A couple weeks ago, I wrote a quick post asking for your opinions on Philip Corbett’s contention that may and might both express possibility, but that might is used when the possibility is less likely. For example, the work in (1a) is more likely to get done than in (1b):
I had never heard this before, and I didn’t find it to be the case in my own usages, so I posed the question to you all, and you didn’t disappoint. Nor did you agree. Three commenters concurred with Corbett about the difference, with may being more probable than might. One felt that the difference was one of involvement, that might suggests the subject is somehow more involved in the action than may. Two thought that the difference was one of formality, but one thought that may was more formal and the other thought it was less. And at least three agreed with me that there wasn’t any clear difference.
I think Bob Hale nailed it in his comment when he wrote
“My usage of “may” and “might” probably doesn’t correspond exactly to your usage of “may” and “might” or to anyone else’s. I don’t think it’s consistent for an individual and it certainly isn’t consistent between individuals.”
It is worth noting that no one felt that might was more probable than may, so maybe there is a grain of truth to Corbett’s contention, but that grain is drowned out by the overwhelming muddle.
Summary: may and might should be regarded as essentially interchangeable, because different people don’t agree on what the difference between them would be.