### Re: Boltzmann Brains, consciousness and the arrow of time

On 09 Jan 2009, at 20:12, Günther Greindl wrote: Hi Bruno, and Cantor get a contradiction from that. You assume the diagram is indeed a piece of an existing bijection in Platonia, or known by God. No, you misunderstand me there - I just meant that we need to take the step to infinity - see below. that you get by flipping the 0 and 1 along the diagonal of the matrix appearing on the right in the diagram. That sequence, thus, exists in Platonia, but definitely cannot belong to the list described above. snip So you have to look at it, in the third person point of view as computations which bifurcate (or differentiate by the rule Y = II), and bifurcate again, and again, and again, OK? Yes, I'm with you so far. And now, what you are missing. I think. It is the distinction between third and first person point of view. As defined in the first and second step of UDA (not the Theatetical one used in AUDA). Looking at the generation of the UD, or dovetailing on all computations, you can see the many computations being generated and you can see them differentiate or bifurcating all the time, where here time is defined by the succession 1, 2, 3, 4, 5, ... itself. If you universal base is two dimensional (like with the Conway Game of Life) you can see the deployment as a static three dimensional conic structure. Everything there, is enumerable. At each UD step, everything is even finite! snip But things changes when you adopt the first person point of view, due to the fact that the first person point of view cannot be aware of the dovetailing delays, nor of the extreme multiplication and redundancy of the computations. And if you are OK with, well, mainly here the step 4, you see that the intuitive measure will have to be made on the union of all computations going through the current state. Agreed. 0... I have already begin the generation of a continuum of binary history: Indeed, all those beginning by 0. Then I write 1... So I have begin the generation of the binary sequence beginning by 1. As you see I am dovetailing (not universally though!). Then i generate all possible extensions, which give me two time more work. First the possible continuation of the one beginning by 0. 00... 01... That is how I visualized it, yes. Now, if you interpret the 1 or 0 as results of a self-bifurcation in the UDA, then by the unawareness of delays, the first person indeterminacy of those in front of a never stopping UD, where your computations are dovetailed, in particular on the binary infinite sequences, bears on set with cardinalities of continua, despite mathematically the third person description does not leave the enumerable. And here is where we seem to disagree - but maybe only in a trivial sense - maybe we mean the same thing actually. I agree that everything is still enumerable from a third person point of view, and that the continuum arises from a 1st person point of view, but also only if I imagine all computations of the UD - also the ones infinitely far away. I don't understand what you mean by computations being infinitely far away. In the UD deployment, which I will wrote UD*, all computations begins soon or later (like all dominoes falls soon or later in the infinite discrete dominoe-sequences). All computations reach any of their relative computational state soon or later always after the UD makes a finite number of steps. *Some* subcomputations can be interpreted as dovetailing on the constructive ordinal, but they still reach any of their computational step in finite time. I am skeptical of actual infinities in the real=physical world (in my 1-OM in only believe in potential infinities. I recall that the physical world is a *first person* plural observation, so with comp with have to expect things behaving like if there was actual infinities. The physical world is just unreal, if we decide to say real = the ontological, in which case something is real if it belongs to the UD*, or if its existence can be proved in Robinson Arithmetic. http://en.wikipedia.org/wiki/Potential_infinity see Bekenstein Bound, and Seth Lloyd's work on the limits of computation), but when we say that physics is emergent from 1st person point of view of the third person UD, we are also aware that this UD does not exist in time and space (but generates it for inside observers). Well, the UD has existed and has run in time 1991 and space Brussels :) UD* does not exist in time and space, given that with comp it is time and space which *appears* from the point of view of the observers generated by the UD. It is an open problem if we can make sense with a notion like Bekenstein bound or just balk hole with comp. So no problem with infinities there - I only have a problem with local physical (1-OM) infinities (as presupposed in textbook physics

