Dear Tommaso
I read your essay with great interest, I think the possibility of model reality based on a digital model is a very interesting point but the potentiality it does not reside on the discreteness but on emergence. I tried to explain this on my essay from a different perspective that reveal the importance or true meaning of the digital approach, I would like to hear your opinions about it.
Regards,
J. Benavides
Hi John,
I've read your essay and I really like it. I will rate it, and comment at your page. Ciao
Tommaso
P.S. Fotini Markopoulou is a 'she', not 'he'.
Hello,
I liked this essay. I think it is more appropriate for this contest although I think it considers a very restrictive view of the problem. Unlike the other three essays of high popularity, which I basically believe they should not have been accepted at all, this essay offers a novel perspective although too "ontological".
Peter, I think your comment is mean and uninformed. You should be reminded to be constructive. Remember that the essays are being rated by the community too, so if you think they don't even deserve to be accepted you are also disqualifying the rest of the participants.
Dear Tommaso,
Your essay offers an impressive look at the idea of emergence from CA and the connection with quantum gravity. Fascinating and well-organized!
Best wishes,
Paul
Thank you Peter.
I guess that any unifying theory of everything, and, in particular, one based on emergence, will be somehow 'restrictive' by definition: it will consist of a simple, completely abstract-looking, computational rule, and all the rest should emerge from there. Proving that the right physics eventually emerges will require a lot of additional brain and computer work, but that would not be, strictly speaking, part of the fundamental theory. Anyway, I suspect this is not what you meant by 'restrictive' -- or was it?
As for the 'ontological' flavor, in fact I am doing a lot of concrete things in my daily research on this topic, as reported in some of the references. Mainly, I am designing and implementing algorithms, turning computations into causal sets (spacetime candidates), monitoring their behaviors by devising appropriate complexity indicators, and so on. Several essays in this contest seem to follow much more philosophical paths.
Thanks a lot for considering my essay well organized. At this point, however, I have clearly identified a presentation bug: I should NOT have included Figure 2 ('Emergent structures in Wolfram's elementary cellular automaton 110'), since it apparently leads readers to erroneously believe that my work is focusing on CA's. Most of my experimental results (as discussed in some of the references) refer to automata with a single control head operating on a graph; these are much more similar to Turing machines than to CAs, and do not require global synchronization.
Dear Tommasso
You do not pay attention to my essay
http://www.fqxi.org/community/forum/topic/946
OK, perhaps I should not have said 'CAs' but rather 'automata or 'digital computation.' All in the spirit of Turing and von Neumann, at any rate!
Best wishes,
Paul
Tommasso
Very nicely written and argued essay, though I note no falsifiability. There are however possible distant parallels with my own, adding one more dynamic dimension, although I believe I show quite conclusively and falsifiably that Lorentz cannot and will not emerge from your pomegranate. I believe this also becomes intuitive. I do however see your essay as more 'on subject' than some.
I know we are close and wish to say I think our concepts are closer than appeared initially the case. I go, and cannot go, beyond the logic and conception, that is my domain but hope you also see both aspects are important. To progress the disparity of mankind needs to work in complementarity not just in competition.
I have just added a logical explanation in my string of where it appears our predecessors got lost over 100 years ago. It is important this is studied and analysed and I hope you will offer comment. If correct it would be nice if we could see it in use before 2020! I have offered other thought experiments in my and other strings, and could do more. If you have a test for the model do ask.
Well written, and very best of luck
Peter
Tommaso
A very interesting essay; definitely one of the more worthy approaches amongst the submissions I have had the time to look through so far.
Has also been very interesting to see in recent times (e.g. from your paper, the discussion here and other related research) that concrete examples of work, concerned with such discrete worldview topics, are now being pursued!
I have spent many years pondering such topics, but have not yet properly delved into fully quantitative modelling; so I will have to look into some of the work you mention or reference here.
From your paper (and this discussion thread) I get the impression we probably have fairly similar views concerning some of the likely underpinnings of macroscopic reality
e.g. the existence of some level of discrete substrate underlying space-time; several levels of emergent order between that substrate's operation (whatever form it is eventually found to have!) and the world we and our instruments actually observe; and some general organising principle possibly accounting for the generation of those differing levels of order/complexity (perhaps an evolutionary/Darwinian-selection type process of some sort??).
I only heard about the contest recently, so was regrettably unable to enter an essay of my own, but if I had been able to enter, my contribution probably would have touched on some of the overall topics your essay addresses.
So, good luck with the contest.
Regards,
David C.
