On 08 Dec 2010, at 22:15, Brent Meeker wrote:

On 12/8/2010 11:19 AM, Bruno Marchal wrote:On 07 Dec 2010, at 22:40, Brent Meeker wrote:My reservation about step 8 is that the activity, in order to be acomputation, must have an interpretation.Hmm... This is already a bit ambiguous. Suppose some (real)computer computes factorial(5). Some people could say that in orderto be a computation of factorial(5) we need a human interpretingthe physical process as a computation of factorial(5).I would not. But I agree we need here some 'physical' interpreterof the program.Suppose someone dream that he computes fact(5). Here we can agreethat we need a physical interpreter interpreting or executing thebrain so as to compute the "dream of the computation of thefactorial by that person". But it is not the physical interpreterwhich computes the factorial, it is the dreaming person. And theperson would be doing that computation even if nobody look at thebrain and interpret that brain as "dreaming that someone computefactorial(5). OK?Sure, the person is interpreting the meaning, but I would say he isonly doing so by reference to a world in which there arequintuples. It is because he can wake up and hold up his hand say,"I dreamed that this many fingers is prime."

`All right. Of course, (but you know this), he is living in the`

`"standard model of arithmetic" where 5 is prime. Actually 5 is prime`

`in all the models of arithmetic: it is stable universal belief.`

If the computation realizes "I'm thinking about the number 5."then "the number 5" must mean something in this context.It must mean something to the person thinking to the number 5. Notto someone observing that person.

OK.

Otherwise the same strings of symbols might compute, "I'm thinkingof blxght." In order for "the number 5" to refer there must be acontext in which the number 5 exists in some sense. This is finefor your theory and in fact that's how you ground it by notingthat we all agree on arithmetic and that there is a number 5 inarithmetic. But then it seems the same applies to "I'm thinkingof a chair." In order for that to be a possible interpretation ofthe strings there must be some referent for "chair". Of courseyou can say the "chair" refers to some bundles of computations ofthe UD that are related to "sitting" bundles, etc.Hmm... the ambiguity is present throughout that reasoning. I think.I will try to answer the next line:But then you are just saving the theory by mapping the physicalworld back into it.Once we assume comp, and assuming that the 'generalized brain' isthe usual biological brain inside the skull (to make the picturesmore easy), all we need is a computation of the relevant states ofthat brain.But here is where I think you help yourself to too much. It is onlybecause the biological brain exists and evolved in a certain worldthat it has "relevant states". We as outsiders cannot generallyobserve what the brain is thinking about (it's as though it hasinvented it's own simulation code for the world), but you helpyourself to the assumption that it is thinking about things - thingsthat you and I can communicate about, i.e. are in our common world.

`But that point is valid both in the "real (putative) physical world"`

`and in a simulation of the "real physical world" occuring in UD* (the`

`entire execution of the UD).`

`So, this kind of argument will not work for distinguishing the two. In`

`both situations there is a referent relatively to the states of his`

`brain, even if immaterial in the second case (but he cannot know that`

`immateriality directly, or there is a magic, non Turing-emulable,`

`property of "real matter" playing a role in consciousness).`

This create a human interpreter experience of "thinking" to thechair. That computation might be a dream by someone who know wellabout chair, and has seen many example of it in his memory-life.Now the UD will "generate", in his special static way, infinitelymany computations going through those relevant states. They are alldescribed by sequence of phi_i^n (j), n = 0 to infinity, with thedifferent computations being distinguished by different i and j.OK? "n" represents the computational steps of the computation ofphi_i(j), and the computation are really given by the arithmetical(and computable, in the mathematical sense) relation linking (i,j, n).For example phi_587610093811908883744(45456901000456338867611906369579006532113536953) could describethe quantum state of a computer emulating that "human thinking ofthe chair",and many others with (actually) much bigger index i and data j.(note that even with the same i and j there are infinitely manycomputations, those being based on different universal interpreters.But each universal interpreter provides a mapping from such numbersto...what? another world, I think.

