Just because the setting isn’t anchored in the real world doesn’t mean that anything goes. Yes, fantasy is one of the genres where you can be the most creative and you aren’t confined by the rules of our world. Either the story takes place in a completely new world, or in a version of ours that has magical elements added to it, therefore changing the rules of our world. But that doesn’t mean basic logic and consistency don’t apply.
Consistency is key
Of course, you’re the writer, and you can do whatever you want. But the reader might not appreciate a fantasy world that changes its rules every five minutes for plot conveniences. They might get very confused, or frustrated, or both. It can also make them disconnect emotionally because there’s nothing to fear for the characters: the conflict will get magically and randomly resolved. And the reader will often lose their trust in both the narrative and the author. Unless the inconsistency is the point and an integral, intentional element of the worldbuilding, in most cases, a rule that is established needs to remain consistent.
If magic only works by reciting precise incantations, a character can’t suddenly use magic to heal someone just by placing their hands over the wound, with no incantation involved (unless there’s a very good explanation for this, preferably established well before the event occurs). Similarly, imagine being told in chapter 11 that a plant is poisonous if ingested raw, but then in chapter 18 one character eats it raw, and it heals them instead. It doesn’t make sense, and it takes the reader out of the story.
Amping up the tension
Consistency doesn’t just add realism. It also amps up the tension by adding clear limits. If anything is possible and can happen randomly, then the reader has nothing to fear. The protagonists will always come up with some magical twist to get themselves out of harm’s way. This doesn’t tend to be very compelling and can get readers to not be emotionally invested because nothing seemingly dangerous that happens actually matters.
But if there are rules to the world, those restrictions introduce obstacles for your protagonists to overcome. The characters will have to find ways to achieve their goals within those limitations. A reader is more likely to feel tension when there are clear and consistent rules, because the character’s means of success (or survival) are limited. There’s actually something to fear: they might lose (or die).
Rules aren’t always a bad thing. Especially when you get to make them.
The deus ex machina
A well-known trope related to this is the deus ex machina. It’s usually an event that occurs in the climax of the novel. All odds are against the character, and so are the established rules. But, lo and behold, something that breaks the rules happens to save the character just in the nick of time.
How is that possible within the established rules? It’s not! And it’s either not explained, or it’s explained after the fact, which leaves the reader feeling cheated either way. Yes, even with a good explanation, because it’s only revealed after the fact. It can feel like the writer could have added a footnote during the climax around the lines of: “By the way, now this is possible because x, y, z, but mostly because I didn’t know any other way to let the character succeed. Didn’t think of it beforehand! Couldn’t be bothered to go back and integrate it.” The writer may not have been intentionally lazy at all, but it’s likely to feel like it for the reader.
If you’ve made an oopsie and you have a deus ex machina during your climax, there are two main fixes: finding another solution that works within the established rules, or foreshadowing the exception to the rule (only if there’s a good explanation for it). Foreshadowing means leaving breadcrumbs hinting at a later reveal. It can be subtle, but it needs to be just visible enough that most readers will go “oh, of course! I should have seen this coming.” Basically, they’ll sort of notice the hints but won’t tie them all together until the climax. And at the end of the day, even if you’re not subtle and establish a clear exception to the rule that the reader sees coming, it’s still better than breaking the reader’s trust.
How can a writer make sure their setting is consistent and realistic?
A different pair of eyes or ears can be instrumental in making sure the manuscript is consistent. Beta readers may clock some of these issues, and an editor will be on the lookout for them. It can be difficult to spot them yourself because you don’t have any distance from your manuscript. You also have all the information about the world, and some of it might be missing or unclear on page.
But before those outside perspectives come into play, it can be extremely helpful to keep notes about the rules of the world. We often call these documents “worldbuilding bibles”, and you can easily find plenty of free templates on the internet, or you can create your own. The idea is to log the information you need to keep consistent and to make sure your notes are easy to sort through.
Having different sections in your worldbuilding bible is really useful. Software like Scrivener can make this easier, and even a Word document can work by applying heading styles to each section title, which you can then see at a glance by toggling the navigation pane (in the menu “view”), which will display a list of your headings that you can click on to access that section. There are plenty of options out there, and some are free. I’m citing these two because they’re the most familiar to me. A good free alternative to Scrivener is yWriter. It’s much more simplistic (at least it was when I last used it), but it does the job quite well. And OpenOffice and LibreOffice are two free alternatives to Word.
As always, folks, consistency is key. Suspension of disbelief is only effective so long as the logic is realistic within the rules of your fictional setting, even if those rules aren’t realistic in the real world.