didn't go well for me - as I'd feared...
The consensus was that (depending on the formulation), the existence of "third-person imperatives": any evidence I put forth was based on intuition, and therefore unscientific, and meanwhile she had no scientific evidence to the contrary; the whole thing is a potential "research topic"
Here are some of the other points I can still articulate by now, some of them related to my auxiliary assertions of third-person imperatives existing in the English language:
*For now, the "third-person imperative" in Greek or any other language should be considered as a jussive sort of mood apart from the 'real' imperative; terminological differences are perfectly fine and even to be expected, but it's not linguistically correct to call this Greek form an "imperative" (at least until such time as research can...)
*Since linguists can't settle on the conclusion that "languages are just different", they must make principles and parameters to account for cross-linguistic variation; by asserting that the 3p imperative in Greek and the imperative (2p) in English are of the same kind, I must create a viable parameter to account for the apparent variation, especially if I'm to violate the (proposed?) principle of imperatives being only 2nd-person in subject
*Any lines I can come up with that have "God" as a subject should be treated as special cases
*The lines I used to demonstrate a third-person imperative in English were mostly using quantifiers, which are "weird"; when modified by of you, their subjects remain grammatically 3rd-person, but semantically should change to 2nd-person; since no one yet can say how that can be (i.e. how to reconcile the two items), no one can really say what these lines mean
*In lines like "Those kids of yours keep out of my garden, or I'll set the dogs on them", how can I be sure that "those kids" is the subject of the sentence? the concept of "subject" is very nebulous and as of yet poorly understood; what makes something a subject? I must create a theoretical argument for a definition of "subject" that is scientific and convincing while applicable to the sentences I use for example
*One proof that imperatives must be 2nd-person in subject is that when an imperative clause contains a reflexive pronoun (which unlike 'subject' is a matter of fixed & accepted definition), it's always second-person, and reflexive pronouns must always be paired "in their local domain" with an analogous subject; and even if I were to somehow start a trend where "The man kill himself" (as a command) were to become widespread and so fully grammatical, I would still need to devise a parameter to explain it
Many other points were put across, demolished, and replaced in the course of this long discussion; I suppose the above are both the most important and the firmest in my memory. Of course, there's always the chance of mis-recall or incomplete (for the purpose of reconstructing her positions) recall or mis-interpretation, but I probably grilled her too thoroughly for those to be concerns.
Well, perhaps it's a shame that I couldn't come up with anything on the spot to spin a convincing case on her
terms. The greater shame, though, is surely that she is already married.