`You can call that an "another world", but those type of worlds are not`

`distinguishable from just another universal computations.`

`A good thing, because in fine, if you ask to a physicist what is (the`

`scientific description of) a physical reality, he will just select one`

`universal computation. He will say something like DeWitt-Wheeler`

`equation + this or that initial condition, without reifying reality.`

`Only an anti-comp, or anti-marchal (I mean anti-UDA), philosopher will`

`insist on reifying matter. The trouble is that such a move makes`

`either my brain non Turing-emulable, or introduces a curious physical`

`supervenience thesis where either neurons have prescience, or where my`

`consciousness depends on future contingent events.`

`(below I will refer to ABOVE. It is here, I mean the paragraph just`

`above).`

Some computation could emulate the quantum state evolution of thesuper cluster of galaxies including the Milky way, and thus the sunand earth and the guy thinking to that chair (and all his life withall its chairs).Now, UDA1-7 and the movie graph (UDA-8) shows that the guy, whichplays the role of the interpreter of its own brain state is unableto distinguish any of those phi_i^n(j). Actually, it shows wecannot distinguish a phi_i(j) computed by the real "galaxy" if thatexist, and the one emulated by the DU in arithmetic, emulating thesame galaxy (at a level relative to the relevant state of its brain'course).This is the tricky part. The same computation in the guy's braincan be interpreted as an emulation of the milky way or as thinkingthat five is prime. He provides the interpretation of the brainstate - in his world.

`OK, except that "his world" is really "his most probable computational`

`history". Typically, like in QM-without-collapse, he "belongs" or is`

`"supported by" an infinity of computations "done" by the UD.`

The physical activity are the one described by those manycomputations, and this predicts that if the guy looks below itssubstitution level, he should find the trace of the infinitelycomputations going through those relevant states (by first personindeterminacy).Are you assuming that, at the substitution level, the interpretationis unique - regardless of which world it is in?

`That's the point. The interpretation is unique at the substitution`

`level. That is why I say yes to the doctor and have to pray he has`

`chosen the right substitution level. It is unique like the`

`interpretation that the heart is pumping the blood is unique once the`

`heart is substituted by a sufficiently genuine pump.`

Suppose someone says that for consciousness to exists we need the"real physical galaxy" (whatever that could mean). Then it meansthat whatever computations going through its states, none areenough for his consciousness to appear (he remains zombie).Or that computations must be physically realized and that determineswhere the consciousness appears.

See ABOVE.

But I'm not arguing that there must be a physical world (thoughthat would be one solution). I'm arguing that there has to be aworld that provides the interpretation of the numbers. I realizethat this world can consist of just some class of numbers, butwhatever it is, it seems to me it must be arbitrarily large andarguments about brain states and substitution are fallacious becausethey implicitly help themselves to the bigger world in order toground their interpretations.

