Re: A thought on MWI and its alternative(s)
On Wednesday, May 31, 2017 at 3:28:18 PM UTC+10, Brent wrote: > > Sorry. Something funny with my verizon account. > > Brent > > On 5/30/2017 8:09 PM, Pierz Newton-John wrote: > > Brent, are you replying from a mobile? I’m still receiving your replies, > as others are, on my private email. That’s what happens to me when I try to > reply using my iPhone. The "reply to all" button is missing. I’ll reply to > your remarks on the list if you post it there... > > > > > >> On 31 May 2017, at 1:05 pm, Brent Meeker > wrote: > >> > >> > >> > >> On 5/30/2017 7:30 PM, Pierz wrote: > >>> Thanks for these clarifications Bruce. I find your explanations to be > very lucid and helpful - they also confirm my own understanding. IIRC, you > weren't a particular fan of MWI when I last conversed with you on this > list. I wonder if you'd care to comment on my original argument on this > thread - which has of course now been swamped by the usual brawls. Does not > a single history + the physical insignificance of the notion of a current > moment mean that there is also only a single possible future? > >> I don't see how that follows. In the usual model of forking in the > future direction every current moment has a single history, but multiple > futures. > Multiple futures = MWI, surely. When I say a single history, I mean that from the Big Bang forward, the universe only followed one branch. > >> > >>> And if the future is predetermined in this way, isn't this a serious > issue for single universe models of QM? How can the outcome of quantum > events be both inevitable and random? > >> Having a single future isn't the same as being determined. A single > future in which situation A is sometimes followed by B and sometimes by C > is still random. > It depends on perspective. It's true that from 1p, it looks random. But from 3p, it is static and always the same, and in this sense determined. The question is, what determined (from the 3p view) that the universe followed that particular path and not any of the others? My assumption here is that "now" does not exist from the 3p POV and therefore the physical structure (whether it branches or not) of the past and the future is the same. >> > >> Brent > > > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: A thought on MWI and its alternative(s)
Sorry. Something funny with my verizon account. Brent On 5/30/2017 8:09 PM, Pierz Newton-John wrote: Brent, are you replying from a mobile? I’m still receiving your replies, as others are, on my private email. That’s what happens to me when I try to reply using my iPhone. The "reply to all" button is missing. I’ll reply to your remarks on the list if you post it there... On 31 May 2017, at 1:05 pm, Brent Meeker wrote: On 5/30/2017 7:30 PM, Pierz wrote: Thanks for these clarifications Bruce. I find your explanations to be very lucid and helpful - they also confirm my own understanding. IIRC, you weren't a particular fan of MWI when I last conversed with you on this list. I wonder if you'd care to comment on my original argument on this thread - which has of course now been swamped by the usual brawls. Does not a single history + the physical insignificance of the notion of a current moment mean that there is also only a single possible future? I don't see how that follows. In the usual model of forking in the future direction every current moment has a single history, but multiple futures. And if the future is predetermined in this way, isn't this a serious issue for single universe models of QM? How can the outcome of quantum events be both inevitable and random? Having a single future isn't the same as being determined. A single future in which situation A is sometimes followed by B and sometimes by C is still random. Brent -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: A thought on MWI and its alternative(s)
On 31/05/2017 12:30 pm, Pierz wrote: Thanks for these clarifications Bruce. I find your explanations to be very lucid and helpful - they also confirm my own understanding. Thank you for the kind comments, I try my best to be clear. IIRC, you weren't a particular fan of MWI when I last conversed with you on this list. That is indeed the case. I have several reasons to be dubious about MWI. Firstly, it amounts to reifying a complex valued function that resides in configuration space -- I am not sure that this is a well-defined procedure. Secondly, MWI doesn't really do what it claims to do, which is to provide a resolution of the measurement problem in QM. MWI doesn't provide any explanation of the transition from a pure state to the mixed state that is required for experiments to give definite results. At the crucial point, MWI simply says "then a miracle happens!" To be more explicit, deterministic evolution of the wave function by the Schrödinger equation gives a full account of decoherence, and the dissemination of the coherence phases into the environment. This reduces the off-diagonal elements of the density matrix so that the diagonal elements become *almost* orthogonal, but unitary evolution can't go the whole way. The only way one can reduce the pure state to a mixture is to trace over the environmental degrees of freedom, which is to say that the residual phase information is simply thrown away. This trace operation is non-unitary, and there is no warrant for it in the SE itself, so it is, in the final analysis, just an appeal to magic. Thirdly, the non-observed branches in MWI play no essential role in the theory, so Occam would say that they are inessential entities that should be discarded. If one is simply going to discard them, and they play no observable role, why invoke these other branches in the first place? I wonder if you'd care to comment on my original argument on this thread - which has of course now been swamped by the usual brawls. Does not a single history + the physical insignificance of the notion of a current moment mean that there is also only a single possible future? We will only experience a single future, but what that future is, is indeterminate at the present instant. And if the future is predetermined in this way, isn't this a serious issue for single universe models of QM? How can the outcome of quantum events be both inevitable and random? I don't see that there is only a single possible future. The block universe notion only requires indeterminate time ordering for spacelike separated events. The future along and inside one's future light cone is in the future for all observers, so need not be determined by some other observer having already seen what happens. The block universe only constrains the future only in very limited sense -- it is only for spacelike separations that simultaneity is ambiguous, timelike separations are not so constrained. Quantum non-locality is another matter, however, and there are growing indications that quantum entanglement and the associated non-locality might prove to be of fundamental significance for physics -- such as the possibility that space-time itself might emerge from quantum entanglements. Bruce On Wednesday, May 31, 2017 at 12:01:23 PM UTC+10, Bruce wrote: On 30/05/2017 9:35 pm, Bruno Marchal wrote: > On 30 May 2017, at 11:28, Telmo Menezes wrote: > >> I get your point with decoherence. >> Again, I would say that it all depends on theories of mind. What does >> mind supervene on? Perhaps it is true that every single coupling with >> the environment prevents the current observer state to become >> compatible with other branches. But can we be sure? I feel that such >> certainties come from a strong belief in emergentism (which I cannot >> disprove, but find problematic). > > It is impossible to recohere the past, FAPP. > > But only FAPP. To make the blue T-rex interfereing with the red-T-rex, > we must erase the trace of particle interaction between the T-rex in > its whole light-cone, and this without forgetting the particles > "swallowed" by the black-holes, etc. It is just completely impossible, > but to derive from that the unicity of the past, is, it seems to me > (and you if I understood well) is invalid. I think the recoherence of paths that have completely decohered is more than just FAPP impossible, I think it is impossible in principle. One major problem with recoherence in general is that information leaks from the paths at the speed of light (as well as less slowly for other interactions). Since this vital information goes out along the light cone, it can never be recaptured and returned to the original interaction. Consequently, indispensable phase information is lost *in principle*, so the recoherence is,
