Paul this is the last time I will reply to any of your extremely repetitive comments.

You say "physical reality obviously occurs in a specific physically existent state. It does not exist in some "unclear" manner. ... The Copenhagen interpretation, and any other theory that assumes there is no 'bottom', or that sensing affects the 'bottom', is invalid."

You seem not to understand either wave particle duality or entanglement. The way experiments are done does indeed affect the properties of the bottom-most particles we can access. Please spend a bit of time reading Feynman or any other good text on basic quantum physics. I do believe that Heisenberg, Bohr, and Feynman understood the physics considerably better than either I or you do.

You continue "The question then becomes, having swept away metaphysical presumptions and invalid theories, what constitutes the 'bottom'? My definition .. is: " the physically existent state which occurs as at any given point in time, is a function of the particular state of the properties of the elementary particles involved, and their spatial position, as at that point in time".

I repeat what I have already said to you: in quantum field theory, particles are not the fundamental entities: they are just excitations of fields. They don't have either definite positions or momenta, according to the uncertainty principle. Your Newtonian model of basic reality is 90 years out of date.

As for time, I have already agreed with your statement "What physically happens is that a different physically existent state subsequently occurs from that which would have otherwise occurred." True. The future does not exist now but it will exist later on. Yes.

I can't see the point of all the further argumentation about this. Whatever else it is about time that bugs you is unclear to me, and repeating it yet again won't help. Please don't repeat it again on this particular forum.

Dear Edwin Eugene Klingman

you ask "where is the top?" A very good question, and the answer depends on context:in the case of structure of the human brain, no top is currently identifiable: things near the top seem to be non-localised. In the case of cosmology, one ends up with philosophy because the largest physical scales are unobservable (there are observational horizons in the real universe) so you can say anything you want about it and no on will ever be able to make observations that contradict what you say. So the claims I make are local claims (for any pairs of related levels) and independent of any global claims about any topmost level.

This applies also to the bottom - there may or may not be a bottom-most level; if there is one we don't know what it is (it may be string/M theory, but then again it may not). Indeed all the levels we deal with in ordinary physics are effective levels, not fundamental;and this does not matter. This is just as well , else we could not do physics.

George Ellis

Anton

"Causality therefore ultimately cannot explain anything." If so please explain to me how you go about your daily life. If you are unable to cause any changes about you in your daily existence, then you don't exist as a person (and you certainly won't be able to get a job).

I explained carefully at the start of my paper that there are always numerous causes in action, and we get a useful concept of "the cause" by taking all except a few for granted. This produces a valid local theory of causation. You don't have to solve problems of ultimate causation to understand local physical effects (e.g. heating water causes it to boil). Your complaint seems to be that if you can't explain the entire universe you can't explain such local phenomena. The whole practice of science disagrees with you.

George

Vladimir you state

"I am conviced that if such a simple theory of everything were to be found, causation would be always local and linear at the smallest scales and the effects of large systems will be the resultant of effects transmitted locally and causally down to the local level and vice-versa simultaneously in a balanced way'

I agree with you completely. My more technical article on the way quantum theory works is based in precisely that premise. You will find it

here .

George

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  • Post #75

Dr. Ellis,

"In addition to contemplating relativistic and philosophical aspects of cosmology, he is now engaged in trying to understand how complex systems such as you and me can arise out of the underlying physics."

Could this be made to work without a thorough simulation, down to the particle interaction level, of the underlying physics -- in this case, of condensed matter physics?

One assumes the higher-level effects ("epiphenomena" seems to be a word to avoid) emerge as interactive constraints upon the substrate physics. (Let's not get into the contentious issue of substrate independence, which isn't a required topic at this point.) Whether or not their emergence is inevitable (and why shouldn't it be?) we know they wouldn't exist, at any rate to begin with, in the absence of the underlying physics. And the more complex the higher-level emergent phenomena, the more you need to know about the operational physics in order to map the emergence ... or is that a fallacious assumption?

Anyway, what about the fermion minus-sign problem? And thanks for your provocative and knowledgeable essay.

    Thanks George

    I just downloaded your paper and it will take me some time to read. My first impression is that it differs from my Beautiful Universe paper in scope and intention (and the presence of non-linearity it appears) as you will see if you read it. Another difference is that mine is the work of someone who has waded in deeper waters than he was trained for!

    Cheers

    Vladimir

    You don't need simulation to establish effective laws at any particular level. For example you can establish the effective gas laws without using any simulations, through two routes: (a) experimentally, (b) by use of kinetic theory. The latter does not need to involve simulations, nor does it need quantum field theory, much less M-theory or string theory.

    "One assumes the higher-level effects ... emerge as interactive constraints upon the substrate physics." I'd phrase it this way: the high level structure emerges somehow (it may be spontaneous, or may be manufactured, or may emerge through developmental processes) and then sets constraints on the underlying physics.

