But it is logically possible to not believe that God exists and to not believe that God does not exist at the same time.I would call that an oxymoron. Not to believe that God exists is equivalent to believing that he does not; by the same token not believing that God does not exist is equivalent to believing that he does. It is logically impossible to believe that God both does and does not exist at the same time.
And if a person has no belief on the subject, does that person believe that God exists? No.If a person is undecided, then he has no belief on the subject.
There is simply no answer contrary to that that you can give (without it being mere arm-waving and evasion).
So if a person says "no" to the question of "do you believe...?", how is that different to the person saying "I do not believe..."?
And if a person who lacks belief says "I do not believe...", and a person who has belief in the non-existence of God also says "I do not believe..." there is clearly an ambiguity to the sentence "I do not believe..." that you have failed to identify, or at least fail to allow for.
None of which alters the person's simple answer of "no" to the question of "do you believe...?"The most coherent thing we could say about him is that he is undecided, that he needs more evidence, that he is waiting for a sign from God, etc.
Q: "Do you believe that God exists?"
A: "No, I do not believe that God exists?" - because they have no belief.
By that answer, are they saying that they therefore believe that God does not exist? You seem to think so, despite accepting that the person may be without belief.
But we have been round this all before and still it doesn't seem to sink in. Old dogs and new tricks, eh?