`Some reality has to provide the interpretation of the symbols, but`

`that is exactly what a model does in logic. To interpret 0, s, +, x,`

`we need a set (N) and the additive and multiplicative relations. That`

`is why comp (DM) needs some amount of arithmetical realism. We don't`

`need, and the argument shows we cannot need, to pick up any special`

`universal function at the bottom. So we can take arithmetic, or the`

`combinators, fortran, lisp, etc., and whatever is that choice, the`

`physics will be given by a "sum" on all computations going through my`

`actual finite computational state (which I hope my doctor has`

`correctly delineate).`

But that means (assuming comp) that we have not choose the rightlevel of simulation, and this means that we have to go deeper inthe UD, using phi_i(j) with still bigger j and i. Or it means thatthe real galaxy contains something which prevent any emulation ofit to appear in the UD, but that means that his generalized brain(of the guy thinking to the chair) is not really emulable by anycomputational process, and this means he should better say no tothe doctor.So, depending of the substitution level, for emulating the rightamount of "activity" we have to map sufficiently deep digitaltruncation of the 'physical world'. But that means that the realphysics, from the point of view of the guy who has his first person(plural) reality) indeterminated on any of his relativeincarnations in the deployment of the UD, will be given by the sumof all the truncated part of all the digital truncations of all themultiverses/multidreams in the whole (sigma_1) arithmetic.We will never been able to map the whole physics in one computationof the UD, given that physics is a first person (plural) viewdefined by all its digital incarnations in the UD, and that leadsto a sum on the entire work of the UD (this really comes from boththe invariance of the first person for the UD-delays, and step 8).So you have to really address the step-8 point, to rejectimmateriality, to link consciousness to something not Turingemulable. But then I'm afraid you have to attribute a physical roleto object having no physical activity relevant to a computationdone in "real relative time". That seems to me to be an ad hoc moveclose to non sense (assuming comp throughout). So consciousness isnot related to a physical active brain, but to the infinitely manyarithmetical relations relating those states.It is not excluded that *some* universal number (a "physics") playsspecial prominent role, but then, what the reasoning shows is thatthe existence of such number(s) have to be derived from the"arithmetical measure problem". The loss, is any simple basicphysics (but then try to predict an eclipse with Feynman integralwith all the decimal exacts). The gain, with the classical theoryof knowledge, is that we get both the quanta and the qualia (by theG/G*, Z1/Z1*, etc. splittings).But doesn't that splitting depend on interpreting relations betweencomputations as representing certain conscious thoughts? I don'treject it on that account, since if it can be shown to predictthings that's as much as we ask of any theory. But it seems to methat you have so far only an analogy between proof and belief.

At last. I was waiting that objection since more than 30 years!

`That 'analogy' is NOT an analogy for the case of ideally correct`

`machine saying "yes" to their doctor. So all what is needed is that`

`your belief system to be close for the same logic as Peano Arithmetic`

`(or any Löbian theory) so that you can follow (if *you* want) the`

`doctor explanation when he talks about the third person description of`

`your brain. So you need only to agree that your beliefs result from`

`rules like "neuron 345 is connected to this and those neurons, and are`

`activated in such an such conditions, etc. + the belief that if you`

`belief A and A->B then you will belief B. This means that (B(a->b) &`

`Ba) -> Bb. etc. It makes you a mechanical extension of Peano`

`Arithmetic. Then, once you accept that there is finite digital`

`description of your instantaneous state, G/G* will apply on you, and`

`this at all level where you can describe yourself in a third person`

`way. It will not apply to your consciousness, which is not even`

`definable (it uses the Theaetetical Bp & p, which is not representable`

`in your brain-system). So G/G* applies to you ... as far as such`

`finite description exist, and as far as you (and your doctor) are`

`correct (which you cannot know, but still bet on) when working on your`

`brain.`

`Your everyday beliefs can be much less correct, making such a`

`mathematical notion of belief looking a bit analogical. But they have`

`to be correct when thinking about your brain, or more indirectly when`

`letting the doctor thinking about your brain, when you accept the`

`digital substitution, because if they are not, it means you will not`

`survive the substitution.`

`Such correctness is absolutely unprovable by you (nor by your doctor)`

`so that you have to be conscious that saying "yes" to the doctor`

`really ask for a leap of faith, making comp really like a religion,`

`which it is, given that it is a belief in a form of reincarnation.`

`And so, scientifically, comp protects, paradoxically, those who want`

`to say "no" to the doctor. The belief in non-comp is consistent with`

`comp, like the belief in the inconsistency of Peano Arithmetic is`

`consistent with Peano Arithmetic.`

`This makes comp a sort of absolute Gödelian sentence for all machine,`

`and this makes comp absolutely unbelievable (when true and it is still`

`'inductively inferable').`

`And that is why I never said that I belief in comp, because I know`

`since 30 years that such a belief would make me inconsistent.`

`And that is why I like to use the term "theology". Comp itself belongs`

`to G* minus G. It is a bit obvious because to say yes to the doctor is`

`like believing in a consistent extension of yourself, that is like to`

`belief in your own consistency, which you can't by Gödel second`

`incompleteness theorem.`

`Comp is a secret, (this is how I call the G* minus G proposition). It`

`is very near inconsistency. Nobody can even take it as an axiom: it is`

`a sort of meta-axiom, which we can bet on without ever being able to`

`prove it, even in a one line theory taking it as axiom.`

`Note that this is the case for any belief in any reality sufficiently`

`rich to encompass ourself. BDt -> Bf. (By Gödel Completeness Theorem,`

`Dt is equivalent with "there is a model (reality) of myself. To be`

`sure this is only provable for Löbian machines talking first order`

`language, and/or sufficiently effective higher order reasoners).`

Bruno 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-l...@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.