Thank you for this reply. You mention a lot of theory I'm unfamiliar with as yet, so I will have to do some study before I can make a sensible response. I've never heard you call it a problem rather than a solution before, but that enhances my understanding of where these ideas fit in your field. I don't know that it's germane to the points I'm making though.

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On Nov 19, 8:49 pm, Bruno Marchal <marc...@ulb.ac.be> wrote: > On 19 Nov 2011, at 03:02, Pierz wrote: > > > In a previous post I launched a kamizake assault on UDA which was > > justly cut to shreds on the basis of a number of misunderstandings on > > my part, perhaps most crucially my conflation of information and > > computation. I claimed that the UD cannot be distinguished from the > > set of all possible information states and therefore from an infinite > > field of static, within which all possible realities can be found, > > none of which, however, have the slightest coherence. I also > > mistakenly used the word 'random' to describe this bit field, which of > > course is wrong. I should instead have used the word 'incoherent'. > > Bruno and others quickly put me straight on these errors. > > > I am still troubled however by the suspicion that UDA, by explaining > > 'everything' (except itself - there is always that lacuna in any > > explanatory framework) also explains nothing. > > The UD is not proposed as an explanation per se. On the contrary UDA > shows that it is a problem we met when we assume that the brain (or > generalized brain) is Turing emulable. > > > Because the UD executes > > every computation, it cannot explain why certain computations (say > > Schroedinger's equation, or those of general relativity) are preferred > > within our presenting reality. > > That is basically my critics of Schmidhuber I have made on this list. > > I'm afraid that you miss the role of the first person indeterminacy. > I will add explanation here asap. You have to follow UDA step by step: > it is a proof (in the theory "mechanism"), so to refute UDA you have > to say where it goes wrong. I insist: UDA is a problem, not a > solution. Indeed it is a subproblem of the mind-body problem in the > mechanist theory. > AUDA will be the solution, or the embryo of the solution. > > > This very universality also insulates > > it against disproof, since although it allows everything we see, it is > > hard to conceive of something it would disallow. > > Not at all. A priori it predicts everything *at once*. That is the > "white rabbit problem". We don't see white rabbits, or everything at > once, so mechanism seems to be disproved by UDA. The point will be > that such a quick disprove does not work, and when we do the math we > see mechanism is not yet disproved, but that it predicts or explain > the quantum weirdness. > > > David Deutsch's idea > > of a good explanation is one that closely matches the structure of the > > thing it describes, allowing for little variation. The vast variation > > in the possible worlds where UDA could be invoked makes it a bad > > explanation, in those terms. > > You have just not (yet) understood the role of the 1/3 person pov > distinction in the reasoning. UDA shows that physics is determined by > a relative measure on computations. If this leads to predict that > electron weight one ton then mechanism is disproved. UDA shows that > physics is entirely reduce to computer science/number theory in a very > specific and unique way (modulo a variation on the arithmetical > definition of knowledge). > > > > > Of course the objection that nobody has yet found an application for > > UDA, a concrete example of its usefulness, is more of an objection to > > it as a scientific theory than a philosophical one. > > UDA is a proof. Unless wrong, it is done. Asking for the use of the > UDA is like asking for the use of the theorem saying that no numbers n > and m are such that (n/m)^2 = 2. > UDA shows a fact to be true and that we have to live with it. UDA > shows that mechanism and materialism are (epistemologically) > incompatible. > > > Still, I believe > > there is an argument against it at the philosophical level. The UDA > > invokes the notion of probability in relation to 1-p states on the > > basis of the "infinite union of all finite portions of the UD in which > > correct emulation occurs". Thus the indeterminacy of 1-p experience is > > a function of the distribution of states within the observer’s > > consistent histories. For instance, there’s a 20% chance of x > > happening, if it happens within 20% of my consistent histories. Please > > Bruno correct me if this is a misunderstanding. > > No, here I mainly agree with you. > > > > > Now we know from QT there is a finite, if absurdly remote, probability > > of my turning into a giraffe in the next minute. So the UD, if not to > > contradict science as it stands, must allow this too. And indeed there > > is no reason for it not to, since there must be computational pathways > > that lead from human to giraffe - a sort of deep version of the > > morphing algorithms used in CGI - or a simple arbitrary transform. In > > fact there must be infinite such pathways leading to slight variations > > on the giraffe theme, as well as to all other animals, inanimate > > objects and so on - okay let’s leave out the inanimate objects since > > they possess no consciousness as far as we know, therefore no 1-p > > experience. > > > Of course, these pathways are an extreme