I thought I would post about this distinction, since I mentioned it yesterday and also because it’s a confusing distinction to talk about and some online sources don’t do a very good job of nailing down the misuse of “may” that was bothering me in Beverly Conner’s books.
So, here we go:
1) May and might are not interchangeable, no matter how many internet sources tell you they are. This is because the two words are not only used to express more or less likely conditionals. Here at Grammar Girl, it says: The difference between may and might is subtle. They both indicate that something is possible, but something that may happen is more likely than something that might happen. So you may go to a party if Matt Damon invites you, but you might go to a party if your least favorite cousin invites you.
This is true, but not exhaustive. I believe it’s this usage that causes various authorities to tell you the two words are basically interchangeable.
2) However, an important difference occurs when you are talking about things that might have happened, but didn’t; versus things that might have happened and you’re not sure whether they did or not.
“My mother was hit by a car and she may have hurt her back” should be followed by something like “She’s having an MRI on Monday to find out.” In this case, the “may” is used to express uncertainty about whether she is or is not hurt.
“My mother was hit by a car! She might have been badly hurt!” should be followed by something like “Thank God she’s all right!” because in this case, the “might” clear indicates that the uncertainty is in the past and she wasn’t hurt. Both the past and the thing not occurring are indicated by “might.”
According to the Oxford English Dictionary online, while you could have some leeway if the situation isn’t clear, you really shouldn’t use “may” if the situation that might have occurred, didn’t:
But there is a distinction between may have and might have in certain contexts. If the truth of a situation is still not known at the time of speaking or writing, either of the two is acceptable:
By the time you read this, he may have made his decision.
I think that comment might have offended some people.
If the event or situation referred to did not in fact occur, it’s better to use might have:
The draw against Italy might have been a turning point, but it didn’t turn out like that.
It’s this specific use of “may” instead of “might” that caught my eye in Conner’s books — and in others. I think if you pay attention, you’ll see that almost any writer you think of as more literary or more a stylist or just especially skilled will make this distinction and use “might” instead of “may” in those contexts.
Also, not sure I’ve seen this at all in the 4th Lindsay Chamberlain mystery, so either that’s pure chance or a copy editor who’s a stickler for this usage or Conner’s trained her ear for this distinction. I know it was a copy editor who finally made me pay attention the the “that” / “which” distinction. More recently, I somehow lost my ear for the “was” versus “were” in the subjunctive mood. Two or three copy editors have more or less been enough for me to retrain my ear for the subjunctive “were.”
No doubt that distinction will vanish eventually, but for now, I prefer to have an ear trained for the more formal usage so that I can choose to disregard it, not accidentally disregard it. I’m sure a less formal character — Natividad, say — might use “was” in dialogue. But Grayson wouldn’t.
Also, in high fantasy, more formal and correct usages are almost always appropriate. That’s part of why elves and hobbits don’t sound the same in Middle Earth. Can you imagine a writer like Tolkien shrugging off these distinctions? Of course not.
That’s why an author should know the most formal and correct usage for these sorts of things as well as the more casual usage. It’s all very well to declare that in modern English no one cares, but clarity of communication not the only goal when writing fiction and the most casual, modern style is not always appropriate.