I would be interested to see them, provided they were in physics journals (except for the Foundations of Physics, which often publishes stuff that can only be very charitably described as physics), and not in philosophy journals (my opinion of those happens to coincide with that of Feynman).
Fair enough. I will admit that the only physics journal in which I am published is in fact Foundations of Physics. You may not see this as a worthwhile venue for publication, but I hope that it will at least absolve me of the charge of dilletantism. I’d also point out that while in the past Foundations has had a reputation for encouraging mild crackpottery, its reputation has substantially improved since Gerard ‘t Hooft (I think probably the most insightful contemporary physicist) took charge. My publication in the journal was in the post-’t Hooft era, for what that’s worth. I’d point you to my paper, but I’d like to retain a little anonymity here.
I disagree very strongly with you on the value of (scientifically informed) philosophy, but that is probably a topic on which we genuinely will not get anywhere, so I’ll drop it.
That said, your response was (as I predicted) beneficial. I take it you are expressing surprise (or perhaps skepticism) at my claim to some degree of expertise. When I comment on physics, I try to balance signalling that I know what I’m talking about against being informal and accessible. Perhaps I’m not getting the balance right.
As for the immediate reason, I pointed out a rather elementary problem with units, which you did not address. Given that we cannot even agree on how propagation rate is defined, I do not see how we can make further progress.
Your point about units seems irrelevant to what I was saying. My comment was not intended to be non-responsive. I was trying to make clear what I was actually claiming, in the hope that it would also make clear that the units worry isn’t a problem. Maybe I’ll try again, at slightly greater length.
Look, here’s the dialectic: Someone said that in MWI, world-splitting is global and instantaneous. I responded that it isn’t, since “world-splitting” is just a consequence of decoherence, and decoherence takes time and relies on system-environment interactions, which are constrained by relativity.
At no point do I commit myself to measuring decoherence rates using units of velocity. I did speak of decoherence propagating, and this is what I meant by it: When a system decoheres its dynamics are no longer unitary. But the dynamics of an informationally isolated system are always unitary, so for a system to decohere, it must exchange information with its environment. Relativity constrains the (spatial) propagation of information.
Whether or not a particular quantum process has led to “world-splitting” is, in a sense, relative to an observer. Say I’m observing a Stern-Gerlach experiment. The spin state of the particle decoheres through interaction with the measuring device, From my perspective, though, this doesn’t correspond to a splitting into two worlds with different spin measurements until information from the measuring device propagates to me. This will take a (slight) additional amount of time. To you, standing outside the lab, there wouldn’t have been world-splitting until some portion of that information propagates to you; again, at finite velocity. Until that point, the whole particle-measuring device-me system will be in a state of superposition relative to you. So if we are dealing with localized systems, and we assume that information propagates through space at finite velocity, world-splitting can also be (crudely) thought of as propagating through physical space.
But I should emphasize that this in fact a crude approximation. I’m glossing a number of complications in this sketch. But these complications do not affect my main (in fact, sole) point: world-splitting in MWI is not global and instantaneous. Perhaps you think I’m making some bigger claim here, like MWI is a spatio-remporally local or relativistically invariant interpretation. I am not claiming anything of the sort. I don’t even think the ordinary notion of spatial locality is well-defined in the MWI framework (since physical space is non-fundamental), and I made a comment above explicitly saying that MWI in its current form cannot be easily reconciled with relativity.
First, I did not mean your personally when I was talking about dilettantes who learned from other dilettantes. I meant the people who read the QM sequence as their only in-depth math-free introduction to QM and took it as a self-evident truth, compartmentalizing away everything EY said about guessing the teacher’s password and such. Again, as EY keeps saying, a belief feels like truth from the inside, so it is extremely hard to argue with such people. I am well aware that this applies just as much to me, as to everyone else, having been burned by false beliefs before multiple times.
I agree that under ’t Hooft FoP gotten better, though it is still more philosophy than physics, hence my reservations.
At no point do I commit myself to measuring decoherence rates using units of velocity. [...] To you, standing outside the lab, there wouldn’t have been world-splitting until some portion of that information propagates to you; again, at finite velocity.
I find these two statements in contradiction. If you can measure the degree of decoherence and pinpoint when something is, say, “50%-decohered”, then you can take two observers at two points in space who measure it and calculate the propagation velocity as (x2-x2)/(t1-t1). If you cannot do that, then propagation of decoherence is not ontologically fundamental and is just a feel-good picture.
But these complications do not affect my main (in fact, sole) point: world-splitting in MWI is not global and instantaneous.
My point is that it makes no sense at all to talk about the “world-splitting process” as anything in any sense “real”.
