Dear Bruno, I've been following the list for a couple of months now and I sort of share Piertz worries about randomness. Here is a summary of what I've understood this far.

The UDA might imply lots of white rabbits but only those computations with self-reference to have to be taken into account. In principle this restriction might reduce the number of white rabbits to a reasonable probability (compatible with QM). But whether this is the case remains to be proved. Is this understanding correct? I mean that if from UDA we get that the probability of me being converted to a giraffe is let's say 50%. then UDA is false. Self-reference might reduce this probability to 0.000000000001%, but we don't know whether this is the case yet. Correct? Do you have an intuition of why this should be the case? Ricardo El nov 19, 2011 9:49 a.m., "Bruno Marchal" <marc...@ulb.ac.be> escribió: > > 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<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://www.entheogen-network.com/forums/> > > > http://iridia.ulb.ac.be/~**marchal/ <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<everything-list@googlegroups.com> > . > To unsubscribe from this group, send email to everything-list+unsubscribe@ > **googlegroups.com <everything-list%2bunsubscr...@googlegroups.com>. > For more options, visit this group at http://groups.google.com/** > group/everything-list?hl=en<http://groups.google.com/group/everything-list?hl=en> > . > > -- 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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