recently,I read a literature about "every" and "each",This involved a theory called the scope between quantifier and negation. "A boy didn't eat every cookie" means "some cookies were eaten"."A boy didn't eat each cookie" means "no cookies were eaten".Are these two sentences right in meaning?
1 Answer
A boy didn't eat every cookie.
✘ This means that "some cookies were eaten."
No. It simply means that not all of the cookies were eaten by the boy. It does not mean that the boy ate some cookies. (Or that even that anybody ate any of the cookies.) The boy could have eaten no cookies at all, and the sentence would still be true.
A boy didn't eat each cookie.
As suggested in a comment under the question, this is unidiomatic.
However, if we take it literally, it still means the same thing as the first sentence.
✘ This means that "no cookies were eaten."
No. It simply means that the boy didn't all of cookies. It does not mean that nobody ate any cookies. The boy could have eaten some, somebody else could have eaten some, or both the boy and somebody else could have eaten some.
In both sentences, all we know for certain is that some or all of the cookies were left uneaten by the boy.
Whether the boy ate some or any cookies, or somebody else ate some or any cookies, or, collectively (between the actions of the boy and other people), all of the cookies were eaten is unknown.