Re: A thought on MWI and its alternative(s)
Thanks for these clarifications Bruce. I find your explanations to be very lucid and helpful - they also confirm my own understanding. IIRC, you weren't a particular fan of MWI when I last conversed with you on this list. I wonder if you'd care to comment on my original argument on this thread - which has of course now been swamped by the usual brawls. Does not a single history + the physical insignificance of the notion of a current moment mean that there is also only a single possible future? And if the future is predetermined in this way, isn't this a serious issue for single universe models of QM? How can the outcome of quantum events be both inevitable and random? On Wednesday, May 31, 2017 at 12:01:23 PM UTC+10, Bruce wrote: > > On 30/05/2017 9:35 pm, Bruno Marchal wrote: > > On 30 May 2017, at 11:28, Telmo Menezes wrote: > > > >> I get your point with decoherence. > >> Again, I would say that it all depends on theories of mind. What does > >> mind supervene on? Perhaps it is true that every single coupling with > >> the environment prevents the current observer state to become > >> compatible with other branches. But can we be sure? I feel that such > >> certainties come from a strong belief in emergentism (which I cannot > >> disprove, but find problematic). > > > > It is impossible to recohere the past, FAPP. > > > > But only FAPP. To make the blue T-rex interfereing with the red-T-rex, > > we must erase the trace of particle interaction between the T-rex in > > its whole light-cone, and this without forgetting the particles > > "swallowed" by the black-holes, etc. It is just completely impossible, > > but to derive from that the unicity of the past, is, it seems to me > > (and you if I understood well) is invalid. > > I think the recoherence of paths that have completely decohered is more > than just FAPP impossible, I think it is impossible in principle. One > major problem with recoherence in general is that information leaks from > the paths at the speed of light (as well as less slowly for other > interactions). Since this vital information goes out along the light > cone, it can never be recaptured and returned to the original > interaction. Consequently, indispensable phase information is lost *in > principle*, so the recoherence is, in general, impossible. Of course, > with carefully constructed systems, where the loss of information along > the light cone is prevented, recoherence is possible in special > circumstances, but not in general. > > From this, the uniqueness of the past of any decoherent history is > assured. So deriving the unicity (if I understand this use of the word) > is by no means invalid -- it is proved. Even if one encounters one of > those rare situations in which recoherence is achieved, that still does > not invalidate the uniqueness of the past history -- recoherence, if it > occurs, simply means that no new branches are formed at that point, so > the decoherent history remains unique. > > > >>> FWIW, you > >>> are expressing my own understanding of the situation: there can be no > >>> superposition of red and green screens or dinosaurs, or dead and > >>> live cats, > >>> because there can be no quantum superposition of macroscopic objects. > >>> Superpositions of wave functions are only possible for systems > >>> isolated from > >>> interaction with their environment, which is why quantum computers > >>> are so > >>> fricking hard to make: keeping aggregates of particles isolated from > >>> interactions with the surrounding environment is exponentially more > >>> difficult as the system grows in size. > >> > >> The main question for me is this: can two branches hold different > >> observer states, if they differ only by things that are not > >> observable? > > > > I would say no, intuitively. I would even say "no" just for the things > > not observed, even when observable. > > I previously answered Telmo's question in the affirmative, viz., two > fully decohered branches will hold different observer states, even if > the differences are not observed or observable. So if some trivial > physical event happens to your body, such as the decay of a K 40 nucleus > in your foot, this would not be noticeable, or even particularly > observable even if you were looking for it. But such an event causes at > least two branches to form every instant -- one in which the decay has > occurred, and one in which it has not. And since this is a beta decay, a > neutrino is lost along the light cone in every case of decay. Perfect > recombination of the branches is, then, according to the above argument, > not possible. You might object that this decay in my toe did not alter > my conscious state -- that is correct, but there are now two copies of > the Moscow man as in step 3, and these can evolve in different > directions while each remains unaware of the existence of the other. > They can never recomb
Re: A thought on MWI and its alternative(s)
On 30/05/2017 9:35 pm, Bruno Marchal wrote: On 30 May 2017, at 11:28, Telmo Menezes wrote: I get your point with decoherence. Again, I would say that it all depends on theories of mind. What does mind supervene on? Perhaps it is true that every single coupling with the environment prevents the current observer state to become compatible with other branches. But can we be sure? I feel that such certainties come from a strong belief in emergentism (which I cannot disprove, but find problematic). It is impossible to recohere the past, FAPP. But only FAPP. To make the blue T-rex interfereing with the red-T-rex, we must erase the trace of particle interaction between the T-rex in its whole light-cone, and this without forgetting the particles "swallowed" by the black-holes, etc. It is just completely impossible, but to derive from that the unicity of the past, is, it seems to me (and you if I understood well) is invalid. I think the recoherence of paths that have completely decohered is more than just FAPP impossible, I think it is impossible in principle. One major problem with recoherence in general is that information leaks from the paths at the speed of light (as well as less slowly for other interactions). Since this vital information goes out along the light cone, it can never be recaptured and returned to the original interaction. Consequently, indispensable phase information is lost *in principle*, so the recoherence is, in general, impossible. Of course, with carefully constructed systems, where the loss of information along the light cone is prevented, recoherence is possible in special circumstances, but not in general. From this, the uniqueness of the past of any decoherent history is assured. So deriving the unicity (if I understand this use of the word) is by no means invalid -- it is proved. Even if one encounters one of those rare situations in which recoherence is achieved, that still does not invalidate the uniqueness of the past history -- recoherence, if it occurs, simply means that no new branches are formed at that point, so the decoherent history remains unique. FWIW, you are expressing my own understanding of the situation: there can be no superposition of red and green screens or dinosaurs, or dead and live cats, because there can be no quantum superposition of macroscopic objects. Superpositions of wave functions are only possible for systems isolated from interaction with their environment, which is why quantum computers are so fricking hard to make: keeping aggregates of particles isolated from interactions with the surrounding environment is exponentially more difficult as the system grows in size. The main question for me is this: can two branches hold different observer states, if they differ only by things that are not observable? I would say no, intuitively. I would even say "no" just for the things not observed, even when observable. I previously answered Telmo's question in the affirmative, viz., two fully decohered branches will hold different observer states, even if the differences are not observed or observable. So if some trivial physical event happens to your body, such as the decay of a K 40 nucleus in your foot, this would not be noticeable, or even particularly observable even if you were looking for it. But such an event causes at least two branches to form every instant -- one in which the decay has occurred, and one in which it has not. And since this is a beta decay, a neutrino is lost along the light cone in every case of decay. Perfect recombination of the branches is, then, according