He very carefully wrote this post to avoid his real objections and instead come across as a neutral-point-of-view expert. I found this disingenuous, and I think that the context might be especially helpful to readers who haven’t been around for all that long.
I wrote the post in order to get a hole in the logic of the Sequences fixed. And the argument I presented was chosen in order to be as simple and convincing as possible: the existence of a whole class of interpretations that are unaddressed in the Sequence, and which exist at approximately the same level of qualitative plausibility as many worlds, when judged by the pre-Copenhagen standards of mathematical physics.
You’re also wrong about my “real objections”, in two ways. The way you put it was that I want consciousness to be explained by something quantum, and MWI kills this hope. But in fact my proposition is that consciousness is based on entanglement—on a large tensor factor of the quantum state of the brain. MWI has no bearing on that! MWI is entanglement-friendly. If some other version of quantum theory says there’s entanglement in the brain, that entanglement will still be present in many-worlds. (Retrocausal theory is actually much less entanglement-friendly, because it generally doesn’t believe in wavefunctions as physical objects.) My philosophy-of-mind objections to MWI-based theories of personhood have to do with MWI tolerance of vagueness regarding when one person becomes two, and skepticism that a branching stream of consciousness is even logically possible.
But more importantly, the other criticisms of MWI that I make are just as “real”. I really do consider a large fraction of what is written in support of MWI, to be badly thought out, describing ideas which aren’t a physical theory in any rigorous sense. I really do think that the only reasonable way to explain the Born probabilities is to exhibit a multiverse in which those are the actual frequencies of events, and that this is not the case for 99% of what is written about MWI. I really do think that the problem posed for MWI by relativity is not properly appreciated.
Despite all this, I’m willing to engage with MWI a little because it still has some microscopic chance of being true, and also because it does have roots in the formalism. I believe the way to the answer does not just involve pluralism of research, but active hybridization of interpretations, especially at their points of contact with the mathematical theory.
He very carefully wrote this post to avoid his real objections and instead come across as a neutral-point-of-view expert. I found this disingenuous, and I think that the context might be especially helpful to readers who haven’t been around for all that long.
I wrote the post in order to get a hole in the logic of the Sequences fixed. And the argument I presented was chosen in order to be as simple and convincing as possible: the existence of a whole class of interpretations that are unaddressed in the Sequence, and which exist at approximately the same level of qualitative plausibility as many worlds, when judged by the pre-Copenhagen standards of mathematical physics.
You’re also wrong about my “real objections”, in two ways. The way you put it was that I want consciousness to be explained by something quantum, and MWI kills this hope. But in fact my proposition is that consciousness is based on entanglement—on a large tensor factor of the quantum state of the brain. MWI has no bearing on that! MWI is entanglement-friendly. If some other version of quantum theory says there’s entanglement in the brain, that entanglement will still be present in many-worlds. (Retrocausal theory is actually much less entanglement-friendly, because it generally doesn’t believe in wavefunctions as physical objects.) My philosophy-of-mind objections to MWI-based theories of personhood have to do with MWI tolerance of vagueness regarding when one person becomes two, and skepticism that a branching stream of consciousness is even logically possible.
But more importantly, the other criticisms of MWI that I make are just as “real”. I really do consider a large fraction of what is written in support of MWI, to be badly thought out, describing ideas which aren’t a physical theory in any rigorous sense. I really do think that the only reasonable way to explain the Born probabilities is to exhibit a multiverse in which those are the actual frequencies of events, and that this is not the case for 99% of what is written about MWI. I really do think that the problem posed for MWI by relativity is not properly appreciated.
Despite all this, I’m willing to engage with MWI a little because it still has some microscopic chance of being true, and also because it does have roots in the formalism. I believe the way to the answer does not just involve pluralism of research, but active hybridization of interpretations, especially at their points of contact with the mathematical theory.