Dear Eckard Blumschein

" Since you are calling yourself a relativist, I doubt that you are open for what the topic of the contest demands: "Questioning the Foundations". Doesn't this include Cantor's naive set theory, Einstein's special theory of relativity, Lorentz covariance, a priori existing Parmenidean spacetime, etc. too? "

I chose to deal with a particular topic that I regard of importance, and you state you doubt that I am up to what the competition is about because I did not deal with a whole set of different topics. What is the point of this gratuitous insult?

"Situation has suddenly changed after I tried and managed to understand an experiment by Norbert Feist. See Fig. 5 of my recent essay. I fear I cannot expect an other factual reply than silence from anybody who has to fear loss of reputation or who is simply lazy." This kind of accusation does not motivate me to read your essay or respond to it. On the contrary.

"You might understand my motivation and uncompromising rudeness ..." I have no intention of responding to any further such rudeness. It is incompatible with my attempts to have cordial collegial discussions on the topic of my essay.

yours sincerely

George Ellis

Hello George,

Thank you for your reply. I didn't mean there was any need to justify your essay, I believe in causality too. I was just trying to show the relevance of the block time issue, and of bringing it into the discussion on this page.

You say that in the EBU "what observers think is past or future on other world lines does not matter". I'm sure it doesn't in many ways, but the point I've made it that it matters if we're trying to pinpoint the crystallation of an event, and look at what could cause it in that context. It's all very well saying that an event goes into the fixed past because of the collapse of the wave function. But if to some observers it already has, while to other observers moving differently it hasn't yet been crystallised, then we end up with what looks like a perception-based thing, and exactly the same setup that led to the problems of standard block time in the first place.

I think it's very good that you're argued for a flow of time, or motion through time, as strongly as you have. I'll look at your work further, and will almost certainly refer to it in mine. People are coming round to the idea that block time is wrong, partly because it seems that something has to give if we're to get to quantum gravity. To me, a slight tweak to spacetime is not enough, and the problems with it do not wash out so easily, as I've shown. I think we need to face up to the fact that we simply have the wrong interpretation in front of us. Spacetime looks right, and it has helped us simplify a lot of theories. There's a great reluctance to reverse out of the cul-de-sac. But it's an interpretation, and if one gets conceptual problems with an interpretation, then one probably needs a new one.

I'd appreciate any thoughts you might have on my essay,

Best wishes, Jonathan

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  • Post #260

You mentioned that the issue was whether algebra can deal with a Modular Hierarchical structure, and the need for graph theory. Just wondering if there are top down aspects to a supernova, just to have a nice physical example to chew on, especially for being so 'event-like', and anthropic questions ? If so, it seems like there is more going on than modular hierarchy and graph theory, like why can't elements build up without kicking leptons out of the neighborhood.

    Hi Joel

    well the supernova stuff you mention is mainly due to local reactions in the core, but the context is set by the star as whole, which generates huge temperatures at the centre due to its global structure and the resulting gravitational field. Hence that's a top-down effect from the star as whole to the nuclear reaction rates at the centre.

    Leptons escaping is possible because the lepton density outside is much smaller than inside (a version of Olber's paradox for leptons): it could not happen if the star were immersed in a high-density lepton sea, just as the sun could not shine if it was immersed in radiation at the temperature of its surface. Such "non-interference" effects can be thought of as a causal relation: the relation is that a possible interaction does not take place! Isolated systems can only occur because the universe does not interfere with local systems; this will not be the case in some possible universes (e.g. ones that are always immersed in dense gravitational radiation).

    George

    Hi Jonathan

    I basically agree with you, and with what is in your essay. Block time is fine if it has a future boundary that keeps changing - that resolves the puzzles you point out in your essay. And spin foam models seem to be like this, in essence, so quantum gravity is not incompatible with this scheme.

    best wishes

    George Ellis

    Hello George,

    Thank you. It seems very premature to say that the puzzles I point out in my essay have been resolved. Because motion through time is not an illusion (in your view and mine), it needs a physical mechanism to explain it. And that mechanism should fit the clues well - it should show why motion through time is slowed down in certain situations, and why the equations that describe how it is slowed down apply.

