On 19 Nov 2011, at 12:27, Pierz wrote:

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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.

OK.

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 might not always be clear. UDA is a proof (or intended or presented as such).

`UDA proves that IF mechanism is true THEN physics is a branch of`

`machines' psychology (or bio-psycho-theology) which is itself a branch`

`of computer science which is itself a branch of elementary arithmetic.`

`SO UDA reduces physics (and actually the whole mind-body problem) to a`

`body problem in (pure, mathematical, non physical) computer science.`

`So, and that might be confusing, UDA definitely shows that in the`

`mechanist theory, physics is reduced to arithmetic. But that result`

`leads to the problem of explicitly deriving physics (body appearance,`

`physical law appearance) from arithmetic, now that we know that`

`physics *is* and* has to be* reduced to number theory.`

`UDA gives also the shape of the physical laws: physics is in principle`

`a relative measure on the computations, or a many-dream, internal`

`(i.e. made by the universal numbers themselves) interpretation of`

`arithmetic.`

`This fits nice in the "everything exists" idea which starts this list.`

`It is *the* precise form of it imposed by the constrains of the`

`computationalist hypothesis.`

`Then AUDA, or the "interview" (the part two of the sane04 paper)`

`explain how to derive "completely" physics, and how to get both quanta`

`and qualia from arithmetic, but it does only the beginning: the`

`extraction of the logic of quanta and of the logic of qualia (and more`

`than that: a complete arithmetical interpretation of Plotinus).`

`So UDA is both a proof of a statement: comp => reversal between`

`physics and machine's dream theory, and at the same time transform a`

`problem (the mind body problem) into another problem (the derivation`

`of the correct universal numbers' belief in persistent matter`

`appearances).`

`My deeper goal was to convince some scientists that Mechanism does not`

`solve the mind-body problem per se, but that it makes it possible to`

`translate that problem into a mathematical problem.`

I don't know that it's germane to the points I'm making though.

and you say in a post to Brent:

I think Evan Harris Walker makes the same point in The Physics of Consciousness (a book that provides a very clear explanation of Bell's theorem, though his speculations on the brain appear egregiously wrong). I don't think though that the point you're making here is quite the same as mine however. I will have to follow up the measure theory mentioned by Bruno below to see how this apparent problem actually isn't one. You mention the Born rule. He was my great grandfather as it happens but I didn't know there was a Born rule...

Max Born?

`That's funny. I like very much the correspondence between Born and`

`Einstein.`

`The Born rule is that if a quantum state is describe by a u + b v + c`

`w, with a, b, c, complex numbers such that a^2 + b^2 + c^2 = 1, and u,`

`v, c being the eigenvectors of some observable (and thus`

`corresponding to the possible results of the experience) then the`

`probability of finding a result corresponding to u (resp. v, w) is`

`given by a^2 (resp b^2 , c^2).`

`So if you look at a particle in the state 1/sqrt(2) (u + v} with a u/v`

`analyser, you will see u or v with probability (1/sqrt(2))^2 = 1/2.`

`a, b, c are usually called amplitudes of the (superposed) wave, and`

`Born rule is that the probability is given by the square of the`

`amplitude. (I guess you know that).`

`If the observable is continuous, like with position, impulsion, ...`

`you have to use an integral instead of a sum, and you have to use`

`probability on a continuous space.`

`I think that your great grandfather got the Nobel price for that idea`

`(30 years after the finding).`

`The Copenhagen school said that the observation collapses the wave,`

`going from 1/sqrt(2) (u + v} to u, for example, and the many-worlders`

`(Everett) said that the observer get just entangled with the state of`

`the particle, going from O * 1/sqrt(2) (u + v} to 1/sqrt(2) (O * u +`

`O* v}. The wave then describes two branching (superposed) observers,`

`each with a definite result in his mind or diary. Everett school just`

`applies QM to the couple observer + particle. Born rule becomes, or`

`should become, a theorem. Everett, argued that it is, and you can`

`indeed recover it by different methods with varying degrees of rigor.`

`This is still a bit controversial, to be sure, like Brent's comment`

`illustrates. Deutsch uses decision theory for doing so, Graham and`

`Preskill use frequentist probabilities and special measurement`

`observable, Everett makes a direct QM derivation, and I use Gleason`

`theorem to get them, but probably none of those approach are entirely`

`satisfactory. In fact the first to "derive" Born rule from QM is the`

`french physicist Paulette Destouche-Février.`

Bruno

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 wasjustly cut to shreds on the basis of a number of misunderstandingsonmy part, perhaps most crucially my conflation of information and computation. I claimed that the UD cannot be distinguished from theset of all possible information states and therefore from aninfinitefield of static, within which all possible realities can be found, none of which, however, have the slightest coherence. I alsomistakenly used the word 'random' to describe this bit field,which ofcourse 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 (saySchroedinger's equation, or those of general relativity) arepreferredwithin 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 bystep: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 insulatesit against disproof, since although it allows everything we see,it ishard 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 ideaof a good explanation is one that closely matches the structure ofthething it describes, allowing for little variation. The vastvariationin 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 thatphysics is entirely reduce to computer science/number theory in averyspecific and unique way (modulo a variation on the arithmetical definition of knowledge).Of course the objection that nobody has yet found an application forUDA, a concrete example of its usefulness, is more of an objectiontoit as a scientific theory than a philosophical one.UDA is a proof. Unless wrong, it is done. Asking for the use of theUDA is like asking for the use of the theorem saying that nonumbers nand 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 thebasis of the "infinite union of all finite portions of the UD inwhichcorrect emulation occurs". Thus the indeterminacy of 1-pexperience isa function of the distribution of states within the observer’s consistent histories. For instance, there’s a 20% chance of xhappening, if it happens within 20% of my consistent histories.PleaseBruno 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,probabilityof my turning into a giraffe in the next minute. So the UD, if nottocontradict science as it stands, must allow this too. And indeedthereis no reason for it not to, since there must be computationalpathwaysthat lead from human to giraffe - a sort of deep version of themorphing algorithms used in CGI - or a simple arbitrary transform.Infact there must be infinite such pathways leading to slightvariationson 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 theonesin which I retain my present form, behaving as we would expect onthebasis of the past."Of course"? No, what UDA shows is that it is not obvious, and that computerscience can show it false, and so refute mechanism. But the mathshowsthat 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 (whichdefine the uncertainty domain for the first person experience), wecanuse 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 nontrivialway 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 morefrequent than the non quantum computations. But this must be shown,orwe 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 thecalculations of the UD must be disorderly. Consider somecalculation cwhich 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. Therewill also be calculations in which the ordering of the naturalnumbersis 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) * 1,000,000Thus the UD cannot rely even on the ordering of natural numbers to ‘prefer’ certain calculations, since the set of variants such as theabove will be infinite, and overwhelm calculations involvingsimple 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 mathematicalself-reference (G, G*, S4Grz, etc.) Then the shadows of why quantaandqualia 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 tocomplex numbers for the measure problem (that's new! but I have yettobe 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 openthat it will lead to a refutation of mechanism, but thecontraidictionhas not yet appear, and on the contrary, what we get is a similar "many-world" problem that the physicists encounter too. This confirmsDigital Mechanism (DM) instead of refuting it. UDA just transformsthemind body problem into a mathematical body appearances problem. BrunoPS have you see that edot has become enet? I will come back on theUDAthere too! 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