One of the more frequent errors I see as an editor is confusion over what relative pronouns to use to introduce a descriptive collection of words.
Years ago, when I was taking a college course in magazine writing, one of my classmates gifted me with an enduring reminder of the need to pay attention to relative pronouns.
The professor had just handed our draft articles back to us, marked up in red. She dismissed the class and started packing up her things. A couple of students lingered to ask questions.
Several of us moved outside to the hall, poring over the comments on our papers. Suddenly there was a loud exclamation:
“That witch!”
The normal hum of activity that accompanied class dismissal stopped dead. Everyone turned to see the student who spoke, assuming she was so unhappy with her grade that she had the temerity to insult a professor who was easily in earshot.
The student looked up from her paper to see maybe a dozen pairs of eyes trained on her.
“Oh,” she said, realizing what she had just said. “I meant ‘that’ and ‘which’ – you know, W-H-I-C-H. I keep getting them confused.”
That’s English for you.
In fiction writing, the distinction between “that” and “which” often is blurred, which sometimes leads writers of business correspondence, reports, manuscripts, news releases and the many forms of journalism to use the two pronouns interchangeably.
In fact, the word “that” introduces a restrictive clause, which means the descriptive words following the noun or subject of a sentence are necessary for the message of the statement to be conveyed. Consider this statement, for example: “Dogs that eat fresh meat are more likely to sport shiny coats.” The writer or speaker is specifying a subset of dogs within the set.
Contrast that to this sentence: “Dogs, which eat fresh meat, are more likely to sport shiny coats.”
The word “which” introduces a nonrestrictive clause, meaning you should be able to remove it and not change the meaning of the sentence. It is added information, not needed for a clear statement. In this case, the writer is saying that dogs are more likely to sport shiny coats. The description set off in commas implies that meat-eating is the reason; but, from a grammatical standpoint, that information is not necessary for the sentence to be clear.
Note that restrictive clauses introduced by “that” are not set off by commas, whereas clauses introduced by “which” sport a comma at the beginning and end.
The relative pronoun “who” is appropriately used to introduce restrictive and nonrestrictive clauses. If the information in the phrase is essential to the meaning of the sentence, the “who” clause will not be set off by commas. If “who” introduces a nonrestrictive clause, the commas are necessary.
Example: The girls who are wearing dresses don’t want to ride bikes.
This sentence specifies certain girls within a set. It presumes that there are some girls who are not wearing dresses; only the girls who are wearing dresses are turning down the bike ride.
Contrast this: The girls, who are wearing dresses, don’t want to ride bikes.
This sentence says, “Look, dummy, the girls don’t want to ride bikes. They’re wearing dresses, for crying out loud!”
Note that people can be referred to as “that” or “who.” Things, including corporations and organizations, are properly referred to as “that” or “which.” Personally, I like to use “who” for animals, who I believe qualify for the pronoun by virtue of having personalities, but many an editor will insist on referring to an animal as “which.”
And thus we end this discussion of grammar rules before it leads us down a path of political and philosophical divide!