minority compared to the ones > > in which I retain my present form, behaving as we would expect on the > > basis of the past. > > "Of course"? > No, what UDA shows is that it is not obvious, and that computer > science can show it false, and so refute mechanism. But the math shows > that such a refutation, if it exists, is not trivial at all, and the > logic of self-reference shows that we are led to absurdities, not > contradiction (yet), and the absurdities are quite similar to the > quantum weirdness that we can "observe" (non locality, indeterminacy, > many worlds/dreams/states, symmetry at the bottom, etc.) > > > But here’s where I see the problem. In a > > mathematical platonia we cannot make such a statement. The notion of > > probability within an infinite set is untenable. > > On the contrary. Probability calculus and measure theory have been > invented to put measure on infinite spaces. > > > It is analogous to > > expecting that a number selected at random from the set of natural > > numbers is more likely to be divisible by 2 than by, say, a million. > > This is only the case of the set is ordered to appear this way, eg > > 1,2,3,4... If we write the set thusly: 1, 1 million, 2 million, 3 > > million, 2, 4 million, 5 million, 6 million, 3, 7 million.... etc > > then our expectation breaks down. > > You can use the usual Lebesgue measure on the > real.http://en.wikipedia.org/wiki/Lebesgue_measure > > Think about the repeated self-duplication. It shows that self- > duplication is a Bernouilli experience, so that in the limit (which > define the uncertainty domain for the first person experience), we can > use the usual normal distribution based on e^(- x^2) with the > normalisation factor. > > > > > So if there are infinite pathways where I turn into a giraffe, as > > there must be, there is no way for my 1-p experience to select > > probabilistically among these pathways. I can no longer say, if the > > set of calculation pathways is infinite, that giraffe transformation > > occurs in, say .000000001% of them, or 5%, or 99% of them. > > Yes, you can. The problem is that the UD does not just iterate self- > multiplication (random noise), but it mixes it in a highly non trivial > way with infinitely many computations. > > > > > This is not a problem for an Everett -type multiverse, in which the > > universes are bound together by consistent physical laws which allow > > one to speak of a proportion of universes in which event x occurs. > > However, in a mathematical platonia where all possible calculations > > occur, and nothing outside of them, there can be no such ordering > > principle. > > If the Everett idea works, and is the solution, (which has not yet > been completely proved) then the UDA conclusion is that the Everett > simultion in the UD wins the "measure battle", and we HAVE to justify > this from computer science alone. > > It would mean that the quantum computation are statistically more > frequent than the non quantum computations. But this must be shown, or > we miss the explanation of the origin of the physical laws, together > with the distinction quanta/qualia that digital mechanism already > explained (by the Solovay split between truth and proof). > > > > > I believe this same principle can be used to show that the > > calculations of the UD must be disorderly. Consider some calculation c > > which employs number n. In the UD there will also be a calculation > > which instead uses the number n+1, another which uses n+2 etc. There > > will also be calculations in which the ordering of the natural numbers > > is rearranged in arbitrary ways such as my example above. Instead of > > using simple n, the calculation will employ someFunction(n), where > > someFunction() transforms the number as per my example, i.e. (in > > pseudocode): > > > if n modulo 4 = 0 > > return n > > else > > return (n-1) * 1,000,000 > > > Thus the UD cannot rely even on the ordering of natural numbers to > > ‘prefer’ certain calculations, since the set of variants such as the > > above will be infinite, and overwhelm calculations involving simple n. > > This shows that the extraction of physics from numbers is not an easy > task, but again, you have to take into account the non triviality of > the 1 and 3 pov relation, and of computer science and mathematical > self-reference (G, G*, S4Grz, etc.) Then the shadows of why quanta and > qualia already appear. > > Recently Eric Vandenbush (a guy who solved the first open problem in > my thesis) has found an explanation why the UD leads necessarily to > complex numbers for the measure problem (that's new! but I have yet to > be entirely convinced). > > Pierz, I insist that the UD is not proposed as a solution, but as a > problem for DM. It is shown to be an unavoidable problem we have to > solve if we keep digital mechanism in cognitive science. I am open > that it will lead to a refutation of mechanism, but the contraidiction > has not yet appear, and on the contrary, what we get is a similar > "many-world" problem that the physicists encounter too. This confirms > Digital Mechanism (DM) instead of refuting it. UDA just transforms the > mind body problem into a mathematical body appearances problem. > > Bruno > > PS have you see that edot has become enet? I will come back on the UDA > there too! Here is the link:http://www.entheogen-network.com/forums/ > > http://iridia.ulb.ac.be/~marchal/ -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. 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