SemicolonsI've been a huge fan of Kurt Vonnegut my entire reading life, but he has given one bit of writing advice that I just can't swallow. "Do not use semicolons," he tells us. "They are transvestite hermaphrodites representing absolutely nothing. All they do is show you've been to college."
I think one of the reasons so many people have a problem with semicolons is that they're misnamed (the semicolons, not the people). In modern usage, the semicolon doesn't have anything at all in common with the colon except how it looks: It's a colon with a tail. People might understand the purpose and use of the semicolon if it were called, maybe, the semiperiod or semistop, or the metacomma or supercomma.
Why would these names make more sense? Because if you already know how a period and a comma work, these names can give you some glimpse into how this semicolon thing works.
The semicolon has only two uses: as a "second-level" comma, and as a "soft" period.
The SupercommaIf you've ever taken an algebra class, you should be fairly familiar with the idea of grouping in equations using parentheses, brackets, and sometimes braces. For example, keeping in mind the order of operations,
5 + 6 × 7 – 8 ÷ 2 = 43but
5 + [6 × (7 – 8) ÷ 2] = –15
The parentheses and brackets allow you to nest individual mathematical statements, so that the final equation says what you want it to say. In the same way, English uses commas to group things together, so we can turn
Jack and Janet and Chrissy and Maddie and Dave and Moe and Larry and Curlyinto the more manageable
Jack, Janet, Chrissy, Maddie, Dave, Moe, Larry, and Curly
But this still doesn't say what we want it to say. Nested within this list of eight names are three groupings that we can't separate using only commas. We need something more — in much the same way that the algebra equation used brackets instead of more parentheses.
Enter the semicolon or, in this case, the supercomma. It allows us to separate items in a list when those individual items themselves use commas, so that the following sentence can be easily understood, even to someone who has never seen Three's Company, Moonlighting, or The Three Stooges:
Three TV comedy groups who have no place on the silver screen — much less in 3D — are Jack, Janet, and Chrissy; Maddie and Dave; and Moe, Larry, and Curly.
That's the first and likely most common use of the semicolon, and a lot of people understand that. The second usage, though, is a bit trickier. At least, it is until you understand it.
The SemistopA semicolon could also be thought of as a semistop (as opposed to full stop) when it's used for its other purpose: To separate two independent clauses* without using a conjunction. Why would you even want to do this? To show or imply a connection between the two clauses. To turn two statements into a single idea, showing cause and effect or some other relationship. To create subtext. Consider this:
Everyone treated the President like an old yet honored friend; only the President's friends could ensure that their children found work outside the mines.
See how the second half of the sentence colors the first half, creating motive and subtext, yielding a single sentence that tells you more than just what is stated in the two halves? You could use a period here instead, but that full stop would weaken the link between the two clauses. In the other direction, joining the two clauses with because would be too blatant and inelegant. The semistop — that is, semicolon — splits the difference perfectly.
And ThenI don't often see the semicolon misused. More prevalent is the use of a comma where a semicolon is called for — especially when then is involved. Take note: Independent clauses in a compound sentence are joined by a coordinating conjunction (and, but, or, for, nor, so, yet). Then is not a coordinating conjunction; it's most often an adverb. Therefore, when you put then between two independent clauses, it should be preceded by a semicolon, not a comma. Or you can write it in other ways.
Take the case of Albus Severus Potter climbing onto the Hogwarts Express to start his first year of wizarding school. First, he waves goodbye to his parents and his little sister Lily. After that, he climbs onto the train. You could write this in a number of ways:
Correct: Albus waved goodbye to his family; then he boarded the train. (two independent clauses joined by a semicolon)
Correct: Albus waved goodbye to his family, and then he boarded the train. (two independent clauses separated by a comma and a coordinating conjunction)
Correct: Albus waved goodbye to his family and then boarded the train. (simple sentence with a compound predicate — that is, two verbs)
Correct: Albus waved goodbye to his family and boarded the train. (simple sentence with a compound predicate minus the adverb — if you really want to put a comma in there, read this to find out why you don't need it)
Incorrect: Albus waved goodbye to his family, then he boarded the train.
And that's it. The semicolon isn't a big mystery. It isn't some ancient rune or mystical symbol. It isn't an invention of sadistic grammarians. And it isn't anything you need to be afraid of.
*You remember independent clauses, right? A clause that has a complete subject and complete verb and that can stand on its own?