QM randomness...

Discussion in 'Physics & Math' started by Seattle, Jun 2, 2017.

  1. Dinosaur Rational Skeptic Valued Senior Member

    Write4U: You seem to be arguing in favor of determinism.

    If so, it is a lost cause. Quantum Theory junked determinism early in the 20th century.
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  3. Write4U Valued Senior Member

    Question, if we knew the frazzle rate of every quark, would we be able to describe it's decay in precise mathematical terms?
    I completely agree, but that describes our limitations, not the limits of mathematical functions.
    Again I agree, but I also submit that it tends to support my question.
    The question is not if we can ever know all values and functions of the wholeness. The question was in context that if we did know, would we be able to mathematically predict the results of the butterfly effect?

    To sum it up, before I'll shut up. When sufficient information is known (to us) and we are able to precisely predict the outcome, we call it a Deterministic event. When we have insufficient information is known (to us) and we are only able to estimate the outcome, we call it Probabilistic.

    Thus both terms are used in context of known values and forces. But does that mean if we don't know something, it doesn't (cannot) exist in reality?

    OK, I have posed the question in context of our very limited knowledge of the wholeness and its inherent mathematical potentials and functions. I won't press it any further.
    Last edited: Jul 16, 2017 at 11:26 PM
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  5. iceaura Valued Senior Member

    The mathematics predicts your failure regardless of the extent of your knowledge.
    You are assuming such impossibilities all along here. You insist on them. Like this:
    So you know the values of the spin states of entangled electrons? You know the position and momentum of elementary particles simultaneously? You know the values of quantities describable only as algebraic combinations of e and pi?
    Compared with that, being in two places at the same time is "mathematically" trivial.
    Again: if you could be in two places at the same time, and got drunk in only one of them, would you have a hangover in the morning?
    Last edited: Jul 17, 2017 at 2:01 AM
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  7. iceaura Valued Senior Member

    He deals with the recovery of former causality assumptions explicitly, and iirc uses Newton's gravity as an example of that - he describes such recovery as valuable, as critical and necessary and so forth.

    That is the opposite of "ignoring", completely or otherwise.

    Meanwhile, the contortions necessary are visible in even the simplest references - such as talking about a field with a speed, and "waves" that are "particles" in it somehow "mediating" a "force".

    And notice, while we're at it, that whatever is being "mediated" is not behaving like Newton's forces. Not exactly. The approximation is good enough for most purposes, but if you get careless and use it where you shouldn't you will screw up. And if you start bringing in causality assumptions you will tend to grasp for causes - and there sits Newtonian "force", ready to hand.
    And are routinely violated.
    QED defines probability as "causal", in that sense.

    Stretching the notion of causality to include mediating fields and probabilities and so forth is exactly what the link is referring to in its introductory paragraphs as emptying the term of physical reference and useful meaning.

    It's something that often happens when rigorous theory attempts to incorporate, rather than abet recovery of, folk taxonomy and terminology - there's nothing wrong with classifying ground squirrels with gophers in daily life, and evolutionary theory abets the recovery via "convergent evolution" and the like, but actually attempting to incorporate such classifications would screw up your rigorous evolutionary theory.
    Last edited: Jul 17, 2017 at 2:16 AM
  8. The God Valued Senior Member

    There are interpretational issues. This fight about randomness has gone on so long that even the macro world has become random......if so all the met guys would have been jobless by now for random forecasting of cyclone 'Trump' on east coast.

    The real issue is not that nature or reality is random but the model which describes the nature at quantum level, Quantum Mechanics is based on probabilistic approach. And this model is quite successful so an inference can be drawn that nature at fundamental level is random or probabilistic. Of course the model is falsifiable but not the nature.

    The model says that the universe (everything) is in multiple possible states and becomes deterministic only when measured or observed. This is fundamental to this QM model, so the argument about omniscient (all surpassing knowledge) becomes redundant, the argument that everything is causal also fails because the best or the worst cause for single state collapse is measurement or observation only, which offers no help.