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Bruno, I don't understand what you mean by computations being infinitely far away. In the UD deployment, which I will wrote UD*, all computations begins soon or later (like all dominoes falls soon or later in the infinite discrete dominoe-sequences). All computations reach any of their relative computational state soon or later always after the UD makes a finite number of steps. snip Hmmm... The phrasing reconstitution at infinity does not make sense, I think. All reconstitutions are done after a finite number of steps of the UD. But you are right that for (the third person description) of the first person probable experience we have to take into account the infinite union of the computations going through the relevant state. The reals appears here and now, because they are generated at the limit, as a infinite union of finite computations, or finite pieces of infinite computations. snip OK. But it is the union which is infinite. The reconstitution can be numbered (by a God). Yes, I see we agree - my fault. I meant the infinite union of computations - maybe rec. at infinity was a bit dramatic way of speaking - the way you put it is clearer. Cheers, Günther --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Bruno, and Cantor get a contradiction from that. You assume the diagram is indeed a piece of an existing bijection in Platonia, or known by God. No, you misunderstand me there - I just meant that we need to take the step to infinity - see below. that you get by flipping the 0 and 1 along the diagonal of the matrix appearing on the right in the diagram. That sequence, thus, exists in Platonia, but definitely cannot belong to the list described above. snip So you have to look at it, in the third person point of view as computations which bifurcate (or differentiate by the rule Y = II), and bifurcate again, and again, and again, OK? Yes, I'm with you so far. And now, what you are missing. I think. It is the distinction between third and first person point of view. As defined in the first and second step of UDA (not the Theatetical one used in AUDA). Looking at the generation of the UD, or dovetailing on all computations, you can see the many computations being generated and you can see them differentiate or bifurcating all the time, where here time is defined by the succession 1, 2, 3, 4, 5, ... itself. If you universal base is two dimensional (like with the Conway Game of Life) you can see the deployment as a static three dimensional conic structure. Everything there, is enumerable. At each UD step, everything is even finite! snip But things changes when you adopt the first person point of view, due to the fact that the first person point of view cannot be aware of the dovetailing delays, nor of the extreme multiplication and redundancy of the computations. And if you are OK with, well, mainly here the step 4, you see that the intuitive measure will have to be made on the union of all computations going through the current state. Agreed. 0... I have already begin the generation of a continuum of binary history: Indeed, all those beginning by 0. Then I write 1... So I have begin the generation of the binary sequence beginning by 1. As you see I am dovetailing (not universally though!). Then i generate all possible extensions, which give me two time more work. First the possible continuation of the one beginning by 0. 00... 01... That is how I visualized it, yes. Now, if you interpret the 1 or 0 as results of a self-bifurcation in the UDA, then by the unawareness of delays, the first person indeterminacy of those in front of a never stopping UD, where your computations are dovetailed, in particular on the binary infinite sequences, bears on set with cardinalities of continua, despite mathematically the third person description does not leave the enumerable. And here is where we seem to disagree - but maybe only in a trivial sense - maybe we mean the same thing actually. I agree that everything is still enumerable from a third person point of view, and that the continuum arises from a 1st person point of view, but also only if I imagine all computations of the UD - also the ones infinitely far away. I am skeptical of actual infinities in the real=physical world (in my 1-OM in only believe in potential infinities. http://en.wikipedia.org/wiki/Potential_infinity see Bekenstein Bound, and Seth Lloyd's work on the limits of computation), but when we say that physics is emergent from 1st person point of view of the third person UD, we are also aware that this UD does not exist in time and space (but generates it for inside observers). So no problem with infinities there - I only have a problem with local physical (1-OM) infinities (as presupposed in textbook physics when using calculus for finite volumes of spacetime)- but then again, where they appear locally I think they are also indicative of the multiverse, as in Max Tegmark's suggestion that natural constants could be viewed as indexicals into the Multiverse). So, actual infinity (as opposed to potential) is always a multiverse-feature. To return to the question at hand: the full continuum, also from a first person perspective, appears only when I also take into account reconstitutions at infinity - because, for every finite section I consider (however large), I only have _stubs_ of full reals - and not all the reals. I think a bit along the lines like when one takes an ordinal, say omega, and imagines that it is infinity completed. In the same sense, we need _completed_ infinity for a real continuum (as opposed to only a subset) to arise. And, as the infinity is completed in Platonia, they contribute to the measure of 1-OMs - with the power of the full continuum. Would you agree? only low levels (not necessarily the bottom). Also, I can sometimes speculate that comp could predict there is no bottom. In what way do you think this follows from comp? Because there are histories for every arbitrarily deep probing of physical reality? The real question is what will you think if you, low-level computationalist father have a daughter falls

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Günther, On 07 Jan 2009, at 22:47, Günther Greindl wrote: thanks for your comments, I interleave my response. showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). I guess you were meaning that we have to take into account an infinity of arbitrary long (but finite) delays. OK. Hmm, if we have an infinity of arbitrary long but finite delays, then I can only see aleph_0 histories (because we never take the step to infinity - we can enumerate all histories. Only if we take the step to infinity (as in Cantor diagonalization, were we presuppose the complete listing of the reals and the diagonal does not fit at infinity) would we get 2^aleph_0 histories - or am I missing something here? Cantor's proof is a reductio ad absurdo. It assumes there is a one one correspondence, or bijection, between the positive integers and the infinite sequence on {0, 1} say. Such correspondence could be partially described by the diagram 1 1001000 ... 2 01101001100 ... 3 11000100111 ... 4 1110000 ... 5 10100110101 ... 6 00010111011 ... 7 ... and Cantor get a contradiction from that. You assume the diagram is indeed a piece of an existing bijection in Platonia, or known by God. But if such a bijection exist, or if God can conceive that correspondence, then there is a special sequence that God can conceive too, and that indeed you can bulld from that diagram, indeed the sequence 001110... that you get by flipping the 0 and 1 along the diagonal of the matrix appearing on the right in the diagram. That sequence, thus, exists in Platonia, but definitely cannot belong to the list described above. If it was in the list, there would be a number k k --- 001110... But by definition of the sequence, the kth decimal of that number k will be the flip of itself, meaning that 0 = 1. OK? The reasoning did not depend on the choice of any one one correspondence, so that we know that for each correspondence there is a corresponding anti-diagonal sequence, refuting the assertion that correspondence could exhaust the set of all infinite binary sequences. The set of binary sequence is thus not listable, not enumerable, not countable. You can visualise geometrically the contradictions for any candidate correspondence by the intersection of the line defined by the corresponding number k and the diagonal of the matrix describing the correspondence. Note that the diagonal makes to contradiction appearing always in a finite time. I insist on this diagonal because it is the main tool of the AUDA. A very similar diagonal shows the existence of enumerable but non recursively enumerable set of numbers, which have some role in machine's theology (or more quotes). But then, recall the UD dovetails on the infinite computation, and sometimes dovetails those infinite computation with the generation of the binary sequences. So you have to look at it, in the third person point of view as computations which bifurcate (or differentiate by the rule Y = II), and bifurcate again, and again, and again, OK? And now, what you are missing. I think. It is the distinction between third and first person point of view. As defined in the first and second step of UDA (not the Theatetical one used in AUDA). Looking at the generation of the UD, or dovetailing on all computations, you can see the many computations being generated and you can see them differentiate or bifurcating all the time, where here time is defined by the succession 1, 2, 3, 4, 5, ... itself. If you universal base is two dimensional (like with the Conway Game of Life) you can see the deployment as a static three dimensional conic structure. Everything there, is enumerable. At each UD step, everything is even finite! But things changes when you adopt the first person point of view, due to the fact that the first person point of view cannot be aware of the dovetailing delays, nor of the extreme multiplication and redundancy of the computations. And if you are OK with, well, mainly here the step 4, you see that the intuitive measure will have to be made on the union of all computations going through the current state. There is a continuum of such infinite computations, if only due to that entangling of computation on the dovetailing on the reals and the Y = II rule. The third person probabilities for the *first* person point of views have to bear on the fact that although the reals or the binary sequence are not enumerable it is easy to write a simple program which generates them all. This is not always well understood, but the trick is very simple; just don't name them. In