Hi Tommaso,
I like your essay, well written and illustrated, and very convincing while still open to other point of view. My own work is in the way of debugging it. But I prefer to use the word hacking. I present a trivalent graph model where GR emerges through Tetrad gravitationnal field as in LQG, and where SM emerges from internal structure as E8 roots from a double D4 lattice. Surprisingly, the emergent structure in my figure 10a (48 valent supernode as a trivalent graph) is very similar to the graph on figure 23 of your paper in Complex System that I am referencing, but I haven't noticed this before. So your c(4, {16, 4}, 199) trinet may represent a fundamental cell of universe before crystallization and polarization. After this phase transition to hyperdiamond universe, spacetime would be born, instead of needing a big bang. (just a big freeze). But this universe, if perfectly crystallographic, would be perfectly void. And some minimal imperfections, yes, bugs, are nothing else that all matter, energy and forces, we have in our universe. I prefer not to remove all the bugs...
Best regards,
Ray
Paul,
sure you are right, that's the general spirit of the approach, which is in itself already quite controversial.
But let me take this opportunity to point out that, within this general approach, several models are available that, in my opinion, should not be considered as equivalent, and not only because of the mentioned issue of global synchonization. I am referring to what Ed Fredkin calls 'the tyranny of computational universality': many models of computation are universal, that is, they can simulate a universal Turing machine and perform any algorithm. So, why bother choosing one in particular, for the foundations of physics?
Well, when model B tries to simulate a computation of model A by using its own mode of operation, it usually needs to perform additional 'spurious' steps, that have to be filtered away in order to retain just the original steps (not to mention the fact that the original input has to be coded before being fed into the simulator). Fredkin suggests that there should be a one-to-one correspondence between the 'states and function' of the model and those observed in the physical universe: so, the choice of a specific (universal) model is indeed relevant, because we would select one, or the one, whose features have a clear physical counterpart, and viceversa.
In my work I have adopted this nice, economical idea by Fredkin, specializing it to a one-to-one correspondence between the events of physical specetime and those of a causal set from a formal computation. And, again, the choice among different causal sets from different models is far from being irrelevant: for example, some causal sets end up being totally ordered, or admit nodes with unbounded degree, others don't. These properties have clearly an impact on the emergent physics.
Regards
Tommaso
I did. I suspect that one could relatively easily 'show' that the ratio 2:1 is equally important...
Well thank you. It seems you have well captured the main ideas of the essay. If you decide to start doing some quantitative modeling of the 'substratum' and find something interesting let me know. Tommaso
Hi Ray,
I've checked the similarity between our two figures. Honestly I am not too surprised by this, since we are essentially talking about a binary tree, possibly with linked leaves. That graph popped up many times in my experiments, and it is far too regular to be of any interest.
I agree with you that 'bugs' make the universe interesting, and, in spite of my essay title, I can guarantee that, if we ever find that code, I will not be the one who starts debugging it :-)
Tommaso
Tommaso,
Many thanks for the clarification! Interesting that there are many models of universal computation, and that one must be careful in choosing the model which would be the most economical.
Best regards,
Paul
I show it in my comment
Drew attention please!
Dear Sir,
You begin with a postulate "There exists a tiniest scale at which the fabric of space-time appears as a pomegranate, made of indivisible atoms, or seeds. This view is reflected in models such as Penrose's spin networks and foams, and is adopted in theories such as Loop Quantum Gravity and in the so called Causal Set Program". In physical terms what does this statement mean? None of these have ever been proved in experiments. None of these terms have been precisely defined. Most of these postulates are based on circular logic as one view is based on another unsubstantiated view that is sought to be proved by the former. Most of these views are mere words and contrary to observation and logic. All through you have not defined what is reality.
You say: "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. Perhaps it is a self-modifying program: code and manipulated data might coincide." Then how could you discuss the issue scientifically? Science is not about beliefs or suppositions. Your entire essay exhibits your beliefs and suppositions that are far from scientific descriptions. This is one of the root causes of the malaise that is endemic in scientific circles. Thus, theoretical physics is stagnating for near about a century while experimental physics is achieving marvelous results.
You say: "sometimes we identify new, unifying laws that allow us to jump one level down: laws that appeared as primitive (e.g. Newton's law of gravitation) are shown to derive from deeper laws (e.g. General Relativity)." But both have been proved wrong by Pioneer Anomaly. This has given rise to MOND, which is also not satisfactory. The reason for such chaos is that modern science has couched in the cloak of incomprehensibility that is hindering progress of science. In several comments under various essays we have shown how gravity is a different category of force that cannot be united with other fundamental forces of Nature. It is a composite force that stabilizes and not attracts.