to the above argument, not possible. You might object that this decay in my toe did not alter my conscious state -- that is correct, but there are now two copies of the Moscow man as in step 3, and these can evolve in different directions while each remains unaware of the existence of the other. They can never recombine and compare diaries! But this has to be tempered by the fact that any interaction will count as an observation, making super-exponentially hard to indeed recover a macroscopic superposition in the past, even the very close past. Of course, that might change the day we succeed in building a fault tolerant (topological perhaps) quantum computer. That will not help in the general case. Our future quantum computer might be able to delay decoherence for some useful finite time, but that still only retaines the superposition in the said computer, it does not help with recombination of decohered branches in general. Unfortunately, the T-rex missed them. yet, if a T-rex made a solid topological quantum qubit, in the state 0+1, we would have a past with 0, and a past with 1, as long as we don't look at it. I read, already a long time ago, some experimental evidence of temporal Bell's inequality going in this direction, and I think we don't even need to test them, as we get them with the usual Be
Re: A thought on MWI and its alternative(s)
On 30 May 2017 at 14:48, Bruno Marchal wrote: > > On 30 May 2017, at 14:10, Telmo Menezes wrote: > > On Tue, May 30, 2017 at 1:35 PM, Bruno Marchal wrote: >> >>> >>> On 30 May 2017, at 11:28, Telmo Menezes wrote: >>> >>> On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: > > > > On Tuesday, May 30, 2017 at 9:14:07 AM UTC+10, Bruce wrote: > >> >> >> On 29/05/2017 11:21 pm, Telmo Menezes wrote: >> >>> >>> On Mon, May 29, 2017 at 3:06 PM, Bruce Kellett >>> wrote: >>> On 29/05/2017 10:42 pm, Telmo Menezes wrote: > > On Mon, May 29, 2017 at 2:26 PM, Bruce Kellett > wrote: > >> >> On 29/05/2017 6:26 pm, Telmo Menezes wrote: >> >>> >>> On Mon, May 29, 2017 at 3:26 AM, Bruce Kellett >>> wrote: >>> I would say that there is only one history leading to our present state. Whether you take an MWI view or a collapse view, the wave function branches deterministically at every point, so if you follow your current twig back down to the main trunk etc, there will be a unique path. >>> >>> I don't think we can say we are in a specific twig. Many things >>> about >>> out present state are unknown/undefined. I can imagine that there >>> are >>> many well-defined present states that are compatible with my >>> current >>> subjective state. >>> >> >> >> Sure, but we are talking about wave functions, not subjective >> states. >> > > Replace "subjective" with "incomplete knowledge". > Doesn't help. Of course our knowledge is incomplete, the wave function isn't completely known either -- but the result of specific measurements are what is at stake here, and they are known quantum states. >>> >>> In my view, what's at stake here is the possibility of latent >>> variables having some degree of freedom leading to the same macro >>> states (provided that there is incomplete information about these >>> macro states, as is the case for humans). >>> >> >> >> I am still not clear about what you are trying to say. It is certainly >> true that many internal details of your microscopic organization could >> be changed and you wouldn't know the difference. For that matter, an >> almost infinite number of details about the rest of the universe could >> be different and you would still be the same. But that is not what we >> were talking about. I understood the issue to be whether there was a >> unique past, or whether several (or many) different paths lead to our >> current state. The determinism of the Schrödinger equation would >> suggest >> that your unique state has a unique history. Variations in microscopic >> details of with your body, or the universe, would correspond to >> different decohered worlds with no overlap with our world. So while >> such >> variations are possible, they do not amount to multiple histories >> leading to our current state. We don't need to know that state in >> detail >> to be able to argue the consequences of determinism. >> >> In fact you can perform a quantum erasure experiment, and be sure >>> that >>> your current state goes through at least two different shortest >>> paths >>> to the root, and it becomes nonsensical to say that one is the >>> "correct" one. I don't think anyone knows how far this can go >>> into >>> the >>> macroscopic world, but I don't see any reason to believe that it >>> doesn't. >>> >> >> >> I don't understand what you think you are getting in a quantum >> erasure >> experiment. If the "which way" information that was gathered is >> erased, >> normal interference patterns are seen in the double slit >> situation. >> The >> two >> paths (through the separate slits) are in unresolved superposition >> until >> they hit the detector, when decoherence takes over. There are not >> two >> separate worlds, and your state is the result of the superposed >> paths, >> not >> of either path separately. There is no ambiguity about which the >> the >> "correct" path -- neither is, both contribute equally. >> > > I would say that the delayed choice version of the experiment makes > it > clear that there are two possible pasts that lead to the same > present >>>
Re: Answers to David 4
On 30 May 2017 at 13:05, Bruno Marchal wrote: > > On 29 May 2017, at 13:42, David Nyman wrote: > > > > On 29 May 2017 at 05:27, Brent Meeker wrote: > >> >> >> On 5/28/2017 3:40 AM, David Nyman wrote: >> >> >> >> On 28 May 2017 5:52 a.m., "Brent Meeker" wrote: >> >> >> >> On 5/27/2017 3:20 PM, David Nyman wrote: >> >> I think what is meant by the reversal is clear enough. The forward >>> hypothesis, mechanism, is that the realization of some information >>> processing in the brain, or other physical system, instantiates >>> consciousness. The reverse, platonism, is that all computations exist and >>> hence among them will be computations that instantiate all possible >>> conscious thoughts. >>> >>> And among all those thoughts there will be some that instantiate exactly >>> those thoughts we have, including those thoughts of perceiving and >>> inferring a physical world and other people. Thoughts are related by >>> threads of computation and consequently they can be classified into some >>> that can be proven and some that are true but can't be proven. One might >>> hypothesize that this division corresponds to what is thought and is >>> communicable versus what is thought but can't be communicated, i.e. the >>> internal thoughts of consciousness. >>> >> >> Yes, although I think you could be more explicit that "those thoughts >> of perceiving and inferring a physical world and other people" must >> encompass the entire spectrum of observable physical phenomena. The >> relevant computation must also precisely mirror the transformational >> schemas of physics. >> >> >> But that's the rub. If the physics is instantiated by the UD >> computation, is it really a "reversal" >> >> >> Yes. You keep missing the point that the reversal is already with the >> 'psychology' of machinery at a fundamental explanatory level, >> >> >> No, the fundamental explanatory level is the set of all possible >> computations - as might be executed in the abstract by a UD. From this >> plethora we are to extract in some sense experiences AND the physics of >> which they are experiences. >> > > Yes, so the explanatory priority is now that of "we are to extract" over > "the physics of which they are experiences". Or in short, subject precedes > object in the explanation. That's the reversal. > > > Maybe it is here that I suspect that we might still differ a little bit, > or not in case you mean "physical object" for "object". > Yes, That's what I mean. Sometimes perhaps I can be a little too short. But on the other hand at times when I ramble on in an attempt to avoid ambiguities Brent tells me I'm being long-winded :( > I would say that subjects precedes physical objects > , > as physics becomes a first person plural notion. > Exactly > But with computationalism, to just gives sense to that word, we have to > admit that the number objects still precedes (in some logical sense) the > subject, which arises from the infinitely many computations which supports > its self-referential modes. > Well I guess the way I'd put it is that their abstract or ontological component is already 'there' (i.e. assumed) in a certain objective sense, but their 'observable' or epistemological