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Bruno, thanks for your comments, I interleave my response. showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). I guess you were meaning that we have to take into account an infinity of arbitrary long (but finite) delays. OK. Hmm, if we have an infinity of arbitrary long but finite delays, then I can only see aleph_0 histories (because we never take the step to infinity - we can enumerate all histories. Only if we take the step to infinity (as in Cantor diagonalization, were we presuppose the complete listing of the reals and the diagonal does not fit at infinity) would we get 2^aleph_0 histories - or am I missing something here? I will let you elaborate on this. But note that if my consciousness here and now supervenes on past activity, I will elaborate, but please give me time till February, before I will not be able to work on this. then the comp substitution level has to be very low indeed. Yes, very low, that was the idea. You will also need a notion of block universe. The comp doctor will have to be able to manipulate time-lines. No, it is only that he will have to respect relative embeddings - scanning and reconsitution will only be correct regarding _this_ universe and very similar universes, but not with regard to arbitrary computations in Platonia. Remember that even deep, in the sense of Bennett(*) , computer state, can be copied efficiently, so that when you say that (*) Bennett, C. H. (1988). Logical Depth and Physical Complexity. In Herken, R., editor, /The Universal Turing Machine A Half-Century Survey/, pages 227-258. Oxford University Press. Thanks for the reference, I will consider this... If we assume the whole universe to be an automaton, also it's inhabitants would be mechanical =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables - which _could_ be necessary for a duplication - unavailable. OK. But your level has to be really at the bottom, not only below the quantum level. I recall you that the no-cloning theorem does not prevent us to be quantum computer. Right: we cannot say yes to any doctor, yet UDA goes through because at the seventh step the copy need is eliminated. We need only turing emulability, because quantum states, although not copyable, are preparable (in the quantum prepare sense) in many exemplaries, and indeed the UD does doevetail on all quantum computations. Agreed. I think that your bottom really means: my brain is the whole of reality. In the sense that the brain state depends on the whole of reality, and if my brain state (or anyone elses) changes then the whole universe transitions into a new state, yes, but not in the solipsitic form. This may only work if consciousness supervenes not on isolated computations, but only if it is embedded in computations constructing whole universes - but then again, we can't exclude this a priori. And we would still have to consider many worlds, but these would then indeed be _worlds_ and not only OMs with incoming/outgoing histories (of course it would still seem this way from the concrete OM, but with greatly reduced danger of white rabbits) - the laws of physics would not emerge for OM's stranded in the UD deployment but for OM's embedded already in highly structured computational environments - we would only have to take into account duplications of OM's where also whole universes are duplicated. Hmmm (I guess I use OM in a larger sense: those worlds remain computable (assuming comp and bottom-level) and, as such, are generated by the UD). I guess I should not! Could you please clarify what exactly you mean with OM? Maybe this can clear up some misunderstandings? Well, if the quantum laws are derived from comp, then the platonic histories are manipulable in a sense similar to the use of parallel universe (or superposition states) in a quantum computer. Also, the comp Platonia need not be greater that Sigma_1 Arithmetical truth (which is a tiny part of arithmetical truth, itself a tiny part of mathematical truth): the deployment is really just the constructives consequences of 0, succession, addition and multiplication. And it is big as seen and infered from inside, cf Hubble and ... the quantum multiverse. The inaccessibility for manipulation is more of the type: no one can make 17 even, not even a God. Agreed. Best Wishes, Günther --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google

