• andrewk
    1.6k
    So my question to you is: do you think my inference that 'what is causing the interference pattern is outside, or not a function of, space-time' is indeed 'gobbledygook'? Or do you think it's a valid inference?Wayfarer
    The problem is that by asking what 'caused' something you are moving from physics to philosophy - metaphysics, and there's quite a bit of sensitivity on physicsforums about discussions veering off into philosophy. They try - not always successfully - to maintain a clear boundary between physics and philosophy and it looks like you inadvertently crossed it. I thought the reaction was a bit harsh, especially as you, not being a regular there, would have no reason to be aware of that sensitivity.

    I wouldn't comment on the validity of your inference because I see discussion of what caused what as frustratingly ambiguous. But I can observe that increasing the time between photon emissions also increases the average distance between photons, which reduces the frequencies of interactions and hence the extent to which interaction effects distort the pure proportionality discussed in the A to the second Q. And that maybe sounds something like what you were saying.
  • Noble Dust
    3.1k
    Is this thread "pseudo-science"? @TimeLine?
  • Wayfarer
    6.6k
    I thought the reaction was a bit harsh, especially as you, not being a regular there, would have no reason to be aware of that sensitivity.andrewk

    I wasn't upset by it in the least. It was instructive. You can see, I didn't push it, but I got the distinct impression that I had crossed a line. I learned something from it.

    I can observe that increasing the time between photon emissions also increases the average distance between photons, which reduces the frequencies of interactions and hence the extent to which interaction effects distort the pure proportionality discussed in the A to the second Q. And that maybe sounds something like what you were saying.andrewk

    Right! Time is NOT of the essence.



    Mum! Mum! Those bad people are saying bad things.
  • Wayfarer
    6.6k
    Only kidding! Have a look at the threads that I linked to in the OP. As I say in both threads on physics forums, I’m not physics-literate. The question I asked might be a bit difficult to comprehend, but I think it’s basically intelligible to the lay-person, and makes a point that I think is philosophically interesting.
  • WISDOMfromPO-MO
    753
    As for the actual flow of time, real time, the duration of life, everyone who is alive has experienced it every day of their life.Rich

    If we do not need any concept of time to explain and make predictions about the physical world, why does this "flow of time" matter?

    Occam's Razor seems to apply here.
  • Noble Dust
    3.1k


    Oh I know, Wayfarer! I was joking myself. This thread has been an interesting read so far. (Y)
  • Rich
    3.2k
    If we do not need any concept of time to explain and make predictions about the physical world, why does this "flow of time" matter?

    Occam's Razor seems to apply here
    WISDOMfromPO-MO

    Duration, real time, comes into play when understanding the nature and creation of the underlying quantum information (memory). This is not scientific clock-time. Bergson warned and challenged Einstein about the attempts to elevate scientific clock time to an ontology. As common in science, politics had a lot to do was at play. You see physicists really don't mind dabbling in metaphysics when it suits their purposes.

    Robert Disalle wrote a book on the Philosophical Development of Space-Time. The Physicist and Philosopher by Canales is also worth noting.

    The upshot is that philosophers should feel quite comfortable challenging the metaphysics of physicists and scientists. Most often they have no idea how poor their metaphysics really is. I loved it when Erik Verlinde came down hard on the Big Bang which is just more metaphysics along with the Laws of Nature.
  • boundless
    79
    Hi @Wayfarer,

    I try to answer in a non-relativistic point of view.

    Short answer: the particle does not interfere with itself. In QM the interference pattern is predicted by the form of the wavefunction which can be inferred by previous observations or by theoretical assumptions.

    But I then introduced the argument that this shows that the 'wave equation' is independent of time (and therefore space, as I had understood these two to be related as 'space-time' in relativistic physics). I said, in particular, that 'what is causing the interference pattern is outside, or not a function of, space-time'.

    In my opinion here you are right. The wave equation is in fact independent of time in QM in form. However the wavefunction is of course a function of the positions (which in QM are (hermitian) operators, i.e. observables) and time (in QM it is a parameter and not an operator).However in non-relativistic QM the "squared modulus" of the wavefunction is proportional to the density probability to find a particle in a position at a given time.

