If you searched “why do writers use similes” and looked at, say, this Quora page, you’d receive the assumption that authors employ metaphor because it’s nice to have. Anyone can say, “It’s fun to be able to compare things with a simile!” But that doesn’t answer the question. Why say something is like another thing, or something is an abstract concept of some sort, when you can just describe what the thing is?
No, seriously, why not? Maybe we should limit ourselves on the whole abstract comparison thing.
There are reasons to use metaphors, and places not to. Let’s establish how writers should use similes, then, from there, elaborate on why they do so to begin with. I may get somewhat passionate here, because I’ve learned all these through writing badly-written stories for many years. Here are three absolute, applies-to-everything rules about Similes and Metaphors (henceforth called S&M, because it’s technically torture if done badly)…
- Needs to narrow down description, not open it up
S&M can create wonderfully witty turns of phrase, tickling us like a feather duster attached to a vibrator. That’s not why they exist. Form follows function, fool! Why would you go off in some weird platonic world to describe the important, real, “working” parts in your story? Only to help the real world make more sense, of course! If you want beauty without purpose, go look up one of those Game of Thrones theme covers done with wine glasses or something. The stranger your real world is, the more essential S&M become. Let’s take a hypothetical science fiction example. Your Bioluminescent AcerBulb is more complex for words, technically, but if you can sum it up by saying it “is a lamp that grows from a tree,” fine. Good. We get it. But if you say, “Bioluminescent AcerBulb “is a booklover’s delight, more beautiful than when HicksMark5 discovered how to air-condition the woods,” … even if it adds a lot of fun information, it tells us nothing about what a Bioluminescent AcerBulb is.
- Needs to be from within the POV of the narrator
So if Bioluminescent AcerBulb (the more I say it, the less stupid it sounds) is a metaphorical lamp, then who’s comparing it to a lamp? Is it your protagonist? That only works if your protagonist knows what lamps are. If you put your own voice in, to explain your world, then you break any illusion you were hoping to create. Third-person narrators have an easier time working with this rule. Regardless, I encourage you to set up a firm POV, and draw all your comparisons from that in that alone. If all else fails for you sci-fi writers, just add, “it looked like a lamp, like the one she read about in an Earth history book.”
- Must be used when all other literal descriptions have been exhausted
This is technically a subset of Rule 1, but I bring it up so other writers don’t fall in the same traps I made. You can use hundreds of great metaphors to describe a failing marriage, but they will all mean nothing if we don’t know what the marriage looks like in the first place. At worst, your S&M will dance around whatever point you’re trying to make. Us English Majors encounter beautiful writing, and then we try to ape it without getting down the basics of communication first.
Writers use similes and metaphors to describe the intangible, incorporeal, and ultimately indescribable. And if you need metaphor to describe a fucking pencil sharpener, then maybe do some extra Googling before your next story.