### Re: Boltzmann Brains, consciousness and the arrow of time

- Original Message - From: Günther Greindl guenther.grei...@gmail.com To: everything-l...@googlegroups.com Sent: Wednesday, January 07, 2009 4:47 PM Subject: Re: Boltzmann Brains, consciousness and the arrow of time We need only turing emulability, because quantum states, although not copyable, are preparable (in the quantum prepare sense) What is the quantum prepare sense? Could someone please clarify the foregoing quote? m.a. --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Günther, I agree with your main point. My comments below concerns only details. On 03 Jan 2009, at 23:53, Günther Greindl wrote: Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). I guess you were meaning that we have to take into account an infinity of arbitrary long (but finite) delays. OK. As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? Both. (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). Me too. Without Everett's confirmation I would perhaps have suspected absence of first person plurality, and I would have believed that comp leads to solipsism (and in that case I would have preferred to be a plumber or something ...). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's meaning is not in the head). I will let you elaborate on this. But note that if my consciousness here and now supervenes on past activity, then the comp substitution level has to be very low indeed. You will also need a notion of block universe. The comp doctor will have to be able to manipulate time-lines. Remember that even deep, in the sense of Bennett(*) , computer state, can be copied efficiently, so that when you say that consciousness here and now could supervene on the past, you will have to use not only a low level, but also a rather sophisticated notion of block universe. I am not sure making the level just low will be enough. But from the logical point of view, this could be conceivable. You should develop perhaps. (*) Bennett, C. H. (1988). Logical Depth and Physical Complexity. In Herken, R., editor, The Universal Turing Machine A Half-Century Survey, pages 227-258. Oxford University Press. I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one worry: what if the subsitution level is at the bottom of the universe - (for a moment drawing on materialist intuitions, the universe in the normal sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be duplicated because of the quantum no-cloning theorem (that is what I mean with at the bottom - not above the quantum level). Svozil for instance refers in a number of papers to the work of Moore and Finkelstein that show, assuming we have an automaton, we would witness complementarity. http://tph.tuwien.ac.at/~svozil/publ/publ.html (see for instance these overview papers: Svozil, K. ``How real are virtual realities, how virtual is reality? The constructive re-interpretation of physical undecidability'', Complexity, 1, 43-54 (1996). Svozil, K. Computational Universes Chaos, Solitons Fractals, 2005, 25, 845-859 Svozil, K. Physical Unknowables physics/0701163, 2007) I have read all Svozil's book (but none of its papers). I appreciate and there are complementarities with the UDA reasoning, although it needs some work to make this precise. By the way the quantum logic automaton is another example to get a quantum logic in a classical frame without contradicting the no-go theorems that Stephen was alluding toward. The results of course would also apply if we were solipsist automatons and the whole not (so the arguments are quite compatible with varying versions of machine conception (universe/person) ). I am just saying that we can't know if we are separable from the universe. To state it differently (and to make the connection with complementarity and duplication): If we assume the whole universe to be an automaton, also it's inhabitants would be mechanical =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables -

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Stephen, Stephen Paul King wrote: Nice post! Coments soon. Thanks :-) Looking forward to the comments. Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical Ones'', Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. Thanks for the tip, will have a look at it! Best Wishes, Günther --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

On 04 Jan 2009, at 03:09, Stephen Paul King wrote: Hi Günther, Nice post! Coments soon. Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical Ones'', Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. Nice work. It is in the line of the beautiful theorem of Kochen and Specker. How can we derive quantum logics from purely integer (or even real number) based logics? This paper seems to yeild a no-go theorem! And this confirms the MEC prediction (or re-prediction) that the logic of the physical reality cannot be boolean. I recall you that the material hypostases, when interpreted in arithmetic, gives quantum like logics. There is no reason to suppose they can be embedded in Boolean logics. The no-go theorems shows that quantum logic cannot be embedded in classical logic in observable value preserving way. Such no go-theorems cannot be applied to the AUDA arithmetical quantization, which concerns the way self-observing machine have to structure the comp physical reality. Remember the result by Goldblatt(*) 1974: there is a boolean way to interpret epistemically quantum logic (by the modal logic B). The arithmetical quantization, which captures the first person (plural) points of view, gives a modal logic B (without necessitation rule). It would be a nice research project to show that this extends the no-go theorems to the comp physical quantum logics. This would confirm the highly non boolean (and non Aristotelian) nature of matter, or appearance of matter. The mechanist quantum logic is not derived from numbers, but from numbers personal points ov view: what numbers can observe and share when they observe themselves, and this with a very general notion of observation. It is like the MWI, the most weird is the quantum world, the more we can believe that comp is correct, given that comp entails a rather highly non classical view of the physical reality. All right? More generally and perhaps more simply the no-go theorems forbid a classical reality, it does not forbid a classical *theory* about a non classical reality. The (meta)logic of quantum mechanics itself is classical. If you believed that the non go theorems is a problem for comp, it means that you could be confusing levels with metalevels. All right? Best, Bruno PS Kim, Günther, I will comment your posts with some details asap, but I have some new year activities ... (*) Goldblatt, R. I. (1974). Semantic Analysis of Orthologic. Journal of Philosophical Logic, 3:19-35. Also in Goldblatt, R. I. (1993). Mathematics of Modality. CSLI Lectures Notes, Stanford California, page 81-97. - Original Message - From: Günther Greindl guenther.grei...@gmail.com To: everything-l...@googlegroups.com Sent: Saturday, January 03, 2009 5:53 PM Subject: Re: Boltzmann Brains, consciousness and the arrow of time Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's meaning is not in the head). I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one worry: what if the subsitution level is at the bottom of the universe - (for a moment drawing on materialist intuitions, the universe in the normal sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be duplicated because of the quantum no-cloning theorem (that is what I mean with at the bottom - not above the quantum level). Svozil for instance refers in a number

