Quantum Fluctuation : Causal

Discussion in 'Physics & Math' started by The God, Mar 12, 2017.

  1. exchemist Valued Senior Member

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    Thanks for the information, but I think I will choose not to go there....

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  3. The God Valued Senior Member

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    Denial of cause is neither natural nor scientific. An acknowledgement that cause is unknown yet is fine.
     
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  5. exchemist Valued Senior Member

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    Fair enough. What I was saying, implicitly rather than explicitly, is that the QM model that we use today does not involve a cause. Those that search for hidden variables etc, to provide a cause, are naturally welcome to do so. It is not a religion, after all.

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  7. The God Valued Senior Member

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    That welcome is there since 1935, with no concrete resolution.
     
  8. exchemist Valued Senior Member

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    That presupposes there is something to "resolve".

    Those of us (most in physics and chemistry) who find the QM model satisfying don't see an issue. If you don't like it, you can join the small but hardy band that works on hidden variables or other ways to get rid of quantum indeterminacy. But don't make the error of presuming, in communications with scientists, that there is a generally acknowledged, so-far unsolved "problem" here. Because that is not so.
     
  9. The God Valued Senior Member

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    True, but there is still some issues like Quantum Non Locality. If not now, tmro that has to be resolved. This is not nature, this is lack of our knowledge about it.
     
  10. exchemist Valued Senior Member

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    Yours! I'm too old now for that sort of caper. I guess from your posts you are a younger person than I am. Good luck.

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  11. Schmelzer Valued Senior Member

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    Wrong, there are causal interpretations. There is de Broglie-Bohm theory, there is Nelsonian stochastics, there is Caticha's entropic dynamics. They have some weak places, but they exist.
     
  12. exchemist Valued Senior Member

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    Well hang on, all he is saying is there is "no concrete resolution".

    That seems fair enough, surely, given that these are all rivals and none has general acceptance, so far.
     
  13. karenmansker HSIRI Banned

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    Agree . . . . . causal inference is limited (almost) to the observational scale of inquiry. One fun part of science is that we can 'infer' to a smaller causal scale, and with qualitative and quantitative improvements in observational methodologies and proofs, we may actually 'get there' in the future. On to the next level . . . . Progress!
     
  14. Dinosaur Rational Skeptic Valued Senior Member

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    From KarenMansker Post #15
    The above is an erroneous (?meaningless?) notion. The notion (if valid) merely pushes the randomness down a level. If there is some cause or trigger at a subquantum level, it is governed by probabilistic laws.

    The Classical Reality of our senses is built on a Quantum Level of reality governed by probabilistic laws.

    The deterministic view of our notion of reality was junked circa 1920 by the notions of Quantum Theory.

    There is a reason the rate of radioactive decay is expressed as the half life, which is the expected time for half the atoms to decay. Examples
    The rate is expressed as the half life because it is a probabilistic phenomenon, not a cause/effect phenomenon.

    If it were possible to rewind the universe to its state at noon 1 January 1900, almost every knowledgeable physicist would expect an entirely different history from that in our current history books.

    Their Point of View is based on the notion that probabilistic laws are the basis of the classical reality of our senses.
     
  15. karenmansker HSIRI Banned

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    Ah yes . . . . Classical Reality . . . . terminology not unlike 'classical physics' (as seen in retrospect). Science will always try to resolve phenonena (stuff) to the smallest causal scale possible using the observational tools that are available. That which does not accordingly resolve can be deemed probabilistic. The operative word is 'possible', which changes with progress and new discovery. IMO, hypothetically (for now) the quantum domain is subsumed within a subquantum, subplanckian domain - problem IS that we are not there (observationally) yet! Therefore we have little choice but to view phenomena, such as radioactivity, as probabilistic with no underlying causality.
     
    Last edited: Mar 21, 2017
  16. rpenner Fully Wired Staff Member

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    Yes, you blinkered pseudoscientist. We have little choice when the evidence does not contradict the most precise prevailing theories. Physics is not about ego or the greatness of one's ideas — it's about describing the behavior of phenomena which actually are observed to happen.

    If I have a manufactured ball bearing, you may observe that it is spherical. The expectation that it is spherical is in the name. The detailed engineering tolerances would prefer it to be exactly spherical but recognize it has to be spherical "enough" for the purpose it is advertised for. So the person claiming it is not spherical needs to make a specific claim: Is it a pedantic claim that nothing made of more than one atom may be spherical or is it a material claim that the ball bearing is not as spherical as advertised and was the proximate cause of machine failure when that advertising was relied upon.

    If you have evidence that nature respects a symmetry, then your first-order model is that symmetry is important to nature and is respected by natural laws so your physical theory had better also respect that symmetry. Having described the symmetry with math, to go beyond the first order model one must have evidence of symmetry violation or else you have no experimental data to test against a hypothesis of symmetry breaking. It's not enough to hypothesize "what if this wasn't a perfectly kept symmetry" but must relate the details of a specific amount of symmetry breaking to a specific measurable outcome of an observation.