    However strictly speaking the cause of the interference pattern is not "outside".In this case, in fact, the wavefunction is a sum of two terms: there is a term that describes the path through the first slit and another relative to the other path. However the wavefunction itself is not an observable. What you can observe is the probability distribution. Forgive me if I use a simplified formula:
    Let F be the wavefunction, f1 the part relative to the first path and f2 the path relative to the second.
    F = f1 + f2. The wavefunction however is complex. So the probability density distribution is:
    FF* = f1f1* + f2f2* + (f1f2* + f2f1*)
    The first two terms (f1f1* and f2f2*) are always positive. The sum of the other two (the interference) however can be negative (hence the minima)! What you observe is that the particles follow that probability distribution (which of course is related to the interference pattern: the maxima of the interference pattern are the points where FF* has a maximum and the minima where FF* has a minimum). The interference therefore is given by the wavefunction itself: if our system is not time-invariant of course the probability distribution can change during time. The interesting feature of QM however is that you do not observe F (and so f1 and f2) itself but FF*. So it does not intefer with itself, simply the interference pattern depends on the (a-priori unknown) expression of the wavefunction.

    The interaction is between the particle and the experimental apparatus. However the wavefunction has all the information about this interaction.

    Remember that in a single experiment what happens is that we observe only one "path". To observe all possible path and therefore to verify that there is a "probabilistic" law we have to do a lot of measuerements. Consider a simplified version ot the experiment. Suppose that the particle can be observed only in two points of space, P1 and P2. Prior to the experiment you cannot know where the particle will be observed. You perform the experiment and you find the particle at P1. You perform a LOT of experiments and you find that with a probability p1 you find the particle at P1. QM says that when you perform another observation you will find the particle at the position P1 with a probailty p1.


    Of course you can also predict the form of the wavefunction theoretically (i.e. from theoretical assumptions) - and in fact it is what is almost always done in physics. In fact you can include in the wavefunction all the information about physical interaction (i.e. for example the influence of a electro-magnetic field).


    Regarding the ontology there is a lot of views.
    Some adherents to the Copenaghen interpretation think that the real is what is observed, therefore until observed we cannot say that the particle "exists". (the wavefunction is not real and until observed the particle does not "exist" - Recall Einstein objections)
    Others adherents instead think that it is an epistemological issue. They think that we can only make meaningful statements on the observed. Therefore prior the observation the "ontic status" of the quantum system is unknowable. In both cases the wavefunction is a "predictive tool".
    Then there is the MWI (many-worlds). They think instead that the only existing thing is the universal wavefunction which never "collpases". All possibilities are actualized (therefore the particle goes to both slits!). The fact that we observe only a determinate path is due to a sort of an illusion.
    The original Bohmian-mechanics treated both the particles and (universal) wavefunction as real. The wavefunction guides all the particles of the universe. Again we observe the probability distribution because of our "ignorance" (we do not observe the whole evolution of the universe).
    The "new" Bohmian mechanics instead treats the wavefunction as a "law". The only reality is given by the particles.
    There is also the Relational Approach, Statistical interpretation and others.



    I suggest this link: https://plato.stanford.edu/entries/qm/

    I hope to have been of help :-#
  • boundless
    79
    A shorter (and possibly clearer answer).

    The wavefunction according to the "standard/pratical interpretation" is merely a tool for the calculations. However the wavefunction itself does NOT give you the probability distribution. So it is not an observable and not therefore a physical "thing". To a physicist what we observe is what is real.

    And what about the unobservable? Here to the pratical physicist you are already in philosophy (and some physicists actually have a sort of "aversion" to philosophy).

    In the case of the experiment therefore: the "real" is the interference pattern (which of course is observed). If you perform a single-particle experiment, of course, you do not observe the interference pattern (and therefore you infer that the "quantum particle" behaves as a particle). However if you do a "large number" of single-particle experiments you will find that the "total" interference pattern follows a wave-like law. And therefore you conclude that the "quantum particle" behaves like a wave. The wave-like nature however is apparent only when you have a statistically significant number of single-particle experiment (or if you perform a single experiment with many particles).

    Consider the case of a single experiment with a single particle. Are the other "possibilities" in some sense "real"?

    1) If you accept the Copenaghen interpretation: no. They are not real. What is real is the observed. The quantum system, when unobserved is either "unknowable" or unreal. So do the other possibilities exist? Possibly some phyicists would say that "it does not apply". The question itself is meaningless. We can only say meaningful things about what we observe (similar to positivism). Or maybe "it does not apply" for other suggests that the "unobserved quantum particle" is indeed a "reality" but we cannot describe it in any ways.

    2) If you accept the Many-Worlds yes. But you cannot observe them since the "other" paths actualize in "other worlds". In this interpretation actually the only fundamental "reality" is the universal wavefunction, which "never collapses". The fact that we observe only one occurence is due to the fact that we cannot observe "the universe".

    3) If you accept the Bohmian mechanics actually the particle follows a precise path. The other paths are so to speak "empty". The other possibilities are "real" if you accept the wavefunction as a "thing" or "unreal" if you do not accept the wavefunction as real. Also in this case the only "true" wavefunction is the universal one which "guides" all the particles in the universe. However in practice since of course we cannot observe the whole universe we have to use "conditional wavefunctions" to describe the dynamics. Are the conditional wavefunctions real? No, they are only a tool.