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's meaning is not in the head). I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one worry: what if the subsitution level is at the bottom of the universe - (for a moment drawing on materialist intuitions, the universe in the normal sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be duplicated because of the quantum no-cloning theorem (that is what I mean with at the bottom - not above the quantum level). Svozil for instance refers in a number of papers to the work of Moore and Finkelstein that show, assuming we have an automaton, we would witness complementarity. http://tph.tuwien.ac.at/~svozil/publ/publ.html (see for instance these overview papers: Svozil, K. ``How real are virtual realities, how virtual is reality? The constructive re-interpretation of physical undecidability'', Complexity, 1, 43-54 (1996). Svozil, K. Computational Universes Chaos, Solitons Fractals, 2005, 25, 845-859 Svozil, K. Physical Unknowables physics/0701163, 2007) The results of course would also apply if we were solipsist automatons and the whole not (so the arguments are quite compatible with varying versions of machine conception (universe/person) ). I am just saying that we can't know if we are separable from the universe. To state it differently (and to make the connection with complementarity and duplication): If we assume the whole universe to be an automaton, also it's inhabitants would be mechanical =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables - which _could_ be necessary for a duplication - unavailable. This may only work if consciousness supervenes not on isolated computations, but only if it is embedded in computations constructing whole universes - but then again, we can't exclude this a priori. And we would still have to consider many worlds, but these would then indeed be _worlds_ and not only OMs with incoming/outgoing histories (of course it would still seem this way from the concrete OM, but with greatly reduced danger of white rabbits) - the laws of physics would not emerge for OM's stranded in the UD deployment but for OM's embedded already in highly structured computational environments - we would only have to take into account duplications of OM's where also whole universes are duplicated. So, what I am getting at, wouldn't you have to modify your argument - the reversal physics/machine psychology - insofar that not only a substitution level exists (COMP), but that this level is separable from a possible universe-machine (the possibility of which we can't exclude at the beginning of the argument). A kind of qualified COMP, QCOMP? Of course, the variant where the whole universe is necessary for duplication would still be machine psychology, but at a different level - at the universe level (classical sense again) and not at the level of everday conception of persons. Maybe COMP with the assumption that consciousness needs whole universes to supervene on (I don't mean that a universe is conscious; persons, brains would be conscious, but they would need the surrounding computations supplied by the universe to provide meaning) is even preferable to the view that one can duplicate a person from _within_ a universe (because of the white rabbit problem). Reading through my post above again, I believe that your COMP argument also works with the

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Günther, Nice post! Coments soon. Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical Ones'', Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. How can we derive quantum logics from purely integer (or even real number) based logics? This paper seems to yeild a no-go theorem! Onward! Stephen - Original Message - From: Günther Greindl guenther.grei...@gmail.com To: everything-l...@googlegroups.com Sent: Saturday, January 03, 2009 5:53 PM Subject: Re: Boltzmann Brains, consciousness and the arrow of time Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a state (do I understand you correctly?). As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's meaning is not in the head). I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one worry: what if the subsitution level is at the bottom of the universe - (for a moment drawing on materialist intuitions, the universe in the normal sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be duplicated because of the quantum no-cloning theorem (that is what I mean with at the bottom - not above the quantum level). Svozil for instance refers in a number of papers to the work of Moore and Finkelstein that show, assuming we have an automaton, we would witness complementarity. http://tph.tuwien.ac.at/~svozil/publ/publ.html (see for instance these overview papers: Svozil, K. ``How real are virtual realities, how virtual is reality? The constructive re-interpretation of physical undecidability'', Complexity, 1, 43-54 (1996). Svozil, K. Computational Universes Chaos, Solitons Fractals, 2005, 25, 845-859 Svozil, K. Physical Unknowables physics/0701163, 2007) The results of course would also apply if we were solipsist automatons and the whole not (so the arguments are quite compatible with varying versions of machine conception (universe/person) ). I am just saying that we can't know if we are separable from the universe. To state it differently (and to make the connection with complementarity and duplication): If we assume the whole universe to be an automaton, also it's inhabitants would be mechanical =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables - which _could_ be necessary for a duplication - unavailable. This may only work if consciousness supervenes not on isolated computations, but only if it is embedded in computations constructing whole universes - but then again, we can't exclude this a priori. And we would still have to consider many worlds, but these would then indeed be _worlds_ and not only OMs with incoming/outgoing histories (of course it would still seem this way from the concrete OM, but with greatly reduced danger of white rabbits) - the laws of physics would not emerge for OM's stranded in the UD deployment but for OM's embedded already in highly structured computational environments - we would only have to take into account duplications of OM's where also whole universes are duplicated. So, what I am getting at, wouldn't you have to modify your argument - the reversal physics/machine psychology - insofar that not only a substitution level exists (COMP), but that this level is separable from a possible universe-machine (the possibility of which we can't exclude at the beginning of the argument). A kind of qualified COMP, QCOMP? Of course, the variant where the whole universe is necessary