component can only be realised (i.e. made true) in terms of a point-of-view. > > We can place the natural object in the mind of the God-subject, but that > would be a bit ad hoc, > Possibly, but in a monopsychic sense they *are* all in the mind of the inner God-subject. That's one of the reasons I find that particular heuristic intuitively helpful. I guess it's my version of the Wittgenstein ladder. But don't worry, I can always let go of it. I hope. > even if for the numbers+addition+multiplication, we can only explains > them by "God made them", in the sense that we cannot recover them by > assuming less than anything Turing equivalent with them. > I can't think of anything less, offhand. > Sorry for splitting the airs, I guess, > Split away! It's hairs, by the way :) David > > Bruno > > > > >> such that in a sense one can think of the entirety of experience in terms >> of that of a single type of psychological agent. This is then the >> subjective filter that effectively constrains stable, pervasive and thereby >> (crucially) *consistently memorable* experiences from the rest of the >> computational Babel. And the consequence of that subjective filtration, in >> conjunction with the transformational computation that effects that its >> very stabilisation, then comprises the effective physics of the >> experiencer, with the caveats already mentioned. So subject precedes object >> in explaining the appearance of physics. That is the reversal. And it is >> necessitated by the not inconsiderable problem that the alternative >> explanatory order cannot help but *omit the explanation of the experiencer >> and its experiences*. >> >> or is it just a Church-Turing version of Tegmark, i.e. replacing the >> equations of quantum field
Re: A thought on MWI and its alternative(s)
On 30 May 2017, at 14:10, Telmo Menezes wrote: On Tue, May 30, 2017 at 1:35 PM, Bruno Marchal wrote: On 30 May 2017, at 11:28, Telmo Menezes wrote: On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: On Tuesday, May 30, 2017 at 9:14:07 AM UTC+10, Bruce wrote: On 29/05/2017 11:21 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 3:06 PM, Bruce Kellett wrote: On 29/05/2017 10:42 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 2:26 PM, Bruce Kellett wrote: On 29/05/2017 6:26 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 3:26 AM, Bruce Kellett wrote: I would say that there is only one history leading to our present state. Whether you take an MWI view or a collapse view, the wave function branches deterministically at every point, so if you follow your current twig back down to the main trunk etc, there will be a unique path. I don't think we can say we are in a specific twig. Many things about out present state are unknown/undefined. I can imagine that there are many well-defined present states that are compatible with my current subjective state. Sure, but we are talking about wave functions, not subjective states. Replace "subjective" with "incomplete knowledge". Doesn't help. Of course our knowledge is incomplete, the wave function isn't completely known either -- but the result of specific measurements are what is at stake here, and they are known quantum states. In my view, what's at stake here is the possibility of latent variables having some degree of freedom leading to the same macro states (provided that there is incomplete information about these macro states, as is the case for humans). I am still not clear about what you are trying to say. It is certainly true that many internal details of your microscopic organization could be changed and you wouldn't know the difference. For that matter, an almost infinite number of details about the rest of the universe could be different and you would still be the same. But that is not what we were talking about. I understood the issue to be whether there was a unique past, or whether several (or many) different paths lead to our current state. The determinism of the Schrödinger equation would suggest that your unique state has a unique history. Variations in microscopic details of with your body, or the universe, would correspond to different decohered worlds with no overlap with our world. So while such variations are possible, they do not amount to multiple histories leading to our current state. We don't need to know that state in detail to be able to argue the consequences of determinism. In fact you can perform a quantum erasure experiment, and be sure that your current state goes through at least two different shortest paths to the root, and it becomes nonsensical to say that one is the "correct" one. I don't think anyone knows how far this can go into the macroscopic world, but I don't see any reason to believe that it doesn't. I don't understand what you think you are getting in a quantum erasure experiment. If the "which way" information that was gathered is erased, normal interference patterns are seen in the double slit situation. The two paths (through the separate slits) are in unresolved superposition until they hit the detector, when decoherence takes over. There are not two separate worlds, and your state is the result of the superposed paths, not of either path separately. There is no ambiguity about which the the "correct" path -- neither is, both contribute equally. I would say that the delayed choice version of the experiment makes it clear that there are two possible pasts that lead to the same present state -- they differ by one bit of information. That is not what is implied by delayed choice quantum erasure. Whether an interference pattern is seen or not is determined by whether the "which way" information is erased or not. But whether it is or not, the interference is only seen when coincidence measurements tell one which photons to count. And the timing information necessary for coincidence determination is available only *after* all decisions about erasure or not have been made, whether that decision is made before or after the other photon of the entangled pair has reached its detector. "Delayed choice" is perhaps a misleading phrase in this context, and it does not lead to an ambiguity of path -- it merely tells whether there was an intact superposition or not. I know, this is not what I am trying to say. I'll choose something much simpler: Suppose there is a computer running in an empty room. This computer is connected to a random number generator. At some point it uses the random value to decide if it's going to show a screen that is all green or all red. Nobody witnesses it. If the random number generator is based on quantum randomness, then in principle you w
Re: A thought on MWI and its alternative(s)
On Tue, May 30, 2017 at 1:55 PM, Bruce Kellett wrote: > On 30/05/2017 7:28 pm, Telmo Menezes wrote: >> >> On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: >>> >>> So you are talking different >>> languages. >> >> Not sure I agree. We are perhaps implicitly assuming different theories of >> mind. >> >>> I don't know if Telmo is aware or not of the conventional view of >>> decoherence - that it is a matter of the spread of information into the >>> environment by means of physical interactions between particles. Telmo's >>> musings about the effect of destroying memory (could it change the >>> measure >>> of different futures?) clearly expresses this subjectivist view. >> >> I get your point with decoherence. >> Again, I would say that it all depends on theories of mind. What does >> mind supervene on? Perhaps it is true that every single coupling with >> the environment prevents the current observer state to become >> compatible with other branches. But can we be sure? I feel that such >> certainties come from a strong belief in emergentism (which I cannot >> disprove, but find problematic). >> >>> FWIW, you >>> are expressing my own understanding of the situation: there can be no >>> superposition of red and green screens or dinosaurs, or dead and live >>> cats, >>> because there can be no quantum superposition of macroscopic objects. >>> Superpositions of wave functions are only possible for systems isolated >>> from >>> interaction with their environment, which is why quantum computers are so >>> fricking hard to make: keeping aggregates of particles isolated from >>> interactions with the surrounding environment is exponentially more >>> difficult as the system grows in size. >> >> The main question for me is this: can two branches hold different >> observer states, if they differ only by things that are not >> observable? > > > Yes, but I think we should be talking about quantum mechanics here, and