Le 15-mars-06, à 10:46, Georges Quenot a écrit :

> > Bruno Marchal wrote: >> >> Le 14-mars-06, à 10:31, Georges Quenot wrote: >> >>> [...] >>> I feel that the computational approach is a wrong direction >>> for the question of existence. >> >> The question is whether comp is true or not. If comp is false then it >> should obviously lead to a wrong direction for the question of >> existence. If comp is true, then we have no choice to derive the many >> form of possible existence or appearances from it. > > Comp might be false. Yes. And I proudly take credit (to speak like Smullyan) of having showed that comp + materialism is actually false, that comp, if true, is not provable, that comp is empirically refutable, etc. Now comp is my working theory. In front of a paradox or amazing consequences you can always say "the theory is perhaps false". Jean-Pierre Changeux just says that to Alain Connes when Alain Connes explained to him some quantum paradoxes : if you are right it should mean the quantum hyp. is probably false. Yes, but "what alternative are you proposing" is the natural remaining question. Also we have not yet discovered any empirical reasons to doubt comp (beside the perhaps missing "white rabbits", but this is exactly what remains to be seen). It is easy, from the UDA, to show that classical physics is incompatible with comp (exercise), but then we have empirical reasons to dismiss it (the quantum phenomena). > >>> A matrix of numbers is not >>> the only type of mathematical object the multiverse can be. >> >> I am not sure what you mean by matrix of numbers. > > I am not sure either :-) I referred to what Norman meant by it. > For what I could imagine, it did not include all mathematical > objects and possibly not the ones that might be isomorphic to > our universe or multiverse. > >> Now I agree with your point in the sense that if follows from the UDA >> that if comp is true then many things, including the appearance of a >> multiverse go well beyond most mathematical object. > > It might well go beyond many mathematical objects (I am not > sure we can say "most" unless yoy meant "most currently known") > and still be (isomorphic to) a mathematical object. I should have said that the appearance of a universe cannot entirely be a mathematical object from the internal (first person) point of view. Arguably so with comp or with weaker hyp. > >>> [...] >>> - The multiverse is isomorphic to a mathematical object, >> >> What do you mean? I guess this: The multiverse is not a mathematical >> object, but still is describable by a mathematical object. > > No. I mean that there is a one to one correspondance between > the "components" of the multiverse and those of a particular > mathematical object and that this correspondance also maps the > "internal structures" of the multiverse with those of this > mathematical object. "Components" and "internal structures" > should not be understood here as atoms or people or the like > but only "at the most primitive level". It seems that this is just a precise formulation of what I did understand, except that I still don't know if you postulate the existence of a physical universe. If not, what is the difference between being a physical object and being a mathematical object ? > >> I don't think so. If comp is true the mutiverse should not be entirely >> describable (in any third person term) by any mathematical object. If >> we are numbers our possibilities go beyond what we can describe in >> term >> of mathematical object (and that is why I insist that comp is >> antireductionist). > > *If* comp is true. I am not sure of that. Me too. But it is the theory I am studying. Also comp provides some neat "etalon philosophy" to compare with other theories. The advantage of comp (which I recall includes Church thesis) is that, at least, many fundamental questions can be addressed. > >>> - Perception of existence is an internal property of the >>> multiverse (mind emerges from matter activity), >> >> The multiverse would be "physical"? > > Yes but what "physical" actually might mean is unclear. > >> But then: What is mind, what is matter, what is activity? > > I would say for all three: emerging properties that appear > as such when "viewed from the inside" of the universe. All right, but then you should make clearer what you mean by "universe". I do think like you that mind, matter, activity, ... are emerging from an inside view (actually it needs to be so once comp is *postulated*), but at least with comp we can say more. Mind matter activity arises from the collection of all the "inside view" (sometimes refer too in terms of observer-moment in this list) which are all implicitly defined in the Arithmetical Platonia. Kronecker said: God created the natural numbers, all the rest has been invented by humans. But with comp you can say: God has created the natural numbers, all the rest has been invented by the natural numbers. Of course here "God creates X" means that we cannot even conceive how X could have appeared or have been created. > >> Are you postulating a physical universe? > > This is an ill-formed question. The universe could be purely > mathematical and still appear as physical from the inside. That what I think. By default I tend to use the expression "physical universe" as a short form for "Aristotelian physical universe", that is one in which there is a primary matter, that is a notion of primitive matter which would not be reducible to anything else. > >> In that case comp-or-weaker is just false. > > Possibly. *Certainly* I would say. If you believe that a "physical universe" is still possible once we postulated the comp hyp, then you should tell me which step of the UDA reasoning you believe is wrong or insufficiently unsupported. Cf: http://iridia.ulb.ac.be/~marchal/publications/SANE2004Slide.pdf (In that version the first seven step are "easy", the last step needs either a strong form of Occam Razor, or the more subtle Movie-Graph argument, or Maudlin's Olympia). > >> Let me recall that the UDA shows that if we can survive >> (in the folk sense) through a digital body substitution, then physical >> appearances must be justified entirely without any physical >> ontological >> commitment. > > The question of whether we would survive a digital body > substitution does not seem solved to me. I am not sure we > would ou could. More can be said: comp has the cute or ugly property (depends on the taste) that if true then it is necessarily hypothetical. Totally unprovable, but still refutable. This is the key reason I put the comp-subject into "theology": to remind we can just hope or fear it to be true. A doctor who would say that "science has proved comp" is a charlatan. > >> Arithmetical truth already contains the full description of >> the deployment of a full quantum universal doevetailer, but it remains >> to explain why such a quantum realm wins the "white rabbit hunting >> battle" (that is how it solve the measure problem). > > Yes. Many things remain to be explained and we may still be > far to discover which mathematical object we live in (if we > do, indeed). I don't think we live *in* anything. It is hard to describe the picture with words. Poetically I would say that we live "in" or through all the numbers dreams which are sufficiently coherent to give the impression of consistent histories, but words like that are always a bit misleading. Recall that your consciousness is distributed in the whole universal deployment. I agree with you on what follows in your post. > >>> - Mathematical existence and physical existence are the >>> same ("there is no need that something special be inside >>> particles", the contrary is an unnecessary and useless >>> dualism, "the fire *is* in the equations"). >> >> All this is too much ambiguous for me. > > This is the hard part. > >> I tend to criticize all *fundamental* dualism. > > Okham's razor doesn't like them too, especially when they > appear unable to help to explain anything more. > >> I agree with you that the fire is in the >> equation (or more aptly in their solutions, > > The difference between equations and their solutions might > only be a question of viewpoint. > >> or still more aptly: in the >> memory of the possible observer-machine described relatively by (all) >> their solutions). > > I do not understand. Unless you refer to the previous > speculation/conjecture. yes. > Indeed, the perception of "actual" > fire in the equation is itself included in the (development > of) the same equations. This is exactly what I suggested. > This indeed questions the meaning we should give to > "physical" existence. > > Georges. 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-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~----------~----~----~----~------~----~------~--~---