Question sent in by e-mail by Miss Mae, Forum member (February 22, 2011):
Dear Mr. Carillo,
Hi! I have just finished reading the 59th chapter of your third book, Give Your English the Winning Edge, and came upon this line: “...that hoary rule that limits [‘which’ and ‘who’] to inanimate nouns and personal nouns, respectively, doesn't necessarily apply.”
That took me by surprise because I have been strictly observing “which” for things and who for “persons.” I also do not put commas before and after a clause introduced by “who.” How can I tell when should I do that?
Thanking you in advance,
Miss Mae
My reply to Miss Mae:
Yes, it does seem surprising that “which” can also be used to refer to persons and not just to things, but this is precisely one of the functions of “which” that was discussed in that chapter of Give Your English the Winning Edge: as a reference word linking dependent clauses or phrases to their antecedent nouns, and doing so either as intermediate subjects or objects of those dependent clauses.
Here’s the example I gave of the relative pronoun “which” as subject of the dependent clause: “Voters have to decide which of the candidates can serve the national interest best.” Here, “which” works as a subordinating conjunction, serving as the subject of the dependent clause “which of the candidates can serve the national interest best” and as the object of the verb “decide” in the main clause “voters have to decide.”
The hoary convention, of course, is to use “who” in that sentence because the noun it refers to is “people,” but among native English speakers, to use “which” in that sentence is more idiomatic than saying it with “who,” as in this version: “Voters have to decide who among the candidates can serve the national interest best.” Both versions are grammatically correct, of course, but note that the “who” version requires adding the preposition “among,” which I must say just puts another grammatical wrinkle to the construction—a wrinkle that native English speakers would rather avoid for the sake of simplicity and ease of articulation. Indeed, for many English speakers, it’s oftentimes hard enough to choose between “who” and “which,” so why further complicate matters by having to choose between “among” and “between” as well? Obviously, the use of “which” instead of “who” in that sentence construction greatly simplifies matters for them.
As to your practice of not using a comma before and after a clause introduced by “who,” I must warn you that it’s not a grammatically correct practice at all. Before deciding on the use of that comma, you need to determine first whether the clause introduced by “who” is a defining (essential) clause or a nondefining (nonessential) clause.
A defining clause is, of course, one that the sentence can’t do without, as in this sentence: “The woman who discovered radium as a chemical element died from overexposure to its radiation.” In this sentence construction, the comma isn’t needed before the clause. The clause “who discovered radium as a chemical element” is a defining or essential element of the sentence, and dropping it would seriously alter the intended meaning of the sentence, as we can see in this version with the defining clause gone: “The woman died from overexposure to its radiation.” This time, the woman has become nondescript—just any woman for that matter.
On the other hand, a nondefining clause is one that the sentence can drop without distorting or ruining the meaning it needs to convey, as in this sentence: “Marie Curie, who discovered radium as a chemical element, died from leukemia due to overexposure to radiation.” See how that sentence can stand by itself even without that nondefining clause: “Marie Curie died from leukemia due to overexposure to radiation.” The comma before and after the clause are absolutely needed as grammatical markers to indicate that the clause is a nondefining or nonessential one.
