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Thread: Wigner's friend, the existence of the Immaterial soul, and death of materialism

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    tWebber
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    Quote Originally Posted by TheLurch View Post


    Glad to hear it. The sort of larger issue here - how do we know how many potentially viable explanations there are for a phenomenon? - is an interesting one to me. I've only seen it stated plainly in a philosophy of science book i read within the last five years or so, but it touches on everything from different glosses on the same theory (ie Darwin's vs. Wallace's presentation of evolution) to the effectiveness of science itself (do successful predictions tell us anything about a theory's status if we don't know how many other theories would also make successful predictions?).

    I don't know how many positions there are, but I think I want to cut to the chase, because I think anyone on this list can understand the math I am going to post if they have had arithmetic. I have been buried up to my head in alligators on another list with this stuff but I just posted a post using quantum formalism that explains the problem and incompatibility between consciousness and quantum.


    Let's look at von Neumann's seminal book on Quantum, in which he explicitly brings in the subjective observer into quantum.
    Quote Originally Posted by John Von Newumann, Mathematical Foundations of Quantum Mechanics: New Edition (Princeton: Princeton University Press, 2018), p. 272-273
    "Let us now compare these circumstances with those which actually exist in nature, or in its observation. First, it is inherently correct that measurement or the related process of subjective perception is a new entity relative to the physical environment, and is not reducible to the latter. Indeed subjective perception leads us into the intellectual inner life of the individual, which is extra-observational by its very nature, since it must be taken for granted by any conceivable observation or experiment. (See the discussion above.) Nevertheless, it is a fundamental requirement of the scientific viewpoint--the so-called principle of psycho-physical parallelism--that it must be possible so to describe the extra-physical process of subjective perception as if it were in the reality of the physical world; i.e., to assign to its parts equivalent physical processes in the objective environment, in ordinary space. (Of course, in this correlating procedure there arises the frequent necessity of localizing some of these processes at points which lie within the portion of space occupied by our own bodies. But this does not alter the fact of their belonging to 'the world about us,' the objective environment referred to above.) In a simple example, these concepts might be applied as follows: We wish to measure the temperature. If we want, we can proceed numerically by looking to the mercury column in a thermometer, and then say: 'This is the temperature as measured by the thermometer.' But we can carry the process further, and from the properties of mercury (which can be explained in kinetic and molecular terms) we can calculate its heating, expansion, and the resultant length of the mercury column, and then say: 'This length is seen by the observer.' Going still further, and taking the light source into consideration, we could find out the reflection of the light quanta on the opaque mercury column and the path taken by the reflected light quanta into the eye of the observer, their refraction in the eye lens, and the formation of an image on the retina, and then we would say: 'This image is registered by the retina of the observer.' And were our physiological knowledge greater than it is today, we could go still further, tracing the chemical reactions which produce the impression of this image on the retina, and in the optic nerve and in the brain, and then in the end say; 'These chemical changes of his brain cells are perceived by the observer.' But in any case, no matter how far we proceed--from the thermometer scale, to the mercury, to the retina, or into the brain--at some point we must say: 'And this is perceived by the observer.' That is, we are obliged always to divide the world into two parts, the one being the observed system, the other the observer. In the former we can follow all physical processes (in principle at least) arbitrarily precisely. In the latter, this is meaningless. The boundary between the two is arbitrary to a very large extent. In particular, we saw in the four different possibilities considered in the preceding example that the 'observer'--in this sense--need not be identified with the body of the actual observer: in one instance we included even the thermometer in it, while in another instance even the eyes and optic nerve were not included. That this boundary can be pushed arbitrarily far into the interior of the body of the actual observer is the content of the principle of psycho-physical parallelism. But this does not change the fact that in every account the boundary must be put somewhere if the principle is not to be rendered vacuous; i.e., if a comparison with experience is to be possible. Indeed, experience only makes statements of this type: 'An observer has made a certain (subjective) observation,' and never any like this: 'A physical quantity has a certain value.'"

