Nice post, but I think you left out what I think is the *most* parsimonious hypothesis, even more parsimonious than that the universe (or the multiverse) contains everything or nothing.
0. Objective physical existence isn't a thing.
This hypothesis collapses the distinction between hypothesis 1 and 2.
This is what I think is actually the case. I think what physically exists is observer-relative. Stuff that's in my universe exists from my POV. Stuff that exists in some other universe doesn't, but may physically exist from the POV of an observer in that universe if it has any observers at all.
The question about whether the whole shebang physically exists is not well-posed. There is no objective distinction to draw such that we can say that some possible worlds exist and others don't.
We can deem them all to physically exist if we want to, but we could also deem none of them to physically exist. But this is just a matter of convention. There is no stance-independent fact of the matter.
(All the above is a particular gloss I put on Max Tegmark's Mathematical Universe Hypothesis)
Maybe different from what you're saying, but I'm reminded of the idea, "We are all just instantiations of possible math, and all possible math is instantiated", which I could definitely see being the case and I'd consider it a special case of "everything exists".
Though I'm not sure I'm understanding your "physicality" distinction. If I see things, then I'm seeing some sort of existence; what does it matter if we label that fact of existence as "physical"?
It's basically the idea you're referencing, but the galaxy-brained version of that is to do away with the idea that math has to be instantiated. (Physical) instantiation is not a thing, ultimately. There is no difference between math that is instantiated and math that is not. There is only math.
The problem is that if you add the premise "all math is intantiated", it seems like that premise needs an explanation, or that it could have been false. It's an assumption which slightly spoils the parsimony, and we're left with the mystery of *why* all math is instantiated and no explanation.
To Wittgenstein's ladder this a bit, let's assume that instantiation is a thing. Now, assume that no math is instantiated. But, in the mathematical object that would look like our universe if it were instantiated, you can find self-aware-substructures like you and me. And from their POV within that object, it sure looks like it's instantiated, even if it isn't. They can't tell the difference.
So we don't need instantiation. That's the point I'm driving at.
Ah, I think I've got you! About that piece at least.
However -- why would this view of math and math's existence be *more* parsimonious than the non-existence of everything? At most I could see myself maybe considering them equally parsimonious
Because the idea is we don’t need math to exist. We don’t need anything to exist. We can discard the assumption that objective existence is a meaningful concept, and so be more parsimonious by making one less assumption.
I call myself a mathematical realist, not because I think mathematical objects exist when they mightn’t’ve, but because I just take the attitude that we should deem them to exist and use existence-language about them. But I don’t think they exist in any sense in which they mightn’t’ve.
On this view, the non-existence of anything is incoherent if seen as distinct from the idea that everything exists. We can say nothing exists or everything does, but these are not distinct hypotheses. They are just different ways of talking.
Nice post, but I think you left out what I think is the *most* parsimonious hypothesis, even more parsimonious than that the universe (or the multiverse) contains everything or nothing.
0. Objective physical existence isn't a thing.
This hypothesis collapses the distinction between hypothesis 1 and 2.
This is what I think is actually the case. I think what physically exists is observer-relative. Stuff that's in my universe exists from my POV. Stuff that exists in some other universe doesn't, but may physically exist from the POV of an observer in that universe if it has any observers at all.
The question about whether the whole shebang physically exists is not well-posed. There is no objective distinction to draw such that we can say that some possible worlds exist and others don't.
We can deem them all to physically exist if we want to, but we could also deem none of them to physically exist. But this is just a matter of convention. There is no stance-independent fact of the matter.
(All the above is a particular gloss I put on Max Tegmark's Mathematical Universe Hypothesis)
Maybe different from what you're saying, but I'm reminded of the idea, "We are all just instantiations of possible math, and all possible math is instantiated", which I could definitely see being the case and I'd consider it a special case of "everything exists".
Though I'm not sure I'm understanding your "physicality" distinction. If I see things, then I'm seeing some sort of existence; what does it matter if we label that fact of existence as "physical"?
It's basically the idea you're referencing, but the galaxy-brained version of that is to do away with the idea that math has to be instantiated. (Physical) instantiation is not a thing, ultimately. There is no difference between math that is instantiated and math that is not. There is only math.
The problem is that if you add the premise "all math is intantiated", it seems like that premise needs an explanation, or that it could have been false. It's an assumption which slightly spoils the parsimony, and we're left with the mystery of *why* all math is instantiated and no explanation.
To Wittgenstein's ladder this a bit, let's assume that instantiation is a thing. Now, assume that no math is instantiated. But, in the mathematical object that would look like our universe if it were instantiated, you can find self-aware-substructures like you and me. And from their POV within that object, it sure looks like it's instantiated, even if it isn't. They can't tell the difference.
So we don't need instantiation. That's the point I'm driving at.
Ah, I think I've got you! About that piece at least.
However -- why would this view of math and math's existence be *more* parsimonious than the non-existence of everything? At most I could see myself maybe considering them equally parsimonious
Because the idea is we don’t need math to exist. We don’t need anything to exist. We can discard the assumption that objective existence is a meaningful concept, and so be more parsimonious by making one less assumption.
I call myself a mathematical realist, not because I think mathematical objects exist when they mightn’t’ve, but because I just take the attitude that we should deem them to exist and use existence-language about them. But I don’t think they exist in any sense in which they mightn’t’ve.
On this view, the non-existence of anything is incoherent if seen as distinct from the idea that everything exists. We can say nothing exists or everything does, but these are not distinct hypotheses. They are just different ways of talking.