On 9 May 2017 9:40 p.m., "Brent Meeker" <meeke...@verizon.net> wrote:
On 5/8/2017 10:16 PM, Bruce Kellett wrote: On 9/05/2017 1:57 am, David Nyman wrote: On 8 May 2017 8:21 a.m., "Bruce Kellett" <bhkell...@optusnet.com.au> wrote: On 8/05/2017 4:53 pm, David Nyman wrote: > Both Hoyle's pigeon holes and Barbour's time capsules assume that there is > a coherent underlying physics with regular exceptionless laws. Until you > have something like that, you cannot define consistent continuations. > > But I'm afraid that's implied by assumption unless one takes the view that > the evolution of physical states is fundamentally incomputable, > But I thought that that was what Bruno claimed. If one assumes physics in one's derivation, then the circularity is vicious. Oh dear no, that's not right at all. What is uncomputable is any extrinsically conceived *extraction* of physics from the computational Babel consequent on the theory. There is no possible search function for this. That extraction then is necessarily a complex consequence of observer selection. Post such extraction, the evolution of physical states is then by assumption finitely computable, modulo the FPI, else computationalism must fail as a theory of mind or of physics. At this point the objective situation, mutatis mutandis, is essentially equivalent to Everett's relative state assumptions. The other point on which I must take you to task is again the question of circularity. It's not the job of computationalism's toy model to explicate every detail of the extraction of physics, although it's already the case that it *predicts* the multiple continuations implicit in the wavefunction, which is more than can be said for QM itself which merely retrodicts them (again modulo the FPI). Given the conjunction of the assumption of computationalism and our observation of the physical environment described by QM, all the theory has to show at this stage is that it is not incompatible with these data (as it would be if, say, the evolution of the wavefunction itself were shown to be uncomputable). It should further explicate some reasonably convincing justification for why just such a physics might be expected to underpin the effective environment we observe. But the *facts* of our observation of such a physics are not at issue. There is no relevant question of circularity to deal with here. As to the so called Occam catastrophe, as exemplified in your Boltzmann brain scenario, potential resolution necessarily can be understood under computationalism only from a first person perspective, as I previously suggested to you. We need to justify, in terms of a subjective measure, why we should indeed expect the physics we observe to emerge as the predominating computational mechanism underlying our normally intelligible perceptions. To do this we only need to show that "last Tuesday" computational snippets can only reinforce, and magical or unintelligible ones cannot interfere, with "normally intelligible" and complexly connected continuations. A way to grasp this intuitively is in terms of something like Hoyle's "amnesic multiple personality" heuristic which, though as you say it was originally based on the assumption of physics, IMO illustrates the relevant considerations equally intuitively on computational assumptions. In any case, the analogy of a multitasking OS that I also mentioned suffices equally well in this regard. >From this perspective, no amount of white noise in continuations of "Boltzmann" computations could make a substantive subjective difference. The reason being that the consequence is overwhelmingly likely to be a total subjective unintelligibility which will plausibly tend to be utterly swamped, in the struggle of forgetting and remembering, by "normally intelligible" continuations. The FPI is, obviously, the relevant consideration in this regard. This is what I meant when I said that an absence of evidence for this sort of pathology or unintelligibility is not evidence of its absence. It suffices that these out of phase components of experience be swamped in the battle for what one might term personal subjective emergence. They just typically get forgotten far more frequently than they get remembered by Hoyle's multiply solipsistic agent. Hence what we may think of as pathological scenarios would be expected to be very poor and haphazard candidates in the ongoing struggle for apparently persistent, pervasive and lawful subjective emergence. What would emerge with these characteristics would then be consistently remembered histories underpinned by a robust and reiterative physical mechanism whose highly selective observation by us would then be the final evidence of its predomination in this epic personal struggle. I gave you an illustration a few days ago (on which you didn't comment) of what one might term the "psycho-theological" aspect of computationalism. I said that consciousness or first person subjectivity was really a pointless cherry on the cake of physics whose mechanism must be assumed to proceed without any a priori need of such a baroque supernumerary assumption. Indeed it can only be an a posteriori datum tacked on to the physical scheme of things. Computationalism, by contrast, can only be understood in the final analysis as a synthesis of all possible subjective personal histories. "Point of view" is then just what prevents them from all happening at once. Thus physics, under the same assumptions, can in turn be understood finally as the successful computational generator underlying the "dreams of the machines". David I find most of what you say here very much a matter of wishful thinking, and not entirely consistent at that. Let me come at it in a different way. I find Barbour's idea of time capsules quite helpful here. Each time capsule is a self-contained conscious moment. There is no progression necessarily involved, so the computation that gives one conscious moment is complete in itself, and independent of other such conscious moments. (In Barbour's picture, these moments are points in configuration space that are related physically, but we do not use that aspect here.) In the moment, you are self-aware, and aware of memories that give you a concept of self. But in that moment there is no way that you can know whether these memories are veridicial or not -- they could well all be completely false, in which case there is no "you" that continues through time as a related series of experiences. Each experienced moment is complete in itself, and there is no continuation. If all you have is the moment of consciousness, you can go no further than this. It is all an illusion, and there is no physics to extract. Of course, this is a solipsistic conclusion, but there is nothing in our experience of consciousness that