### Re: Boltzmann Brains, consciousness and the arrow of time

On 31 Dec 2008, at 23:53, Brent Meeker wrote: The present moment in quantum cosmology: challenges to the arguments for the elimination of time Authors: Lee Smolin (Submitted on 29 Apr 2001) Abstract: Barbour, Hawking, Misner and others have argued that time cannot play an essential role in the formulation of a quantum theory of cosmology. Here we present three challenges to their arguments, taken from works and remarks by Kauffman, Markopoulou and Newman. These can be seen to be based on two principles: that every observable in a theory of cosmology should be measurable by some observer inside the universe, and all mathematical constructions necessary to the formulation of the theory should be realizable in a finite time by a computer that fits inside the universe. We also briefly discuss how a cosmological theory could be formulated so it is in agreement with these principles. Comments: This is a slightly revised version of an essay published in Time and the Instant, Robin Durie (ed.) Manchester: Clinamen Press, 2000 Subjects: General Relativity and Quantum Cosmology (gr-qc) Cite as: arXiv:gr-qc/0104097v1 And On 02 Jan 2009, at 04:01, Kim Jones wrote: Edge Question 2009: What Will Change Everything? http://www.edge.org/q2009/q09_9.html#smolin By some token which would be premature to explain, Smolin's 2001 papers is very near the correct physics that we can extract from the talk of the self-observing universal machine, especially from the 3th and 5th arithmetical hypostases. This includes an impossibility of eliminating time, a non standard notion of truth, etc. But such physics is really a first person construct of the lobian machine, and to explain this you have to agree that elementary arithmetical truth is just out of time, out of space, actually out of physics, and indeed it is math. So to be frank, I disagree strongly with many points of his Edge Question 2009, even if I can agree with the type of physics he is working about. But more generally, any physics, theoretical or experimental, which would contradict the physics extracted from the comp hyp, would be an empirical refutation of the comp hyp. Now Everett physics confirms most of the easiest physical things you can derive from MEC, and, well Smolin's physics too. The apparent contradiction between Smolin and Everett-Deutsch are more due to the attachment to physicalism and Aristotelism than facts or even theory. I am afraid that Smolin's 2009 reifies good ideas in Smolin's 2001, sending him to inconsistency or (cosmo)solipsism. I need some amount of timeless truth to even take my doubt on many other so-called timeless truth seriously enough. Descartes saw this. If you want make me believe that the primality of 17 is time and space dependent, I will ask you to give me the function describing this dependence, or give me an argument explaining why such a function has to exist. And take care that your argument is not time and space dependent itself. I don't understand either (in the Edge 2009) is argument for ethics, just after his argument for relativism. You can search Smolin in the everything archive, for what I have already said about his work here, and we can come back on this, perhaps when everyone grasp the UDA proof, and a bit of the AUDA. I just see Lennart Nilsson post: yes I think so too, although I guess Smolin could perhaps give a more apt and nuanced answer, but reintroducing an absolute moment contradict Einstein relativity (but perhaps not Poincaré's very close relativity theory, sometimes confused with Einstein one). 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

Hi Günther, On 01 Jan 2009, at 23:58, Günther Greindl wrote: Bruno, I have also wanted to ask how you come to 2^aleph_zero Well, in part this results from the unbounded dumbness of the universal doevtailing procedure which dovetails on all programs but also on all non interacting collection of programs (as all interacting one). How do you discern interacting/non-interacting programs? What do you mean exactly with the term in regard to UD? To write and implement a Universal Dovetailer, you have to fix a universal programming language (or machine). Then the UD will generate the list of programs P_1, P_2, P_3, ... and run them by little pieces, let us say of one running step, and this for each program in such a way that it dovetails on all the executions, including those who does not stop, which we cannot avoid. Let us assume tthat the sequence P_1, P_2, P_3, ... P_i ... is the sequence of the zero variable programs (this changes nothing). Now a computation, for example, the computation of P_0, will itself be a sequence of computational steps, like P_1^1, P_1^2, P_1^3, etc ... To run the UD, we dovetail or zig zag on the programs and their computational steps. Exercise: add some relevant zig zagging to the following infinite diagram: P_1^1, P_1^2, P_1^3, P_1^4, ... P_2^1, P_2^2, P_2^3, P_2^4, ... P_3^1, P_3^2, P_3^3, P_3^4, ... P_4^1, P_4^2, P_4^3, P_4^4, ... ... A solution: P_1^1, P_1^2, P_2^1, P_3^1, P_2^2, P_1^3, P_1^4, P_2^3, P_3^2, P_4^1, ... Each computational step P_i^j, of the ith program up to the jth step is completely independent of any other computations P_k^h, when i is different from k. Such computations do not interact. The DU, if programmed correctly, will never let them share the memories or interact in any way. But for each couple (P_i, P_k) there is another program, P_h in the (infinite but enumerable) list P_i which is a mini-dovetailer of the pair of programs (P_i, P_k). This means P_h dovetails itself on the execution of the two programs P_i and P_k. Indeed, trivially, the universal dovetailer execute all the possible dovetailing, the universal one and all the other one. Again, the two new computations of P_i and P_k does not interact. But that is not enough, for all couple of programs (P_i, P_k) there is third program P_g, which you can seen as a bad or buggy dovetailer on the pair (P_i, P_k), which will execute P_i and P_k again, but with just one shared memory, so that progress in the running of one of them will destroy the memory of the other. In that sense the buggy mini- dovetailer makes P_i and P_k interact, in one way. Given that any digital interaction process, it can be simulated by a program, and the UD will soon or later simulate that interaction. For another example, the UD will run all patterns of the game of life, but also all couple of such patterns, all triples, all quadruples, actually all finite pieces of possible Eden garden of possible cellular automata. You can actually imagine any ways of making two programs or machines interact, soon or later the UD will generate ONE computation which will run the interaction of those machines, yet such computation will not interact with the proper other UD-computations. The UD will even generate a universal buggy dovetailing computation which makes all programs interact with each other, in all possible ways. All right? Please ask if something is not clear. It is simpler to explain all this with conical drawings, and the internal zig zagging. In particular each computation is entangled to dovetailing on the reals, What do you mean by this? How do the reals enter the picture? Do you remember the iterated self-duplication experiment? Suppose I invite you to make that experience. But your boss asked you to do some computation P (and thus your computation looks like P^1, P^2, etc... (the number = the steps of your computation). So, you will do your computation and simultaneously do the iterated self-duplication. To simplify I will assume that you do one step of your computation at each duplication. I duplicate you iteratively in two rooms, one with the number zero written on the wall, the other with the number one on the wall. OK? And during that time you make the computation (to please your boss). So you compute P, get the first step of the computation: P^1, go to my duplicator (where you are scanned---and this includes your step result P^1annihilated, and reconstituted in the zero-room and in the one-room. The two of you come back, each one of you compute one step of the computation to get P^2, and enter the duplicator again. Both are scanned, including the P^2 step-result, and then annihilated and reconstituted again in the two rooms. The four of you come back, compute the third step of the computation, and enter again the annihilator , the eight of you come back, compute

