If the mathematical multiverse hypothesis is true, then that is the underlying unique reality. The different physical worlds perceived by different minds are different parts of the mathematical multiverse. Minds perceive the physical world they are embedded in, and there is a fact of the matter as to which physical world a particular mind is embedded in, just as within our own physical world, our minds are embedded in particular locations and we perceive those locations rather than our entire physical world.
From Being a Realist (even if you believe in God):
My mother, who doesn't call herself a theist (I think she's agnostic), doesn't even accept realism. She doesn't even agree with this:
That's little more than tautologies here. Yet it elicited an impression of being forced to believe. I know because she told me about the totalitarian dangers from such narrow thinking.
I'm happy to have finally found the root cause of our ongoing disagreement, but now, how can I deal with that? It looks pretty hopeless, but just in case, does someone have a suggestion, or should I just leave it at that? (My ego doesn't like it, but giving up is an option.)
Now I'm relieved to know that in near mode, she's a complete realist. This craziness only shows up in far mode.