    There are also other interpretations. However they are all in agreement with the "observed reality". The contention is about how to interpret what we cannot observe. And in a sense speaking about what we cannot observe is "meta-physics". And in fact many physicists do not engage in philosophical discussions because of this, To them speaking about the "unobservable" is futile or "beyond our range". Therefore when someone begins to "philosophize" sometemise they grow angry!

    However the real problem is not philosophy. The problem is that sometimes people try to use QM to "prove" that nonsense like "law of attraction" & similar are "true". For this reasons many physicists have a strong aversion to philosophy and tend to react "badly" IMO to honest philosophical discussions.
  • Wayfarer
    6.6k
    I hope to have been of help :-#boundless

    Sure! Apart from anything else, it is preferable to be told that I’m right, than that I’m speaking gobbledegook ;-). And also, I thank you for the lucid explanation, it makes sense to me, and is useful for understanding the subject better.

    I do understand why physicists get exasperated with homespun philosophers using their discipline to justify crank ideas. But on the other hand, science is often cast in the role of being arbiter of what ought to be considered real. So the fact that this ontological ambiguity exists at the heart of physics ought to be more than simply a source of irritation; it ought to be a reminder of the mystery of existence.
  • Rich
    3.2k
    For specificity, it should be pointed out that Bohmian Mechanics it's based upon a very specific field that c appears in its equations which Bohm/Hiley called the cops quantum potential. Following is a short description of the quantum potential which is copied from this paper:

    Quantum Interference and the Quantum Potential∗
    C. Philippidis, C. Dewdney and B. J. Hiley† (1978)

    "Our results using the quantum potential show that one can, in fact, re-
    move the ambiguity of whether quantum objects are waves or particles and
    provide, instead, a clear intuitive understanding of quantum interference in
    terms of well-defined particle trajectories. More important than this, how-
    ever, is the new perspective it gives to quantum interconnectedness. We
    have shown that the quantum potential combines properties of all the par-
    ticipating elements—masses, velocities of particles, widths and separation of
    slits—in an irreducible way and suggests that, as far as the quantum domain
    is concerned, space cannot be thought of simply as a neutral back cloth. It
    appears to be structured in a way that exerts constraints on whatever pro-
    cesses are embedded within it. More surprisingly still, this structure arises
    out of the very objects on which it acts and the minutest change in any of
    the properties of the contributing objects may result in dramatic changes in
    the quantum potential.
    This gives a new appreciation of Bohr’s insistence that quantum phe-
    nomena and the experimental situation are inseparable. Moreover, it recalls
    the relativistic relationship between space and inertial mass, and seems to
    extend this relationship to include the geometrical and possibly the topo-
    logical configu-rations of matter.
    It is clear, therefore, that the quantum potential is unlike any other field
    employed in physics. Its globalness and homogeneity in the sense of not
    being separable into well-defined source and field points indicates that it
    calls for a different conceptual framework for its assimilation. Notions of
    structure, structural relationships and stabilities seem to be more appropri-
    ate than those of dynamics (even though here we have started with what
    appeared to be dynamical equations). However, a more detailed discussion
    of these points will be presented in a further paper."

    More importantly, Bohm, in his book, specifically describes his model as causal. I quote from his book Science, Order, and Creativity:

    "Although the interpretation is termed causal [author's italics], this should not be taken as implying a form of complete determinism. Indeed it will be shown that this interpretation opens the door for the creative operation of underlying, and yet subtler, levels of reality."

    Why do I bring this up? I invite readers to search for internet for information about Bohmian Mechanics and it's interpretation and you will find one physicist after another describing it as deterministic (including the Stamford Encyclopedia of Philosophy). They never studied his works. They are parroting what they read elsewhere, including the incorrect conclusions. I let you decide from now this what you wish regarding the reliability of information derived from "trusted sources".
  • bahman
    530

    The idea of particle passing from two slits and interfere with itself is nonsense. Please read this article for further information.

    The Bohmian mechanics is the way to go.
  • Rich
    3.2k
    physicists get exasperated with homespun philosophers using their disciplineWayfarer

    That is not why they get exasperated. They get exasperated when any philosopher or scientist challenges the hegemony of their materialist metaphysics which is indoctrinated in education from the earliest grades. It is not accidental. It is as much part of "science" as God of part of various religions. In your particular case you were subtly challenging the materialist doctrine of space-time.