    To prove that it is widely beleived that there are interpretations of quantum which incorporate consciousness, I would present how Zvi Schrieber's view of von Neumann's position. In his thesis, Schrieber entitles a chapter, Mind causes collapse and says

    Quote Originally Posted by Zvi Schrieber, "The Nine Lives of Schrodinger's Cat, University of London: MS Thesis, Oct 1994, p. 46 [url
    https://arxiv.org/pdf/quant-ph/9501014v5.pdf][/url]
    "It is therefore possible to assume that the unitary mechanics applies to the entire physical universe and that wave function collapse occurs at the last possible moment, in the mind itself. This, of course, assumes a non-physical mind.
    ...
    The rules of quantum mechanics are correct but there is only one system which may be treated with quantum mechanics, namely the entire material world. There exist external observers which cannot be treated within quantum mechanics, namely human (and perhaps animal) minds, which perform measurements on the brain causing wave function collapse."
    It is interesting that Schrieber understands that there are formulations of quantum involving the immaterial soul, namely the late great John von Neumann's who was a better mathematician/physicist than anyone on this list. Mind and consciousness are synonyms for the same thing.

    Ok, let's get mathematical Sorry everyone else, I think this is necessary but I will try to go slow and explain things. This is taken from Squires' book Conscious Mind in the Physical Universe pages 184-191. It is simplified a bit to the relevant parts of the equations so that it is easier to follow by those with no experience with this notation.

    Lets consider the spin of an electron. It is measured in a Stern-Gerlach device and one spin will be deflected upward, and the other spin deflected downward. We will call the upward spin + and the downward spin -. Since I can't use greek letters here or don't know how to, I will use English letters. Wavefunctions are described by | ...> and attributes are put inside where the ... is. I am going to use colors to help those who fear looking at an equation. When you see both colors in an equation, it means that both answers are in superposition.

    A particle with an upward spin would be | + > and a particle with a negative spin would be | - >

    Before we observe the spin the electron is in the state:

    |Psi>=a| + > +b | - >

    In words, Psi is the wave function and is it is a mixture of + and - states. a and b are coefficients that for our purposes we don't need to worry about.

    One must understand that in quantum, whenever something that is subject to the laws of quantum interacts with an object, it goes into superposition with that object. So, when we add a pointer to the apparatus, which would point up or down , prior to observation of the apparatus, the quantum state would be:

    |Psi>=a| +, up > +b | -,down >

    The added up and down refer to the direction of the pointer. Before observation, the pointer and the electron are both in mixed states of superposition. In other words, it is in both states at once. This is why one hears that in quantum all possible answers exist at the same time in the wavefunction.

    This addition to the chain of objects in superposition can go on forever. Kuttner and Rosenblum describe this von Neumann chain as it is known, because John von Neumann was the first to describe it.

    "In his rigourous 1932 treatment, The Mathematical Foundations of Quantum Mechannics, John von Neumann showed that quantum theory makes physics' encounter with consciousness inevitable. He considered a measuring apparatus, a Geiger counter, for example. It is isolated from the rest of the world but makes contact with a quantum system, say, an atom simultaneously in two boxes. This Geiger counter is set to fire if the atom is in the top box and to remain unfired if the atom is in the bottom box. Von Neumann showed that if the Geiger counter is a physical system governed by quantum mechanics, it would enter a superposition state with the atom and be, simultaneously, in a fired and an un fired state. (We saw this situation in the case of Schrodinger's cat.)"
    "Should a second isolated measuring apparatus come into contact with the Geiger counter-for example, an electronic device recording whether the Geiger counter has fired-it joins the superposition state and records both situations existing simultaneously. This so-called "von Neumann chain" can continue indefinitely. Von Neumann showed that no physical system obeying the laws of physics (i.e., quantum theory) could collapse a superposition state wavefunction to yield a particular result."
    "However, when we look at the Geiger counter, we will always see a particular result, not a superposition. Von Neumann concluded that only a conscious observer doing something that is not presently encompassed by physics can collapse a wavefunction. Though for all practical purposes one can consider the wavefunction collapsed at any macroscopic stage of the von Neumann chain, von Neumann concluded that only a conscious observer can actually make an observation." Bruce Rosenblum and Fred Kuttner, Quantum Enigma, (Oxford: Oxford University Press, 2006), p. 184

    It is also interesting that Rosenblum and Kuttner interpret von Neumann the same as Schrieber does.