### Re: Boltzmann Brains, consciousness and the arrow of time

2009/1/1 Hal Finney h...@finney.org: I want to emphasize that this picture of how Boltzmann fluctuations would work is a consquence of the laws of thermodynamics, and time symmetry. Sometimes people imagine that the fluctuation into the Boltzmann low-entropy state is fundamentally different from the fluctuation out of it. They accept that the fluctuation out will be similar to our own existence, with complex events happening. But they imagine that the fluctuation into low entropy might be much simpler, molecules simply aggregating together into some convenient state from which the complex fluctuation out and back to chaos can begin. While this is not impossible and hence will happen occasionally among the infinity of fluctuations in the Boltzmann universe, it will be rare. It will be no more common for a simple fluctation-in process to occur than for a simple fluctuation-out process. In our universe, knowing it will evolve to a chaotic heat death, we might imagine that molecules would just fly apart into chaos, but we know that is highly unlikely. Instead, by far the most likely path is a complex one, full of turbulence and reactions and similar activity. By time symmetry, exactly the same arguments apply during the fluctation-in phase. The vast majority of Boltzmann fluctuations that achieve a particular degree of low entropy will do so via complex, turbulent paths which if viewed in reverse will appear to be perfectly plausible sequences of events for a universe which is decaying from order to disorder, like our own. This is an interesting idea. I had imagined that the fluctuations in the decreasing entropy or winding up direction would involve chaotic aggregation of matter which would then wind down in a more organised way, giving rise to stars and planets and so on, but as you point out there is no reason to assume this. I am not sure why you suggest that the winding up direction lacks causality (leading to your question about whether it could give rise to consciousness): if all the air in the room moved to one side because, with incredible luck, the molecules all vibrated in the same direction for a few seconds should this event be called acausal? If we are conscious in winding up direction and winding up is no less likely to occur though interesting pathways than winding down, this would imply that at any point, we have about an equal chance of living in the winding up as the winding down phase: we would have no way of knowing. This would be the case whether we are ordinary brains or Boltzmann Brains, since in either case there has to be a winding up before the winding down can happen. A further implication is that there will be far more observer moments in the later stages of the universe than in the earlier stages. This is because unlikely as it is that the universe will wind up all the way to January 1st 2009, it is even less likely to continue winding up to 31st December 2008 (it is far more likely of course to only wind back to a state near the heat death end times, but there are less likely to be observers there). If you support the ASSA, that would imply that you are near your last moment of consciousness, since OM's later in your life have a much higher measure than earlier ones. Under the RSSA or if you take into account Boltzmann Brains that would not be a problem. -- Stathis Papaioannou --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA. In any case the Universal Dovetailer generates all such gaz universes generating the Boltzmann brains. Now the probability that you are implemented by a particular Boltzmann brain is null, as it is null for any particular. With the comp supervenience you have to attach consciousness on ALL the histories going through your computational state. It is a sort of double cone of histories. We cannot belong to the aleph_zero Boltzmann brains state, because, from our first person (plural) point of views we already belongs to the 2^aleph_zero winning (infinite) histories. (or comp is wrong). This is a case for RSSA indeed. I think. Bb are reduced to the usual white rabbits histories, with RSSA, it seems to me. Bruno On 31 Dec 2008, at 22:58, Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going forwards. Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards during the first half of the Boltzmann scenario? The answer is, nothing but very, very odd luck. Time is no more likely to continue to run backwards, or to run backwards the same everywhere in the local fluctuation-area, than it is to start running backwards right now in the universe around you. Nothing stops eggs from unscrambling themselves except the unlikelihood, and the same principle is at work during the Boltzmann time-reversal phase. It is merely that we select, out of the infinity of time, those rare occasions where time does in

### Re: Boltzmann Brains, consciousness and the arrow of time

Bruno Marchal wrote: It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA. In any case the Universal Dovetailer generates all such gaz universes generating the Boltzmann brains. Now the probability that you are implemented by a particular Boltzmann brain is null, as it is null for any particular. With the comp supervenience you have to attach consciousness on ALL the histories going through your computational state. It is a sort of double cone of histories. Are you assuming time as fundamental here? If time is merely inferred then it seems that states of Bbs could fit into the inferred time sequence as well as states that arose in some other way. We cannot belong to the aleph_zero Boltzmann brains state, because, from our first person (plural) point of views we already belongs to the 2^aleph_zero winning (infinite) histories. (or comp is wrong). I don't understand the counting measure. Why are histories order 2^apleph_0? Brent This is a case for RSSA indeed. I think. Bb are reduced to the usual white rabbits histories, with RSSA, it seems to me. Bruno On 31 Dec 2008, at 22:58, Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going forwards. Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards during the first half of the Boltzmann scenario? The answer is, nothing but very, very odd luck. Time is no more likely to continue to run backwards, or to run backwards the same everywhere in the local fluctuation-area, than it

