Not on topic, but these are answers to some questions asked.
I find this fascinating - maybe better forked to another thread.
What do you think the effect on player choice is in this scenario? In order to make meaningful decisions you need to have some information... could you go so far as to say that the game is about getting to know the DM's worldview?
Player choice is unlimited as in any kind of guessing game (barring table rules).
Since the referee can only express the rules behind the screen (i.e. repeat the pattern) everything he or she says is information relevant to succeeding in the game. Finding what is meaningful is central to the design.
I would say the game is about getting to know the underlying laws the DM has made up for the fiction rather than finding a path the players are to follow. What is in the world is a joint creation of everyone who plays or contributes both during actual play and during prep, background creation, fiction suggestions like modules, etc.
Howandwhy99 is sitting in a chair. Umbran walks up with an apple, and holds it over Howandwhy99's head. When Umbran lets go of the apple, it falls and lightly bonks off said head.
This is objectivity. No amount of communal viewing or common belief changes how the apple falls. Objectivity is not common belief - it is what happens irrespective of what we believe.
That's one story. But you cannot know fundamentally that apple will do as you predict. It is impossible to predict the future except pragmatically. Objective truth is not noumenal reality, it is shared agreement of subjective experiences amongst people. Is reality really there? It's pragmatic to behave so, but we cannot absolutely know such a thing. To say, "this is the way things are no matter what" is to slip into dogmatism.
And I can take some apple bonking. I am aware of tilting the apple cart, but I'd rather just talk about gaming. No personal vendettas here, but if my posts tread to close to the borders, please PM me with specifics.