Considering that sentences can be separated with semicolons, what’s good will it do the piece of writing? Will it make the sentence sound more sophisticated as compared to using a comma and a coordinating conjunction?

—Chad the Velociwritetor

First, for those who don’t know, let me back up a couple steps.

When you have a part of a sentence that could stand on its own as a separate sentence, that’s called an independent clause. Like this: “We went to the store, and then we got stoned and played Nintendo ‘Duck Hunt’ for six hours.” The phrases on either side of the comma are each independent clauses. You’re not usually supposed to join two independent clauses with just a comma; when you do, that’s called a comma splice. So the solution is either to join them with a comma and a conjunction, like I did in my sample sentence, or with a semicolon, like I did in the sentence before this one. You can also split them into two separate sentences, which is grammatically sound, but hey, if you wanted them to be separate sentences, you’d have written them that way to begin with, right?

So Chad is asking, basically, why we should ever bother using a semicolon when joining two independent clauses. (We are setting aside, for the moment, other uses for the semicolon, including in lists and winky faces.) I suppose some people will think that sentences containing a correctly used semicolon seem a bit more sophisticated (or snobby)—the writer, it seems, is showing off their ability to use a relatively uncommon punctuation mark whose use is often not properly explained in schools. Those people are mistaken. A semicolon is a tool, like all other punctuation marks, and useful to both the reader and writer; it’s not some kind of artfully tied bow fancying up an otherwise mundane sentence.

If there’s no fanciful reason to use it, then, there must be a practical one. And indeed there is! Not every two independent clauses can easily be joined with a comma and a conjunction. Let’s imagine, for example, a murder mystery in which identical twins Jane and Janet are suspects. In the climactic accusation scene, Jane cries out, “But I wasn’t in the barn that night; Janet was!” How would you perform a semicolonectomy on this sentence?

1. “But I wasn’t in the barn that night! Janet was!”
2. “But I wasn’t in the barn that night, but Janet was!”
3. “But I wasn’t in the barn that night, and Janet was!”

The first one is OK, but it paints a slightly different picture. In the original, you can infer that she’s saying this all in a rush, because the semicolon tells you that the two halves of that sentence are part of a single thought. In this two-sentence version, I picture instead Jane protesting her own innocence and then, after a beat wherein she puts two and two together, swiveling to accuse her sister. Also, in the original version, I read it with the emphasis on the word I, but I read option 1 with the emphasis on wasn’t. These are subtle distinctions, but they affect the flavor of the scene, and I like a writer who can almost invisibly influence my perceptions when they want to.

The second two… eesh, right? You might say I’m stacking the deck with the repeated but in number 2, but what would you have me do? To eliminate the first but reduces the vehemence of her denial, but but certainly seems like the conjunction you want there if you must have one. I gave you option 3 to show you that even without the doubled word, adding a conjunction totally changes the rhythm of the sentence, makes it kind of clunky, takes away from the impact of the revelation.

There is a fourth option that I haven’t mentioned here yet: the em dash. The em dash can indicate an abrupt break in the train of thought or a dramatic pause, so it could work here: “But I wasn’t in the barn that night—Janet was!” That’s not too bad; if you’re really determined not to use a semicolon, it’ll do fine.

Consider another example: “I failed my anger management class; they showed me a picture of that laughing dog and I freaked.” What conjunction would you put here? You could say you failed your anger management because they showed you a picture of that horrible hound, but then you technically don’t have two independent clauses anymore—because is a subordinating conjunction, which means that it makes what comes after it into a dependent clause that can’t stand on its own. The only other way I can think to do it is to flip the sentence around: “They showed me a picture of that laughing dog, so I failed anger management class.” The meaning is the same, but the punchline sure ain’t. You could try the em dash again here, but this isn’t really an abrupt change, is it? One thought flows logically into the next. But the em dash’s rules are fuzzy, so maybe it works for you here, too.

OK, so one final example sentence, this time one that I stole: “Happiness isn’t something you experience; it’s something you remember.” –Oscar Levant

Now what? You can’t break that into two sentences; they don’t retain their intended meaning when split apart. You can’t use a coordinating conjunction—one that would allow both halves to remain independent clauses—because there aren’t any that work. Nor can I think of any subordinating conjunctions that apply, even if you accept that that will change the structure of the sentence. You could add instead, but that would still require a semicolon—it’s called a conjunctive adverb, and since it’s not a true conjunction, it doesn’t count for the joining-with-a-comma-and-conjunction strategy. Besides, then you’d just be cluttering up a nicely balanced sentence. You could try an em dash, but I would fight you. Those two thoughts cannot be so dramatically separated. Semicolon it is; semicolon it must be.

Certainly you can often avoid the semicolon if you don’t like it—a simple rewrite or an em dash will get rid of it in most instances without any significant change to meaning. And if you’re not clear on the rules of semicolon usage, that’s a good strategy. But we can’t just banish them altogether, no matter what Kurt Vonnegut said. They are important. They do something essential. We should take care when we use them, but we should be allowed to use them.