• [deleted]

  • Post #41

Dear Tommaso,

Welcome to the essay contest. This essay contradicts quantum mechanics: How your digital/computational universe conjecture theory manages the Heisenberg uncertainty? For this purpose your digital computer must know the definite, absolute information about the position and momentum of every particle. Moreover, this ''computer'' must know all quantum information with absolute precision before events occurs - it is forbidden by quantum mechanics. Also, to perform such processing, the exchange of information and the work of computer must be faster that light. How your digital computation theory explains the EPR paradox and nonlocality?

I can prove a theory false by simply finding one example in which the theory does not hold. Let us analyze your statement: ''all the complexity we observe in the physical universe, from subatomic particles to the biosphere, is a manifestation of the emergent properties of a digital computation that takes place at the smallest spacetime scale''.

I can show you a place where the digital/computational universe conjecture theory is wrong: 1) At the center of a black hole as described by general relativity lies a gravitational singularity, a region where the spacetime curvature becomes infinite. Thus, at the center of a black hole a digital computation is not possible because spacetime curvature becomes infinite. You see, there are places and phenomena which exist without need in the digital computation. Since I found at least one place where the digital computation can not exist, it is a proof that this theory is wrong.

Besides, to process an event the digital computation needs the exchange of information. Inside of the black hole (event horizon) all paths bring the particle closer to the center of the black hole. It is no longer possible for the particle to escape. Since the signal can neither escape from a black hole nor move inside of a black hole, it means the exchange of information is not possible. Since the exchange of information near the event horizon is not possible, it mean that digital computation also is not possible. Pay attention that the digital computation is not possible even outside of the Black Hole, near the event horizon because the exchange of information is forbidden.

The essay is inconsistent; I found propositions which contradict each other. For example: ''There exists a tiniest scale at which the fabric of spacetime appears as a pomegranate, made of indivisible atoms, or seeds''. ''all the complexity we observe in the physical universe, is a manifestation of the emergent properties of a digital computation that takes place at the smallest spacetime scale''.

Suppose that at the level of indivisible atoms a universal computation keeps running and manage the external physical processes. There appears a question: who/what manage this ''digital computer' and the work of the indivisible atoms? It means the existence of the deeper background structure which process and manage the activity of "indivisible" atoms this ''digital computer''. If the universal computation sits at the bottom of a multi-level hierarchy of emergence then where sits the computation which manage ''the universal computation''? Thus, the idea of the digital/computational universe conjecture contradicts to the idea of indivisible atoms.

In conclusion, I agree with you that Reality is ultimately digital, but the digital/computational universe conjecture theory is wrong and inconsistent.

Sincerely,

Constantin

  • [deleted]

  • Post #42

The previous post is my post, by Constantin Leshan. The login does not hold.

Soncerely,

Constantin Leshan

    • [deleted]

    • Post #43

    Hi Tommaso

    My rate is done and you got a good grade. A very well written essay. I agree with the essence of it as I hope you could verify on my essay, even that the style of my writing is quite different.

    Now having said that, I would say:

    I agree our universe is made from some simple basic cellular automata and most things are emergent phenomena.

    I don't agree to identify those automata to space-time and see particles and every thing else emerge from there.

    My position is quite the opposite. I identify the basic automata with particles and see space and time derived from the interaction. Unfortunatly I haven't done concrete definitions and experimentation with my approach.

    I feel my approach may have the problem of having more complex automata but might be easier to codify relativity in there.

    Could you comment ?

    Regards

    Juan Enrique Ramos Beraud

      • [deleted]

      • Post #44

      Hi Juan Enrique,

      Tommaso Bolognesi's essay contradicts quantum mechanics: How the digital/computational universe conjecture theory manages the motion of particle and Heisenberg uncertainty? For this purpose this digital computer must know the definite, absolute information about the position and momentum of every particle. Moreover, this ''computer'' must know all quantum information with absolute precision before events occurs - it is forbidden by quantum mechanics. Also, to perform such processing, the exchange of information and the work of computer must be faster that light. How your digital computation theory explains the EPR paradox and nonlocality?

      I can prove a theory false by simply finding one example in which the theory does not hold. Let us analyze your statement: ''all the complexity we observe in the physical universe, from subatomic particles to the biosphere, is a manifestation of the emergent properties of a digital computation that takes place at the smallest spacetime scale''.

