I’m not stupid, but: what’s with “and I”?

Did you ever have an exchange like this with your parents when you were growing up?

Me: “Me and Mark had a great idea.”

Parent: “You mean, Mark and I had a great idea.”

This “and I” meme is stuck in the heads of many of our generation, and all over the place I see people applying it as though it’s a hard and fast rule. It’s not.

First, let’s deal with the order. Why is it “Mark and I” and not “I and Mark”? There’s no grammatical reason for this order at all, except that it sounds better to put the nouns before the pronouns.

But here’s the awkward bit. Sometimes it’s “Mark and I” and sometimes it’s “Mark and me”.

In fact, the grammatical reason is to do with the nominative and objective1 cases, which are to do with whether the thing in question is the subject or object of the sentence. Although these sound really complicated, most of us are actually very good at determining the case.

Try this trick: replace the people in your sentence with we or us and see which sounds right. If it’s we then you’re in the nominative (Mark and I) and if it’s us then you’re in the objective (Mark and me).

• Mark and me had a great idea. ? Us had a great idea. (Sounds wrong!)
• Mark and I had a great idea. ? We had a great idea. (Sounds right!)
• You should join Mark and me for dinner. ? You should join us for dinner. (Sounds right!)
• You should join Mark and I for dinner. ? You should join we for dinner. (Sounds wrong!)

In fact, if you’re having trouble remembering which is we and which is us, you can usually work out which is right by simply dropping the other person from the sentence:2

• Mark and me had a great idea. ? Me had a great idea. (Sounds wrong!)
• Mark and I had a great idea. ? I had a great idea. (Sounds right!)
• You should join Mark and me for dinner. ? You should join me for dinner. (Sounds right!)
• You should join Mark and I for dinner. ? You should join I for dinner. (Sounds wrong!)

I’m afraid once you know this rule you’ll start seeing mistakes being made everywhere!

1. OK; there’s not really a single objective case, but the distinction between accusative and dative is irrelevant here. [↩]
2. Often the verb will sound wrong here so you have to go with which sentence sounds better rather than which sentence sounds right. [↩]