    The symmetry common to all quantum physics phenomenon is called unitarity, the property that changes to physical systems preserve the sum of the probability of all outcomes. The symmetry common to special relativity is called Poincaré invariance and it states that nature is indifferent to position, direction or choice of an inertial motion as the standard for "motionless". The combining of these two principles from circa 1905 special relativity and early quantum mechanics circa 1900-1928 led to the prediction of massive and massless particles of fixed intrinsic angular momentum.
     
  17. karenmansker HSIRI Banned

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    Yes? . . . and your point IS? . . . . if you have one! BTW: When you have determined that the evidence does not contradict the most precise, prevailing theories . . . . does that mean that it IS correct? . . or ONLY as correct as the limits of your current observations allow. Perhaps the earth would have remained flat if only we knew when to stop observing!! I prefer to keep looking/observing . . .
     
  18. rpenner Fully Wired Staff Member

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    Real "truth" if you mean being correct about the inner working of natural phenomena is not on the table. Even if we knew how gravity related to quarks and electrons and light in a single unified picture, where that picture discussed moving parts not in evidence those parts would remain unknowable to us our picture of reality would untested with respect to such parts. And to the extent that picture left out parts, "why" questions would remain in an infinite regress. Why does gravity and quarks and electrons and light relate in the way that picture says? The answer is either in the picture with no demonstration of its truth value or it is left out of the picture. One may claim insight without being able to convince another of it. That cannot be a working system of knowledge.

    The epistemology of physics is that the inner workings of reality are unknowable but concordance of the behavior of observable phenomena with physical theories is knowable, so physical theory when uncontradicted by new observations represents humanity's closest approach to the truth of reality and are provisionally accepted as reliable within the described domain of observational testing. That's perhaps a more flexible approach to truth than you care to accept, but we are not the architects of the world, we are just those that live in it and seek to understand how it behaves.

    The ones that rejected observation as a path to a working surrogate to truth included the celebrated ancient Greek philosophers, like Plato. But in the third century BC, Eratosthenes not only knew the Earth was round, but had used observations to compute its circumference and tilt. The celebrated Columbus read and ignored Eratosthenes so was badly mistaken on which continent he had arrived. So that is perhaps not an example which points out scientific errors as Eratosthenes and Columbus both predated even Baconian ideals which eventually led to modern physics.

    Science started off as a jealously guarded endeavor, with people and nations competing for prestige. Leonardo da Vinci wrote his discoveries in code. Galileo's coded announcement of his observation of what we later know to be Saturn's rings was mistaken by Kepler to be an announcement of the moons of Mars. Despite his status and acclaim, Newton fell into a row over the origin of calculus and even as late as the nineteeth century, we saw national prestige driving differential acceptance of such pseudoscholarship as Piltdown man.

    The revolution of physics was an important step in the abolishment of ego and human authority from science. Evidence that Newton was wrong about absolute space only began piling up circa 1859 but it took integration with the 1865 electromagnetic theory of Maxwell and the precision experiments towards the end of the 1800's before the gap between theory and experiment was clearly delineated. Nowadays, those that advance new hypotheses cannot be expect to rely on authority and institutional prestige but must relate to the data. Even medicine, where the human stakes would seem to be the most obvious, is now increasingly being subjected to scientific review.

    Look at the LHC. That's over 10 billion dollars in construction alone to search for new phenomena not predicted by existing theory and to refine our knowledge of known phenomena. That's what looking for new physics looks like.

    Look at the measurement of the anomalous magnetic moments of the electron and muon; that's what looking for new physics looks like.

    Look at the details of the power spectrum of angular distribution of the cosmic microwave background; that's what looking for new physics looks like.

    So there is no danger of humanity deciding to stop looking in the near future.
     
  19. karenmansker HSIRI Banned

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    Agree . . . . . . except last statement may be hampered if funding is curtailed (HAHA!)
     
  20. The God Valued Senior Member

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    I did not say lack of your knowledge....I said lack of knowledge in general at scientific level. You misread.
     
  21. The God Valued Senior Member

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    Its more or less like your Aether theory. The question is resolution of issues and acceptance. You claim to resolve issues around GR in your theory, theory is published, but..
     
  22. The God Valued Senior Member

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    That brings us back to 'spin'. When they made the prediction it was based on certain maths and in that maths spin was spin as classical as we understand. So when it became metaphysical?
     
  23. The God Valued Senior Member

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    Very nice and very lengthy post. I forgot to ask you when you type those formula, you copy paste from your record with formatting, or it is that cumbersome method here which you have mastered?

    On the quoted extract of yours...GR cannot be said to be uncontradicted, but still.
     

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