that > is a well-defined physical theory that is not really concerned with any > theory of mind. Ok. > There have been some interpretations of quantum mechanics > that ascribe the mind a role in the collapse of the wave function, or some > such; and some who re-interpret the many worlds idea as a 'many minds' > picture; but these issues do not seem to be relevant to any discussion of > the quantum formalism itself. > > In the discussions on this list, it seems that MWI is the dominant > understanding of QM. That is fine, one can certainly talk about things in > this way. But it should be borne in mind that MWI is actually equivalent to > the less well known decoherent histories approach. I guess that in my > comments earlier in this thread, I was emphasizing the decoherent histories > understanding. In many worlds, worlds separate off when irreversible > interactions with the environment zero out the interference terms between > different elements in the superposition. This happens inevitably all the > time, and measurements, or observers, play no essential role in the process. > Each world of the MWI is thus produced by the process of decoherence acting > on the initial quantum state. Each decoherent line then evolves on to > produce its own set of future decoherent lines. Following through any > particular line gives a decoherent history -- one for each world of the MWI. > > Since the processes of decoherence and the formation of histories or worlds > are independent of the observer and of the mind, it is clearly possible that > different branches (or histories) can differ only by things that are not > observed, or even not observable. And this is just a matter of the formalism > of quantum mechanics -- it has nothing to do with any theory of mind. The > only thing that I would say, though, is that your theory of mind, and your > theory of the origin of physics, must be compatible with this understanding > of quantum mechanics -- or else your theory of mind/physics is falsified. > > > Bruce > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: A thought on MWI and its alternative(s)
On Tue, May 30, 2017 at 1:35 PM, Bruno Marchal wrote: > > On 30 May 2017, at 11:28, Telmo Menezes wrote: > >> On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: >>> >>> >>> >>> On Tuesday, May 30, 2017 at 9:14:07 AM UTC+10, Bruce wrote: On 29/05/2017 11:21 pm, Telmo Menezes wrote: > > On Mon, May 29, 2017 at 3:06 PM, Bruce Kellett > wrote: >> >> On 29/05/2017 10:42 pm, Telmo Menezes wrote: >>> >>> On Mon, May 29, 2017 at 2:26 PM, Bruce Kellett >>> wrote: On 29/05/2017 6:26 pm, Telmo Menezes wrote: > > On Mon, May 29, 2017 at 3:26 AM, Bruce Kellett > wrote: >> >> I would say that there is only one history leading to our present >> state. >> Whether you take an MWI view or a collapse view, the wave function >> branches >> deterministically at every point, so if you follow your current >> twig >> back >> down to the main trunk etc, there will be a unique path. > > I don't think we can say we are in a specific twig. Many things > about > out present state are unknown/undefined. I can imagine that there > are > many well-defined present states that are compatible with my > current > subjective state. Sure, but we are talking about wave functions, not subjective states. >>> >>> Replace "subjective" with "incomplete knowledge". >> >> >> Doesn't help. Of course our knowledge is incomplete, the wave function >> isn't >> completely known either -- but the result of specific measurements are >> what >> is at stake here, and they are known quantum states. > > In my view, what's at stake here is the possibility of latent > variables having some degree of freedom leading to the same macro > states (provided that there is incomplete information about these > macro states, as is the case for humans). I am still not clear about what you are trying to say. It is certainly true that many internal details of your microscopic organization could be changed and you wouldn't know the difference. For that matter, an almost infinite number of details about the rest of the universe could be different and you would still be the same. But that is not what we were talking about. I understood the issue to be whether there was a unique past, or whether several (or many) different paths lead to our current state. The determinism of the Schrödinger equation would suggest that your unique state has a unique history. Variations in microscopic details of with your body, or the universe, would correspond to different decohered worlds with no overlap with our world. So while such variations are possible, they do not amount to multiple histories leading to our current state. We don't need to know that state in detail to be able to argue the consequences of determinism. > In fact you can perform a quantum erasure experiment, and be sure > that > your current state goes through at least two different shortest > paths > to the root, and it becomes nonsensical to say that one is the > "correct" one. I don't think anyone knows how far this can go into > the > macroscopic world, but I don't see any reason to believe that it > doesn't. I don't understand what you think you are getting in a quantum erasure experiment. If the "which way" information that was gathered is erased, normal interference patterns are seen in the double slit situation. The two paths (through the separate slits) are in unresolved superposition until they hit the detector, when decoherence takes over. There are not two separate worlds, and your state is the result of the superposed paths, not of either path separately. There is no ambiguity about which the the "correct" path -- neither is, both contribute equally. >>> >>> I would say that the delayed choice version of the experiment makes >>> it >>> clear that there are two possible pasts that lead to the same present >>> state -- they differ by one bit of information. >> >> >> That is not what is implied by delayed choice quantum erasure. Whether >> an >> interference pattern is seen or not is determined by whether the >> "which >> way" >> information is erased or not. But whether it is or not, the >> interference is >> only seen when coincidence measurements tell one which photons to >> count. And >> the timing information necessary for coincidence determination is >> available >> only *after* all decisions about erasure or not ha
Re: Answers to David 4
On 29 May 2017, at 13:42, David Nyman wrote: On 29 May 2017 at 05:27, Brent Meeker wrote: On 5/28/2017 3:40 AM, David Nyman wrote: On 28 May 2017 5:52 a.m., "Brent Meeker" wrote: On 5/27/2017 3:20 PM, David Nyman wrote: I think what is meant by the reversal is clear enough. The forward hypothesis, mechanism, is that the realization of some information processing in the brain, or other physical system, instantiates consciousness. The reverse, platonism, is that all computations exist and hence among them will be computations that instantiate all possible conscious thoughts. And among all those thoughts there will be some that instantiate exactly those thoughts we have, including those thoughts of perceiving and inferring a physical world and other people. Thoughts are related by threads of computation and consequently they can be classified into some that can be proven and some that are true but can't be proven. One might hypothesize that this division corresponds to what is thought and is communicable versus what is thought but can't be communicated, i.e. the internal thoughts of consciousness. Yes, although I think you could be more explicit that "those thoughts of perceiving and inferring a physical world and other people" must encompass the entire spectrum of observable physical phenomena. The relevant computation must also precisely mirror the transformational schemas of physics. But that's the rub. If the physics is instantiated by the UD computation, is it really a "reversal" Yes. You keep missing the point that the reversal is already with the 'psychology' of machinery at a fundamental explanatory level, No, the fundamental explanatory level is the set of all possible computations - as might be executed in the abstract by a UD. From this plethora we are to extract in some sense experiences AND the physics of which they are experiences. Yes, so the explanatory priority is now that of "we are to extract" over "the physics of which they are experiences". Or in short, subject precedes object in the explanation. That's the reversal. Maybe it is here that I suspect that we might still differ a little bit, or not in case you mean "physical object" for "object". I