• [deleted]

Ben,

Indeed I interpolated closed and exact. I have done this in the past as well.

I read last night Barbour's essay and had some thoughts about this that I will relay to Julian later today. This touches on ideas of graphs, causal sets and dynamic triangulation.

Cheers LC

Dear Viraj,

You're absolutely right... the form evidently won't accept a "less than" sign without putting it in a latex environment, and it deleted everything below, which was 80 percent of my post. I finally got it right, but there was another abortive post in between. I apologize for cluttering your thread, but all the comments are there now at least!

Regarding your remarks about the contest and the rating, there are many more than 35 good essays among the 270 or so in the contest, so no one should be too disappointed if his or her own submission isn't a finalist. For a complete outsider and first-time contributor like myself, the whole point of participating in this contest is to have the opportunity to discuss many interesting ideas with serious and original thinkers, and to make contacts with other scientists of similar interests.

In my opinion, the final community ratings are unlikely to look anything like what they do now; probably most people have not yet voted and it wouldn't be surprising if submissions in the top 10 now finish out of the top 100. The FQXi membership includes many of the most distinguished physicists in the world, and I imagine most of them are very busy. I seriously doubt if they are paying very close attention to this contest on a daily basis or have read or rated most of the essays.

In my view, the ratings are not worth worrying about too much, since doing so only distracts from the science. A high rating would be nice, but I would prefer to try to understand other people's ideas, circulate my own, and let the chips fall where they may. Take care,

Ben

Lawrence,

Thanks... I'll be sure to look at that. There are at least two other essays involving shape dynamics that I think are interesting, the one by Sean Gryb and Flavio Mercati, and the one by Daniel Alves. My general inclination is to regard this form of relationism as less well-motivated and compelling than the causal versions, but it has some attractive qualities, and some of the authors here have expressed it quite well. Take care,

Ben

Hi Ben,

Quite an ambitious essay indeed! If we ever meet, I suspect we will have many interesting discussions.

I applaud your courage for trying to reject so much structure and still try to reproduce the rich structures of GR and the Standard Model. It is certainly not an easy task as is evidenced by the efforts of the Causal Sets people. However, I have always found that these approaches are well motivated. Good luck with your approach and in this competition!

Sean.

    • [deleted]

    Hi Ben,

    Thanks for re-posting your message in my thread.

    About your other comments:

    It is not that I am dead keen to get a good rating. I too am in the 'contest' more to use it as a forum to get to know people and ideas, and to circulate my own. You know the long forgotten motto of the Olympics - "Not to win but to take part".

    But an important aspect of taking part amounts getting the attention of independent parties (eminent scientists who are FQXi members) to my essay for whatever it is worth, as much my reading other participants' essays. But the avenue to reach FQXi members is blocked, while 'Top Essays' are freely advertised in the Main blog. It is also a fact that the content of some of these "Top Essays", do not conform to the context of the topic of the contest.

    This is a genuine concern I have about the way the "Contest" is run.

    However, I am not worried about the 'contest'. If things are left for chance without manipulations, I know the chips would have fallen in a cetain way, but the way things are it appears they won't. It is just the instinct in me not to take things sitting down that bugs me.

    Quite apart from the contest and FQXi community, do you know of any scientists who are likely to take an interest on essays like ours concerning fundamental problems of physics. If you feel it appropriate I request you to let me know.

    My email: virajplf@yahoo.co.uk

    Best regards,

    Viraj

    Dear Sean,

    Thanks for your kind remarks. I think you have characterized the obvious advantages and disadvantages of an approach like mine quite correctly: it's well-motivated and would be terrific if it worked but may fall well short of the level of structure necessary to describe the real world.

    One remark I will make (I said something similar on Daniel Alves' thread) is that perhaps one way to think about the relationships among approaches such as causal sets, causal dynamical triangulations, shape dynamics, and my approach, is to consider the symmetry, antisymmetry, or asymmetry of the relations involved. Shape dynamics seems to involve symmetric relations, since separation does not specify order. Causal sets involves strictly antisymmetric relations because of the acyclicity hypothesis. Causal dynamical triangulations uses both symmetric and antisymmetric relations, and my approach uses mostly antisymmetric relations, although I admit the possibility of cycles. Of course, shape dynamics assigns weights (separations) to the symmetric relations, which gives more information. Anyway, maybe this is wrong, and I'm certainly a fool to talk about shape dynamics two weeks after first learning it existed, but it seems on the surface that there might be dualities among appropriate versions of some of these theories. Oh well, just a wild thought. Take care,

    Ben

    • [deleted]

    "Regarding the constancy of the speed of light, my guess would be that a concept like this only makes sense at sufficiently large scales."

