world. That sort of non-violent upbeat stuff.