    Yes, this emergence would not take place in the absence of the underlying physics. "The more complex the higher-level emergent phenomena, the more you need to know about the operational physics in order to map the emergence" - well not really. Digital computers are really good examples: they are the most complex things we have built. You don't need to know anything about the underlying physics to design the computer itself, you just need to know that it established the possibilities of existence of transistors and hence various kinds of gates. On that basis you can work out the logic of integrated circuits and make CPUs, memory banks, etc. Hence computer scientists are not taught quantum theory as part of their computer science courses. Someone else needs to know how the transistor works but you don't need to do so: you can take the transistors as the bottom level, for your purposes. And it's crucial that we are able to do so, for as I've already said we don't know what the bottom level is: we'd be unable to do most of present day physics if it was requisite that we understand the quantum gravity foundation layer first. The key question is, Which is the operational level? It's the one that is convenient for you to choose as the lowest level in your particular analysis.

    The fermion minus-sign problem is to do with quantum Monte Carlo simulations; a technique for trying to understand specific types of emergent systems. I cannot meaningfully comment on that technique and problem, except to say that I don't think it helps understand systems such as the brain or a computer.

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    • Post #78

    Thanks for the extended response. We'll simply have to disagree that manufactured artifacts are useful analogues of complex nonequilibrium systems -- complex natural processes -- to the extent I read you as believing them to be.

    "Hence computer scientists are not taught quantum theory as part of their computer science courses."

    Actually, that's not true in the case of quantum computation itself. And perhaps overly optimistic though it may seem, qcomp programming is taught on the theoretical level. You can't understand quantum algorithms without some fundamental knowledge of QM. Anyway, my own paradigm these days is the role of proton-coupled electron transfer (PCET) in photosynthesis. Now, to be sure, a plant doesn't need to understand anything at all about quantum tunneling in order to do its photosynthesizing thing, but if you're designing an artificial leaf (vide the Nocera team's ambitious project) you definitely do. Anyway you and I, a couple of complex systems, generate information no computer can, no matter how sophisticated its programming.

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      • Post #79

      Note. Anticipating a possible objection here. An artificial leaf, albeit a manufactured artifact, doesn't stand in relation to a real leaf as a digital computer does to a brain. An artificial leaf reproduces a known process selected from a real leaf's repertoire of physics, whereas a computer can't be demonstrated to reproduce any process selected from the physics or systemic functionality of the brain.

      An artificial leaf copies to some degree a real leaf. The computer is sui generis, a physically realized TM, as anyone familiar with Turing's papers from the 1930s realizes. Is the brain a TM? A lot of people seem to think so, but haven't proven it.

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        • Post #80

        Dear George,

        I agree with your point. It is also necessary to beware of linking unrelated events and so inventing a causation story when it didn't happen in that way. It can happen in science,( including social science), that correlation is mistaken for causation.It probably occurs more often than is realised. Particularly important and well known is the placebo effect, where getting better may be nothing to do with the treatment given.

        I read an interesting item a long time ago about a study into the effect of high fat diets on rabbits. Rather than getting more unwell the badly fed rabbits remained healthy. Eventually it was found that the animal handler looking after the badly fed rabbits was giving them extra attention and fondling. Presumably reducing the animals stress level and making them better able to handle the bad diet ill treatment.

        The book "Freakonomics" Steven D. Levitt and Stephen J. Dubner has many amusing stories of how correlation might be mistaken for causation. Fascinating.

        "We'll simply have to disagree that manufactured artifacts are useful analogues of complex nonequilibrium systems -- complex natural processes -- to the extent I read you as believing them to be." Well I don't want to overdo the analogy, but for me a key similarity is they both are hierarchically structured modular systems with information hiding. This kind of structuring is very nicely described by Grady Booch in his book on object oriented programming. The mechanisms used in these two kinds of systems are quite different, but some of the logic is similar. And of course you can get the digital system to simulate many aspects of the physical system to high accuracy, basically because digital computers are universal computers (Turing).

        Yes of course I agree about quantum computing. I should have added the caveat "classical computing" in all above.

        Proton-coupled electron transfer seems fascinating. I'd be really interested to know how it relates to quantum state vector reduction. And I agree with you about the limitations of computers (though many don't).

        "a computer can't be demonstrated to reproduce any process selected from the physics or systemic functionality of the brain." The physics functionality, I agree; the systemic functionality, perhaps not. The brain is an embodied brain certainly; but it also carries out pattern recognition and prediction processes that can be digitally simulated to some degree (indeed that's where Artificial Neural Nets came from). Furthermore computers can indeed learn to some degree, through adaptive programs such as genetic algorithms.