    No it makes sense locally. See this:

    "vO is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c vO. (...) The motion of an observer does not alter the wavelength. The increase in frequency is a result of the observer encountering more wavelengths in a given time."

    This author teaches that the speed of light is VARIABLE (varies with the speed of the observer). If he thought it was constant, he would have written:

    "vO is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. The velocity of waves relative to the observer is constant,c, because the motion of the observer alters the wavelength. The increase in frequency is a result of the motion of the observer altering the wavelength."

    Pentcho Valev

    Interesting thought.

    I don't know much about the difference between symmetric and anti-symmetric relations so I can't comment much. However, I would just point out that, in shape dynamics, the conformal factor of the metric is pure gauge, up to a constant. Because of this, the causal structure is really the main information that we are keeping aside from the total volume. Thus, I suspect that there is a way to map causal structure onto shape space. Indeed, this could have something to do with the isomorphism between the de Sitter group and the conformal group. Probably there is a way to map the conformal structure of de Sitter to the isometries of the conformal sphere in one less dimension. Then one could use a framework similar to what Flavio and I are discussing the paper we're about to post to understand this better in gravity. The discreteness is another issue but I have some ideas about that as well. There may be a way to make some connections.

    Cheers,

    Sean.

    Sean,

    I believe it's precisely because of the conformal factor that Rafael Sorkin incorporates the (constant discrete) measure in his "order plus number equals geometry;" i.e., because "order" by itself is not enough to recover the metric. That was part of what interested me about shape dynamics, because throwing in the scale seems artificial. You note that I have to keep repeating "up to a scale factor," in my own essay. Take care,

    Ben

    Sean,

    Also, Lawrence Crowell (who seems capable of instantly making precise remarks about almost any subject) has made some comments on Daniel Alves' thread along the same lines (possible duality/complementarity of symmetric/antisymmetric relations). I'm sure you are following Julian Barbour's thread; there is some relevant discussion there as well. Take care,

    Ben

      I'll take a look. I haven't had much time to check the discussions but I will but we just posted our new paper so I will have some time next week. I think there is definitely a connection. It would be nice to make this more rigorous though!

      Cheers,

      Sean.

      • [deleted]

      Heaven Breasts and Heaven Calculus

      http://vixra.org/abs/1209.0072

      Since the birth of mankind, human beings have been looking for the origin of life. The fact that human history is the history of warfare and cannibalism proves that humans have not identified their origin. Humanity is still in the dark phase of lower animals. Humans can see the phenomenon of life only on Earth, and humans' vision does not exceed the one of lower animals. However, it is a fact that human beings have inherited the most advanced gene of life. Humans should be able to answer the following questions: Is the Universe hierarchical? What is Heaven? Is Heaven the origin of life? Is Heaven a higher order of life? For more than a decade, I have done an in-depth study on barred galaxy structure. Today (September 17, 2012) I suddenly discovered that the characteristic structure of barred spiral galaxies resembles the breasts of human female essentially. If the rational structure conjecture presented in the article is proved then Sun must be a mirror of the universe, and mankind is exactly the image on earth of the Heaven.

      http://galaxyanatomy.com

        Hi Ben --

        I'd just like to register my support for your viewpoint on foundational assumptions. For reasons probably unrelated to yours, I think the "causal set" approach has a lot of promise, and I wish you every success in working out your hypothesis. I find it very impressive that a mathematician would approach physics by doubting the validity of continuous manifolds at a fundamental level! And I've appreciated the very clear and sensible comments you've made to many of the other contest essays.

        My own interest is in learning to describe the physical world that can actually be experienced, whether by us or a measuring device or any other local entity. Traditionally this "view from inside" is treated merely as a means for gaining knowledge of an objective reality that exists in itself. While that's obviously reasonable, I tried to argue in my essay ("An Observable World") that fundamental physics also need to deal with the context-structure of the physical environment that makes information observable. I argue that regardless of the nature of any background reality, the ability of the world to communicate about itself is a basic feature we need to understand.