would say that subjects precedes physical objects, as physics becomes a first person plural notion. But with computationalism, to just gives sense to that word, we have to admit that the number objects still precedes (in some logical sense) the subject, which arises from the infinitely many computations which supports its self-referential modes. We can place the natural object in the mind of the God-subject, but that would be a bit ad hoc, even if for the numbers+addition +multiplication, we can only explains them by "God made them", in the sense that we cannot recover them by assuming less than anything Turing equivalent with them. Sorry for splitting the airs, I guess, Bruno such that in a sense one can think of the entirety of experience in terms of that of a single type of psychological agent. This is then the subjective filter that effectively constrains stable, pervasive and thereby (crucially) *consistently memorable* experiences from the rest of the computational Babel. And the consequence of that subjective filtration, in conjunction with the transformational computation that effects that its very stabilisation, then comprises the effective physics of the experiencer, with the caveats already mentioned. So subject precedes object in explaining the appearance of physics. That is the reversal. And it is necessitated by the not inconsiderable problem that the alternative explanatory order cannot help but *omit the explanation of the experiencer and its experiences*. or is it just a Church-Turing version of Tegmark, i.e. replacing the equations of quantum field theory with some computational sequences that have the same effect at the level of our experience. But why be so cavalier about "the level of our experience"? It's that very level that is omitted or merely taken for granted in the conventional explanatory order. Remember that the point of departure for all this is the computational theory of *mind*. Nonetheless, the price of the ticket turns out to be a computational theory of everything. Should this surprise us? But it's not clear to me that it has *mind* as fundamental. Mind is to be explained by relations of provability (which doesn't seem very plausible - but maybe). Well, mind here is explained in a sort of duality of provability and truth, or externality and internality. The internal or 'qualitative' aspect is captured both by its incommunicability (as seen from the 'outside') and its indubitability (as seen from the 'inside). The fundamental stuff is all possible computations, or arithmetic. If so, in this characterisation there would
Re: A thought on MWI and its alternative(s)
On 30/05/2017 7:28 pm, Telmo Menezes wrote: On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: So you are talking different languages. Not sure I agree. We are perhaps implicitly assuming different theories of mind. I don't know if Telmo is aware or not of the conventional view of decoherence - that it is a matter of the spread of information into the environment by means of physical interactions between particles. Telmo's musings about the effect of destroying memory (could it change the measure of different futures?) clearly expresses this subjectivist view. I get your point with decoherence. Again, I would say that it all depends on theories of mind. What does mind supervene on? Perhaps it is true that every single coupling with the environment prevents the current observer state to become compatible with other branches. But can we be sure? I feel that such certainties come from a strong belief in emergentism (which I cannot disprove, but find problematic). FWIW, you are expressing my own understanding of the situation: there can be no superposition of red and green screens or dinosaurs, or dead and live cats, because there can be no quantum superposition of macroscopic objects. Superpositions of wave functions are only possible for systems isolated from interaction with their environment, which is why quantum computers are so fricking hard to make: keeping aggregates of particles isolated from interactions with the surrounding environment is exponentially more difficult as the system grows in size. The main question for me is this: can two branches hold different observer states, if they differ only by things that are not observable? Yes, but I think we should be talking about quantum mechanics here, and that is a well-defined physical theory that is not really concerned with any theory of mind. There have been some interpretations of quantum mechanics that ascribe the mind a role in the collapse of the wave function, or some such; and some who re-interpret the many worlds idea as a 'many minds' picture; but these issues do not seem to be relevant to any discussion of the quantum formalism itself. In the discussions on this list, it seems that MWI is the dominant understanding of QM. That is fine, one can certainly talk about things in this way. But it should be borne in mind that MWI is actually equivalent to the less well known decoherent histories approach. I guess that in my comments earlier in this thread, I was emphasizing the decoherent histories understanding. In many worlds, worlds separate off when irreversible interactions with the environment zero out the interference terms between different elements in the superposition. This happens inevitably all the time, and measurements, or observers, play no essential role in the process. Each world of the MWI is thus produced by the process of decoherence acting on the initial quantum state. Each decoherent line then evolves on to produce its own set of future decoherent lines. Following through any particular line gives a decoherent history -- one for each world of the MWI. Since the processes of decoherence and the formation of histories or worlds are independent of the observer and of the mind, it is clearly possible that different branches (or histories) can differ only by things that are not observed, or even not observable. And this is just a matter of the formalism of quantum mechanics -- it has nothing to do with any theory of mind. The only thing that I would say, though, is that your theory of mind, and your theory of the origin of physics, must be compatible with this understanding of quantum mechanics -- or else your theory of mind/physics is falsified. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: Answer to David 3
On 30 May 2017 at 12:10, Bruno Marchal wrote: > > On 29 May 2017, at 20:30, David Nyman wrote: > > On 29 May 2017 at 17:40, Bruno Marchal wrote: > >> >> On 28 May 2017, at 19:32, David Nyman wrote: >> >> On 28 May 2017 at 18:02, Bruno Marchal wrote: >> >>> >>> On 28 May 2017, at 16:53, David Nyman wrote: >>> >>> >>> On 28 May 2017 at 14:38, Bruno Marchal wrote: >>> >>> Yes, that's what I meant. >>> >>> It is there that many confuse: the number s(0), the Gödel number of s(0), the Gödel number of the Gödel number of s(0), which plays very different role, all important, when we translate UDA in arithmetic. Of course, this needs a good familiarity with the understanding of the difference between language, theories, and truth (models). >>> >>> Indeed :( >>> >>> >>> Well no, I still don't quite understand. I didn't mean that we couldn't >>> accept a physical universe as 'true' in the sense of a brute fact. What I >>> meant was in that case how would a notion of truth be related to the >>> perception of that world? Would it merely be an identity relation between >>> it being true that such a world was primitive and consequently true that >>> this also entailed a perception of it on behalf of a subject? If so, I >>> wouldn't find that either coherent or intelligible. >>> >>> >>> It would make the identity-thesis consistent. I agree it is not really >>> intelligible, but the actual infinities would could consistently be used to >>> justify the magic. That crazy (I think we share the intuition here) move is >>> no more available when we assume mechanism, as we inherit from arithmetic >>> infinitely many copies, and we have to take them into account. >>> >> >> Yes, and then in that case Brent really would be correct that an >> 'engineering solution' would be about as close as we could get. >> >> >> Yes. It is akin to the usual use of mechanism by atheists, to dismiss all >> "religious" notions, from God to ... consciousness, and which lead to a >> sort of eliminativism. >> > > Yes, it even seems to lead to a kind of reactive or defensive dogmatism. > I appreciate very much Feynman's suggestion that science is a method of > checking that we aren't fooling ourselves. But of course we must remember > that