What is the difference between Who and Whom? I and Me? He and Him? They and Them?
At the art show, I met an artist ______ sold me this magnificent landscape painting.
The officer stumbled across a fleeing soldier ______ he suspected was deserting the battlefield.
In the above examples, we need to fill in the blank with a pronoun that refers to the antecedant before it (either the artist in the first example, or the soldier in the second). An appropriate pronoun would be who/whom, but which one? Could you use either? Is there a difference between them?
Let's first take a step back and define what a pronoun is. A pronoun is a type of noun. It's a more general noun that is used to refer to some existing noun. That existing noun is known as the antecedant. For example:
The author sat down to write his book, but discovered that he had writer's block and ended up only staring at his blank paper.
In this example, the author is the antecedant and the pronouns his and he refer to back that antecedant.
Unlike normal nouns, pronouns retain a lot of the rules from older forms of English. One of these is the rule that a noun will change form based on its role in a sentence. Is it doing the action? Is it receiving the action? Is it acting as an indirect object? Each role has a different noun form. However, today, nouns don't change form depending on their role in the sentence (other than possessive forms vs. other forms).
The dog bit the mailman.
The mailman bit the dog.
In the first sentence, the dog is doing the action, doing the biting. Therefore, it is the subject of the sentence. In the second sentence, the dog is receiving the action, being bitten. Therefore, it is the object of the sentence. Similarly, the mailman is the object in the first sentence: he is being bitten. But, in the second sentence he turns the tables on the dog and now becomes the biter, the subject, in the second sentence. But, they retain the exact same form in each sentence, despite their roles changing.
Now, if we replace mailman with a pronoun, we will see a form change since most pronouns retain that rule from older English.
The dog bit him.
He bit the dog.
Since the pronoun, in the first sentence, is the object, it takes the object form: him. And, since the pronoun, in the second sentence, is doing the action (acting as the subject of the sentence), then it takes the subject form: he.
So, the difference between him and he is one is the object form and one is the subject form. In the same way, the difference between I and me, they and them, and even we and us is object vs. subject.
The same is true of whom and who. Whom is the object form of the pronoun and who is the subject. That's it! With this in mind, let's go back and take another look at the first two sentences I showed you:
At the art show, I met an artist who sold me this magnificent landscape painting.
The officer stumbled across a fleeing soldier whom he suspected was deserting the battlefield.
It should be pretty clear, now, why, in the first sentence, we would fill in the blank with who. The who is doing the action. It's doing the selling. In the second sentence, the whom is the person that the officer is suspecting (not the person doing the suspecting); therefore, we need the object form.
Below is nice little chart that lists the most common pronouns and their subject and object forms. Note that some pronouns (like you) behave similarly to regular nouns in that they don't change form whether they are the subject or object.
One other thing that is interesting to take note of is that many of the object forms of these pronouns either end with an m or begin with an m. If you are ever confused about whether a pronoun is in the object form or in the subject form, just remember the Rule of M: any pronoun that contains an m is in the object form. For example, me and them are both object forms. Not all of the object forms of these pronouns have an m in them, but all the pronouns that do are in the object form.
Let's take a look at how they might test you on this concept with a sample ACT English question:
This question is clearly testing pronoun case: we have several different forms with me (object), I (subject), myself (reflexive), my (possessive). It's not reflexive since the subject and object are not the same. The person who is sending the birthday cards is not sending it to himself. It's also not possessive since there is a missing noun after my, which would state the thing being possessed.
However, is this pronoun the subject (I) or the object (me)? The action is sent, so would have to identify who is sending these cards to identify the subject. It is clear that the father is doing the sending and that the sister and I is doing the receiving. So, we need the object form here, and the object form is me. Remember, the object form receives the action, in this case, receives the card.
Ok, hopefully that clears up the differences between these pronouns. Now, if you are ever asked to choose between something like who and whom, you know what to do.