        So for me, what's important about "the binary relation generating the causal order" is that it describes an element in the structure of observable interaction, in contrast with background-structures like spacetime manifolds, fields and particles.

        I do have one comment on the "causal metric hypothesis" and the problem of the "recovery of established physics at appropriate scales." A basic point made in my essay is that any physical parameter is only measurable in a context defined by other measurable parameters. This suggests that an observable world like ours has to be based on several essentially distinct types of interaction-structure. We can imagine that some of these are more basic than others -- for example, it seems significant that electromagnetic field-structure is largely independent of the metric, and so perhaps reflects a more "primitive" structural layer. But I suspect a successful theory won't just reduce every kind of interaction to a single elementary structure that explains everything at one shot. More likely it will focus on the differences between interaction-modes, explaining what each contributes to the emergence of an observable environment, and perhaps sort them into some sort of evolutionary sequence.

        Again, best wishes for success with your theory -- you have a lot going for you.

        Conrad

          Dear Conrad,

          I appreciate the kind remarks. You make several distinct and important points, so let me itemize my reply.

          1. Regarding the general theory of observation and its importance, my impression is that one reason why it is often neglected even in new theories is simply because the problem is so difficult, and is in some ways unlike the types of problems that physicists and mathematicians are used to solving. This remains true in spite of the attention the "quantum measurement problem" has received over the last generation. I am somewhat guilty of this myself; in my "secret papers" I have written down a lot of thoughts about this subject, but haven't felt sufficiently justified or confident to say much about it publicly.

          2. I am glad you alerted me to the presence of your essay; I have read a fair number of them, but I am sure there are many good ones that have escaped my notice. I will be sure to read yours carefully. I think I agree with what you said in the paragraph above, but I hope to be able to say more after reading it. Let me repeat that I regard the problem as very difficult, however.

          3. One of the aspects of the manifold assumption that bothers me is precisely that it postulates an entity that cannot possibly be observed, even with arbitrarily advanced technology. However, what bothers me even more is the extremely special structure ("too good to be true"), which makes the mathematics convenient at the expense of assuming a number of properties (least upper bound property? nonmeasurable subsets?!?) that seem obviously irrelevant to physics. In my mathematical work, I spend a lot of time studying things like complex manifolds and algebraic schemes, which constantly reminds me how very special, uniform, and "idealistic" such mathematical objects are. I get the impression that many physics students still get the impression that the shifts of paradigm from Euclidean spacetime to Minkowski spacetime to Riemannian manifolds represent vast and perhaps final generalizations of what is possible, when in fact all these constructs are perched on a tiny ledge over a vast gulf of models that might be relevant at much smaller scales.

          4. I think that your expectation that the observable world "has to be based on several essentially distinct types of interaction-structure" is perfectly reasonable; indeed, it appears this way at ordinary scales, and the radical position, requiring the greater justification, is to assume otherwise. However, there are hints that a simpler picture might be possible. We seem to observe one arrow of time, not several, and to the extent that the arrow of time can be identified with the direction between cause and effect, it seems reasonable to ascribe causality to a single binary relation. If "essentially distinct types of interaction-structure" correspond to multiple distinct binary relations, then from this point of view you would expect "multiple time dimensions," which seems dubious, at least to me. There are several ways in which this chain of reasoning could be wrong, however.

          In any case, I won't remark further on this until I have read your essay! Take care,

          Ben

          Dear Jin,

          Thanks for informing me of your paper. Take care,

          Ben

          Dear Benjamin F. Dribus

          I have liked your essay and I agree with your abandon of the ordinary concepts of symmetry, conservation laws, covariance, and causality in a spacetime context.

          Effectively spacetime is emergent, not fundamental and, therefore, the above assumptions have to be abandoned during the development of a fundamental theory. For instance, the conservation of dynamical quantities in a Liouville space cannot be related to the Noether's theorem, because this theorem is only an approximation and does not apply in the framework of the generalized theory. Another example is causality. We would distinguish between t-causality and tau-causality, with the former being not fundamental as you correctly notice. The more general tau-causality solves several problems of current quantum gravity such as the problem of time (the Hamiltonian associated to tau does not vanish).

          I gave not many details in my reply to your question on what kind of spacetimes we can derive from the Liouvillian approach. I would add now some info that I wait you will find useful. I only commented on the derivation of the more common spacetimes of special or general relativity, but we can take a pure quantum approach and derive a non-commutative spacetime of the kind postulated in string theory and other approaches, with ordinary products being replaced by star products.