this method should also be applied to itself. > > >> Somehow, mysteriously the mind and the brain becomes identifiable, by >> being both actual non duplicable infinite entities. Typically, you can no >> more say yes to the doctors, or if someone say yes, they can invoke that >> infinities, as there are mysterious anyway. Everything becomes magic here: >> the physical universe, consciousness, etc. It looks like a fairy tale >> identifying all the mysteries, but logically, it can make sense by pushing >> the substitution level in the infinitely low, if that can make sense. >> > > Yes, it can make sense. In another, perhaps related sense the > 'substitution' level is almost infinitely low, if indeed the 'tuning' were > fine enough such that only a unique physics can be associated with our own > existence. But nevertheless the assumption of CTM implies that the > substitution level of our minds isn't necessarily that low, but could be > approximated classically by a digital prosthesis. The doctor will have a > lot to answer for. > > > That moves seems to me premature to say the least, but we have to find a >> difference between quantum logic, and the quantum logic associated to Z1* >> to get a clue on the necessity of such moves. >> > > I won't hold my breath. > > > >> Usually, the scientists tries to discard the commitment into actual, >> physical and psychological entities. >> > > Understandably perhaps. > > > > I would say that this is the only right attitude. The whole point of doing > "scientific metaphysics or theology" is to be agnostic all the times, and > not to assume any answers, at any time. Only hypothesis and deductions, and > interpretation means, if possible with experimental verification means. > > > > > > > >> I'm not sure I fully understand you here. My intention recently has been >>> to clarify >>> in a certain way >>> an explanatory distinction between ontology and epistemology in terms of >>> theory in general. In this way of parsing the thing any 'observable', even >>> if viewed from the imaginary Wittgenstein's ladder perspective of 3p, is >>> part of the epistemological component of the theory. To simplify a bit, >>> anything that requires interpretation and hence explanation is an inference >>> from, not a part of, the assumptive ontology, which is by definition *not* >>> itself in need of >>> such >>> explanation. Consequently it was that ontology that I referred to as 0p. >>> >>> >>> OK. But when making the mechanist assumption explicit, that 0p becomes >>> 3p, or that 3p becomes 0p, (unlike the apparent "3p physics", which becomes >>> 1p plural). >>> >> >> I'm OK with this. I think that people sometimes forget the cr
Re: A thought on MWI and its alternative(s)
On 30 May 2017, at 11:28, Telmo Menezes wrote: On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: On Tuesday, May 30, 2017 at 9:14:07 AM UTC+10, Bruce wrote: On 29/05/2017 11:21 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 3:06 PM, Bruce Kellett wrote: On 29/05/2017 10:42 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 2:26 PM, Bruce Kellett wrote: On 29/05/2017 6:26 pm, Telmo Menezes wrote: On Mon, May 29, 2017 at 3:26 AM, Bruce Kellett wrote: I would say that there is only one history leading to our present state. Whether you take an MWI view or a collapse view, the wave function branches deterministically at every point, so if you follow your current twig back down to the main trunk etc, there will be a unique path. I don't think we can say we are in a specific twig. Many things about out present state are unknown/undefined. I can imagine that there are many well-defined present states that are compatible with my current subjective state. Sure, but we are talking about wave functions, not subjective states. Replace "subjective" with "incomplete knowledge". Doesn't help. Of course our knowledge is incomplete, the wave function isn't completely known either -- but the result of specific measurements are what is at stake here, and they are known quantum states. In my view, what's at stake here is the possibility of latent variables having some degree of freedom leading to the same macro states (provided that there is incomplete information about these macro states, as is the case for humans). I am still not clear about what you are trying to say. It is certainly true that many internal details of your microscopic organization could be changed and you wouldn't know the difference. For that matter, an almost infinite number of details about the rest of the universe could be different and you would still be the same. But that is not what we were talking about. I understood the issue to be whether there was a unique past, or whether several (or many) different paths lead to our current state. The determinism of the Schrödinger equation would suggest that your unique state has a unique history. Variations in microscopic details of with your body, or the universe, would correspond to different decohered worlds with no overlap with our world. So while such variations are possible, they do not amount to multiple histories leading to our current state. We don't need to know that state in detail to be able to argue the consequences of determinism. In fact you can perform a quantum erasure experiment, and be sure that your current state goes through at least two different shortest paths to the root, and it becomes nonsensical to say that one is the "correct" one. I don't think anyone knows how far this can go into the macroscopic world, but I don't see any reason to believe that it doesn't. I don't understand what you think you are getting in a quantum erasure experiment. If the "which way" information that was gathered is erased, normal interference patterns are seen in the double slit situation. The two paths (through the separate slits) are in unresolved superposition until they hit the detector, when decoherence takes over. There are not two separate worlds, and your state is the result of the superposed paths, not of either path separately. There is no ambiguity about which the the "correct" path -- neither is, both contribute equally. I would say that the delayed choice version of the experiment makes it clear that there are two possible pasts that lead to the same present state -- they differ by one bit of information. That is not what is implied by delayed choice quantum erasure. Whether an interference pattern is seen or not is determined by whether the "which way" information is erased or not. But whether it is or not, the interference is only seen when coincidence measurements tell one which photons to count. And the timing information necessary for coincidence determination is available only *after* all decisions about erasure or not have been made, whether that decision is made before or after the other photon of the entangled pair has reached its detector. "Delayed choice" is perhaps a misleading phrase in this context, and it does not lead to an ambiguity of path -- it merely tells whether there was an intact superposition or not. I know, this is not what I am trying to say. I'll choose something much simpler: Suppose there is a computer running in an empty room. This computer is connected to a random number generator. At some point it uses the random value to decide if it's going to show a screen that is all green or all red. Nobody witnesses it. If the random number generator is based on quantum randomness, then in principle you will get a superposition of red and green screens, but this is like the question as to whether we see a superposition of live and dead cats
Re: Answer to David 3
