The case for the em dash

Somewhere in the last year, a punctuation mark I have used since secondary school became evidence of a crime I did not commit. A friend read a draft of mine, paused, and said—gently, the way you tell someone they have spinach in their teeth—“You know this reads a bit AI, right? It’s the dashes.”

The dashes. My dashes. The ones I have been sprinkling through sentences since long before ChatGPT was a glimmer in a venture capitalist’s spreadsheet, back when “prompt engineering” meant your English teacher reminding you to start with a topic sentence.

I wanted to be offended. Mostly I was tired.

A punctuation mark walks into a chatbot

Here is the situation we have wandered into. Large language models, trained on rather a lot of edited prose from places that know what an em dash is, learned to use them. Then they learned to use them slightly too much. Then everyone noticed. And now we live in a world where people earnestly instruct their AI assistants—and I am not making this up—to “never use em dashes” so the output will sound more human.

Read that sentence again. We are coaching machines to write worse so they can pass for us. Meanwhile, those of us who have always written this way are being mistaken for the machines.

It’s a bit like deciding that, because forgers have got good at signatures, the solution is for everyone to start signing their cheques in crayon.

What the thing actually does

An em dash is not a hyphen, and it is not an en dash, and the three of them are not interchangeable just because they share a vague horizontal vibe. They are, in fact, a family: the hyphen, the en dash (as wide as a lowercase n), and the em dash (you can guess). The hyphen joins things: well-read, twenty-three, mother-in-law. The en dash spans things: pages 34–58, the London–Paris train, the 2002–present life of this blog. The em dash does something else entirely. It interrupts. It pivots. It lets a thought breathe, and then ambushes it.

You can do most of what an em dash does with a comma, or a colon, or a pair of brackets. But none of them do quite the same job. A comma is polite. A colon is formal, the writerly equivalent of clearing your throat before an announcement. Brackets whisper. The em dash, by contrast, swings the camera. It is the punctuation of the second thought, the aside that turns out to be the real point, the punchline that arrives a beat later than expected.

Take that mark away from a writer who knows how to use it and you have taken away a gear.

The uncomfortable bit

Here is where I have to say something that will sound snobbish, and I have spent two paragraphs trying to phrase it kindly and failed, so I will just say it: using an em dash well takes a certain command of the language. Not a degree, not a fancy school, just a feel for rhythm and a willingness to read your sentences aloud.

The reason em dashes have become an AI tell is not that AI uses them. It is that AI uses them indiscriminately—the way a tourist in a new city uses every adjective in the phrasebook because they have not yet worked out which ones mean anything. A model will drop an em dash where a comma would do, where a full stop would do, where nothing at all would do. The result is prose that feels emphatic about everything, which is the same as being emphatic about nothing.

A writer who knows the mark uses it sparingly, and on purpose, and the effect is the opposite. The sentence lands.

So the test was never “is there an em dash here”. It was always “is this em dash earning its keep”. That distinction has been lost in the panic, and the people losing it loudest are often the same ones who never quite got the hang of the thing in the first place. They are now wandering about with em dashes in both fists, swinging them at every passing clause, indistinguishable from the bots they were trying to flush out.

The plan

I am going to keep using em dashes. I am going to keep using them where a comma would be too quiet and a full stop too loud. I am going to use them when I want to interrupt myself, which, as anyone who has met me will tell you, is often. If a reader mistakes me for AI because of it, I will take the compliment on the AI’s behalf and move on.

The alternative is to let a perfectly good piece of punctuation get cancelled because some software learned it slightly too enthusiastically. And I am not prepared to write worse English to prove I am a person.

If anything, the dash is how you can tell.

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This blog has used em dashes since 2005. AI arrived in 2022—the dashes were here first.