    As it turns out, Bohmiam interpretation provides you with the clearest explanation of the issue you are investigating. If any of the physicists on that forum ever studied Bohmian Mechanics they would right away understand you are bringing up a reasonable issue regarding space-time and quantum behavior.
  • Rich
    3.2k
    The idea of particle passing from two slits and interfere with itself is nonsense. Please read this article for further information.

    The Bohmian mechanics is the way to go.
    bahman

    Personally I wish that philosophers wo(man)--up, develop a spine, do the necessary work, and stop accepting junk scientific materialism metaphysics as gospel, because that is all it is. Read the works of Bohm and Bergson as a starting point. Rupert Sheldrake and Stephen Robbins provide further valuable insights.
  • boundless
    79


    Actually I am a student of physics at the university and I have to say that I agree with you! To be honest I am quite dissatisfied by the "strict pragmatic approach" that many physicists use, especially after the '80s (however the problem is very old. For example Einstein famously was concerned with the hostility against what he called "epistemology", i.e. philosophy of science amongst some physicists of his time*). According to them physics deals with finding the best way to make "predictive calculations". In my opinion instead physics gives us information about "reality" and when you see it in this way, it is impossible to "separate" it from philosophy (epistemology and metaphysics). For example while the mathematical formalism of QM is well estabilished, there are a lot of interpretative problems. For example those who support the "pilot-wave theory" (let me call it "PWT") are very adamant in criticizing their colleagues because they feel that the lack of realism is meaningless. At the same time however some "Copenaghists" criticize the PWT for its explicit non-locality (this is the most serious problem of PWT, but not the only one) and other more techical stuff. A very interesting "school of thought" derives directly from the founder, Bohr. According to Bohr the "quantum world" is unknowable. Therefore concepts like "position", "velocity" do not apply to the "quantum world" because they were introduced for the classical "realm". This in a way resolves the "non-locality" problem, since even in quantum entanglement you cannot "see" the "supposed" faster than light interaction simply because the "signaling" process is a "classical concept" and it does not apply to quantum world**.

    The Copenhagists on the other hand are criticized because they create a dichotomy between the quantum and the classical "realms", that sounds quite arbitrary (Bohr response to this issue, the so-called "correspondence principle" (https://plato.stanford.edu/entries/bohr-correspondence/) to someone is not really satisfying) So there is also the "relational approach" proposed for example by the Italian physicist Rovelli. Briefly according to Rovelli QM must be able to describe all non-relativistic physics (and relativistic QM also the relativistic, but i prefer to not consider now relativity, since the relativistic version of QM, QFT, among other things is a field theory and there is even more confusion). The idea is that each "observer" "sees" his own "reality". Therefore in the "Schroedinger cat experiment" while, say, the cat observes its state as "alive" (fortunately for the cat, I love cats X-) ) while for the evil experimenter the cat the cat is "neither alive not dead" until he performs the observation. I do not know the precise details but according to Rovelli the non-locality is a non-issue in his interpretation. Then there is the MWI which is mathematically the simplest one but has problems with justifing the "Born Rule" (i.e. the "probabilistic rule for predictions") and also has a technical problem, the preferred basis problem (i.e. it does not really explain why we "observe" a classical world). So as you can see once you step in "philosophy" (personally I would call it "physics" but I am a "weirdo", it seems 8-) ) the views are many. It is IMO a shame that in the university classes it is seldom (if ever) mentioned.

    *https://en.wikiquote.org/wiki/Albert_Einstein#1910s see the quote relative to EInstein's speech at the obituary of Planck.
    **Since I noted (from other threads) that you have at least a very strong interest in buddhism, I find it somewhat reminiscent to the (mainly Mahayana) buddhist position about the fact that for "conditioned phenomena" neither "existence" nor "non-existence" apply. However do not take too seriously the analogy, take it just for "fun".



    Regarding materialism, I also agree. But IMO in fact there are a lot of scientists that are actually "open". The problem however is that there is an awful number of (often "self-described") "gurus", "spiritual teachers" etc that insist that science either "proves" nonsense or that science is useless***. This behaviour causes a lot of skepticism among scientists. Also science is very empirical and therefore when one makes a lot of claims about "reality" which is not "in line" with the accepted theories (even after being corrected more than once...), scientists are (rightly IMO) adamant in dismissing him/her. The problem is that somewhat unconsciously this "aversion" sometimes is also "extended" to honest "inquirers", simply because sometimes the language is different. There is too much "suspiciousness" which is partly justified by the real presence of "crackpots" but I agree it is excessive (for example I find Krauss argument against the existence of God quite "shallow", since he does not really understand that "nothing" cannot be compared to either the "vacuum state" in physics or "the phyisical laws").

