I’ve gone over what makes a sentence quite a few times lately (subject + verb + direct object if needed), so now seems a good time to go over who and whom, since those two words are closely related to sentence structure.
The question of when to use who or whom is one of the most common grammatical questions in the English-speaking portion of the world.
(Toby was right, naturally.)
The explanation is actually pretty simple: use who when the word is the subject of the sentence (or an embedded clause—more on that in a moment) and use whom when it isn’t the subject.
Who bought these cookies?
Subject Verb Direct Object
To whom should I give the cookie?
Indirect Object Verbal Subject Verb Direct
(i.e. not the subject) Auxiliary Object
An embedded clause is basically a sentence within a sentence—it has its own subject and verb:
We need to find out who bought these cookies.
Subject Verbs Embedded clause with who as its subject
I could go on for much longer about how to properly use who and whom, but I’m not going to; Matthew Inman has already done a great (and much more entertaining) breakdown of that over at The Oatmeal. What I would like to delve into is why—why whom is so tricky, and why you should (or shouldn’t) use it.
Why Whom Is Tricky
(This section is pretty in-depth, so if you’re just interested in advice on using whom, skip to the next section)
There are quite a few pronouns that have both a subjective form and an objective form. For example:
I and me, she and her—we’re all used to these pronoun pairs, right? We don’t have to stop and think for a moment to figure out whether to say they or them. So why are who and whom difficult to keep straight?
Part of the answer is that who is different from the other pronouns shown in that chart. I, you, he, she, and they are all personal pronouns. Who, on the other hand, is what we call an interrogative pronoun—a pronoun that asks which person or thing is meant. Let’s look at who and whom on a chart with other interrogative pronouns:
Notice how who stands out? It’s literally the only interrogative pronoun in the English language that changes depending on how it is used. No wonder it’s so hard to use, when every similar word works in a completely different (and far simpler) manner!
So why is who different from all the other interrogative pronouns? Well, language is constantly evolving—new uses for words develop while old ones fall away and disappear. All those other interrogative pronouns probably used to have objective forms that fell out of use long before the language began to form into what it is today. The same thing happened to you. Take a look at that first chart up above—notice how you is the only personal pronoun on the chart that doesn’t have a distinct objective form. But that wasn’t always the case.
There was a time when you not only had an objective form, but also had a separate singular form that declined into its own objective. So our chart above would once have looked something like this:
Over time, thou, thee, and ye all fell out of use; these days, we use you in all of the instances where we would once have used those other words. Imagine if English teachers around the world suddenly began to demand that we all resume using thou, thee, and ye. It wouldn’t go well—it would be confusing and irritating if people tried to force us to use words that don’t improve or enhance our ability to communicate. But, for some stubborn reason, that’s exactly what people do with whom. We don’t need the word; it doesn’t improve the language. But people just won’t let it go.
Why You Should Use Whom and Why You Shouldn’t
Whom is on its way out—give us another century, tops, and it won’t really be part of the language anymore. It’ll be an abandoned, archaic word like thou or whence; a word we all know used to be part of the language, something we can find in older books, but not a word that even the most demanding college professors demand we use. And good riddance to it.
Most of the time, my advice to new writers is to pay attention to all of the rules of grammar—don’t risk looking inept because you don’t care about comma splices or the difference between amused and humored. Whom, on the other hand, is one of the rare bits of grammar that I feel beginning writers can safely ignore. In fact, you'll look worse if you use whom incorrectly than you will if you don't use it at all!
Generally, whom is not a word you should bother with unless you have a specific purpose in mind. If you are striving for an intellectual and formal tone to your story, than go ahead and whom it up. If you have an educated or pedantic character, you can pepper their language with whoms. But if you want your dialog or your prose to feel more relaxed and natural, then get rid of the word. It’s not something that most editors will be bothered by—if they really feel that you need to use whom, then they’ll tell you; but they won’t reject your manuscript because of it.