    So as long as QM is there, we will have to leave with this pseudo randomness but can we dig deeper and claim that everything is entangled and when we are observing something, the entangled (to it) object is already observed somewhere else prior to that and hence our observation is also deterministic? This is a fair and simple assumption.
  9. Write4U Valued Senior Member

    Thank you for that thoughtful response.
    I am sure you have gathered by now that I believe the Universe functions in accordance with forms of mathematical laws and functions, even if we identify these functions by different names. I believe this is Max Tegmark's hypothesis.

    Obviously Probability is a mathematical function.
    As I understand it even Randomness is a mathematical function
    As I understand it Chaos is also a mathematical function
    What then is left that would not qualify as a form of mathematical function?

    But from this discussion I have come to understand that mathematical functions need not necessarily be linearly Deterministic (until they are observed). Thank you all for your patience.
    Last edited: Jul 17, 2017 at 7:24 AM
  10. Schmelzer Valued Senior Member

    Until Bohm's paper, which gives a deterministic interpretation of Quantum Theory.
    No. We have, in fact, now already all several times both switches from random to deterministic.

    de Broglie-Bohm (deterministic) -> quantum theory (random) -> classical mechanics (deterministic) -> Brownian motion (random) -> condensed matter (determinstic) -> weather (random) -> climate (deterministic).

    That one can give confusing descriptions of GR is known but proves nothing. Certainly it does not prove that Newton was wrong in that quote. He was, instead, recognizing that his own theory is not the final word, given that it has obvious philosophical problems.
    No. I have read Arntzenius and was not impressed by his examples.
    QED in the minimal interpretation defines no causality which follows Reichenbach's principle.
    In this sense, I see Reichenbach's principle, understood as a metatheoretical, methodological principle, as a rigorous version of causality. And what Norton is doing as developing some folk science.
  11. iceaura Valued Senior Member

    At the expense of physical cause, which is limited to the speed of light.

    You can also get a "deterministic" interpretation of QED by adopting a different logical modeling of existence - so that "B and not-B" can acquire a different truth value than the simple "false", for example, and Bell's Inequality no longer holds in all situations. But this also discards physical cause as we know it.

    If your system is "determined" without cause and effect, and you reject "superdeterminism" and such top-down formulations, what role is left for causality?
    We don't "switch". We handle each situation with the appropriate, competent, valuable theory. We comprehend in each case by way of valuable heuristics and reliable metaphorical simplifications.
    Classical mechanics includes air pressure and other thermodynamics (probability based), Brownian motion reproduces classical mechanics, climate is no more determined by cause and effect than weather, and so forth. In each case one missing issue is cause and effect - put another way: there are two radically different kinds of "determinism" mixed up there: constraint and cause.

    Another continual glitch in there is chaos and similar considerations, which created an apparently intractable problem for reductionist - cause/effect - determinism long ago, largely ignored until failure at weather prediction brought it to unavoidable attention.

    The implication there that climate restores a cause-determined status to weather, for example, misleads. Knowing the climate does not tell you the weather, and vice versa.
    That was your description of GR, as used to recover Newtonian gravity. It exemplifies the current problems with causation.
    Nobody said any different. Deflection?
    Evidence never impresses you, when it conflicts with your assumptions.
    Then you have a problem. Because QED shows no sign of going anywhere, and if you reject the offer of probability itself as a cause you don't have one.
    Causality without causes or causation, so that it can produce violations of Bell Inequalities, according to you. OK. If that makes you happy, at least it won't get in the way.
    He's describing a situation that already exists, and that you exemplify a couple of times above - not developing anything.
    And when you asserted that he ignored Newton's philosophical point, you had his extended attention to Newton's philosophical point right in front of you. Hello?

