This week one of my online students wrote, "My friend, Monique, became a certified naturalist last year." This sentence put me in a bit of a quandary. I try to care about the whole person (as you will find if you register for my upcoming Writing with Flannery O'Connor class), and I didn't know whether this writer needed punctuation advice or relationship advice. The commas around Monique suggest that Monique is the writer's only friend. If, however, the writer has other friends besides Monique, those commas are extraneous and misleading. I hope, for my student's sake, that this is merely faulty punctuation, which is easy to fix. There are worse things than punctuation errors, and being nearly friendless is one of them.
Today I am talking about punctuating essential and non-essential elements. One of the eight or ten uses of the comma is to set off so-called "non-essential" words, phrases, and clauses in a sentence. I'm not crazy about that terminology "essential" and "non-essential." It makes one think "important" and "less important" or, perhaps, "adding meaning" and "not adding meaning." If you add any word, phrase, or clause to a sentence, hopefully it is important and has meaning. If not, my advice to you is to leave it out of the sentence entirely, not to set it off with commas.
The difference between essential and non-essential elements is often explained in terms of whether or not the element changes the essential meaning of the sentence. Consider the following two sentences (which tell a mostly true story that you can read about here):
The playwright Samuel Beckett gave young Andre the Giant a ride to school.
Samuel Beckett, the playwright, gave young Andre the Giant a ride to school.
These sentences are nearly identical. So why does the second have commas but not the first?
Each sentence has an appositive, a noun or noun phrase that renames the noun that immediately precedes it. In the first sentence, Samuel Beckett is an appositive renaming playwright. In the second sentence, playwright is an appositive renaming Samuel Beckett.
In the first sentence, Samuel Beckett is considered essential (and therefore requires no commas) because to leave it out would change the essential meaning of the sentence:
The playwright gave young Andre the Giant a ride to school.
That is a very different sentence from the original. Playwrights are a dime a dozen. But that image of the black-turtleneck-clad Samuel Beckett, icon of the Theatre of the Absurd, trundling Andre the Giant to school is pretty irresistible.
On the other hand, look again at the second sentence:
Samuel Beckett, the playwright, gave young Andre the Giant a ride to school.
In this case, the commas around the appositive phrase the playwright signal that this is bonus information. The appositive may be helpful to the reader who can't put her finger on who Samuel Beckett is, but to leave it out doesn't change the essential meaning of the sentence:
Samuel Beckett gave young Andre the Giant a ride to school.
Sometimes it can be tricky to say whether an element changes the essentialmeaning of a sentence. This can feel like the kind of judgment call that puts you right back at square one if you don't already trust your own judgment about such things.
I find it helpful to ask instead whether an element adds meaning by narrowingor by expanding. An essential word, phrase, or clause moves from the general toward the specific--from the broad category playwright to the specific instance Samuel Beckett. A non-essential element offers additional information after you have already gotten as specific as you're going to get.
The proper noun Samuel Beckett narrows things all the way down to one man, so any modifying elements I might attach would be bonus information and should be set off by commas.
Samuel Beckett, driving a flatbed truck, drove young Andre the Giant a ride to school.
Samuel Beckett, who had a house in Andre the Giant's hometown, gave young Andre a ride to school.
Samuel Beckett, not knowing he was in the presence of greatness, gave young Andre the Giant a ride to school.
There's no need to wrap yourself around the question of whether the elements driving a flatbed truck, who had a house in Andre the Giant's hometown, or not knowing he was in the presence of greatness change the essential meaning of the sentence. Just think in terms of narrowing and expanding. None of these elements narrow Samuel Beckett to anything more specific, so all should be set off by commas.
Proper nouns make things quite easy on this count. A proper noun, by definition, has already narrowed things down from a category to a specific instance of that category. So be ready with your commas when you shift from common nouns to proper nouns:
I like living in a state where there is no income tax.
I like living in Tennessee, where there is no income tax.
On rare occasions you may use an essential clause to modify a proper noun, if you are trying to distinguish between more than one thing with the same name. If you think your reader might mistake playwright Samuel Beckett for some other Samuel Beckett, you might write something like,
The Samuel Beckett who wrote Waiting for Godot gave young Andre the Giant a ride to school.
But this is an exception precisely because the proper noun Samuel Beckett is operating here not as a proper noun, but as a small category that needs to be narrowed down further.
When you are dealing with elements that modify common nouns rather than proper nouns, the same principle applies: does the modifier add meaning by moving from more general to more specific, or by providing bonus information? Consider these two sentences:
Sentence A: Cilantro that tastes like soap grosses me out.
Sentence B: Cilantro, which tastes like soap, grosses me out.
Which of these sentences is correctly punctuated? My friend Russ Ramsey thinks all cilantro tastes like soap. It's a genetic thing, apparently. So for Russ, the clause which tastes like soap doesn't narrow anything down. Sentence B communicates Russ's position on cilantro. The clause which tastes like soap is explanatory information, bonus information, so it should be set off by commas.
You and I, however, like cilantro. Still, we would be grossed out if ever we ran across some cilantro that tasted like soap. Sentence A communicates this position. The absence of commas communicates that the clause that tastes like soap is essential, narrowing the category down from cilantro to a specific kind of cilantro.
Notice also that in Sentence B, the commas indicate that you can omit the adjective clause without changing the essential meaning of the sentence: Cilantro grosses me out. Russ would nod in agreement. But the absence of commas in Sentence A signals that we would have a very different sentence if we omitted the clause.
One more thing about the cilantro sentences: you may have noticed that Sentence A uses that and Sentence B uses which. This is a good place to speak of relative pronouns. Use that to introduce essential clauses and whichto introduce non-essential clauses--in other words, use which with commas and that without commas. HOWEVER, when you are writing about people, always use who or whom, not that or which ("The driver who delivered my refrigerator," not "The driver that delivered my refrigerator").
Let us now, at last, circle back to my online student and her friend Monique.
My friend, Monique, became a certified naturalist last year.
You can see why those commas caused me concern. They suggest that the appositive Monique is non-essential. That is to say, it does not narrow the category my friend to a specific member of that category named Monique. Perhaps this is true. Perhaps the writer in question has only one friend and her name is Monique. In that case, she should be thankful; there are plenty of people who don't even have one friend. Still, I would suggest that the writer join a bowling league or something. And it can't be easy on Monique to be this person's only friend.
It is possible, on the other hand, that this writer has more than one friend and that this is merely a punctuation error. I'm still trying to get to the bottom of it.