      I can show you a place where the digital/computational universe conjecture theory is wrong: 1) At the center of a black hole as described by general relativity lies a gravitational singularity, a region where the spacetime curvature becomes infinite. Thus, at the center of a black hole a digital computation is not possible because spacetime curvature becomes infinite. You see, there are places and phenomena which exist without need in the digital computation. Since I found at least one place where the digital computation can not exist, it is a proof that this theory is wrong.

      Besides, to process an event the digital computation needs the exchange of information. Inside of the black hole (event horizon) all paths bring the particle closer to the center of the black hole. It is no longer possible for the particle to escape. Since the signal can neither escape from a black hole nor move inside of a black hole, it means the exchange of information is not possible. Since the exchange of information near the event horizon is not possible, it mean that digital computation also is not possible. Pay attention that the digital computation is not possible even outside of the Black Hole, near the event horizon because the exchange of information is forbidden.

      The essay is inconsistent; I found propositions which contradict each other. For example: ''There exists a tiniest scale at which the fabric of spacetime appears as a pomegranate, made of indivisible atoms, or seeds''. ''all the complexity we observe in the physical universe, is a manifestation of the emergent properties of a digital computation that takes place at the smallest spacetime scale''.

      Suppose that at the level of indivisible atoms a universal computation keeps running and manage the external physical processes. There appears a question: who/what manage this ''digital computer' and the work of the indivisible atoms? It means the existence of the deeper background structure which process and manage the activity of "indivisible" atoms this ''digital computer''. If the universal computation sits at the bottom of a multi-level hierarchy of emergence then where sits the computation which manage ''the universal computation''? Thus, the idea of the digital/computational universe conjecture contradicts to the idea of indivisible atoms.

      In conclusion, I agree with you that Reality is ultimately digital, but the digital/computational universe conjecture theory is wrong and inconsistent.

      Sincerely,

      Constantin

      Dear Constantin,

      would it be wise to say that Quantum Field Theory is wrong because it does not predict the existence of unicellular organisms?

      This is not meant to be provocative, but only to express what I believe is the 'delicate' status of any conjectured theory of everything (QFT not even pretending to be one). Any such conjecture should maximize the number of explained physical phenomena while minimizing the machinery of the explanations, for example by getting rid of universal constants such as c and G, which should be derived, not assumed.

      I believe that the digital/computational reality conjecture (I wrote 'conjecture', not 'theory'), could hardly be beaten in terms of simplicity -- any kid can understand and reproduce the steps of, say, a deterministic Turing machine moving on a binary tape, or on a graph -- and this is already a great incentive for investigating it. But it is equally clear that the number of 'proof obligations' assigned to the conjecture is explosive, offering much room to criticism, until these are not discharged.

      Then, looking at the long list of TODO's , let me first summarize the good news, and tick the phenomena that occur in spacetime, that the conjecture can comfortably explain, via emergence in computation (see also essay and references):

      - random-like behaviors;

      - periodicity, and co-existence of regular-periodic and random-like structures;

      - self-replication;

      - localized periodic structures that interact with one another, similar to particle scattering diagrams.

      All these can be observed in cellular automata as well as in algorithmic causal sets.

      What I find almost miraculous is that we get these features for free, that is, without coding anything of physical flavor into those simple models of computation. And I do hope that you agree in considering the above as fundamental PHYSICAL phenomena, in the broad sense that they characterize qualitatively our universe, as we perceive it.

      I would not endorse any ToE proposal that does not perform VERY well at these tasks -- first qualitatively, and then, of course, also quantitatively. In my essay I additionally suggest that these properties, in duly varied forms, should manifest very early in the history of the universe.

      I realize that this conjecture represents a radical shift of perspective, in open violation with a principle supported by many scientists (e.g. Carlo Rovelli), also expressed somewhere in these blogs, that science always progresses incrementally, by smooth improvements of the best existing theories. To say that this has always been, and will ever be the case, is quite a strong statement (proposal for the next FQXi Contest: 'Is the History of Physics Discrete or Continuous'?). But, if the 'continuous' solution is preferred, it would be certainly wise to widen the domain of theories to be considered for improvement or integration, including not only SR, GR and QM, but also Complex Systems, Self-Organization, and, or course, Darwin.

      I have taken a larger tour than you probably expected. You raise specific points and I do want to answer them as punctually as possible. Take this as a preamble. I'll be back.

      Bye for now

      Tommaso

      Constantin (and Juan-Enrique), I have given a first answer to your objections up in the blog where you raised them first. The rest of my replies comes hopefully tomorrow. Look for it by scrolling up to that same place. Thanks. Tommaso.

      SECOND PART of my answer.

