1.

Here’s one particularly common kind of metaphor:

Literary metaphor: a sentence with multiple possible interpretations, where one possible interpretation, the “literal” one, is false and used purely for rhetorical effect

And here are a few examples:

“His heart skipped a beat”: On a literal reading, he had heart palpitations. On a non-literal reading, he was startled.

“It’s raining men”: On a literal reading, men are falling out of the sky. On a non-literal reading, there are a lot of available men around.

“All the world’s a stage/And all the men and women merely players;/They have their exits and their entrances”: On a literal reading, the surface of the Earth is an enormous stage, and men and women live their lives according to a script. On a non-literal reading (not the only one), human behavior is fairly predictable and not of lasting significance.

2.

Here’s a less familiar concept, developed and defined by the philosopher Daniel Dennett:

Deepity: a proposition that seems to be profound because it is actually logically ill-formed. It has (at least) two readings and balances precariously between them. On one reading it is true but trivial. And on another reading it is false, but would be earth-shattering if true.

And here are a few examples (two of them courtesy of Deepak Chopra):

“When you make a choice, you change the future”: One one reading, when you make a choice, something different happens compared to if you hadn’t made that choice. On another reading, when you make a choice, you overcome predestination.

“Love is just a word”: On one reading, the word “love” is a word. On another reading, the concept referred to by the word “love” is a word.

“Everything is connected“: On a few readings, everything is connected by space (i.e. there is a path between any two points), every physical object exerts some influence on every other physical object (if only through indetectable gravitational attraction), and events on one part of the planet can have long-run effects on events anywhere else on the planet. On a few different readings, everything — from the way you hold your pencil, to the outcome of a skirmish in the Syrian civil war, to the current average temperature of Jupiter’s moons — has significant relevance to the consideration of anything else, is connected as part of some cosmic plan, or, in some metaphysically interesting sense, does not truly exist as a distinct entity.

3.

Here’s another less familiar concept, developed by the philosopher Nicholas Shackel and given the following definition by RationalWiki:

Motte and bailey: a combination of bait-and-switch and equivocation in which someone switches between a “motte” (an easy-to-defend and often common-sense statement) and a “bailey” (a hard-to-defend and more controversial statement) in order to defend a viewpoint…. Instead of defending a weak position (the “bailey”), the arguer retreats to a strong position (the “motte”), while acting as though the positions are equivalent. When the motte has been accepted (or found impenetrable) by an opponent, the arguer continues to believe (and perhaps promote) the bailey.

And here are a few examples:

“Reality is socially constructed”: On the “motte” reading, our beliefs about reality and the concepts we use to make sense of it are heavily influenced by our social context. On the “bailey” reading, reality itself — for example, the chemical composition of water — is determined by one’s social context.

“Killing is killing”: On the “motte” reading, killing is the same thing as itself. On the “bailey” reading, some relevant form of killing (for example, the killing of farm animals, the killing of embryos, or the killing of people who have received the death penalty) is morally equivalent to any other act of killing. [1]

“It’s impossible to be racist toward a white person”: On the “motte” reading, no white person can credibly claim to be overall worse off because of their race or to have been wronged by large-scale institutions with long histories of disproportionately harming them. On the “bailey” reading, it is impossible to hold excessively prejudicial attitudes toward white people or for a white person to be disadvantaged by their race even in a narrow, rare, and relatively unimportant context.

4.

Now, finally, here’s another concept that’s a generalization of all these concepts:

Blurry sentence: a sentence with at least two possible interpretations, where one is both much more interesting and much less plausible than the other. The effect is to make the reader feel that the sentence is both interesting and plausible. The implausible interpretation also does not help the reader to understand the plausible one.

Here’s how the generalization works:

Literary metaphor: a blurry sentence where the plausible interpretation is the most salient one to the reader.

Deepity: a blurry sentence where neither the plausible interpretation nor the implausible interpretation is much more salient than the other, leaving the reader with a sense of vagueness or ineffability. The feeling is: There is something true and interesting here, although I can’t quite put my finger on it.

Motte and bailey: a blurry sentence where the implausible interpretation is the most salient one. If the reader objects that the sentence is in fact implausible, then the writer has the option of switching to only the plausible interpretation.

These revised definitions reveal that there is a spectrum here, such that the names “literary metaphor,” “deepity,” and “motte and bailey” are only calling out particular regions of the spectrum.

