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.


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/

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