But why? We ourselves are extremely different from "outside". I am aware of the posture of my body. I am not aware of the posture of the universe. I can move my foot. I cannot move the moon.
There is scarcely anything more obvious in experience than that "me" is different than "not me". That is the entire essence of the realization that there is an outside world.
Now, if you merely are claiming that it would be more parsimonious to have only a difference in organization, not kind, between self and non-self, sure, maybe that's a little bit simpler. But given the outrageous apparent complexity, our complexity budget for our models should reasonably be quite high. We can spend a bit of the budget on different natures of things, if that's how things are.
Even so, why would one suggest that it is the mentality that is what is in common? It seems blatantly obvious that I have mental capacity which the moon does not, and yet I am an object in and of myself and so is the moon. This is, literally, kid stuff. Baby stuff.
There's simply no reason that this is the natural simplification. You can't introspect your mental nature and understand how it works or even if there is a mechanism or algorithm involved; but you also can't introspect your circulatory system. Even you yourself is a pretty big mystery to you.
Going from existential ("there is at least one mind: mine") to universal ("there is nothing but mind") is a huge leap. We have oodles and oodles and oodles of experience that, in general, universals and existentials are not the same. There exists me. Not all is me. There exists the moon. Not all is the moon. I have a mind. But now we're suddenly supposed to conclude all is mind? Huh?
Dualism is parsimonious not because it adds no new premises, but that the new premise does an outsized amount of work. It pays for itself and then some, seemingly. That's why it's the default. The great challenge of materialism or idealism is to show that what you've already paid for the one realm is enough to give both, so why pay more?
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"you have to both postulate and prove the entire ontological foundation of that world in a way that deviates entirely from your experience of it in a way that you can never even hope to prove"
How does the idealist postulate and prove the entire ontological foundation of the world-that-seems-physical to the dualist, and without charging them for infinite parameters of explanatory power (or at least as many as the dualist has already spent on dualism).
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"As I've said before and will repeat as many times as is necessary, Materialism has never explained anything"
Saying things more times doesn't make it true.
Can you explain what it means to "explain" something?
I think, for instance, that statistical mechanics has done an absolutely lovely job of explaining how the effectively random motion of tiny particles causes the bulk properties of pressure and so on with which we're all familiar. Why isn't that an explanation?
Materialists have trouble with Hume, admittedly, but Idealists do too.
So, anyway, what do you even mean by "explains"?
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"holding me to an unreasonably high standard when it comes to mentality"
Absolutely not. All I want is you to show even comparable explanatory power given the amount you have to assume.
Or admit that you don't care about that, it's still miracle-phase, but grant me the same degree of miracle to use however I wish.
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"the argument for the universe being ontologically mental is that that's how we experience it"
We also experience it as epistemologically solopsistic.
But you reject that without argument because it's obvious.
Yet it's also obvious that the universe has mental and non-mental bits.
So this isn't even consistent with your own argumentation, let alone objectively convincing.
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"I would submit to you a study back in 2020 that rigorously studied the universe at very large scales and that found that, according to Italian astrophysicist Franco Vazza and neuroscientist Alberto Feletti, there was a "remarkable similarity" to the universe and the structure of the human brain"
This is one of the stupidest papers I've ever read, to be honest. Some of the methods they use are highly dependent on staining technique and section thickness, others are bafflingly irrelevant (like drawing lines between cell bodies instead of drawing how the neurons are actually connected), and after that and picking the right magnification they only manage to fit a gently curving line over about two orders of magnitude, and don't pick any controls where there is a characteristic scale (as opposed to a pure power-law process where there is no characteristic scale). The only reason it's flatter at 40x than 10x is that the section is too thick and you're effectively blurring in depth. It's so dumb. The only reason I'm not completely embarrassed by its existence is that the paper itself is fairly restrained in its conclusions (but not nearly enough), and the number of people who have expertise enough in both areas is fairly small. But it's so dumb. It would be un-dumb if they played with the math a bit more, or with more data with the same features, or talked about how physical constraints coupled with somewhat scale-free processes result in certain spectral contrast relationships or something.
Studies of scale-free networks often are too rich in hype and too poor in actual scrutiny, e.g. https://www.quantamagazine.org/scant-evidence-of-power-laws-found-in-real-world-networks-20180215/, and this is sadly in the same vein.
Hossenfelder also says, to her credit, "Let me be clear that there is absolutely zero evidence that non-local connections exist, or that, if they existed, they’d indeed allow the universe to think."
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"Why are you conflating truth w/ what's necessary for survival?"
Because that's Hoffman's framework for analyzing the verisimilitude of perception.
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"that local realism has been disproven shows that what we regard as physical objects don't have absolute values before they're observed"
No, it just shows that really tiny objects are weird and only act like we expect when interacting with large object.
Observables' indeterminacy is almost always collapsed, if you take that interpretation, by interaction with a measurement device. It doesn't matter if or when anyone is around to read the device.
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"So where, in all of that, is even the smallest implication of hope that actual Truth is being represented"
At most scales, we can predict things extremely well. So the truth that matters is apparently very well understood. If there are all manner of extremely complex dark matter interactions, it's true that we'd be unaware of that.
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"This is a pure handwave and doesn't actually answer anything."
Of course it doesn't answer anything. It's a refutation of a claim you made as to why there couldn't be an answer, and it was clearly stated as such.
Your logic was faulty. I showed as much.