    The von Neumann chain is due to the fact that anything subject to the laws of quantum goes into superposition with what it interacts with. This is a problem. Bryce S. Dewitt talked about quantum putting the apparatus into a schizophrenic state in which it has two different answers at the same time. He says:

    Quote Originally Posted by Bryce Dewitt,Quantum Mechanics and Reality, PHYSICS TODAY /SEPTEMBER 1970, p. 30- 31
    How can they prod the apparatus into making up its mind? "
    "The usual suggestion is to introduce a second apparatus to get at the facts simply by looking at the first apparatus to see what it has recorded. But an analysis carried out along the above lines quickly shows that the second apparatus performs no better than the first. It too goes into a state of schizophrenia. The same thing happens with a third apparatus, and a fourth, and so on. This chain, known as "von Neumann's catastrophe of infinite regression," only makes the crisis worse.
    This von Neumann chain can continue indefinitely by adding commas and attributes to the chain in between the | and the >. But we won't go there. We will add a conscious observer in at this point and show why he can't be subject to quantum laws.


    Back to the math, Let's add me as an observer to the apparatus with the pointer. IF my mind is subject to quantum laws, then I too, must go into superposition with the system. This is just like the pointer in our example or the counter and Geiger counter of Rosenblum and Kuttner's example. In that case, the wave function would be:

    |Psi>=a| +, up, Me+ > +b | -,down, Me- >

    Where Me+ is the me who sees a positive spin and the Me- is the one who sees a negative spin.

    And here is the kicker. Squires says:
    Quote Originally Posted by Euan Squires, Consciousness Mind in the Physical World, (Adam Hilger, New York, 1990, p. 191

    "At this stage and only at this stage the wavefunction is apparently unacceptable, because it fails to describe my experience of one result."

    Quantum mechanics does not correctly predict my subjective mental state, which is that I am experiencing only one of the two possible realities.

    Squires presented this argument in a paper "Quantum Theory and the Relation between Conscious Mind and the Physical World," Synthese, Vol. 97, No. 1 (Oct., 1993), pp. 109-123. His conclusion there is a bit more interesting:

    Quote Originally Posted by Euan Squires, "Quantum Theory and the Relation between Conscious Mind and the Physical World," Synthese, Vol. 97, No. 1 (Oct., 1993), p.111-112
    "It is quite clear that we have made no progress. Indeed the problem might be considered to be even more acute: my brain is in a confused state containing some combination of both answers; I am, nevertheless, apparently convinced that I know one answer."
    If you assume that consciousness mind or soul is subject to the laws of quantum, quantum WILL describe any observer in a confused state seeing both possible outcomes. This is the fundamental problem of consciousness in quantum. I only see unmixed states, like:

    |Psi>= | +, up, Me+ >

    or |Psi>= b | -,down,Me- >

    The thing I don't see is the mixed state

    |Psi>=a| +, up, Me+ > +b | -,down,Me- >

    Now, Everett proposed the many worlds interpretation in 1957 and he would say that I have split into two different Me's one seeing the up branch and one seeing the down branch. Such a situation is the draw of the many worlds view. But there are other reasons for rejecting the many worlds view.

    Point is, this is the problem with consciousness in quantum. If my mind/consciousness/soul is subject to the laws of quantum, it creates a situation where reality (me seeing only one reality) is said to be false by the application of quantum rules.

    Again, I affirm that observers external to the physical world is NOT a looney bin idea, but a great problem in the logical structure of quantum. Again, (one of those quotes Pevaquark but a repeat, lol)

    "A careful analysis of the logical structure of quantum theory suggests that for quantum theory to make sense it has to posit the existence of observers who lie, at least in part, outside of the description provided by physics." Stephen M. Barr, Modern Physics and Ancient Faith, (Notre Dame: University of Notre Dame Press, 2003), p. 27-28

  2. #22
    tWebber seer's Avatar
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    Quote Originally Posted by grmorton View Post

    "A careful analysis of the logical structure of quantum theory suggests that for quantum theory to make sense it has to posit the existence of observers who lie, at least in part, outside of the description provided by physics." Stephen M. Barr, Modern Physics and Ancient Faith, (Notre Dame: University of Notre Dame Press, 2003), p. 27-28

    Is it possible that the quantum world is supernatural, or medium between the spiritual world and the material world?
    Atheism is the cult of death, the death of hope. The universe is doomed, you are doomed, the only thing that remains is to await your execution...