    Regarding Bohm, we have to remember that his work had different phases and the latter part was not always "in line" with the early. The original article of Bohmian mechanics (the 1952 article I mean) does cite the "quantum potential" but it is a non-local deterministic theory. Later however he tried to introduce in physics his (interesting) concepts of "implicate and explicate order" in his scientific work. However usually physicists refer to the "early stages" of his work. And also now many "bohmians" do not accept the ontological status of the wavefunction and reject the "quantum potential" altogether (they do accept the strong non-locality of the theory, though, and consider the "wavefunction" simply as a sort of "physical law"... it is called the "nomological variant of Bohmian mechanics"). Also "Nelson mechanics" is causal, but non-deterministic, pilot-wave theory to my knowledge. If I do recall correctly it is partly based on the Pilot-Wave theory of Bohm (1952)| .

    *** Edit: minor correction in this phrase.
  • boundless
    79
    Other interesting info:

    Another variant of PWT is the "t'Hoof theory" where however superdeterminism is accepted (and therefore it is local!).

    Also see these links:
    https://www.physicsforums.com/threads/the-refutation-of-bohmian-mechanics.490095/ (where many "objections" to Bohmian PWT are refuted... there are a lot of similar threads in "physicsforums")
    http://www.bohmian-mechanics.net/whatisbm_links.html
    also these Wiki articles are fine: https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory and https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics


    To me it is a very interesting "perspective" on QM, even if however I am more drawn to something along the lines of Rovelli and (especially) Bohr (of which I like his emphasis on the epistemological, rather than the ontological...). However to be honest all interpretations seem to me incomplete. However this does not of course undermine their value! It only reveals IMO that there is "something deep" beyond QM (and QFT), so to speak.
  • Rich
    3.2k
    Thank you for your thorough response. I do realize that Bohm's (later Bohm-Hiley) works went very through phases as do all authors of any work. We change as we gain experience and knowledge. The problem is that physicists in general never study Bohmian Mechanics a little, much less thoroughly, thus they never passed through these phases and therefore they don't understand anything that Bohm's physics and metaphysics is offering. Yet, they have no problem passing judgment based upon some hearsay coming from who knows where?

    It is important for philosophers to understand this. They are using sources to pass judgement that wholely unreliable. If they wish to study and understand Bohm, they have to study it themselves. They cannot rely on some scientists hanging out on some forum no matter what kind of credentials they may present. This is most especially true when it comes to understanding any metaphysical questions since scientists are not trained in, and maybe don't even care about, metaphysical questions. They simply don't understand why the question even arises, as in the case that Wayfarer presented.

    I would like to see philosophers to gear up and get up with modern ideas and problems and stop playing around with proofs of God's existence. I consider that lazy philosophy.
  • Rich
    3.2k
    To me it is a very interesting "perspective" on QM, even if however I am more drawn to something along the lines of Rovelli and (especially) Bohr (of which I like his emphasis on the epistemological, rather than the ontological...).boundless

    Bohm articulated a very interesting" holographic view of the universe which is now being picked up indirectly by many theoretical quantum physicists. As I observe the trajectory I believe that his thoughts will eventually bare out as fundamentally in the right track.
  • Metaphysician Undercover
    4.4k
    I would like to see philosophers to gear up and get up with modern ideas and problems and stop playing around with proofs of God's existence. I consider that lazy philosophy.Rich

    The question of God is very relevant. Understanding the nature of God, fundamentally "I am that I am", provides us with a perspective of time which is deeply incompatible with the perspective of time employed by relativistic physics. Simply stated, if God is proven to be real, then the space-time perspective of time is proven to be false, because the two are incompatible.

    To arrive at a true understanding of time requires that we dismiss all prejudices and address the soundness of the premises and the logic of the arguments. Arguments concerning God's existence, are good practise, and the cosmological argument for one, which delves into the distinction between "potential" and "actual", is very important toward understanding the true nature of time.
  • Rich
    3.2k
    Simply stated, if God is proven to be real, then the space-time perspective of time is proven to be false, because the two are incompatible.Metaphysician Undercover

    There are many ways to approach the nature of duration (time) and if God is the preferred approach, that is fine. But who ever is discussing time in such a fashion had better be well versed in space-time metaphysics or risk being bullied by the science police. Proving God real is as difficult as proving space-time real and is a difficult path to follow.

    In general, it is my observation that philosophy is atrophying for want of commitment to understand and apply the necessary effort. Philosophers have punted to scientists (a bad play) while they ease themselves into the same old games. Wayfarer would get better answers from a philosopher-scientist than from a scientist, any day of the week. Scientists, for the most part, do not understand philosophical inquiry. They only understand their own agenda.