        The brain is not a Turing Machine inter alia because emotion plays a key role in its functioning (see for example Damasio's writings). You can to some degree simulate those effects but I certainly don't believe you can reproduce them.

        Dear Georgina,

        yes indeed, in general separating out correlation from causation is very difficult, which is why I stated my definition of causation at the start of my essay in terms of the reliable consequences of an action. That makes clear what the initiating event is.

        The placebo effect is fascinating; of course from my viewpoint it's a case of top-down action from beliefs (abstract entities) to physical systems (human bodies). Placebos are certainly effective, which is why drug treatments are compared to placebo treatments.

        I like your story about the rabbits. The welfare of human children is similarly crucially affected by being given attention; it affects their bodily weight and even their survival.

        Dear Avtar

        I am glad we agree on top down causation.

        George Ellis

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        • Post #85

        "Proton-coupled electron transfer seems fascinating. I'd be really interested to know how it relates to quantum state vector reduction."

        This topic has never been mentioned in any paper I've seen. The question for me has been to what extent is PCET a coherent quantum phenomenon. You don't even need to believe in wave function collapse to wonder about that, as one is interested also in the whole emerging discussion of room-temperature and high-temperature quantum coherence. (See Vlatko Vedral on the ubiquity of entanglement. Seth Lloyd on entanglement as crucial to ordinary bivalent bonds. And when you visited the IQOQI you were doubtless regaled with an account of the super-hot double-slit buckyball experiment.) Nocera & Co. are adamant that PCET's a coherent quantum tunneling effect, and appear to have established this contention to the satisfaction of those sectors of the scientific community that have paid attention.

        Here's a now-defunct webpage from Daniel Nocera's MIT site, undoubtedly not technical enough for you but okay for most kibbitzers, which a friend of mine downloaded and converted to pdf a while back. It lays out the basic stuff:

        http://www.dancing-peasants.com/Proton-Coupled_Electron_Transfer.pdf

        I can cite deeper material if desired.

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        • Post #86

        looked okay in the preview

        http://www.dancing-peasants.com/Proton-Coupled_Electron_Transfer.pdf

          Dear George Ellis,

          In a comment above, you state, "Proton-coupled electron transfer seems fascinating. I'd be really interested to know how it relates to quantum state vector reduction."

          I do invite you to read my current essay, The Nature of the Wave Function, as I address the issue of "quantum state vector reduction" and I would very much appreciate your thoughts on my approach.

          Edwin Eugene Klingman

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            • Post #88

            Dear George,

            re the placebo I should have said; nothing to do with a pharmacological effect of the treatment, not nothing to do with the treatment. As the treatment might include the lengthy and concerned consultation, diagnosis and prescription which can make a person feel important, valued and cared about and so affect neurotransmitter levels, their balance and so psychology.

            The brain has executive control of the body including maintenance of health. The function of the organs and tissues and biochemistry of the body can be affected by changes of activity within the very complex neural networks of the brain. Which is altered by changes in neurotransmitter availability and balance.It seems to me, the interaction of the complex external environment and social interaction upon the -complex organised brain- and its body interaction, causes the change in health and not the simple sugar pill and mere (abstract) belief in its power.

            As you have pointed out the effect is relevant to your top down control concept.I think even more so than you have intimated- I think it is a good example of a specific effect (output) arising from complexity and organisation, not from very simple inputs. It can't be explained as the result of the simple "sugar pill" input.

            Paul Davies and Sara Walker have put up two very useful papers on the internet that will interest those of you involved on the biology side. They are

            Evolutionary Transitions and Top-Down Causation

            and

            The Algorithmic Origins of Life

            Here is the abstract of the latter paper:

            "Although it has been notoriously difficult to pin down precisely what it is that makes life so distinctive and remarkable, there is general agreement that its informational aspect is one key property, perhaps the key property. The unique informational narrative of living systems suggests that life may be characterized by context-dependent causal influences, and in particular, that top-down (or downward) causation -- where higher-levels influence and constrain the dynamics of lower-levels in organizational hierarchies - may be a major contributor to the hierarchal structure of living systems. Here we propose that the origin of life may correspond to a physical transition associated with a fundamental shift in causal structure. The origin of life may therefore be characterized by a transition from bottom-up to top-down causation, mediated by a reversal in the dominant direction of the flow of information from lower to higher levels of organization (bottom-up), to that from higher to lower levels of organization (top-down). Such a transition may be akin to a thermodynamic phase transition, with the crucial distinction that determining which phase (nonlife or life) a given system is in requires dynamical information and therefore can only be inferred by identifying causal relationships. We discuss one potential measure of such a transition, which is amenable to laboratory study, and how the proposed mechanism corresponds to the onset of the unique mode of (algorithmic) information processing characteristic of living systems."