Still, people tend to get very heated about commas. Once someone has decided on a “standard” rule, it’s almost as if he’s chosen a political party: If anyone tries to cross him, he’ll defend his rule to the death. This is why I’ve taken a decidedly neutral stance on the matter and chosen to follow the basic rules outlined in popular grammar books. If someone cares to debate, I’ll hear him out. But I won’t waste precious neurons in a philosophical debate between my instincts and my inclinations. I don’t know who the comma policy-makers are, but I propose they form a sort of comma UN to sort these matters out once and for all. In the meantime, here’s a summary of some basic rules to remember when it comes to commas. Where you take them from here is your own mini-revolution.
Per Garner’s Modern American Usage (simply because Bryan A. Garner seems to be the most bipartisan of the grammarians I’ve encountered), use commas in the following situations:
- To separate items in a list of more than two: "I ate cheese, crackers, and apple slices for lunch." (Most newspapers and some magazines omit the last comma, called a serial comma.)
- To separate coordinated main clauses: "She said they all agreed to go, and they didn’t deny it." But, "She said that they all agreed to go and that she expected nothing less." The idea here is that the comma separates two complete sentences in the first example—two subjects ("she" and "they") and two verbs ("said" and "deny").
- To separate most introductory matter from the main clause: "When summer rolls around, I’d like to get back into surfing."
- To mark the beginning and end of a parenthetical word or phrase, an appositive, or a nonrestrictive clause: "The contestants have plenty of chances to prove themselves to the audience. This moment, however, is the only chance they have to prove themselves to the judges."
- To separate adjectives that qualify a noun in the same way: "He called the clunky, poorly designed technology 'absurd.'" Not to be confused with: "She thought big strong men made the best husbands."
- To separate a direct quotation from its attribution: "Smith says, 'We've always seen a demand for alternative energy.'"
- To separate a participle phrase, a verbless phrase, or a vocative: "Having been tied up at work all day, I finally found a moment for reflection." And, "Matt, would you mind editing this for me?"
- To mark the end of a formal salutation in informal letters: "Dear friends, …"
- To separate parts of an address: "He lives at 1234 Main St., Boston, Massachusetts."
And, yes, there are exceptions and further qualifications for each of these (the entry in Garner’s is almost two pages long); but what else can we expect from the comma?