If we are in the level IV multiverse, then ontological claims about our world are meaningless, because we simultaneously exist in worlds where they are true and worlds where they are not true
There are a number of different claims jammed together, there.
Firstly, its not clear whether a level IV multiverse means there are multiple copies of you with identical brain states but living in different environments—why would you be in a “seeing a tree” brain state if you are on a planet with no trees? It’s also not clear whether you can have qualitatively identical counterparts that don’t share brain states—what then makes them identical? It’s also not clear that qualitative identity is sufficient for numerical identity. Basically, multiversal theories don’t supply a theory of personal identity—that has to be an additional assumption.
(Oddly enough, there is a better way of getting to the same point. If we can’t prove that we are not living in a simulation, then we can’t resolve basic ontological questions, even if we have excellent predictive theories).
Secondly, even if ontological questions can’t be answered , that doesn’t mean they are meaningless, under the one and only definition of “meaning” anyone ever had.
So, I think the crux of why I don’t really agree with your general gist and why I’m guessing a lot of people don’t, is we see meaningfulness as something bigger than just whether or not something is a fact (statement that has a coherent truth value).
Firstly, its not clear whether a level IV multiverse means there are multiple copies of you with identical brain states but living in different environments—why would you be in a “seeing a tree” brain state if you are on a planet with no trees?
It’s very clear, to the contrary. A universe with an identical brain state but without any trees absolutely is part of it, there is a mathematical structure corresponding to the brain state that doesn’t also contain trees.
what then makes them identical
My standard criteria is subjective indistinguishability. Any universe that we can’t tell that we’re not in contains a copy of us.
Re simulation: level IV contains a broad range of theories even weirder than simulations of us, infinitely many of which make ontological claims come out alternatively true or false. We certainly can’t prove any ontological claim.
Secondly, even if ontological questions can’t be answered , that doesn’t mean they are meaningless, under the one and only definition of “meaning” anyone ever had.
We’d at least have to significantly complicate the definition. I think people generally intend and expect ontological claims to have a coherent truth value, and if that’s not the case then there’s no referent for what people use ontological claims for. If you don’t want to call it meaningless, fine, but it’s certainly weird.
You are making two claims..about whether ontological indeterminacy holds, and about the meaning of “meaning” .
Setting aside the second claim , the first claim rests on an assumption that the only way to judge a theory is direct empiricism. But realists tend to have other theoretical desiderata in mind..a lot would reject simulations and large universes on the basis of Occams Razor, for instance.
As for the rest..you might have a valid argument that it’s inconsistent to believe in both empirical realism and large universes.
I accept Occam, but for me it’s just a way of setting priors in a model using to make predictions.
And part of my argument here is how the mere possibility of large universes destroys the coherency of realism. Even those rejecting simulations would still say it’s possible.
(Putnam would say it’s meaningless, and I would in fact agree but for different reasons.)
I accept Occam, but for me it’s just a way of setting priors in a model using to make predictions.
But you don’t have a proof that that is the only legitimate use of Occam. If realists can use Occam to rescue realism, then realism gets rescued.
And part of my argument here is how the mere possibility of large universes destroys the coherency of realism. Even those rejecting simulations would still say it’s possible.
That would be the sort of problem that probablistic reasoning addresses.
That doesn’t mean that Occam grounding realism is at all plausible. I’ve laid out an argument for verificationism here and met my burden of proof. Suggesting that there might possibly be a counterargument isn’t meeting the opposing burden of proof.
Meeting contrary arguments is part of a making an argument. There definitely is such a counterargument, even if you have never heard of it. That’s what steel manning and strong manning are all about.
I don’t know what a plausible version of the argument you’re hinting at would look like. If you think there’s such a plausible argument, please point me at it.
I don’t know what your thoughts on plausibility are. But multiversal theories are straightforwardly excluded by the original version of Occams Razor, the one about not multiplying entities.
Since the argument does not mention probability, it doesn’t refute the counterargument that unlikely scenarios involving simulations or multiple universes don’t significantly undermine the ability to make claims about ontology.
If you take that as a premise and you consider it contradictory to my conclusion and you accept my premises, then the premises you accept imply a contradiction. That’s your problem, not mine.
There are a number of different claims jammed together, there.