    Closing remark: the laws of chance - rigorous mathematical formulations of randomness - produce the most reliable, unavoidable, inevitable, pre-determinations of event we have.
    Last edited: Jul 17, 2017 at 8:00 PM
  12. Dinosaur Rational Skeptic Valued Senior Member

    From Write4U Post #82
    The Butterfly effect is a bit out of context in this discussion.

    It refers to deterministic situations for which future effects cannot be calculated due to inability to obtain precise enough initial conditions as well as all the pertinent subsequent data required for the calculations.

    The term might have been due to a SciFi time machine story in which time travelers to the age of dinosaurs are told not to stray from the time machine platform. One of the travelers kills a butterfly which flutters near the platform. On return to their present time, they do not recognize the environment nor the operators of the time machine.

    At least the SciFi story is consistent with the use of the term.​

    There are also some real time considerations for situations not involving the Butterfly Effect: It would not help if the time for the calculations did not occur fast enough to be useful. Your visual system, brain, & reflexes might be able to avoid tracer bullets from a machine gun 1000 yards away, but you would have no chance at much shorter distances.

    The context here is the issue of deterministic versus probabilistic laws being applicable to reality.

    Prior to the early 20th century, mainstream science believed in a completely deterministic universe.
    The science of that era also believed in energetic processes being continuous phenomena.

    Quantum Theory & the discovery/analysis of processes like radioactive decay changed the above mainstream view.

    Radioactive decay displays all the characteristics of a random process, which is why the decay rate is defined as the half life of a radioactive substance. There are other processes for which the mathematics of probability are applicable.

    From a previous Post of mine.
    BTW: The classic world of our senses provides us an erroneous view of reality, although that view is well suited to coping with our environment. For example so called solid objects are mostly empty space. The illusion is due to the fact that our interactions with solid objects is via electromagnetic effects.
  13. The God Valued Senior Member


    This is bad. This is neither QED not QM.
  14. The God Valued Senior Member

    1. Then what is the correct view of reality?

    2. And then what is empty space?

    3. Just because we understand the electromagnetism, it does not make everything around us illusory.

    You seem to be taking this random maths business beyond it's brief.
  15. iceaura Valued Senior Member

    Of course it isn't. It's regular old reality, classic regression to the mean and law of large numbers and bell curve stuff.

    It's worth noticing, because the weirdness of the special place cause/effect analysis has in people's thinking - to the point that they mistake it for reality itself, and regard anything else as some kind of mysticism or fuzzy thinking - is so common as to be invisible if you have nothing to contrast with it.

    Here's another: The Second Law of Thermodynamics is not founded in cause and effect. Nothing in particular "causes" entropy to only increase in a closed system. And the determinism derived from that Law is as certain as anything we know.
  16. Write4U Valued Senior Member

    Question; Is it possible that continued existence of anything (including closed systems) requires expenditure of energy (entropy)?
    If so, would that not count as causality?
  17. Schmelzer Valued Senior Member

    You cannot. But this is not a problem in that logic, because can and cannot can above to true. (Or cannot. Whatever.)

    More seriously, QED is a standard quantum theory, so that you can have a causal interpretation, namely the standard Bohmian interpretation.

    If a theory/interpretation decides to forbid FTL causal influences, ok, then it has a problem with the violation of Bell's inequality. But if a theory/interpretation does not restrict physical causes to the speed of light, then not.
    The Bohm interpretation has also been named "causal interpretation", and has good reasons for this, given that it is a deterministic theory.

    Seems like you have completely misunderstood my list of theories. Each describes a theory, which approximates the theory listed before, and can be used to derive, as an approximation, the following theory. The odd theories are deterministic, the even one random. ("classical mechanics" was meant as the classical mechanics of point particles, as used as the base for kinetic gas theory). The list illustrates that it is not a good idea to think that once the actually most fundamental theory is random/deterministic, this would remain so forever. It was not a remark about causality.
  18. Dinosaur Rational Skeptic Valued Senior Member

    From a Post of mine
    From The God Post 91
    1. Solid objects are mostly empty space. Our interaction with them is via electromagnetic effects. Our notion of a solid object is erroneous, but our view of interactions with solid objects is valid.