    And because a physical mechanism is needed, it can't be one that seems to point at a purely perception-based effect, as in what led to standard block time, and as in the weakness I've mentioned about the EBU picture. The observer must be somehow partly incorporated into the picture, but not in a way that seems to rule out anything other than the perception of the observer.

    That's what standard block time does, and as you say, it simply doesn't work. But we may well find that more is needed than a repair job on the spacetime interpretation, to make it do the opposite of what it used to do. If the Rietdijk-Putnam argument is wrong, then spacetime in all forms may fail to fit the clues, as the same problems might keep on cropping up. To me it seems very likely that a new interpretation is needed, and that frequent failure to separate SR from spacetime has held us back.

    Best wishes, Jonathan

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    • Post #264

    Dear George Ellis,

    While H. v. H. soon excused himself for his rudeness, it was demanding for me to force him by factual arguments to admit that he was wrong. I doubt that the question "Which of Our Basic Physical Assumptions are Wrong?" can be really answered in a cordial discussion among colleagues.

    I see what you are calling bottom up causation the principle of superposition of influences. If you could really question it, then it then I was surprised. I will read you essay again. Maybe I overlooked something.

    Yours sincerely,

    Eckard Blumschein

    "I doubt that the question "Which of Our Basic Physical Assumptions are Wrong?" can be really answered in a cordial discussion among colleagues."

    - what an extraordinary statement. I hope to never be in an institute where this is true. My own personal colleagues are able to behave in a collegial fashion. It is the hallmark of civilised discussion that you don't have to be rude to your opponent if you disagree with her/him.

    "I see what you are calling bottom up causation the principle of superposition of influences. If you could really question it, then it then I was surprised. I will read you essay again. Maybe I overlooked something." Superposition is a linear interaction. Most real system in the universe are not linear. Yes they are based in linear interactions at the bottom level, where superposition holds, but these are put together in structures and complex interaction networks that result in non-linear behaviour at the higher level. These structures then act down in a non-linear ways on their component entities to allow them also to behave in a non-linear way. Example: state vector preparation (a non-unitary process). Example: superconductivity, where the lower level entities (Cooper pairs) only exist because of the context provided by specific crystal structure.

    Many other examples are given in my more technical article on which this essay is based, see here .

    George Ellis

    Just for information, re the previous interchange: this is the proposal for the Nature of physical reality I make in the technical article I referred to:

    1. Combinatorial structure: Physical reality is made of linearly behaving components combined in non-linear ways.

    2. Emergence: Higher level behaviour emerges from this lower level structure.

    3. Contextuality: The way the lower level elements behaves depends on the context in which they are imbedded.

    4. Quantum Foundations: Quantum theory is the universal foundation of what

    happens, through applying locally to the lower level (very small scale) entities at all times and places.

    5. Quantum limitations: The essential linearity of quantum theory cannot be assumed to necessarily hold at higher (larger scale) levels: it will be true only if it can be shown to emerge from the specific combination of lower level elements.

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    • Post #267

    "wherever equivalence classes of entities play a key role, ... this is an indication that top-down causation is at play."

    The real numbers are defined as equivalence classes. OK, perhaps "functional" equivalence classes are meant, and I do not know what functional means in this context.

    Are standing waves a convincing example for top-down causation? As an EE, I would like to distinguish between waves that are really bouncing back and forth in a cavity and the abstract mathematical model which endlessly extends within the abstract fictitious time scale from minus infinity to plus infinity and ignores the trifle that a real "standing" wave always has a begin and an end, cf. my Fig. 1.

    Let me go one searching for something truly basic that elucidates at least one out of the various enigmas and paradoxes I listed at the beginning of my essay.

    Eckard

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    • Post #268

    Dear Johnathan Kerr,

    In my essay thread "What basic physical assumptions are wrong?" Georgina Parry, there is a high resolution version of diagram 1. which shows an explanatory framework for physics that addresses the problem you have just mentioned.