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    tWebber TheLurch's Avatar
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    Quote Originally Posted by grmorton View Post
    OK, your subjective experience. That is consciousness defined for everyone. I somehow feel you were asking me to explain how it arises from the brain. But , my definition above is probably the best one because everyone can understand it even if they can't put into words WHAT it is.
    No, i'm not asking you how it raises from the brain. I'm asking how it functions as a quantum system, and interacts with quantum systems. Even macroscopic objects like molecules that behave as waves obey a wavefunction. And when we entangle macroscopic objects like the resonators, the math that describes the situation isn't focused on the object, but rather the phonons that it's acting as a container for. So, i'm curious as to how you see consciousness integrating with systems like this.

    This, i think, is a bit relevant to this in your later post:

    Quote Originally Posted by grmorton View Post
    One must understand that in quantum, whenever something that is subject to the laws of quantum interacts with an object, it goes into superposition with that object.
    I'm pretty sure that's not accurate. Let's take the entangled resonator example again. In the experimental setups, you have two resonators set up more or less facing each other. If you just send a photon in from the left, even though that photon its obeying quantum mechanics, it will hit the right resonator and deposit a phonon there. The object is not entangled, because we (or at least the computers we have controlling events) know what the result must be.

    To get entanglement, you have to have a half-reflective mirror between the two resonators. Now you don't know whether a photon sent from the left hits the right resonator, or reflects back and hit the left one. Only then do you actually get entanglement.

    In addition, if you don't have this system chilled to near absolute zero and isolated from all other sources of photons, you don't get entanglement. That's because, even though the photon being used is still a quantum object, environmental noise causes it to loose quantum information about its state (read up on quantum decoherence if you want to know more).

    The net result is that, unless conditions are incredibly carefully managed, a quantum object interacting with something else typically just loses quantum information into it, rather than becoming entangled with it. That's why stipulations like the one you quote - "if the Geiger counter is a physical system governed by quantum mechanics" - are incredibly important. Because most things are decoherent, and thus can't be described by the rules of quantum systems.

    Note also that decoherence dates from thee 1970s, and thus long after von Neumann was writing much of what you're quoting.
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  4. Amen shunyadragon amen'd this post.
  5. #24
    tWebber shunyadragon's Avatar
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    Quote Originally Posted by seer View Post
    Is it possible that the quantum world is supernatural, or medium between the spiritual world and the material world?
    The Quantum World is very natural world that our macro-world arises from the quantum world and not supernatural.
    Last edited by shunyadragon; 05-15-2019 at 06:23 PM.
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    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

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    I do not know, therefore everything is in pencil.

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    Quote Originally Posted by TheLurch View Post
    We've been around this before here at TWeb - as noted at the top of the initial post, this is philosophy, and not science. The basic issue is what happens when the state of a quantum system starts getting tangled up (note: not entangled, we don't know if that's possible) with non-quantum objects?The most famous examples is Schroedinger's cat, which may be alive or dead or a superposition of the two based on the behavior of a quantum system. This happens all the time; in practical terms, the "cat" is just some bits on a hard drive that record the results of a quantum experiment. But you can potentially tie the state of those bits to the state of any unobserved object you want - the toppling of a Stonehenge-sized block of rock, for example.

    So the question is what state is the rock in before someone observes it? The scientific answer is that we don't know.

    grmorton prefers that it's actually in a physically indeterminate state, neither standing or toppled. This position has support within the physics community, as his use of quotes from physicists indicates.

    Because we don't have any indication of physics that describe a sort of indeterminate state for non-quantum objects, i personally suspect that the block its in a specific, if not yet determined state. (Put differently, i find it easier to accept "we don't know until we look" than that there's an entire field of physics affecting the objects we observe around us every day, and we've seen no indication of it.) This position also has support within the physics community.