Firstly, its not clear whether a level IV multiverse means there are multiple copies of you with identical brain states but living in different environments—why would you be in a “seeing a tree” brain state if you are on a planet with no trees? It’s also not clear whether you can have qualitatively identical counterparts that don’t share brain states—what then makes them identical? It’s also not clear that qualitative identity is sufficient for numerical identity. Basically, multiversal theories don’t supply a theory of personal identity—that has to be an additional assumption.
(Oddly enough, there is a better way of getting to the same point. If we can’t prove that we are not living in a simulation, then we can’t resolve basic ontological questions, even if we have excellent predictive theories).
Secondly, even if ontological questions can’t be answered , that doesn’t mean they are meaningless, under the one and only definition of “meaning” anyone ever had.
Indeed!
It’s very clear, to the contrary. A universe with an identical brain state but without any trees absolutely is part of it, there is a mathematical structure corresponding to the brain state that doesn’t also contain trees.
My standard criteria is subjective indistinguishability. Any universe that we can’t tell that we’re not in contains a copy of us.
Re simulation: level IV contains a broad range of theories even weirder than simulations of us, infinitely many of which make ontological claims come out alternatively true or false. We certainly can’t prove any ontological claim.
We’d at least have to significantly complicate the definition. I think people generally intend and expect ontological claims to have a coherent truth value, and if that’s not the case then there’s no referent for what people use ontological claims for. If you don’t want to call it meaningless, fine, but it’s certainly weird.
You are making two claims..about whether ontological indeterminacy holds, and about the meaning of “meaning” .
Setting aside the second claim , the first claim rests on an assumption that the only way to judge a theory is direct empiricism. But realists tend to have other theoretical desiderata in mind..a lot would reject simulations and large universes on the basis of Occams Razor, for instance.
As for the rest..you might have a valid argument that it’s inconsistent to believe in both empirical realism and large universes.
I accept Occam, but for me it’s just a way of setting priors in a model using to make predictions.
And part of my argument here is how the mere possibility of large universes destroys the coherency of realism. Even those rejecting simulations would still say it’s possible.
(Putnam would say it’s meaningless, and I would in fact agree but for different reasons.)
But you don’t have a proof that that is the only legitimate use of Occam. If realists can use Occam to rescue realism, then realism gets rescued.
That would be the sort of problem that probablistic reasoning addresses.
>But you don’t have a proof that that is the only legitimate use of Occam. If realists can use Occam to rescue realism, then realism gets rescued.
Surely the burden of proof is on someone suggesting that Occam somehow rescues realism.
Besides, level IV is arguably simpler than almost any alternative, including a singleton universe.
That’s not sure at all. Anti realism is quite contentious.
It can come out as very simple or very complex depending on how you construe Occam.
That doesn’t mean that Occam grounding realism is at all plausible. I’ve laid out an argument for verificationism here and met my burden of proof. Suggesting that there might possibly be a counterargument isn’t meeting the opposing burden of proof.
Meeting contrary arguments is part of a making an argument. There definitely is such a counterargument, even if you have never heard of it. That’s what steel manning and strong manning are all about.
I don’t know what a plausible version of the argument you’re hinting at would look like. If you think there’s such a plausible argument, please point me at it.
I don’t know what your thoughts on plausibility are. But multiversal theories are straightforwardly excluded by the original version of Occams Razor, the one about not multiplying entities.
To the extent Occam is interpreted as saying that more complicated theories are impossible, as opposed to unlikely, it’s not plausible.
As above, my claim rests only on the possibility of a multiverse.
Why should something that is possible but low probability have so much impact?
The argument is laid out in OP.
I don’t see any mention of probability.
The argument does not depend on probability.
If you disagree with the conclusion, please explain which premise is wrong, or explain how the conclusion can be false despite all premises holding.
Since the argument does not mention probability, it doesn’t refute the counterargument that unlikely scenarios involving simulations or multiple universes don’t significantly undermine the ability to make claims about ontology.
That’s not a counterargument, as it’s fully consistent with the conclusion.
If you take that as a premise and you consider it contradictory to my conclusion and you accept my premises, then the premises you accept imply a contradiction. That’s your problem, not mine.
Read back,there’s an even number of negatives.
Not following. Can you state your point plainly? Which part of my argument do you reject?