If there’s one thing that can kick me out of a story —
Oh, who am I kidding. There are many things that can kick me out of a story. But one of them — the one we’re going to look at today — is when authors don’t think through the logical consequences of their own ideas. They fail to see that if X, then Y, or they put something (particularly magic) into the story without thinking about how it could potentially be used.
Now, let’s be clear: humans are entirely capable of failing to apply technology in ways that seem obvious to us later. In fairness to our species, though, many of those gaps — e.g. “why did it take so long to get from having gunpowder to having guns” — were created either by a lack of the associated technologies or technical skill necessary to take the next step, or by a lack of conceptual understanding that the next step was even possible. (Ryan North’s book How to Invent Everything is pretty good at showing how some of those gaps occur.) Or maybe the capacity exists, but the money and/or will to use it for certain ends is insufficient.
In fiction, however, we hold ourselves to a higher degree of plausibility. If your reader sees an obvious gap that all the characters seem oblivious to — and the story isn’t about that gap being found and filled — then they’re likely to be annoyed.
This has come up quite prominently in one of the tabletop roleplaying games I’m in. Pathfinder, like its parent game Dungeons & Dragons, is largely built for combat, but my group in playing the Kingmaker adventure path, wherein your characters become the leaders of a small, frontier realm. As such, it has additional “Sim Kingdom”-style rules bolted on to model the economics and so forth of that realm. One element of those rules says that each segment of your territory designated as “farms” contributes to economic productivity.
I looked at the spell plant growth — which has a brief line at the end noting that it can increase the productivity of plants by one-third for a period of a year — and asked the friend running the game what would happen if we used that on our farms.
Granted, this wasn’t cheap. For a small realm, 27,000 gold pieces for a magic item some designated official could carry around the land to bless all our fields once a year is a non-trivial investment. But it’s an investment that pays off enormously — as is 1000 gold pieces for an item that can purify the outflow of a sewer. Or if we’re feeling particularly fancy, another 27,000 for a statue that residents can touch and be cured of disease. And that’s just with us looking at a spell list designed with adventurers in mind, not kingdom administration! In a world like the one in Pathfinder, there should be tons of this stuff, used for all kinds of pragmatic ends.
There are counter-arguments to that, of course. Not every realm is benevolent . . . though when you reframe it from “benevolence” to “increasing the productivity of your citizens and therefore the wealth that can be extracted in taxes,” even kingdoms less utopian that the one my group is ruling would have good reason to pay attention. (And/or to use sinister means to spy on and control their own populace.) D&D has also long tried to push varying levels of “magic items are rare” in how it describes its setting, not always convincingly. But fundamentally, the real answer is that it suits the purposes of the game more to have sewage eaten by dangerous monsters the characters might have to fight than to have the local rulers invest in infrastructure — an answer which can only fly in a certain type of fiction.
This isn’t only about the uses of magic. Sometimes it’s just about basic math. I love the comic book series Elfquest, but one of the more jaw-dropping details in its worldbuilding is the idea — laid out explicitly in the companion role-playing game — is that “for an elf female to bear more than one child in her lifetime is remarkable.”
My friends, this means that elves are going extinct.
It may happen very very slowly, since most of them are immune to dying of old age, and even the ones who can perish like that will live for centuries. But longevity is not true immortality, and so any given elf will eventually die. Assuming an equal distribution of the sexes, any elf capable of bearing children needs to bear two: one to replace herself, and one to replace a male counterpart. Actually, it needs to be a little higher than that, to account for those who never have any children at all, whether by reason of choice, infertility, or untimely death. If fundamental biology places them below that line, the species is quite simply headed for extinction.
A similar equation, applied in the other direction, rears its head in the game Legend of the Five Rings. (I suspect many of my examples are game-related because they, by necessity, state their assumptions outright in the rules, instead of leaving them implicit the way fiction often does.) Depending on the edition of L5R you look at, the setup around the Shadowlands Taint varies, but in its grimmest form, it’s a kind of spiritual corruption that can never be cured. Removing it from the land leaves the place physically and spiritually lifeless; removing it from a person is impossible. It even follows them into death, sending their soul to the Realm of Evil instead of on through the cycle of reincarnation.
This is a world in which the Realm of Evil is inevitably going to win.
If its influence, once ingrained, cannot be removed without total destruction, then eventually everyone and everything will be either Tainted or destroyed. The one way out of that trap is the one found in an ancient Japanese text, the Kojiki: when the progenitor deity Izanagi-no-Mikoto seals his dead and rotting wife Izanami-no-Mikoto in the underworld, she vows in retaliation to kill a thousand people a day, whereupon Izanagi-no-Mikoto vows to create one thousand five hundred people a day. But despite the Japanese inspirations behind L5R, no such myth exists there. Instead, other versions of the game provided ways — rare and difficult, but at least existing — to cure the Shadowlands Taint, balancing the scales by other means.
(Of course, the Kojiki tale has its own implication: eternal, inevitable population growth. Which could be a different kind of problem in the long run . . . but what gets said in sacred myths is not necessarily expected to apply as literal reality.)
There’s no checklist you can run down to make sure you’ve caught the logical results of your own worldbuilding. You just have to step back and try to think it through: how might people try to apply this magic? If these conditions remain true for an extended period of time, what will be the long-term effect? Is there an easy solution to a given problem which you haven’t taken into account? It can help to get outside eyes on your ideas, recruiting someone else to look them over and tell you if they see any obvious holes. Then either patch the holes . . . or use them to enrich your story!