    It isn't a block universe model but there is sequential iteration of the material aspect according to the existing relations and various constraints of physics and biology. Eg.conservation of energy, Pauli exclusion principle, minimisation of potential energy,inverse square law, relationships of volume and surface area, effects of concentration gradients, natural selection. The visible universe (including that which is visible using technology) is not that material one but a fabrication generated from received data, that was emitted or reflected from the material universe. This structure allows the universe of atoms and material things, going about their actions simultaneously, to coexist without contradiction with Einsteinian relativity.

    It is an unusual structure because observer fabrications must exist wholly within the material reality even though they are different from it and show something different from what exists independently and simultaneously.For analogy: As Terry Pratchett's Disc World and Tolkien's Middle Earth exist within our world but are at the same time not our world.

    The time that is shown by observation of the distant clock is different from the number or hand position that -is on the clock- independently, and the objects that are seen are also amalgamations of data formed by the observer not independent things-overcoming many paradoxes.

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    • Post #269

    This is a matter of preference. You cite the incorrect Dirac's phrase. I cite the modern correction by P.W. Anderson.

    The Science paper does not confound reductionism with causality and shows how the emergence of new properties at higher levels is compatible with the ordinary bottom-up causation of physics. Murray Gell-Mann, another Nobel laureate who is now working in complexity at SFI, has an entire book devoted to such issues. The physiology of the heart is also compatible with ordinary bottom-up causation.

    Anyone reading this amusing essay should look at Weinberg's proof of Boltzmann's H-theorem (p.150 of volume 1 of "The Quantum Theory of Fields"). This modern proof of entropy increase is formulated in the language of quantum field theory and avoids approximations, such as the Born approximation or time-symmetry invariance, which are used in ordinary statistical physics proofs. Cosmology is unneeded in the proof of the H-theorem.

    You name two cosmologists. Their work is incorrect. One of them gave a talk in Santa Cruz promoting the idea that cosmology is the cause of the second law of thermodynamics. One expert at the audience said:

    "Finally, the magnitude of the entropy of the universe as a function of time is a very interesting problem for cosmology, but to suggest that a law of physics depends on it is sheer nonsense. Xxxxxxx's statement that the second law owes its existence to cosmology is one of the [dumbest] remarks I heard in any of our physics colloquia, apart from [Rosenblum & Kuttner]'s earlier remarks about consciousness in quantum mechanics. I am astounded that physicists in the audience always listen politely to such nonsense. Afterwards, I had dinner with some graduate students who readily understood my objections, but Xxxxxxx remained adamant."

    You write "It is conceivable this review could lead me to change my opinion". My goal was to expose some elementary facts ignored in your amusing essay.

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    • Post #270

    1: "Murray Gell-Mann, another Nobel laureate who is now working in complexity at SFI, has an entire book devoted to such issues." That book is about adaptive selection, which is a form of top-down causation, as has been very clearly demonstrated in many writings since the seminal paper on the topic by Donald Campbell; see for example the book The Re-emergence of Emergence edited by Clayton and Davies.

    2. "The physiology of the heart is also compatible with ordinary bottom-up causation." This dogmatic statement is simply wrong. Denis Noble is a world authority on the physiology of the heart, and there is no reason what ver to believe you know more about it than he does.

    3. "Cosmology is unneeded in the proof of the H-theorem." Indeed. And the result is a theorem which does not resolve the problem of the arrow of time because it continues to hold when you reverse the direction of time. Extraordinary that you call time-symmetry invariance an approximation, when it is at the heart of all fundamental interactions except the weak interaction. Are you trying to say that the cause of the arrow of time is the very small weak time asymmetry of the weak interaction? If so please explain how this works. No one who has looked at it seriously believes this.

    4. "You name two cosmologists. Their work is incorrect." I am totally unimpressed by someone hiding behind a cloak of anonymity making such a statement. What standing do you have to dismiss two of the deepest thinkers in cosmology? You then quote some unnamed other person who is supposed to an expert on the subject. The tone of the response shows they, like you, are simply unable to engage with the core issue: it is not that the second law owes its existence to cosmology, it is that the statistical derivation of the second law predicts equally that entropy will increase both to the past and the future because it applies whichever arrow of time you choose. The same applies to any derivation from quantum field theory, unless it claims to derive the arrow of time for all physics from the weak interaction, which is totally implausible. If they and you can't even admit the problem exists, then you have nothing useful to say on the arrow of time.

