My question is as the title says: Is it allowed for a pronoun and its referent to have different plurality? A specific example I am considering is a sentence like this:
I love this cookie so much that I bought dozens of them and distributed them to my friends.
I am curious whether this kind of sentence is grammatically correct or not.
Hmm… Did you consider that “them”‘s referrent might be unexpressed? Them refers not to cookie, but to “cookies”, the plural form of the noun expressed in the sentence and whose existence is implied.
Not all pronouns belong to nouns that are expressed elsewhere in the sentence. “Are they going to help?” “They” is all by itself. Or try: “The man called and said that they would fix everything.” “They” does not mean “man”. It means some men/workers at the company.
I can also assure you that “cookie” here is not collective. If it read family: “I love this family so much that I hugged all of them”. “All” quite obviously, and ridiculously, pretends to mean all families, not all members of this particular family.
I think some people here missed this, hiding in plain sight.
One more thing is that, a hundred years ago, is was perfectly common to just use the singular: “I like this cookie so much that I bought dozens of it…” Nowadays this sounds kind of stilted, but it’s probably better English.