Now, I do not expect you to agree with me, that is why I tried to drop the issue. And the reason I do not expect you to agree with me is a pragmatic one (pun intended): actions speak louder than words. And by “action” I mean an experiment differentiating between our points of view. That’s why I asked you how such an experiment would look. Until this is settled, we can continue back and forth with little hope of coming to an agreement. It might or might not work out better in person, though my observations of metaphysical debates between some rather smart people makes me skeptical that it would.
Fair enough. I will admit that the only physics journal in which I am published is in fact Foundations of Physics. You may not see this as a worthwhile venue for publication, but I hope that it will at least absolve me of the charge of dilletantism. I’d also point out that while in the past Foundations has had a reputation for encouraging mild crackpottery, its reputation has substantially improved since Gerard ‘t Hooft (I think probably the most insightful contemporary physicist) took charge. My publication in the journal was in the post-’t Hooft era, for what that’s worth. I’d point you to my paper, but I’d like to retain a little anonymity here.
I disagree very strongly with you on the value of (scientifically informed) philosophy, but that is probably a topic on which we genuinely will not get anywhere, so I’ll drop it.
That said, your response was (as I predicted) beneficial. I take it you are expressing surprise (or perhaps skepticism) at my claim to some degree of expertise. When I comment on physics, I try to balance signalling that I know what I’m talking about against being informal and accessible. Perhaps I’m not getting the balance right.
Your point about units seems irrelevant to what I was saying. My comment was not intended to be non-responsive. I was trying to make clear what I was actually claiming, in the hope that it would also make clear that the units worry isn’t a problem. Maybe I’ll try again, at slightly greater length.
Look, here’s the dialectic: Someone said that in MWI, world-splitting is global and instantaneous. I responded that it isn’t, since “world-splitting” is just a consequence of decoherence, and decoherence takes time and relies on system-environment interactions, which are constrained by relativity.
At no point do I commit myself to measuring decoherence rates using units of velocity. I did speak of decoherence propagating, and this is what I meant by it: When a system decoheres its dynamics are no longer unitary. But the dynamics of an informationally isolated system are always unitary, so for a system to decohere, it must exchange information with its environment. Relativity constrains the (spatial) propagation of information.
Whether or not a particular quantum process has led to “world-splitting” is, in a sense, relative to an observer. Say I’m observing a Stern-Gerlach experiment. The spin state of the particle decoheres through interaction with the measuring device, From my perspective, though, this doesn’t correspond to a splitting into two worlds with different spin measurements until information from the measuring device propagates to me. This will take a (slight) additional amount of time. To you, standing outside the lab, there wouldn’t have been world-splitting until some portion of that information propagates to you; again, at finite velocity. Until that point, the whole particle-measuring device-me system will be in a state of superposition relative to you. So if we are dealing with localized systems, and we assume that information propagates through space at finite velocity, world-splitting can also be (crudely) thought of as propagating through physical space.
But I should emphasize that this in fact a crude approximation. I’m glossing a number of complications in this sketch. But these complications do not affect my main (in fact, sole) point: world-splitting in MWI is not global and instantaneous. Perhaps you think I’m making some bigger claim here, like MWI is a spatio-remporally local or relativistically invariant interpretation. I am not claiming anything of the sort. I don’t even think the ordinary notion of spatial locality is well-defined in the MWI framework (since physical space is non-fundamental), and I made a comment above explicitly saying that MWI in its current form cannot be easily reconciled with relativity.
First, I did not mean your personally when I was talking about dilettantes who learned from other dilettantes. I meant the people who read the QM sequence as their only in-depth math-free introduction to QM and took it as a self-evident truth, compartmentalizing away everything EY said about guessing the teacher’s password and such. Again, as EY keeps saying, a belief feels like truth from the inside, so it is extremely hard to argue with such people. I am well aware that this applies just as much to me, as to everyone else, having been burned by false beliefs before multiple times.
I agree that under ’t Hooft FoP gotten better, though it is still more philosophy than physics, hence my reservations.
I find these two statements in contradiction. If you can measure the degree of decoherence and pinpoint when something is, say, “50%-decohered”, then you can take two observers at two points in space who measure it and calculate the propagation velocity as (x2-x2)/(t1-t1). If you cannot do that, then propagation of decoherence is not ontologically fundamental and is just a feel-good picture.
My point is that it makes no sense at all to talk about the “world-splitting process” as anything in any sense “real”.
Now, I do not expect you to agree with me, that is why I tried to drop the issue. And the reason I do not expect you to agree with me is a pragmatic one (pun intended): actions speak louder than words. And by “action” I mean an experiment differentiating between our points of view. That’s why I asked you how such an experiment would look. Until this is settled, we can continue back and forth with little hope of coming to an agreement. It might or might not work out better in person, though my observations of metaphysical debates between some rather smart people makes me skeptical that it would.