May versus Might: A grammar lesson on modals

By popular demand! From Dad, you get farm updates. From Mom, it's grammar lessons!

Here goes. I have evidently made Dad insecure by pointing out to him offline that there was a grammar error in his Red Sox post entitled "No Joy in Mudville." I told him that, in the sentence below, he should have used the word might instead of may.

If Schilling and Foulke had been healthy it may have been different.

OK, class, why is this wrong? Now, now, don't all shout out at once. Raise your hands . . . Right! The reason that might should have been used is that there is no longer any doubt. We know how things turned out. Schilling and Foulke weren't healthy, the season's over now, and it's too late to change anything. So, the correct word is might and not may.

Here's why. May and might are "modal" verbs, used to express shades of possibility. In the present tense, there is little or no difference between them, and either one can usually be used correctly. For instance:

I may go grocery shopping later. I might stop at Wal-Mart while I'm out.

Both of these sentences are correct. As used here, there is actually a subtle difference between them -- the first sentence suggests a possibility that is a bit more likely than the possibility suggested by the second sentence. May indicates that it's possible that the speaker will go grocery shopping. Might indicates that it's also possible, but a little bit less likely, that during the trip, she'll also stop at Wal-Mart. But this difference is minor, and in practice, the two words are used interchangeably.

In the past tense, on the other hand, may and might are not interchangeable at all. They carry distinctly different meanings, and this difference is what sometimes causes Mom to shout at sports broadcasters on TV. May is used to describe a possibility in the past about which there is still doubt. Might is for possible past outcomes that we now know did not happen. So:

The battle was so intense that Private Jones was lucky to survive it. He might have been killed. Private Smith, on the other hand, is still missing in action. We hope that he is all right, but he may have been killed.

See the difference? Both Jones and Smith were in danger, but we now know that Jones is okay. We still aren't sure about Smith -- he could be alive, or he could be dead. So, for Smith, we use may. For Jones, who is safe, it's might.

Some more examples, with the first two sentences in the past tense, and the second two sentences in the present tense:

I am angry with myself for failing last week's grammar test. If I had studied harder, I might have passed it. I studied much more carefully for yesterday's test. I am not sure yet, but I think I may have passed this time. The grades may (or might) be ready by now. I might (or may) stop by the classroom later to ask Mrs. Grundy how I did.

(A side note: May, used in the present tense, also carries a second meaning of ability, as opposed to possibility, with an overtone of permission. Thus: Mother, may I leave now? Yes, you may go, but not until I have finished this lecture about grammar. Here, may indicates both the ability to go, and permission to do so. In the present tense, might does not have this additional meaning. That brings us to this sentence of Dad's, from his long-awaited Farm Update:

You may (might?) submit names for heifer calves anytime.

This sentence is not about possibility -- it's about ability and permission. Dad is saying, with no doubt, that anyone can submit names, and that he grants permission to everyone to do so. May, here, is the correct word. Might would be wrong unless Dad wanted to change his meaning to add the layer of doubt and possibility that might conveys: I know that it's hard to think of heifer names, but if you can think of any, you might want to submit a few. )

So, now, a quiz! Some of the following statements are grammatical; others are dead wrong. The first person to post the correct answers in the comments gets an A.

1. If Dave Roberts had not stolen second base in last year's ALCS, the Red Sox may not have gone on to win the World Series.

2. If Dad had not happened to see "Flight of the Conchords" on HBO, this family might never have started making jokes about racist dragons and sick monkeys and big fat crazy pictures of New York.

3. It's a good thing that Panda chased those sheep and got himself banished from Virginia. If he hadn't done that, we may never have gotten a dog.

4. The summer drought made a big difference in the cows' productivity. If only it had rained sooner, they may have made more milk.

5. (From one of Dad's Red Sox posts. Extra credit if you can spot an error unrelated to may and might.) Pedroia can back up, or be the regular if Graffy can't be signed. He may be kinda hot now that we "discovered" him.

6. Did you check the family blog yet? I haven't had time to look at it yet today, but from all the excitement in the streets, I think Dad may have posted a new farm update!

7. Nobody has posted song # 73 yet. That may mean that we are running out of songs, or it might mean nothing.

8. If Dad had not posted "I am sixteen going on seventeen" in the first place, the whole song project might never have gotten started.

9. On the other hand, just think how terrible it would have been if we had not started the song project. In that case, you may never have heard that unforgettable recording of "Ayy Wah Doopah! Ayy Wah Doopah!"

10. If I hear the words may and might used incorrectly one more time, I may scream.