On 29 May 2017, at 20:30, David Nyman wrote: On 29 May 2017 at 17:40, Bruno Marchal wrote: On 28 May 2017, at 19:32, David Nyman wrote: On 28 May 2017 at 18:02, Bruno Marchal wrote: On 28 May 2017, at 16:53, David Nyman wrote: On 28 May 2017 at 14:38, Bruno Marchal wrote: Yes, that's what I meant. It is there that many confuse: the number s(0), the Gödel number of s(0), the Gödel number of the Gödel number of s(0), which plays very different role, all important, when we translate UDA in arithmetic. Of course, this needs a good familiarity with the understanding of the difference between language, theories, and truth (models). Indeed :( Well no, I still don't quite understand. I didn't mean that we couldn't accept a physical universe as 'true' in the sense of a brute fact. What I meant was in that case how would a notion of truth be related to the perception of that world? Would it merely be an identity relation between it being true that such a world was primitive and consequently true that this also entailed a perception of it on behalf of a subject? If so, I wouldn't find that either coherent or intelligible. It would make the identity-thesis consistent. I agree it is not really intelligible, but the actual infinities would could consistently be used to justify the magic. That crazy (I think we share the intuition here) move is no more available when we assume mechanism, as we inherit from arithmetic infinitely many copies, and we have to take them into account. Yes, and then in that case Brent really would be correct that an 'engineering solution' would be about as close as we could get. Yes. It is akin to the usual use of mechanism by atheists, to dismiss all "religious" notions, from God to ... consciousness, and which lead to a sort of eliminativism. Yes, it even seems to lead to a kind of reactive or defensive dogmatism. I appreciate very much Feynman's suggestion that science is a method of checking that we aren't fooling ourselves. But of course we must remember that this method should also be applied to itself. Somehow, mysteriously the mind and the brain becomes identifiable, by being both actual non duplicable infinite entities. Typically, you can no more say yes to the doctors, or if someone say yes, they can invoke that infinities, as there are mysterious anyway. Everything becomes magic here: the physical universe, consciousness, etc. It looks like a fairy tale identifying all the mysteries, but logically, it can make sense by pushing the substitution level in the infinitely low, if that can make sense. Yes, it can make sense. In another, perhaps related sense the 'substitution' level is almost infinitely low, if indeed the 'tuning' were fine enough such that only a unique physics can be associated with our own existence. But nevertheless the assumption of CTM implies that the substitution level of our minds isn't necessarily that low, but could be approximated classically by a digital prosthesis. The doctor will have a lot to answer for. That moves seems to me premature to say the least, but we have to find a difference between quantum logic, and the quantum logic associated to Z1* to get a clue on the necessity of such moves. I won't hold my breath. Usually, the scientists tries to discard the commitment into actual, physical and psychological entities. Understandably perhaps. I would say that this is the only right attitude. The whole point of doing "scientific metaphysics or theology" is to be agnostic all the times, and not to assume any answers, at any time. Only hypothesis and deductions, and interpretation means, if possible with experimental verification means. I'm not sure I fully understand you here. My intention recently has been to clarify in a certain way an explanatory distinction between ontology and epistemology in terms of theory in general. In this way of parsing the thing any 'observable', even if viewed from the imaginary Wittgenstein's ladder perspective of 3p, is part of the epistemological component of the theory. To simplify a bit, anything that requires interpretation and hence explanation is an inference from, not a part of, the assumptive ontology, which is by definition *not* itself in need of such explanation. Consequently it was that ontology that I referred to as 0p. OK. But when making the mechanist assumption explicit, that 0p becomes 3p, or that 3p becomes 0p, (unlike the apparent "3p physics", which becomes 1p plural). I'm OK with this. I think that people sometimes forget the crucial distinction between 3p and 1p-plural, by referring to epistemological constructs as 3p. That's why I thought of the Wittgenstein ladder as a reminder of the implicit adoption of a privileged interpretation in this case. It seems to be quite difficult sometimes for people to intuit t
Re: A thought on MWI and its alternative(s)
On Tue, May 30, 2017 at 3:47 AM, Pierz wrote: > > > On Tuesday, May 30, 2017 at 9:14:07 AM UTC+10, Bruce wrote: >> >> On 29/05/2017 11:21 pm, Telmo Menezes wrote: >> > On Mon, May 29, 2017 at 3:06 PM, Bruce Kellett >> > wrote: >> >> On 29/05/2017 10:42 pm, Telmo Menezes wrote: >> >>> On Mon, May 29, 2017 at 2:26 PM, Bruce Kellett >> >>> wrote: >> On 29/05/2017 6:26 pm, Telmo Menezes wrote: >> > On Mon, May 29, 2017 at 3:26 AM, Bruce Kellett >> > wrote: >> >> I would say that there is only one history leading to our present >> >> state. >> >> Whether you take an MWI view or a collapse view, the wave function >> >> branches >> >> deterministically at every point, so if you follow your current >> >> twig >> >> back >> >> down to the main trunk etc, there will be a unique path. >> > I don't think we can say we are in a specific twig. Many things >> > about >> > out present state are unknown/undefined. I can imagine that there >> > are >> > many well-defined present states that are compatible with my current >> > subjective state. >> >> Sure, but we are talking about wave functions, not subjective states. >> >>> Replace "subjective" with "incomplete knowledge". >> >> >> >> Doesn't help. Of course our knowledge is incomplete, the wave function >> >> isn't >> >> completely known either -- but the result of specific measurements are >> >> what >> >> is at stake here, and they are known quantum states. >> > In my view, what's at stake here is the possibility of latent >> > variables having some degree of freedom leading to the same macro >> > states (provided that there is incomplete information about these >> > macro states, as is the case for humans). >> >> I am still not clear about what you are trying to say. It is certainly >> true that many internal details of your microscopic organization could >> be changed and you wouldn't know the difference. For that matter, an >> almost infinite number of details about the rest of the universe could >> be different and you would still be the same. But that is not what we >> were talking about. I understood the issue to be whether there was a >> unique past, or whether several (or many) different paths lead to our >> current state. The determinism of the Schrödinger equation would suggest >> that your unique state has a unique history. Variations in microscopic >> details of with your body, or the universe, would correspond to >> different decohered worlds with no overlap with our world. So while such >> variations are possible, they do not amount to multiple histories >> leading to our current state. We don't need to know that state in detail >> to be able to argue the consequences of determinism. >> >> > In fact you can perform a quantum erasure experiment, and be sure >> > that >> > your current state goes through at least two different shortest >> > paths >> > to the root, and it becomes nonsensical to say that one is the >> > "correct" one. I don't think anyone knows how far this can go into >> > the >> > macroscopic world, but I don't see any reason to believe that it >> > doesn't. >> >> I don't understand what you think you are getting in a quantum >> erasure >> experiment. If the "which way" information that was gathered is >> erased, >> normal interference patterns are seen in the double slit situation. >> The >> two >> paths (through the separate slits) are in unresolved superposition >> until >> they hit the detector, when decoherence takes over. There are not two >> separate worlds, and your state is the result of the superposed >> paths, >> not >> of either path separately. There is no ambiguity about which the the >> "correct" path -- neither is, both contribute equally. >> >>> I would say that the delayed choice version of the experiment makes it >> >>> clear that there are two possible pasts that lead to the same present >> >>> state -- they differ by one bit of information. >> >> >> >> That is not what is implied by delayed choice quantum erasure. Whether >> >> an >> >> interference pattern is seen or not is determined by whether the "which >> >> way" >> >> information is erased or not. But whether it is or not, the >> >> interference is >> >> only seen when coincidence measurements tell one which photons to >> >> count. And >> >> the timing information necessary for coincidence determination is >> >> available >> >> only *after* all decisions about erasure or not have been made, whether >> >> that >> >> decision is made before or after the other photon of the entangled pair >> >> has >> >> reached its detector. >> >> >> >> "Delayed choice" is perhaps a misleading phrase in this context, and it >> >> does >> >> not lead to an ambiguity of path -- it merely tells whether there was >> >> an >> >> intact superposition or not. >> > I know, this is not what I am t
