another thing fantasy writers should keep track of is how much of their worldbuilding is aesthetic-based. it's not unlike the sci-fi hardness scale, which measures how closely a story holds to known, real principles of science. The Martian is extremely hard sci-fi, with nearly every detail being grounded in realistic fact as we know it; Star Trek is extremely soft sci-fi, with a vaguely plausible "space travel and no resource scarcity" premise used as a foundation for the wildest ideas the writers' room could come up with. and much as Star Trek fuckin rules, there's nothing wrong with aesthetic-based fantasy worldbuilding!
(sidenote we're not calling this 'soft fantasy' bc there's already a hard/soft divide in fantasy: hard magic follows consistent rules, like "earthbenders can always and only bend earth", and soft magic follows vague rules that often just ~feel right~, like the Force. this frankly kinda maps, but I'm not talking about just the magic, I'm talking about the worldbuilding as a whole.
actually for the purposes of this post we're calling it grounded vs airy fantasy, bc that's succinct and sounds cool.)
a great example of grounded fantasy is Dungeon Meshi: the dungeon ecosystem is meticulously thought out, the plot is driven by the very realistic need to eat well while adventuring, the story touches on both social and psychological effects of the whole 'no one dies forever down here' situation, the list goes on. the worldbuilding wants to be engaged with on a mechanical level and it rewards that engagement.
deliberately airy fantasy is less common, because in a funny way it's much harder to do. people tend to like explanations. it takes skill to pull off "the world is this way because I said so." Narnia manages: these kids fall into a magic world through the back of a wardrobe, befriend talking beavers who drink tea, get weapons from Santa Claus, dance with Bacchus and his maenads, and sail to the edge of the world, without ever breaking suspension of disbelief. it works because every new thing that happens fits the vibes. it's all just vibes! engaging with the worldbuilding on a mechanical level wouldn't just be futile, it'd be missing the point entirely.
the reason I started off calling this aesthetic-based is that an airy story will usually lean hard on an existing aesthetic, ideally one that's widely known by the target audience. Lewis was drawing on fables, fairy tales, myths, children's stories, and the vague idea of ~medieval europe~ that is to this day our most generic fantasy setting. when a prince falls in love with a fallen star, when there are giants who welcome lost children warmly and fatten them up for the feast, it all fits because these are things we'd expect to find in this story. none of this jars against what we've already seen.
and the point of it is to be wondrous and whimsical, to set the tone for the story Lewis wants to tell. and it does a great job! the airy worldbuilding serves the purposes of the story, and it's no less elegant than Ryōko Kui's elaborately grounded dungeon. neither kind of worldbuilding is better than the other.
you do have to know which one you're doing.
the whole reason I'm writing this is that I saw yet another long, entertaining post dragging GRRM for absolute filth. asoiaf is a fun one because on some axes it's pretty grounded (political fuck-around-and-find-out, rumors spread farther than fact, fastest way to lose a war is to let your people starve, etc), but on others it's entirely airy (some people have magic Just Cause, the various peoples are each based on an aesthetic/stereotype/cliché with no real thought to how they influence each other as neighbors, the super-long seasons have no effect on ecology, etc).
and again! none of this is actually bad! (well ok some of those stereotypes are quite bigoted. but other than that this isn't bad.) there's nothing wrong with the season thing being there to highlight how the nobles are focused on short-sighted wars for power instead of storing up resources for the extremely dangerous and inevitable winter, that's a nice allegory, and the looming threat of many harsh years set the narrative tone. and you can always mix and match airy and grounded worldbuilding – everyone does it, frankly it's a necessity, because sooner or later the answer to every worldbuilding question is "because the author wanted it to be that way." the only completely grounded writing is nonfiction.
the problem is when you pretend that your entirely airy worldbuilding is actually super duper grounded. like, for instance, claiming that your vibes-based depiction of Medieval Europe (Gritty Edition) is completely historical, and then never even showing anyone spinning. or sniffing dismissively at Tolkien for not detailing Aragorn's tax policy, and then never addressing how a pre-industrial grain-based agricultural society is going years without harvesting any crops. (stored grain goes bad! you can't even mouse-proof your silos, how are you going to deal with mold?) and the list goes on.
the man went up on national television and invited us to engage with his worldbuilding mechanically, and then if you actually do that, it shatters like spun sugar under the pressure. doesn't he realize that's not the part of the story that's load-bearing! he should've directed our focus to the political machinations and extensive trope deconstruction, not the handwavey bit.
point is, as a fantasy writer there will always be some amount of your worldbuilding that boils down to 'because I said so,' and there's nothing wrong with that. nor is there anything wrong with making that your whole thing – airy worldbuilding can be beautiful and inspiring. but you have to be aware of what you're doing, because if you ask your readers to engage with the worldbuilding in gritty mechanical detail, you had better have some actual mechanics to show them.
