Semicolons have only two purposes. That’s it. Two. No more.
We talked about one of those purposes last week (“Semicolons separate items in a series that already contain commas”). We’ll talk about the other—and only remaining—purpose this week.
Semicolons separate closely related complete thoughts.
Let’s suppose you’re writing a damage report.
You’ve determined that the basement flooded because the sump pump failed. You have several ways to describe the situation:
The basement flooded because the sump pump failed.
The sump pump failed. The basement flooded.
The sump pump failed, so the basement flooded.
A semicolon allows you a close, causal relationship in the sentence:
The sump pump failed; the basement flooded.
The semicolon allows you a bam-Bam! picture. Cause and effect.
A comma (“The sump pump failed, the basement flooded”) will not do it. It’s not strong enough. (Miss Landers, your fourth-grade teacher, would call the punctuation error a “comma splice” or a “comma fault.”)
As we mentioned, you have several ways to describe the situation. Because you’re the writer, you make the call. It’s an option.
Let us know your questions and concerns. We love this stuff.
A special note from two hundred and thirty-seven years ago in Philadelphia. The words still prompt awe, respect, and goose-bumps:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the pursuit of Happiness.
Happy Birthday, United States of America.