    If anyone comes across an exceptional philosopher-scientist I would love to know the name. The best I've seen so far is Stephen Robbins. He gets the whole picture.
  • apokrisis
    4.3k
    But if it's a wave, how can the rate NOT matter?Wayfarer

    Again, the wave refers to the probability of observing a particle at some location. It applies to the individual event and does not describe some collective weight of particles as you seem to imagine.

    So the wave is happening, or evolving, while the emission/absorption event is happening. Its "rate" is one such probability wave per event. Or if you instead want to focus on the collective view that is the experimental apparatus expressing its statistics over time, then the rate is continuous over all the identically prepared events. The same probability wave is in play while trials are indistinguishable in terms of their spacetime reference frame.

    So again, your issue seems to be to wanting to think of it as an actual wave - some kind of substantial force - rather than as a description of observables.

    Of course you can go Bohmian despite all its well know issues - like no sensible way to give a relativistic version of BM, no good answer on the question of contextuality, etc.

    And frankly - for me at least - there is just a basic metaphysical inelegance with a deterministic/substantialist ontology. QM really ought to be much more of a challenge to materialism and locality. So why try to make a Bohmian uber-materialism be the one that comes out right?

    I mean I find it weird that the folk like Rich who seem happy with the whackiest kinds of idealism are also the first to commit to the most materialist versions of QM they can find. Well I guess maybe that if you treat the divine, or mind, as some kind of pseudo-substance, then perhaps there is some kind of consistency there.
  • Rich
    3.2k
    And frankly - for me at least - there is just a basic metaphysical inelegance with a deterministic/substantialist ontology. QM really ought to be much more of a challenge to materialism and locality. So why try to make a Bohmian uber-materialism be the one that comes out right?apokrisis

    Absolutely 100% wrong again.

    I mean I find it weird that the folk like Rich who seem happy with the whackiest kinds of idealism are also the first to commit to the most materialist versions of QM they can find. Well I guess maybe that if you treat the divine, or mind, as some kind of pseudo-substance, then perhaps there is some kind of consistency there.apokrisis

    If there was a way to be 200% wrong, this would be it.

    A complete mess in all respects in a most profound manner.
  • apokrisis
    4.3k
    The problem is that physicists in general never study Bohmian Mechanics a little, much less thoroughly, thus they never passed through these phases and therefore they don't understand anything that Bohm's physics and metaphysics is offering.Rich

    Physicists don't think like crackpots. They've got better things to do than obsess over an interpretation with no observable consequences - and one not even able to make proper predictions in a relativistic setting.

    So if BM had some metaphysical advantage in theory building - as in paving a way to a testable theory of quantum gravity - then the theoreticians would be all over it. No ambitious post-grad is going to overlook something that offers even an outside chance of stealing that ultimate glory. Your reading of the situation is comical just based on ordinary competitive human behaviour.

    You will note that by contrast, holography is really hot. Every ambitious post-grad is all over that. They can see that bandwagon having an excellent chance of getting somewhere.

    Sadly, your understanding of holography is as far off the mark as it is with anything else to do with physics. You've got stuck at the point where they mention a hologram as a helpful beginning analogy.
  • Rich
    3.2k


    Your understanding of Bohm is the absolute worse I've ever seen. I can only presume that you are equally messed up on all other subjects you speak of because you apparently you don't care how messed up your understanding is. I guess your forte is making up stuff.
  • Wayfarer
    6.6k
    So again, your issue seems to be to wanting to think of it as an actual wave - some kind of substantial force - rather than as a description of observables.apokrisis

    Everywhere, it is described as a wave, and the whole interference pattern phenomenon is based on what waves do. The equation is described as 'a wave equation'. But if it's NOT an actual wave, then it's not physical. It is, as the description says, a 'probability wave'. And I think that undermines the so-called 'causal closure' principle - that physical effects can only have physical causes. Because 'a possibility' is not a physical entity, right? It's only the likelihood of one. That is why electrons don't actually exist; they only have a tendency to exist.

    That is why I mentioned the article co-authored by Stuart Kaufman (who, perhaps mistakenly, I thought was one of the theorists in your general orbit.) The key sentence in that paper is '“This new ontological picture requires that we expand our concept of ‘what is real’ to include an extra-spatio-temporal domain of quantum possibility" - which is pretty well exactly what I think is the implication of my argument.

    On this scale, we're on the edge of where 'the unmanifest' becomes 'the manifest'. Making an observation actually does create the object - not from nothing, but from a range of possibilities. But it's not as if 'the thing' is hiding there in those possibilities; it is only possibility, up until it is measured. It's not objectively existent until that point. That is why realists, like Einstein, objected violently to quantum physics - because it suggests an anti-realist ontology. It's why Einstein asked that exasperated question, 'does the moon not exist when we're not looking at it?' It's why he devised the EPR paradox, and look how that panned out.