      (The ultimate bottom)

      You find a contradiction between placing indivisible atoms of spacetime at the bottom of reality, and the need for a digital computer that runs the evolution of this collection of atoms. You seem annoyed by the fact that such a digital computer would represent a 'deeper background structure' beneath the level of these indivisible spacetime atoms, requiring perhaps even an operator (you ask 'who/what manages this digital computer'?): discrete spacetime would no longer be the very 'bottom' of the universe. The answer is simple: I do NOT postulate the existence of such a computer, in the basement or elsewhere, as clearly written at the bottom of page 1 in my essay. An algorithm, as well as a differential equation, is simply a formal way to describe dynamics. No need for hardware.

      (Computation and curvature)

      You write that 'at the center of a black hole, a digital computation is not possible because spacetime curvature becomes infinite'. I completely agree that your PC (or even my Mac!) would start having computing problems a while after crossing a black hole horizon. But, again, we are not talking about hardware, we are abstractly talking about computation. Better: computations on graphs. The variety of structures and phenomena that one can obtain out of algorithmically evolving graphs is formidable. A cheap proof of this, if you wish, is that when you describe phenomena such as those involving black holes, you tend to visualize things precisely in terms of points and arrows, which is what directed graphs are made of...

      By the way, a very good 1999 paper by Margenstern and Morita proves that, in the context of cellular automata, spatial (negative) curvature offers indeed a great computational advantage over flat space (M. Margenstern, K. Morita, 'A Polynomial Solution for 3-SAT in the Space of Cellular Automata in the Hyperbolic Plane', Journal of Universal Computer Science, vol. 5, no. 9, Springer, 1999, pp. 563-573). Amazing.

      However, to me, the appropriate question is not whether a computation is possible inside a black hole, but, rather, what IS a black hole, how does it look like or manifest, in a graph-based, computational spacetime. I don't know. But simple concepts such as sink node (one with only incoming arcs), or strongly connected components are available that may help. Curvature can also be defined for (planar) graphs, called 'combinatorial curvature'. It is only finite, but possibly unbounded, if you grow the number of faces sharing the inspected node, as it can indeed happen in some of my algorithmic causal sets.

      (Quantum effects)

      If I had good answers for these problems, they would have appeared very early in the essay. Stephen Wolfram has some potentially useful suggestions for entanglement (NKS book, ch. 9). I have long discussed the quantum effects issue with Alex Lamb, who is also participating to this Contest , and he half-managed to convince me that a form of nonlocality could be achieved if we imagine the algorithmic graph rewriting to take place directly on the causal set, rather than on an underlying spatial support, as I've done so far.

      But the more general question is: are we going to eventually apply the standard QM techniques and compose instances of discrete spacetime in a gravitational path integral -- a sum over histories? Perhaps... but later. In doing so, we could follow, for example, the work of Renate Loll and collaborators, who take sums of causal dynamic triangulations (CDT) of spacetimes, and investigate consequences such as emergent spacetime dimension. But I am reluctant to do this, at least before having fully explored the potential of a classical approach to emergence in discrete, computational spacetime. Exciting phenomena such as those illustrated at Figures 3 - 5 of my essay would probably be obscured by a QM treatment.

      Finally, while I have no problems in conceiving 'computations' without 'computers', I am more skeptical about defining 'observations' without 'observers', and QM effects do depend on rather intrusive observers, engaging in interactions that affect both the observed and the observer subsystem. In a tiny, discrete, newborn universe that has just reached the size of say 33 elements -- counting edges, nodes, faces, or simplices -- is there enough room for this interaction? Is there room for an observer? (an INTERNAL observer, that is). Maybe quantum effects, and perhaps even relativistic ones, unfold only at a later stage, when entities emerge that can play the role of (proto-)observers. But this is only wild speculation.

      • [deleted]

      • Post #49

      Dear Tommaso,

      My remark concerns your as well as other purely 'computational approaches' to physics.

      What troubles me about them is that they fail to address the nature of physical reality: as I discussed elsewhere, theory of computability came out of logic and has never been concerned with this question.

      At the same time, physics is the central natural science, and if it does not address the above question, as it has tried to do so far, we are left with no science addressing it.

      • [deleted]

      • Post #50

      Dear Tommaso:

      I think my previous question - or the answer for it- got lost with the answer from an for Constantin.

      I think your essay is great and your proposal of identifying space time "atoms" with a cellular automata yet to be debugged and understood is plausible. From experiments - or simulations- like the ones presented in "new kind of science" and in your essay we see "particles" and all sorts of things emerge. We could even find quantum mechanics emerging from there.

