I saw this on social media the other day. Someone had commented on a popular author's post that a character in a piece of artwork was holding his wrist the wrong way for a flute player. Other commenters (including the one you see here) ganged up on her, wondering why she’d be concerned with something so trivial in a world that’s obviously so far removed from our own.

Here’s the thing: I’m with the original commenter. Not about the hand position specifically (I don’t play the flute, but I imagine it’s easy to make a small error like that), but about the need to get ostensibly mundane details right.

And no, it’s not about the darn flute. It’s not about describing Renaissance clothing to the minute detail or showing off how much you know about late medieval England or whatever. It’s merely about the general idea that fantasy and sci-fi, no matter how outlandish, need to be grounded in credibility. The more effort you put into that grounding, the more of the fantastical your audience is willing to accept.

There are lore-based reasons for the teleporting and the glowing energy-laden diamonds (yes, we’re talking about Sanderson here), so none of those things strain my disbelief—but there’s no reason a flute player shouldn’t hold his hands like a flute player. Whether your story happens in a world that looks a lot like ours or in some fantastical realm where knights ride dinosaurs into battle, logic should still apply. So should basic physics and other natural principles, unless there’s a good reason for them to act otherwise.

It’s why I won’t bat an eye when Jon Snow faces an ice zombie dragon, because ice zombies and dragons are established parts of the Game of Thrones lore. But it strains my suspension of disbelief when Jon falls into a frozen lake in a realm of eternal winter and then crawls right out again, ready to ride off without a trace of hypothermia. That’s when I start to reevaluate whether I want to keep watching the show. (I did stick it out to the end, much to my chagrin.)

Or to use another example (one that I always use to make this point), the horses at the end of The Two Towers should never have been able to charge down an incline that steep or willingly throw themselves into a wall of orcish pikes. In the words of the commenter below, that’s where I said, “This is just unbelievable!”—not the fire demons or the talking trees.

Treating fantasy as historical fiction with a twist, therefore, is a good place to start if you want to help your world feel believable. You can’t devote so much attention to the magical that you neglect the mundane—but once you get the basics right, you can introduce more fantastical elements.