In most poetry and fiction, it is easy to come across lines that cover the range from literary metaphors to deepities. For example, Paulo Coelho’s writing is filled with literary metaphors, but as a Guardian writer points out, it is also a rich source of deepities, like, “There are no ends, only means,” “The wise are wise only because they love,” “In love, no one can harm anyone else; we are each of us responsible for our own feelings,” and, my favorite:

A flower is not better when it blooms than when it is merely a bud; at each stage it is the same thing — a flower in the process of expressing its potential.

Philosophy or social commentary written in a literary style also tends to go further, covering the full expanse. For example, Ta-Nehisi Coates’ Between the World and Me is full of literary metaphors, like, “My soul is the voltage conducted through neurons and nerves, and my spirit is my flesh,” but it also has some lines closer to the motte-and-bailey end of the spectrum, like, “The police departments of your country have been endowed with the authority to destroy your body.”

5.

So what’s the point?

Maybe just this:

Our brains don’t work right, and it’s worth paying this fact more mind.

In the case of visual processing, we are all pretty familiar with our own inadequacies, due to the prevalence of optical illusions. You look at an ink shape, and your brain switches back and forth, almost at random, between processing a duck and processing a rabbit, rather than processing the simple fact of what’s actually there.

In the case of verbal processing, though, we think less about this point. A blurry sentence is a sort of verbal illusion. Your brain takes a sentence that might stand for a true but boring sentiment, or might stand for a false but interesting sentiment, and tells you: Hey, here’s a true and interesting sentiment.

This is a bit embarrassing on the part of our brains.

But, of course, it’s also nice. Literary metaphors are core to much of art, and I’m mostly glad that this art exists [2]. Rather than reading the flat sentiment, “We are unable to conceptualize or empathize with the experiences of all other humans at once,” I can read these beautiful lines, from Middlemarch:

If we had a keen vision and feeling of all ordinary human life, it would be like hearing the grass grow and the squirrel’s heart beat, and we should die of that roar which lies on the other side of silence. As it is, the quickest of us walk about well wadded with stupidity.

Deepities and motte-and-baileys can be beautiful, too. I like how the line “Everything is connected” feels, sitting in my brain. And even if the line fails to represent any true and interesting claim about the world, it isn’t unexpressive — it evokes a certain mood or mental state that many people can recognize and value.

The trouble just comes in if we’re trying to figure out what’s true. In these cases, blurry writing is (blurrily speaking) a minefield: it will not necessarily be easy to distinguish the benign metaphors from the confused deepities and misleading motte-and-baileys. We are liable to end up fascinated by claims that don’t actually mean any particular thing, or to believe false claims because they’ve had a sense of plausibility smuggled in from elsewhere.

I think, therefore, that we ought to be very wary about forming beliefs on the basis of blurry writing. This means holding a skepticism toward a large portion of literary non-fiction (especially philosophy written in a literary style), or toward arguments produced by writers who either lean heavily on non-trivial metaphors or fail to be careful about clearly defining their claims. Fiction may be the riskiest place to form beliefs about the world.

I think, also, that when we are trying to figure out what is true, we should be much more proactive about drawing distinctions. Deepities and motte and baileys are less likely to arise if we take pains to restrict the possible interpretations of our words. Broad-tent terms like “meaning” and “racism” are dangerous, and broad-tent sentences like “We are all fundamentally alone” or “This election was stolen” are much more likely to lend themselves to fruitful debates after the range of possible interpretations is narrowed down.

Neither of these suggestions is original. But I’m inclined to think that their importance is greater than most people realize.

[1] It is actually pretty common for controversial claims to take the form of claims that “X is X.” See also: “The law is the law” for “There is a duty to enforce the law, no matter how unethical particular laws may be.” Or: “Business is business” for “Otherwise unethical things done for the sake of company profit are morally acceptable, or at least should be regarded as unsurprising.” (Apparently, sort of distressingly, there’s also a whole philosophy literature on sentences like these.)

[2] Although, one metric I’d be interested in having is the percentage of sentences in a given writer’s work that can be classified as literary metaphors (or as blurry sentences of another sort). I suspect that there is a lot of variation here, with some fiction writers using almost none (even if, at the same time, they use ‘macro’ metaphorical devices like symbolism and parallelism) and some fiction writers deploying literary metaphors in almost every sentence. I also suspect that overuse of literary metaphors is one of the hallmarks of pretentious writing — very few thoughts, but still trying hard to sound interesting and honest.