    I think where grmorton and I would agree is that we look forward to a day where someone exceptionally clever figures out a way of determining which of the two options is more likely to be the case.
    I'm wondering if consciousness, i.e. conscious observation, has anything at all to do with the so called wave function collapse, or if there is even any such thing as a wave function collapse. That the cause of wave function collapse were conscious observation, would, I think, establish consciousness as a distinct nature apart from the objective material world. Personally I've been thinking that consciousness/awareness of the state of a system is simply part of the system, not the cause of the change, but an effect of the change. Does that make sense at all? For one thing, doesn't change must needs occur before we actually observe it since it takes time for light to travel from the observed object to the observer. Hope this isn't too ignorant of a question, but thinking about this subject from a laymans perspective is dizzying!

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    tWebber TheLurch's Avatar
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    Quote Originally Posted by JimL View Post
    I'm wondering if consciousness, i.e. conscious observation, has anything at all to do with the so called wave function collapse, or if there is even any such thing as a wave function collapse.
    Your second question, about whether wavefunction collapse exists, is actually something that's seriously debated among physicists. Per wikipedia, "collapse is merely a black box for thermodynamically irreversible interaction with a classical environment" (which is decoherence, as discussed in my previous post). The fact that something so fundamental its still a black box should be an indication that anything on this topic is going to be speculative.

    Quote Originally Posted by JimL View Post
    Does that make sense at all?
    Nothing in quantum mechanics makes a ton of sense to most people.
    "Any sufficiently advanced stupidity is indistinguishable from trolling."

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    The case against decoherence--the view mentioned by Lurch

    Quote Originally Posted by TheLurch View Post
    Your second question, about whether wavefunction collapse exists, is actually something that's seriously debated among physicists. Per wikipedia, "collapse is merely a black box for thermodynamically irreversible interaction with a classical environment" (which is decoherence, as discussed in my previous post). The fact that something so fundamental its still a black box should be an indication that anything on this topic is going to be speculative.


    What you speak of Lurch is the decoherence view. and I posted on another board I am on, where I have been very busy, which has been more active than this one of late, the following about your interaction with a classical environment" Decoherence claims that it solves the collapse problem by modeling all the environmental interactions, but it turns out it really doesn't work when one digs into the details and sees the 'engine'. Indeed, even the founders of decoherence claim it doesn't solve the observer problem. here is that post and the little mat there is, can be ignored by those who don't want to deal with it.

    The case against decoherence

    Gordie asked me to address decoherence which in my view was developed with the goal in mind of ridding the quantum world of spirits and souls. My normal snide self thinks this is mission impossible to demonstrate the false promise of decoherence when almost no one will read this, and some will not want to give up cherished beliefs. . But, the importance of this issue lies in the question, can the wavefunction collapse without an observer? We strongly say NO for the reasons below. Much of this will come from a hillarious and devastating critique of decoherence by Phillip Pearle, True Collapse and False Collapse in Quantum Classical Correspondence: Proceedings of the 4th Drexel Symposium on Quantum Nonintegrability, Philadelphia, PA, USA, September
    8-11, 1994, pp. 51-68. Edited by Da Hsuan Feng and Bei Lok Hu. Cambridge, MA: International Press, 1997. https://arxiv.org/pdf/quant-ph/9805049.pdf

    First we need to understand what collapse is.

    Quantum descriptions of things always involves at least two possible outcomes. The quantum description is a mixture of those two

    Uncollapsed state= Reality 1 option AND Reality option 2 added together.

    Collapsed state = Reality 1 OR Reality 2, no longer mixed. the state. it is one or the other. The famous physicist John Bell said:

    "The idea that elimination of coherence, in one way or another, implies the replacement of “and” by “or” is a very common one among solvers of the “measurement problem.” It has always puzzled me." John Bell (Pearle page 9)

    As Pearle says:
    Quote Originally Posted by Pearle p 1
    What is wrong with standard quantum theory (SQT)? Doesn’t it give wonderful agreement with every experiment so far performed? Then why should anyone wish to change it?
    ...
    What is wrong with SQT is its description of quantum events. It doesn’t
    describe them. (Pearle p. 1)
    and he goes on to describe the situation:

    Quote Originally Posted by Pearl p.1
    While the experimenter turns on the apparatus and monitors its smooth functioning, the theoretician follows the smooth evolution of the statevector according to Schrodinger’s equation. Suddenly, the experimenter sings out “An event has occurred, and this is the result.” Abruptly, the theoretician stops his calculation, replaces the statevector, which has by now become the sum of states corresponding to different possible outcomes of the experiment, by the one state which the experimenter told him had actually occurred, and then continues his calculation of the smooth evolution of the statevector.
    In other words, the practitioner of SQT must go outside the theory, to obtain additional information, in order to use the theory correctly. What is missing is that the theory doesn’t give the probability that an event occurs between t and t + dt."
    The Schrodinger equation has no collapse mechanism in it It is an equation in which no reality is ever chosen. Left to its own mathematical devices the Schrodinger equation would crunch endlessly onward with no reality option ever chosen. This is important: Decoherence specifically doesn't change the Schrodinger equations. Some approaches have tried to add terms to it, but decoherence ISN'T one of those approaches. The entire problem is that when we observe a system we see ONE reality not a SUM of two realities.

    So with an unchanged Schrodinger equation, Pearle emphasizes the point above by:

    Quote Originally Posted by Pearle, p. 6
    "It follows from Eqs.(2.1) and (3.1) that the statevector at any time T which evolves under a particular w(t) is

    [GRM: Schrodinger equation with 2 mixed states] (3.3)

    Now, according to Eq.(3.3), NOTHING has HAPPENED, i.e., the statevector is still a superposition of the states |a > and |b > with unchanged squared amplitudes. Of course, the phases of the amplitudes are changing, but certainly one cannot find in this statevector evidence that an event occurred or, supposing that an event occurred, whether it resulted in a or b." Pearle p. 6
    Decoherence advocates go on "unphased" as Pearle says, and create a density matrix each of whose elements describe a different possible environmental interaction. They whole matrix is said to represent all the possible quantum level environmental interactions, and when superposition is lost, all elements of the matrix go to zero except the diagonal values. As long as the off-diagonal elements are not zero, the superposition is still in effect.

    The Stanford Dictionary of Philosophy says:

    Quote Originally Posted by The Standford Dictionary of Philosophy [url
    https://plato.stanford.edu/entries/qm-decoherence/#ConApp][/url] "We are left with the following choice whether or not we include decoherence: either the composite system is not described by such a sum, because the Schrödinger equation actually breaks down and needs to be modified, or it is described by such a sum, but then we need to understand what that means, and this requires giving an appropriate interpretation of quantum mechanics. Thus, decoherence as such does not provide a solution to the measurement problem, at least not unless it is combined with an appropriate interpretation of the theory
    "Unfortunately, naive claims of the kind that decoherence gives a complete answer to the measurement problem are still somewhat part of the ‘folklore’ of decoherence, and deservedly attract the wrath of physicists (e.g. Pearle 1997) and philosophers (e.g. Bub 1997, Chap. 8) alike." https://plato.stanford.edu/entries/q...erence/#ConApp
    To head off an objection here about philosophers and feelings, raised on the other board I am on an where this work was first posted, philosophers of science are required as part of their degree program to take the course work of that area they want to be involved with--in otherwords, they do both math, physics and philosophy. They have to be experts in all of it.

    Problem 1. The off-diagonal values NEVER go exactly to zero--they contain small values

    In other words decoherence is an approximation. They feel if the values of the off-diagonal elements are small enough we can ignore them---for all practical purposes.

    Quote Originally Posted by Moses Fayngold and Vadim Fayngold, Quantum Mechanics and Quantum Information: A guide through the Quantum World, Wiley 2013, equation 23.13
    "The off diagonal elements contain multiple inner products whose magnitude is less than 1. As time goes on, the cat will have interacted with more and more mice, and new innerproducts will appear in 23.13. Hence, the off-diagonal elements will decrease exponentially with time until the cat's state becomes indistiguishable from the mixture:
    ...
    though, formally speaking, the system remains entangled at all moments, the eventual outcome is classical for all practical purposes. In other words, diagonal form of the density matrix is classically interpretable.""
    I used to tell my math and physics teachers, well I got the answer correct, for all practical purposes. It never got me the grade I erroneously thought I deserved.