      As you say, the automata are not yet "seen" and not debugged.

      I think - as I propose in my essay- it might also be plausible to search the basic automata on the particles or sub particles instead of in space-time. I identify the basic automata with particles and see space and time derived from the interaction. Unfortunatly I haven't done concrete definitions and experimentation.

      I feel my approach may have the problem of having more complex automata but might be easier to codify relativity and quantum mechanics in there.

      Now, again, could you comment on the different approaches?. I do believe in an algorithmic universe, as many others -like Hector Zenil- do.

      Regards

        • [deleted]

        • Post #51

        Dear Juan Enrique Ramos Beraud,

        You supports Tommaso' essay because you have the same essay ''Universe is a computer'' with the similar statements and errors. If you want I can review your essay and show you a lot of flaws in your essay.

        Sincerely,

        Constantin

        • [deleted]

        • Post #52

        Dear Tommaso,

        Your answers are unconvincing and wrong. Moreover, I suspect that you are trying to suppress my questions by the stream of senseless information. It is impossible to find the answers for these questions because this theory is fundamentally wrong.

        Let us begin again with quantum mechanics. Your essay states that all the complexity we observe, from subatomic particles to the biosphere, is a manifestation of the emergent properties of a digital computation that takes place at the smallest spacetime scale. How this digital computation can explain the simple motion of free particle, the Heisenberg uncertainty? For this purpose this digital computation must know the absolute information position-momentum about every particle before events occurs, that is forbidden by quantum mechanics.

        And I don't see any answer for this problem; your words about Quantum effects, Stephen Wolfram, Renate Loll explain nothing; It is a stream of senseless information. You cannot explain it by definition; it is a fundamental flaw in this theory.

        The next flaw about black holes: I found at least one place where the digital computation can not exist, it is a proof that this theory is wrong.

        And your answer is senseless: ''I completely agree that your PC (or even my Mac!) would start having computing problems a while after crossing a black hole horizon. But, again, we are not talking about hardware, we are abstractly talking about computation''. Do you think your spatial atoms will be able to process information inside of black hole, in singularity? Inside of the Black Hole the exchange of information is not possible, therefore the digital computation cannot work. Since I found at least one phenomenon/place that exist without need in the digital computation, it is a proof this theory is wrong.

        Another argument also is not valid: ''By the way, a very good 1999 paper by Margenstern and Morita proves that, in the context of cellular automata, spatial (negative) curvature offers indeed a great computational advantage over flat space''. They refer about the usual curvature but not infinite curvature, singularity.

        Thus, this theory is fundamentally wrong.

        Regards,

        Constantin

          • [deleted]

          • Post #53

          Constantin:

          If you find my essay wrong, it's own thread is the place to comment it, and yes I would love the criticism.

          Tommaso:

          I would like some comments any way.

          Yours.

          Juan Enrique Ramos Beraud

          • [deleted]

          • Post #54

          Dear Tommaso

          After recovering from my cataract operations I re-read your essay, and enjoyed the lovely photo of the pomegranate and the beautiful causal set plots. I also read the paper by Reid that you referred to. I still do not understand several aspects of causal sets. With my limited understanding of the technicalities involved I will try to express my reaction to the concept as applied to physics: You started by discussing automata and I could follow the logic of causality between nodes following a simple algorithm as in Wolfram's NKS. I have no access to the printed references of your other papers and could not understand the Termite simulations.

          Generally I think complications occur when applying the automata concept to physics. GR and Quantum mechanics are accepted as they are now formulated, and the simplicity of a node structure has to be abandoned to accommodate their physically unrealistic and mutually incongruous methodologies. The resulting causal sets are bloated beyond necessity. In my earlier 2005 Beautiful Universe theory on which my present fqxi paper is based, both GR and QM have to be reverse-engineered and some complications discarded before my simple dielectric node-interactions are applied. Hope this makes some sort of sense!

          Best wishes from Vladimir

          At that level, a universal computation keeps running. We do not know yet

          the program code, but, in accordance with a fundamental principle of minimality

          ('Occam razor'), we like to believe that it is small, at least initially.

          Tommaso,

          Do you think we will ever know the "program code"? You provide a fetching argument, but I tend to believe that reality is unknowable, though my argument isn't as definitive as yours.