    5. I note with interest how you fail to respond in any way to my remarks on the issue of superconductivity as discussed in Laughlin's Nobel lecture. It shows conclusively your sneering comments are simply wrong, and I do not believe for one minute that you understand it better than he does. No wonder you ignore it.

    By the way as regards the pseudonym you hide behind ("There is nothing new under the sun"): this is of course also incorrect. Amongst the thousands of examples I could cite, one will do: digital computers and the internet.

      That previous post was me. I thought I was logged in.

      George Ellis

      For those of you who are interested in the relation of this topic to the brain, Karl Friston's article A theory of cortical responses is excellent. He emphasizes the key role of hierarchical structuring in the brain. His "forward connections" are what I call bottom up, and his "backward connections" are what I call top-down (the difference in nomenclature is obviously immaterial). He makes quite clear that a mix of bottom up and top down causation is key as to how the brain works; backward connection mediate contextual effects and coordinate processing channels.

      This is how the theme works out in a genuinely complex case. It is obviously compatible with the underlying physics, because it does indeed work. As in the case of digital computers, which can run any algorithm whatever, in the case of the brain the underlying physics enables us to think, but does not constrain what we are able to think about.

      George

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        • Post #273

        Dear George

        I would like to show interesting story where Top-Dawn approach get useful

        http://vixra.org/abs/0907.0022

        I mean trick with inversion dark green column

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        • Post #274

        Ok I have looked at the Weinberg derivation (pages 150-151 in his book). I agree it's good to have a derivation that depends only on unitarity. Unitary transformations however are time reversible. There is therefore nothing in the dynamics that can choose one time direction as against the other as far as any dynamical development is concerned, just as there is no intrinsic difference between the particles alpha and beta.

        Consequently just as in the case of the Boltzmann derivation of the H-theorem, the H-Theorem (3.6.20) will hold for both directions of time (just reverse the direction of time and relabel alpha to beta: the derivation goes through as before). This is the point which is explained very clearly by Penrose in his various books as regards Boltzmann's derivation. Weinberg's derivation of the H-theorem does not determine a preferred direction of time from the underlying unitary dynamics. It can't do so, as there is no preferred direction of time in that dynamic.

        " As in the case of digital computers, which can run any algorithm whatever, in the case of the brain the underlying physics enables us to think, but does not constrain what we are able to think about."

        Right on, George. Androids may dream of electric sheep, but only a human brain can dream of an android dreaming of electric sheep.

        The capacity for infinite regress cannot be programmed into a finite state machine.

        Tom

        The point of the above is that it is impossible to derive the arrow of time - one of the most important aspects of macro physics and biology - from microphysics alone. Both statistical physics and quantum field theory give you a beautiful H-theorem: and the derivation applies equally in both directions of time (this applies for example to Weinberg's derivation of the H-theorem: see my last comment). Supposing you break this symmetry somehow by random fluctuations: you have no guarantee the direction of time will be the same everywhere. We do not see opposing arrows of time in the real universe. Bottom up causation alone is incapable of giving an explanation of one of the most important features of everyday physics.

        Consequently, as pointed out by Wheeler, Feynman, Sciama, Davies, Zeh, Carroll, Penrose, and many others, one needs some global boundary condition to determine a consistent arrow of time in local physics:a top-down effect from the cosmological scale to everyday scales. This is what the Santa Cruz "experts" have not understood, even though the issue has been known since the time of Boltzmann and Loschmidt.

        This global coordination is plausibly provided by a macro-scale low entropy condition of the early universe, see the writings of Carroll (From Eternity to Here: The Quest for the Ultimate Theory of Time) and Penrose (Cycles of Time). For readers who have not encountered this debate, a useful summary by Sean Carroll is here ; and

        here he gives extensive quotes from Feynman on the issue. For my own summary of this and other top-down effects in cosmology, see here .

        George