Why is a distinction between private appearance, intersubjective world and metaphysical reality not the main attitude in metaphysics?
I distinguish between 3 levels of "being".
1st is the direct personal phenomenological level. Hallucinations and inconsistencies can occur here.
2nd is the shared phenomenological reality. For example, when I see a table, it will change color at level 1 because the sun is hitting it. But when I rotate around the table, I see that the table really is a uniform color. Other people can look at the table too and see it's the same color, feel it. This is the level where science operates
3rd level is the metaphysical. It's what actually exists beyond how things appear to us. It's inaccessible because we can only see things how they appear to us. But we can develop frameworks to fit the data of a world we have built at level 2. This way, there are multiple metaphysical "as if" frameworks that say our shared reality behaves as if this or that was the true inner working of all of reality. There can be multiple metaphysical theories that explain our current level 2 reality (it's real enough for us humans to call level 2 reality); for example: we can be either a brain in a vat that is being fed electron stimulations to feel like we are experiencing this, or there is a natural world that corresponds to our senses. Either way, the only thing we can't doubt is that we are having this experience.
Of course, some points need to be sharpened, for example, how exactly we can move from level 1 to level 2, what makes a good scientific theory, etc., but I feel like the structure of this framework is just undeniable and explains quite a lot. If you doubt level 1, there is already something occurring phenomenally. If you doubt level 2, go out in the world, bash your head against a table and come back.
Is this really as undeniable as I think?