    It applies to the individual event and does not describe some collective weight of particles as you seem to imagine.apokrisis

    It describes a wave, in which time is not a factor - hence, a timeless wave. Fire one particle over X seconds, or X particles over 1 second, you get the same result. I'm a bit disappointed you're not seeing the significance of that.

    why try to make a Bohmian uber-materialism be the one that comes out right?apokrisis

    I'm not. From what I understand, I'm nearest to the Copenhagen Interpretation. Last year I read Manjit Kumar's Quantum, and also Stephen Lindley's Uncertainty, and I find overall I'm in agreement with Heisenberg (and the so-called 'Copenhagen' interpretation, which is not even a scientific theory, in my understanding, but a kind of heuristic). And again, Heisenberg is the main source for the Kastner/Kaufman article.


    But IMO in fact there are a lot of scientists that are actually "open". The problem however is that there is an awful number of (often "self-described") "gurus", "spiritual teachers" etc that insist that science either "proves" nonsense or that science is useless***. This behaviour causes a lot of skepticism among scientists. Also science is very empirical and therefore when one makes a lot of claims about "reality" which is not "in line" with the accepted theories (even after being corrected more than once...), scientists are (rightly IMO) adamant in dismissing him/her. The problem is that somewhat unconsciously this "aversion" sometimes is also "extended" to honest "inquirers", simply because sometimes the language is different. There is too much "suspiciousness" which is partly justified by the real presence of "crackpots" but I agree it is excessive (for example I find Krauss argument against the existence of God quite "shallow", since he does not really understand that "nothing" cannot be compared to either the "vacuum state" in physics or "the phyisical laws").boundless

    Agree. Krauss, and others of his ilk, are motivated by a deep animus towards religion. He and Dawkins formed a kind of anti-religion roadshow. But I think there is a general consensus that Krauss’ grasp of philosophy is practically non-existent. There was a damning review of his book in the NYT by a philosopher of physics named David Albert. Also see The Metaphysical Muddle of Lawrence Krauss. Many of the New Atheists verge on the crackpot in their own right, mainly because of their caricatured understanding of religion.

    The thing I like about Bohr and Heisenberg’s attitude is that it’s epistemologically modest. It is mainly about what we can claim to know. I have read snippets from Heisenberg’s Physics and Philosophy and I find them pretty congenial. Actually there was an interesting review from a couple of years back which you might find interesting, Quantum Mysticism: Gone but not Forgotten.
  • Metaphysician Undercover
    4.4k
    There are many ways to approach the nature of duration (time) and if God is the preferred approach, that is fine.Rich

    The thing is, there is a lot more to time than duration, a fact which many of us overlook. More fundamentally, it is a distinction between past and future. That we can measure the distinction between past and future, and determine duration, is another thing. But one's measurements of duration are only as accurate as one's capacity to distinguish between past and future.

    That is why I mentioned the article co-authored by Stuart Kaufman (who, perhaps mistakenly, I thought was one of the theorists in your general orbit.) The key sentence in that paper is '“This new ontological picture requires that we expand our concept of ‘what is real’ to include an extra-spatio-temporal domain of quantum possibility" - which is pretty well exactly what I think is the implication of my argument.Wayfarer

    What is required is to turn around the accepted relationship between space and time, such that time becomes the 0th dimension rather than the 4th. This allows for real non-spatial existence in relation to time, and for the possibility of inverted spatial dimensions as negative dimensions on the other side of the 0th dimension.
  • boundless
    79


    Yea, I agree. Bohm was a very interesting scientist (and philosopher). I find him very insightful. But actually many of the "founders" of QM and relativity were in fact very nice philosophers and scientists (and also there was much less "aversion" between philosophers and science until circa the '80s).

    Thank you for the mention of his "holographic view". I will check as soon as possible. ;)

    For all,

    Regarding the issue about "Bohm as a materialist"... Well the original work (i.e. the article of 1952) describes a "world" made of "point-like" particles which move in a deterministic fashion. It sounds pretty materialistic to me (however it is also true that the position of each particle in the universe depends on all other particles - the "influence" does not really decrease with the distance etc so while being "materialistic" it is of a curious kind!). I also agree that it is not the most mathematically elegant theory, but IMO it is very interesting. However some time later Bohm created an interesting philosophical system about "the implicate order" and "the explicate order". See for example https://en.wikipedia.org/wiki/Implicate_and_explicate_order . The later Bohm IMO cannot be "called" materialist, at least not in the "common" sense of the world (for those who are a bit familiar with Hindu philosophy, the "implicate" order seems quite similar to the notion of Brahman of some Vedanta Schools (Advaita and Vishishtadvaita for example)).



