I am not talking about RL. I made that verify clear. RL doesn't have any bearing on a fantasy mythology. So I am not sure why you keep bringing it up.
When I say it is a verifiable fact that gods existed in Greek mythology, I am talking about what happens in that mythological space. The peoples and heroes of Greek Mythology could verify the existence of Athena and Ares. That is a core aspect of Greek mythology. I assume you are not arguing otherwise, but I am not sure because you continue to talk about RL peoples and that is not what this is about!
And I'm telling you that that's a false comparison,
because that mythology IS the story being told.
Like...let me make this very specific.
You keep saying that
in the world of D&D, this thing is JUST one story among many. You have said repeatedly that all of these stories-about-reality could be true or false. Such a situation can only arise when the different stories
cannot be verifiably and repeatably distinguished from each other--in other words, the situation just like real life, where we can't really be sure which is true and which is false. In other words, you take the story as being just that--a story told that may or may not actually be true.
Then you start talking about how
within ancient Greek or Norse or Vedic etc. mythology, these places are verifiable, existent places that are real and present. In other words, you take the story as-is, accepting that it is a real and correct depiction of reality
within the story itself.
You can't have that both ways. You cannot simultaneously have that Valhalla is a verifiably real place that souls go to under testable, verifiable conditions, AND have it be the case that Valhalla is merely one unverifiable story among many that people tell to each other, which
might be true, but nobody can ever truly know. In exactly the same way, you cannot simultaneously have it that the Great Wheel's locations are verifiably real places that souls go to under testable, verifiable conditions, AND have it be the case that the Great Wheel is merely one unverifiable story among many that people tell each other, which
might be true, but nobody can ever truly know.
Either the Great Wheel is verifiable, and thus the characters live "in" the mythology as it were, or it is
not verifiable, and the characters
believe the mythology without testable, verifiable fact. There can be no either-or on this; either the verifiability is possible or it is not. If it is verifiable, then it is true, and because of its nature, hegemonic. If it is not verifiable, then it is no more true than any other, and it has to be impossible for folks to know that (for example) a concertedly Lawful Good soul 100% always goes to Celestia.
The Great Wheel is not
simply a mythology. It is a cosmological hypothesis. It makes specific, clear, testable, verifiable claims about reality. Either those claims can be verified, and thus proven objectively true or objectively false, or they cannot be verified, and thus other competing, contradictory hypotheses can also be entertained. Likewise, the World Axis is not
simply a mythology. It, too, is a cosmological hypothesis, and not only does it make specific, clear, testable, verifiable claims about reality,
those claims contradict the claims of the Great Wheel.