### Re: Boltzmann Brains, consciousness and the arrow of time

On 01 Jan 2009, at 21:10, Brent Meeker wrote: Bruno Marchal wrote: It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA. In any case the Universal Dovetailer generates all such gaz universes generating the Boltzmann brains. Now the probability that you are implemented by a particular Boltzmann brain is null, as it is null for any particular. With the comp supervenience you have to attach consciousness on ALL the histories going through your computational state. It is a sort of double cone of histories. Are you assuming time as fundamental here? If time is merely inferred then it seems that states of Bbs could fit into the inferred time sequence as well as states that arose in some other way. I assume only the sequence 0, 1, 2, 3, 4, 5, ... or the axioms of Robinson arithmetic, or Peano. This is enough to recognize the working of a universal dovetailer, and the execution of all programs. It is not infered but postulate. You can call it a digital time, or you can unravel such a dynamical deploiment into a statical n n+1 dimensional cone (with n the dimension of the space used by your starting universal machine (but some have no concept of dimension, and the statical picture is more a logical than a geometrical one). It is not physical time, nor even the subjective time builded by internal entities. We cannot belong to the aleph_zero Boltzmann brains state, because, from our first person (plural) point of views we already belongs to the 2^aleph_zero winning (infinite) histories. (or comp is wrong). I don't understand the counting measure. Why are histories order 2^apleph_0? Well, in part this results from the unbounded dumbness of the universal doevtailing procedure which dovetails on all programs but also on all non interacting collection of programs (as all interacting one). In particular each computation is entangled to dovetailing on the reals, and infinite computations are multiplied into 2^aleph_zero by this entanglement with the reals. Now this is a good thing because it means that the stable histories will be those who manage that background noise, who exploits it probably. Our mind states are enumerable, but our histories are not. Bruno Brent This is a case for RSSA indeed. I think. Bb are reduced to the usual white rabbits histories, with RSSA, it seems to me. Bruno On 31 Dec 2008, at 22:58, Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving

### Re: Boltzmann Brains, consciousness and the arrow of time

Hal, I have entertained quite similar musings some time ago, and this led me to a position I called naive materialism NMAT some time ago on this list - that causality does not matter, and consciousness would supervene on the material states directly - and both backward and forward versions would actually be the same from an endophysical perspective. But the problem of these considerations is that indeed we get the BB issue and causality loses it's role, leaving us with a quite strange tangle of states. Considering that in a fundamental theory, time shouldn't be a parameter chugging along, and we are still considering an external time (where the cosmic perturbations are actually happening) as opposed to the endophysical time registered by the brains in the fluctuations, the thinking along these lines reveals itself to be even more disappointing. In the meantime I have come to agree with Bruno: It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA. The solution Bruno has worked out is much more satisfying - supervenience on computations, and the physical emerging from the most probable histories. It is a form of objective idealism, avoiding the problems of subjective idealisms which are inimical to scientific inquiry. In sum, BBs and perturbing universes are, I think, more evidence that there is something wrong with materialism (and I say this having arrived on this list being a materialist ;-). Cheers, Günther Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going forwards. Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards

### Re: Boltzmann Brains, consciousness and the arrow of time

Bruno, I have also wanted to ask how you come to 2^aleph_zero Well, in part this results from the unbounded dumbness of the universal doevtailing procedure which dovetails on all programs but also on all non interacting collection of programs (as all interacting one). How do you discern interacting/non-interacting programs? What do you mean exactly with the term in regard to UD? In particular each computation is entangled to dovetailing on the reals, What do you mean by this? How do the reals enter the picture? Cheers, Günther --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---

### Re: Boltzmann Brains, consciousness and the arrow of time

Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going "forwards". Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards during the first half of the Boltzmann scenario? The answer is, nothing but very, very odd luck. Time is no more likely to continue to run backwards, or to run backwards the same everywhere in the local fluctuation-area, than it is to start running backwards right now in the universe around you. Nothing stops eggs from unscrambling themselves except the unlikelihood, and the same principle is at work during the Boltzmann time-reversal phase. It is merely that we select, out of the infinity of time, those rare occasions where time does in fact "happen to happen" like this, that allows us to discuss it. I want to emphasize that this picture of how Boltzmann fluctuations would work is a consquence of the laws of thermodynamics, and time symmetry. Sometimes people imagine that the fluctuation into the Boltzmann low-entropy state is fundamentally different from the fluctuation out of it. They accept that the fluctuation out will be similar to our own existence, with complex events happening. But they imagine that the fluctuation into low entropy might be much simpler, molecules simply aggregating together into some convenient state from which the complex fluctuation out and back to chaos can begin. While this is not impossible and hence will happen occasionally among the infinity of fluctuations in the Boltzmann universe, it will be rare. It will be no more common for a "simple" fluctation-in process to occur than for a simple fluctuation-out process. In our universe, knowing it will evolve to a chaotic heat death, we might imagine that molecules would just fly