          Jim Hoover

            Hi Juan Enrique,

            first let me clarify once more that the computational model I regard as most promising for deriving causal sets (that is, instances of spacetime) is NOT cellular automata, but network mobile automata, a sort of Turing machine acting on graphs by applying graph rewrite rules. In the causal sets derived from the computations of this model, MANY 'particles' may emerge as a result of the operation of ONE single, state-less control head, as it happens with Turmites. With cellular automata you may also obtain many particles, but you have to assume the synchronous action of MANY cells (many active elements). One active element is cheaper than many.

            It seems that the ingredients you require for cooking your universe are MANY particles, modeled as some sort of relatively complex automata. It would be interesting to run some simulation of your system, for checking what might possibly emerge. Being very lucky, this might give some anticipation of what could happen when starting with more minimalistic assumptions.

            But, for interacting, your automata probably need a background where to move. That's additional work to be carried out, and another elements that adds 'weight' to the model...

            Cheers

            Tommaso

            • [deleted]

            • Post #57

            Constantin,

            your last post is basically a cut and paste of your original message: I could probably cut and paste my original answer again here (but I won't). Apparently, none of my arguments has succeeded in convincing you that there are many good reasons for investigating the computational universe conjecture (not 'theory'), in spite of the many problems that are still open. Never mind. I still see the glass half-full, while you see it half-empty...

            Tommaso

            PS - When you cross a black-hole horizon, nothing special happens to you; hitting the singularity at its center is another story. But in a discrete model of spacetime there is no room for infinities, and we talk, for example, of huge, but still finite curvature. A computation may well produce (or take place on) a graph with huge curvature!

            • [deleted]

            • Post #58

            Thanks on the comments. Very enlightening.

            • [deleted]

            • Post #59

            Yes, my last post is basically a cut and paste of my original message because I don't received any rational answer. Your ''answer'' explains nothing, it is a stream of senseless information; I'm afraid it is impossible to find an answer because it is a fundamental flaw in this theory.

            ''I could probably cut and paste my original answer again here.'' It makes no sense to cut and paste it, since it is a senseless information. Your ''original answer'' cannot explain my questions and therefore it is senseless.

            ''But in a discrete model of spacetime there is no room for infinities, and we talk, for example, of huge, but still finite curvature''.

            Please read Wikipedia Black Hole - ''At the center of a black hole lies a gravitational singularity, a region where the spacetime curvature becomes infinite. Inside of Black Hole the exchange of information is not possible, consequently no computation is possible. Since I found at least one phenomenon that exist without need in computation conjecture, it is a proof this theory/essay is wrong.

            Also this theory is forbidden by quantum mechanics and Heisenberg Uncertainty. The computational conjecture is not able to explain the motion of a simple particle and Heisenberg Uncertainty. To process the motion of particle, your computation conjecture must know the complete information about position and momentum before events occurs. Also I found other errors yet in this theory.

            ''there are many good reasons for investigating the computational universe conjecture''

            We need the true, powerful Science, if we support the erroneous theories our civilization may die. There are revolutionary theories supported by nobody because all money are absorbed by false theories. It is a crime against humanity and science to support the false theories.

            Constantin

            Hi James,

            I am certainly optimistic about the possibility for science to understand more and more about nature, but I can imagine at least one way in which this process will never come to a conclusion. The upper end of the hierarchy of natural emergence is a moving target, that science cannot anticipate, but only monitor. I believe that science will never be able to predict the major evolutionary steps in the history of the universe, or the next layer of emergence (a simple retrospective example of such a step would be the appearance of life as we know today). The reason is that simulating this evolution would take at least as much time as the time taken by nature for unfolding it for real. There is no computational shortcut. In this respect, Wolfram had the right intuition with his concept of 'computational irreducibility'.

            Nevertheless, I expect a number of nice progresses to happen, as we try to figure out the 'program code' for nature. To me, one of the most desirable achievement is as follows. We should be able to find a simple program in which the localized entities that emerge should not only be capable of Turing-universal interactions (this has been done), but should also manifest some ability to modify their own behavior, to compete, and to evolve, giving rise to a sort of Darwinian ecology. I am fully convinced that the mechanisms of natural selection and evolution should play a role also at the level of physics, not only of biology. Perhaps a first indication of this trend would be the emergence of a population of entities that act as sequential (in the sense of stateful), as opposed to combinatorial (stateless) devices. Note that this whole system should be fully supported by the operation of ONE control head only. And, we should not explicitly program the system for behaving like that -- it should all emerge for free. This is what I believe is possible, and has NOT been done yet!

            As I suggest at the beginning of my essay, it would also be great if the rule of operation of this little automaton were not fixed apriori, but evolved itself...