    2. Empty space is just what it sounds like. It contains no matter.

    3. Our interactions with our environment is not illusory. It is our notions about the underlying reality that is erroneous or illusory.

    Consider an analogy with the ancient Hebrew explanation for rainbows.
    A rainbow is not an illusion, but the ancient explanation is nonsense, although I suppose there are some ultra orthodox Jews & Christians who accept the view expressed in the bible.

    Similarly If a one pound piece of iron were not mostly empty space it would weigh too much for a person to lift against the pull of Earth’s gravity. It would have the density of a neutron star.

    However our notions or POV of that piece of iron is that it is solid matter rather than mostly empty space.
  19. Write4U Valued Senior Member

    I agree that a one pound piece of iron could have the density of a neutron star, but it would still only weigh one pound. ( a pound of feathers weighs the same as a pound of lead)

    I am sure you mean if the size of a one pound piece of iron had no empty space it would in fact have the weight of a neutron star....

    Please Register or Log in to view the hidden image!

    a small attempt at humor.
    Last edited: Jul 18, 2017 at 6:20 PM
  20. iceaura Valued Senior Member

    Bohmian is not causal, unless you simply (as in science fiction movies) assume the existence of superluminal "cause" - in current theory, and all extant evidence, there is no such cause.
    Yep. That would be all the actual theory we have, and all the evidence.
    General Relativity does the restricting. Bohm is not "interpreting" GR - it's still there.
    I didn't misunderstand it, I pointed out that it was mistaken and confused, and I said why. (Those aren't theories, they are not either "random" or "deterministic" arenas, you have ignored chaos, and so forth.).

    You appear to have caught on to the basic insight of the link I posted, Norton, in which he describes the recovery of invalidated causal approximation (very useful, very valuable, "folk science") from more accurate and conceptually valid theory that is inconvenient. You can see that in your posted sequence. Now all you have to do is pay careful attention to the details.

    Start here: climate is no more "deterministic" than weather - and no less. Brownian Motion is no less deterministic than classical mechanics - and no more.
    Last edited: Jul 18, 2017 at 8:42 PM
  21. Write4U Valued Senior Member

    I can't judge, but assuming you are right, how can we use this knowledge for practical purpose and application?
  22. iceaura Valued Senior Member

    Generally, my rule of thumb (picked up from a school of Zen influenced I believe by Taoist thought), better philosophy is mainly good for excluding worse philosophy. Here that would mean it allowed practical purposes and applications that might otherwise be excluded, removed obstacles to thought and approach and explanation.

    In practical terms it might help in overcoming the Gambler's Fallacy, and in getting out of the rut of having all observation of patterned and connected behavior devolve mentally into projections of conspiracy and intention ("cause"), that kind of thing.

    I don't know, is the short answer.
    Write4U likes this.
  23. Schmelzer Valued Senior Member

    And that I have to consider c as the ultimate speed of causal influences is the decision of the Imperator or what? Of course, in de Broglie-Bohm theory there are superluminal causal influences. Live with this.
    No, Bohmian theory we have too. Since 1952. And, given that the other theories we have in the quantum domain ignore causality (or use nonsensical definitions of causality so that not even Reichenbach's common cause principle holds there) it is the only causal theory in this domain we have.
    Yep. So there is a problem of compatibility between Bohm and GR. Big news.
    I understand Norton's point in developing his "folk science" but I think he is wrong, and what he thinks is impossible, namely a precise notion of causality, exists. With Reichenbach's principle of common cause, interpreted as a metatheoretical (methodological) principle.
    I end with this, rejecting this as nonsense, without even a need of further comment. (Feel free to give further explanations, so that one could try to make sense of of this nonsense.)

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