Doug and his friend Grant were standing in the kitchen yesterday, trying to figure out what they wanted to do.
“So, what do you want to do?” Doug asked.
“Something Adam doesn’t want to do,” Grant answered. “Wait, that sounded bad! I meant, I wanted to play Hide-and-Seek, but Adam never wants to play that.”
I looked up from my computer. “Oh, you got caught in a de dicto / de re ambiguity!”
It seems Grant had never heard of de dicto / de re ambiguities. I enlightened him. “What you meant was, you wanted to play Hide-and-Seek; Adam never wants to play that; so you want to play something Adam didn’t want to play.”
“That’s called the de re meaning. But it sounded like you were saying, ‘I don’t care what we do, just as long as it’s something Adam doesn’t want to do.’ That’s the de dicto meaning.”
“Oh, uh, OK,” Grant said.
The ambiguity comes down to a difference in whether or not the something takes wide scope over the (unstated) want in his elliptical statement (I want to do) something Adam doesn’t want to do. If it does, we get Grant’s intended de re meaning: “There exists an activity X that Adam doesn’t want to do, and Grant wants to do X.” If it doesn’t, we get the exclusionary de dicto meaning: “Grant wants it to be the case that there exists an activity X such that Adam doesn’t want to do it and Grant does.”
Of course, I didn’t get into that with Grant. I could tell he was happy enough just to have this useful new vocabulary!