You say: "Emergence in reality calls for abstraction in description, and implies accuracy loss. Abstraction - e.g., assuming perfectly spherical planets of uniform density - is the price we pay for keeping mathematical formalizations simple at all levels." Is it true or necessary? In our essay we have discussed this problem. One of the contributors has made a proposition relating 3:1 to the universal law. We have given a physical explanation to this view in some of our threads under various Essays. Similarly, we have described under various threads that density variation (and not uniform density) causes all movements in the fields whose effects on bodies appear as different forces.
You say: "complexity in physics = emergence in computation". This statement is true only in a limited sense. Computation is related to accumulation or reduction of numbers. Numbers are a property of all objects by which we differentiate between similars. Linear accumulation or reduction of numbers is called addition and subtraction respectively. Non-linear accumulation or reduction of numbers is called multiplication and division respectively. Non-linear accumulation or reduction of numbers is relatively complex. As you say: "the fabric of space-time appears as a pomegranate; made of indivisible atoms, or seeds." They can accumulate linearly, but mostly they accumulate non-linearly. To that extent your statement is correct. But "pattern of interacting particle trajectories" are not numbers (unless you are talking about distance or thickness etc). They are effect of various forces acting on particles. You can only compute the effect of various forces acting on particles - the more non-linear the interaction, the more complex it is to compute.
You "believe that cellular automata provide only a nice metaphor for learning about emergence, not a satisfactory choice for an actual fundamental theory of physics, due to the annoying presence of a predefined background and the costly assumption of global synchrony for cell updating". But we hold that if you understand it correctly, cellular automata can provide an effective approach to understand reality. Rule 110, which requires an infinite number of localized patterns to be embedded within an infinitely repeating background pattern, can be the basis. But unless one knows how the images are generated, one would end up disappointed. The background pattern is fourteen cells wide and repeats itself exactly every seven iterations. We have a model that explains it correctly.
Regards,
basudeba
Sir,
In the above thread, we had spoken of gravity as a different type of force from other fundamental forces of Nature. Here is a brief discussion on that.
Before we discuss whether the force we were referring to was gravity, we will like to discuss something about force itself. A force is experienced only in a field (we call it rayi). Thus, it is a conjugate of the field. If something is placed in a field, it experiences something else. This something else is a kind of force. Depending upon the density variations of the field, we experience the force differently. Hence we call it by different names. While the field is one, the forces are many. Since they are conjugates, we can also say that different forces create different variations in the field.
The basic nature of the field is equilibrium. The basic nature of forces is displacement. This gives rise to two different types of inertia: inertia of motion due to forces and inertia of restoration (elasticity) due to the field. This leads to both these inertia acting against a point of equilibrium. In such a scenario, the combined effect leads to confinement around the point of equilibrium. The confined structure is called particle. Thus, all particles have a central point of mass or nucleus, an extra nuclear field surrounding it and fixed orbitals confining it. This is the common feature of all particles be they quarks or the Cosmos. The confinement may also cover the field without the central point. This is caused due to non-linear interaction of the forces. We will describe the mechanism separately. In such a case the field behaves like a fluid. The latest finding of LHC is that the Universe was created from such a super-fluid and not gases. The confined field also interacts with the Universal field due to difference in density. This in turn modifies the nature of interactions at different points in the medium (Universal field).
A force can act only between two particles as only a particle can influence the field, which in turn can be experienced by another particle. If the external force of the field is more than the confining force of the two particles, then the two particles break up and join to form a new particle. We call this "sambhuti". In the opposite case, the two particles experience the force without being internally affected. The force acts between the centers' of mass of each treating each as a point particle. We call it "bibhuti". This second category of relationship, which we call "udyaama", is known as gravity. Since it stabilizes the two bodies at the maximum permissible distance between them depending upon their respective masses, we call it "urugaaya pratisthaa". For reasons to be discussed separately, this is possible only if gravity is treated as a composite force.
The first category of forces, which are interactions between two bodies, acts differently based on proximity-proximity, proximity-distance, distance - proximity and distance - distance variables. We call these relationships "antaryaama", "vahiryaama", "upayaama" and "yaatayaama" respectively. This interaction affects the field also inducing various local disturbances. These disturbances are known as "nitya gati", "yagnya gati", "samprasaada gati" and "saamparaaya gati" respectively. Any particle entering the field at those points feels these disturbances, which are known as the strong nuclear interaction, weak nuclear interaction, electromagnetic interaction and radioactive disintegration respectively. Thus, you can see that gravity belongs to a completely different group of forces and cannot be integrated with other fundamental forces of Nature in the normal process. Yet, it has a different function by which other forces can be derived from it. We will discuss that separately.
According to our theory gravity is a composite force of seven forces that are generated based on their charge. Thus, they are related to charge interactions. But we do not accept Coulomb's law. We have a different theory for it. We derive it from fundamental principles.
Regards,
basudeba.
