Recently, I received this question from a reader:
Help! How do you know when to use “who,” “that,” or “which” in a sentence?
Good question, dear reader. These are difficult words to tell apart. I’ll do my best to explain.
What’s Up With Who?
In general, who refers to people. As Karen Elizabeth Gordon explains in The Transitive Vampire, “Who refers only to persons, who may be intelligent living beings” (64).
“Philippe Petit was the man who walked the wire.”
The phrase “who walked the wire” describes “the man.” Man is a word that refers to people, and so who is therefore appropriate.
Which Which Is Which?
Which, on the other hand, “refers only to animals and to inanimate, unmoving things” (64).
“The stunt which Philippe performed was daring.”
In this example, “which Philippe performed” describes “the stunt.” Since a stunt is not a person but rather a thing, which is the appropriate word to use.
A Trickier Case
When it comes to the word that, however, the rules aren’t so clear. All Gordon says on the matter is “That refers to animals and things, and sometimes to persons,” but she doesn’t give any clear examples of the “sometimes” she mentions.
Well that’s not very helpful! I did some further research, and here’s what I came up with:
Mignon Fogarty of Grammar Girl says that, if you want to be safe, use who to refer to people and that to refer to inanimate things.
She admits that there are some gray areas, though, as in when talking about a beloved pet. “I would never refer to my dog as anything less than who,” she says, and I’m sure most pet owners would agree.
She also mentions another reason to refer to people using who: it’s polite; referring to a person as that is dehumanizing.
Now that we have a better understanding of the differences among who, which, and that, let’s go through a couple final examples where it’s easy to get confused, just to make sure you understand.
For instance, should you say, “There’s the thief who stole my hat!” or “There’s the thief that stole my hat!”?
Since the thief is a person, you could use who, but since you’re probably not too happy with the thief and don’t (given the situation) respect him as a person, that would also be appropriate.
Finally, here’s an example of when it’s unclear whether you should use which or that or even who.
“Is this the squirrel which/that/who pelted you with acorns?”
Unless it’s your beloved pet squirrel, you’re probably not going to refer to it as who, so we can easily rule that one out.
Which and that, however, are both acceptable to use, as both refer to non-human beings. And I doubt you’re too thrilled with that squirrel; respecting its “humanity” is not foremost in your mind after all the scrapes and bruises it gave you.
For quick reference and easy recall I made an image to help you remember the general ways you use who, which, and that:
I hope that helps answer your question. Remember, I’m happy to answer any grammar or writing question you may have. Email me at firstname.lastname@example.org or leave a question in the comments below, and I’ll do my best to answer it.
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Photo Credits: squirrel via Steve Baker