shows solipsism to be false. The "I" is the "I" of the moment, nothing more. Now consider the UD in arithmetic. It dovetails all possible programs -- does all possible computations -- but most computations have nothing to do with consciousness. If we use Boltzmann's thermodynamics as an illustration of the situation, the computations of the dovetailer represent a state of thermal equilibrium, a state of maximum entropy. The characteristic of thermal equilibrium is that every microstate is equally likely -- a state of complete chaos. Similarly, in the dovetailer, every computation is equally likely and there is no order whatsoever. Occasionally, in Boltzmann's thermal equilibrium there are fluctuations to states of lower entropy in which some order emerges, but according to the second law of thermodynamics, these always return to equilibrium. Similarly, in the computations of the dovetailer, there are occasionally computations that make some sort of internal sense. Some of these correspond to conscious moments. But, as in the thermal case, these rapidly return to meaningless noise. Small fluctuations to momentary order are overwhelmingly more likely than larger fluctuations to order that persists over time -- or computations that correspond to an extended sequence of (consistent) conscious states. In fact, within the dovetailer there are undoubtedly sequences of computations that correspond to the entire history of the observable universe, from the big bang through to the final heat death. But such calculations are of measure zero in the overall picture. So, if one is to take the statistics of computations that pass through one's instantaneous conscious state in order to extract meaningful physics, one will find that the overwhelming majority of these computations are of short-lived conscious moments that rapidly return to meaningless chaos, nothing more. The dovetailer would then say that no consistent physics can ever be extracted from the statistics over conscious moments, because these statistics are dominated by chaotic continuations. I agree with that except I think you are not recognizing a drastic difference of scale. A human conscious thought is something with duration, something on the order of tens of milliseconds. The substitution that you say "yes, doctor" to, must operate at a much higher frequency. So I conceive of the UD producing threads of computation consisting of many successive states within one "thought" and there will be threads in other programs being executed by the UD which are sufficiently similar over this sequence of states as to constitute the "same thought" because thoughts are classical level emergent things. In Barbours metaphor this a kind of stream of fog. If you take this view of thoughts having duration then they can overlap and form a kind of continuum. Bertrand Russell gives this analysis of time as a perception in one of his more technical papers. But a consequence of this is that what picks out a "thought" from just noise is this persistent coherence over the duration of many (countably infinitely many) thread of UD computations. This persistence is what constitutes physics in that consciousness because it must account for all interactions that are perceived as external and it must make them more coherent than just noise. So a happy solution to the measurement problem would be to show, purely as a matter of arithmetic, that such coherent threads of significant length have high measure. This is very helpful Brent. I particularly appreciate your phrasing of "This persistence is what constitutes physics in that consciousness because it must account for all interactions that are perceived as external". ISTM that this essentially concurs with Bruno's definition of physics (or as you say externally perceived actions) as a 1p plural phenomenon, which I tend to equate with a Hoylean or Barbourous multiple-solipsism So physics here is represented by highly robust and consistent appearances (as indeed it must be for us to observe it) and the computations that underpin them bear somewhat of an analogous relation to those appearances as, say, the mechanism of a TV might bear to the images it displays. As to the question of measure, I wonder what you think, if anything, about my rather hand-wavy analogy with the path integral idea. I don't know if it makes any sense at all, but I was thinking that random fluctuations outside the scope of the coherent threads of significant length you describe would tend to either duplicate finite segments, represent pathologies that would, in the net, cancel out (get forgotten and lapse into irrelevance in my solipsistic amnesiac analogy) or just degrade into noise. IOW insofar as these random components were "in phase" they would cohere and insofar as they were "out of phase" they would dissipate. So the persistent threads would become a sort of pathway of least effort for coherent histories such as our own and hence they would tend to predominate in the effective measure battle for personal subjective emergence. I'm groping a bit more here, but another analogy that occurred to me was this. Suppose you are at a very noisy party where almost everyone is literally babbling random gibberish. However there is one person standing very close to you who is speaking very clearly, compellingly and coherently and hence rivetting your attention. Occasionally, random words or phrases drift in from the babble that mirror something he is saying and you unconsciously incorporate them into his fascinating narrative. At odd moments something else is half overheard that might seem fleetingly at odds with what your compelling orator is now saying but so powerfully and convincingly does he continue to rivet your attention that you immediately forget what you had briefly overhead and it leaves no imprint on you. For the most part however the background to this uniquely powerful narrative is mere noise. As an extra freebie I'm also reminded of how concentrating on counting basketball passes leads to failure to either perceive or recall the otherwise ostentatious presence of a man in a gorilla suit. Anyway, that's probably more than enough hand waving from Taormina for the moment. The full moon is shining on the placid Mediterranean and a cooling cocktail beckons. David Brent That does not necessarily mean that no consistent physics exists -- as I said, all of physics will be in the computations of the dovetailer somewhere. All it means is that such physics cannot be extracted by considering individual conscious moments as primary. Physics has to have an independent existence, or it has no existence at all, and solipsism is the only answer. 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. -- 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.