          The really interesting is that we can take an intermediate stage between the pure quantum spacetime and the ordinary classical spacetime and obtain the causal and geometrical properties of the dummy spacetime of the quantum field theory:

          "Every physicist would easily convince himself that all quantum calculations are made in the energy-momentum space and that the Minkowski x^\mu are just dummy variables without physical meaning (although almost all textbooks insist on the fact that these variables are not related with position, they use them to express locality of interactions!)"

          --------

          H. Bacry

          "It is important to note that the x and t that appear in the quantized field A(x, t) are not quantum-mechanical variables but just parameters on which the field operator depends. In particular, x and t should not be regarded as the space-time coordinates of the photon."

          ----------

          J. Sakurai

          This very important limitation of the spacetime used in quantum field theory (QFT) is ignored in the textbooks by Weinberg, Kaku, and others --Mandl & Shaw emphasize in their textbook that there is not position operator in QFT but they do not explain why--.

          We can demonstrate that the position operator is not Hermitian (due to QFT deficiences in the direct merge of Lorentz invariance with a Hilbert space structure), explaining why position is not observable in QFT and has to be downgraded to a dummy parameter. We can derive Landau & Lifshitz relativistic uncertainty from first principles confirming that time in QFT is also a dummy parameter.

          Regards

            • [deleted]

            Dear Benjamin,

            I have an idea that I hope can be of some interest to you. Nothing mathematically fancy, I find that the zero spin quantum field can be reconciled from a system with vibrations in space and time. The model has some unique features that seem to be extendable to gravity and non-locality of quantum theory.

            Is there really no reality in quantum theory

            Best wishes for you in the contest.

            Hou Yau

              Dear Juan,

              I appreciate the details. Actually, I need more details on this subject, because the Liouvillian approach that you describe is something that largely escaped my notice in my program of physics self-education. Let me ask a few more questions:

              1. Where can I read about the derivation of spacetimes in the Louivillian approach?

              2. I am not sure what you mean between t-causality and tau-causality. Is it related to what I call the "causal order" and refinements of the causal order given by "frames of reference?"

              By the way, I downloaded 5 or 6 papers of yours from viXra, but haven't got a chance to read them yet. Perhaps some of the information is there.

              Thanks again, and take care,

              Ben

              Dear Hou,

              Thanks for pointing out your essay to me. As it happens, I had already seen from reading the abstract that your essay was interesting and had it highlighted to read more carefully. I will post some remarks about it over on your thread in a day or two when I have looked at it in detail. Take care,

              Ben

              • [deleted]

              Dear Ben,

              i now read your essay and it is indeed interesting. You begin with very clear and well-ordered introductions to the whole problem fields of modern physics and you clearly write what are rejected assumptions for you and what you consider as working hypothesis. I enjoyed reading your essay, albeit not understanding every line of reasoning you made during your elaboration.

              I found it intelligent to explicitely write about some phenomenons in the way that the community "interprets" them as "...". This clears up a lot and makes the whole argumentation of yours very easy to follow.

              As i understood it at this point of my reading, your approach is in some way a reinterpretation - surely with the important! fact of abandoning some "fundamental" principles and adding! some interesting new ones - of large parts of the common deduction sheme that is incorporated into classcial physical thinking.

              In some way you "play" - in combination with thoughtfull reasoning - with the building blocks of the classical physical framework and this is exactly what seems interesting and creative to me.

              Nonetheless, in my opinion, wether we interpret some building blocks as "universes", as "virtual Feynman paths" or something other, it seems to me that the ontological meaning of the whole building blocks stays somewhat ambigious for the reader. Therefore i would prefer to explicitely state that the very foundation of your framework is in its essence a logical (mathematical) and therefore "non-physical thing". For me i understood it as an informational theoretic approach that is at its core deterministic in the same sense the Everett worlds are. Moreover, at the end of your essay you outline the difficulty to decide/test the hypothesis, - please don't get me wrong - your approach deserves further examination, surely more examination than my own approach/interpretaion does. I write this to be intellectually honest and because i know the problem of reinterpreting the commonly used framework and at the same time give some reasonable proof of the exclusiveness of such a reinterpretation.

              All in all, i wish you good luck with your work and because you gave me some inspiring new points to think about, i thank you having visited my page and left a commment.

              All the best,

              Stefan