    Yeah, I do not like the "new atheist" movement. I find their arguments very shallow and motivated by a sort of "a-priori" rejection of religion and metaphyisics. While of course for certain types of "religions/metaphysics" (i am thinking about the "anti-science" movements) they are right in their criticisms, I do not think that they raise serious objections to any religion. They seem, as you note, stubbornly convinced that religion and metaphysics cannot do anything good for the human being. They are dogmatic in their own positions. And sadly, I know many people who are "in agreement" with them. They are just too skeptical... But I want to emphasize the fact that this general aversion and skepticism is also due to the fact that too many religious people are skeptical about science (or even averse to it). And of course those "false gurus" are the worst!

    Regarding Bohr and Heisenberg I agree (actually Bohr IMO was a really good philosopher). Thank you for the various link ;)
  • apokrisis
    4.3k
    It was your focus on the "rate" which was the confusing issue.

    If you had made a contextual claim - talked about the apparatus having some particular "interference pattern causing" arrangement - then it would have been clear that you weren't thinking the fact that individual events reflected the holistic constraints of their world was a puzzle. The issue of the "rate" making a difference couldn't even have arisen. It would be an obvious non sequitur - to you as well.

    So I am taking a constraints-based view that endorses a spooky non-locality ... as it must. The path determines the nature of the event. If you have two slits open and unobserved, then the "particle" must take both of them to find its way to the detector screen. In just that single event, already the outcome speaks to the downward causal impact of the apparatus having a particular set-up in terms of its act of measurement.

    And likewise, if there is just a single slit, or one of the two slits is being observed, then we get the statistics that that kind of path set-up would predict.

    We can even choose to observe the slits after the particle is meant to have already passed and still change its statistics - the quantum eraser effect. So the spooky non-local holism transcends our ordinary notion of a smoothly unwinding passage of time. It seems causation can act backwards, with our choices as observers making changes that happened in the collective past of the Universe.

    So yes, in some sense the full metaphysical picture of what is going on must transcend our usual Newtonian notions of space and time. It's non-local for Pete's sake!

    And QM wavefunction formalism models this by talking about the evolution of the probabilities taking place in infinite dimensional Hilbert space. This is an abstract calculational space - although some interpretations would like to treat it as itself now the "true reality". Another can of worms along the lines of block universes, multiverses and modal realism.

    But rather than treating a calculus of probabilities as a direct representation of an underlying metaphysical reality - that is, maxing out on fecundity of any numerical technique - I take the view that it is better to actually believe in a constraints-based ontology where classical regularity is what emerges from a generalised quantum potential. To the degree that you place macroscopic thermal constraints on existence, you will tend to restrict the kind of microscopic thermal fluctuations that then occur.

    Any act of measure is a physical interference in that it creates an irreversible energy transfer and so forces that part of reality to become woven into the general emergent story which is the Cosmic clock of time winding down from the extreme energy density of the Big Bang to the least possible energy density of the Heat Death.

    That is why the spread out wave-like potential of "an event" contracts, or decoheres, to become some highly located particle-like occurrence when there is any kind of thermal interaction. Time itself is emergent. Its "rate" is the cosmic-level rate at which the Universe is cooling or entropifying. And that flow of time is created out of a myriad of these little quantum events which fix the history of the Universe as some set of actual happenings - actual energy transfers.

    So a post-QM theory - like a quantum gravity theory - is likely to explain time itself in this emergent fashion. And folk like Kauffman are talking about that.

    Then whether you see reality behaving in a particle fashion, or a wave fashion, is really about the degree to which the inherent quantum uncertainty of any event has been constrained. If it is only weakly constrained - as in the very special thermal circumstances of a twin-slit apparatus - then you get "weird" single particle interference patterns. If it is more strongly constrained - as in that there is an act of observation effectively closing down one slit with its thermal interaction - then you instead get the kind of probability wave you would predict for the scattering of individual particles by a single narrow slit.

    So this is a thoroughly contextual or holistic view - one where the organisation of the whole shapes up the identity of the parts. Particles are emergent features that reflect the constraints of their world.

    And the wrinkle is that this emergent story applies even to space and time now as feature of that "world". Well, at least that is the story that quantum gravity would have to tell.
  • Rich
    3.2k
    such that time becomes the 0th dimension rather than the 4thMetaphysician Undercover

    Yes, time isn't spacial and any ontology that spacializes it is going to yield all kinds of problems such as Zeno's paradoxes and time travel.
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