    In reality this means the superposition/entanglement continues forever. Others say the same thing:

    Quote Originally Posted by Herve Zwirn The Measurement Problem: Decoherence and Convivial Solipsism, [url
    https://arxiv.org/ftp/arxiv/papers/1505/1505.05029.pdf[/url] p.1]
    " For the second one, decoherence is only a way to show why no macroscopic superposed state can be observed, so explaining the classical appearance of the macroscopic world, while the quantum entanglement between the system, the apparatus and the environment never disappears."
    In the above, the small probabilities in the off-diagonal locations are a sign that entanglement remains and no collapse to a single reality has happened. Collapse isn't a partial thing that we get to 'for all practical purposes'. It is an event that happened or didn't happen, period. We see one reality or mutliple realities, and since we NEVER see multiple realities, collapse must be complete and decoherence doesn't provide that.
    Quote Originally Posted by Roland Omnes, Results and Problems in DecoherenceTheory, Brazilian Journal of Physics, vol. 35, no. 2A, June, 2005, p. 210
    "Decoherence is, formally, never complete. There always remain exponentially small non-diagonal terms in the reduced density matrix, reminding us that an initial pure state remains pure according to basic quantum mechanics. Does it mean that decoherence is only a phenomenological theory ,or is there some deeper way of interpreting very small probabilities ?"
    If quantum entanglement doesn't disappear completely, there is NO collapse!!!!

    Problem 2. The environmental interactions in the off diagonal positions are just as quantum as any other event, and thus are in mixed states themselves without having a definite reality. That is, they represent interactions that may never be real.

    Pearle says this of the idea:

    Quote Originally Posted by Pearle p. 7
    "The False Collapse claim is that, at some large time, when the off-diagonal density
    matrix elements are suitably small (in current parlance, at the decoherence
    time), an event (a or b) occurs for any system.
    This claim makes no sense, for two reasons. The behavior of an ensemble
    of evolutions which have not taken place cannot be crucial in determining the
    occurrence of an event in one evolution which did take place (what is not real
    cannot have an effect upon what is real). If no individual statevector describes
    events, an ensemble of these statevectors cannot do so (a property missing in
    each element of a collection must be missing in the collection). Therefore this
    scheme cannot solve the events problem. Although the density matrices (2.7)
    and (3.4) have the same form, this does not mean that the arguments leading
    to these expressions are equally sound." Pearle, p.7


    Problem 3. A contradiction

    Adler points out a stunning contradiction in his strongly argued critique of decoherence. Due to the nature of Hilbert space (go look it up), the off diagonal terms do which are performing an inner tensor sum, have nothing to do with the evolution of the main object of the experiment. Adler says:

    Quote Originally Posted by Stephen L. Adler [url
    http://cds.cern.ch/record/531385/files/0112095.pdf[/url] p. 7,8
    ]"Thus, when quantum mechanics is applied uniformly at all levels, to the apparatus and its environment as well as to the system, we are faced with a contradiction. This contradiction is in no way ameliorated by decoherence, since the inner product of Eq. (5b) plays no role in the final state vector of Eq. (6a) or Eq. (6b) that describes the outcome of the measurement." Stephen L. Adler http://cds.cern.ch/record/531385/files/0112095.pdf p. 7,8
    I refer people to that for details.

    Problem 4 basis dependence of decoherence.

    According to Fayngold and Fayngold, one must pick which parameter to write the density matrix on, and then that parameter or basis, will collapse. Other basis's won't collapse! What kind of deal is it when an object only collapses on one basis but not another?

    Quote Originally Posted by Moses Fayngold and Vadim Fayngold, Quantum Mechanics and Quantum Information: A guide through the Quantum World, Wiley 2013, Box 23:1
    "There is a common misconception that td is the time for a system to become 'classical.' The truth is that decoherence is basis dependent. You must make your choice of basis before writing the density matrix. Then decoherence will cause the off-diagonal elements to vanish, but only in that basis!
    ...
    Suppose now that the qubit has fully relaxed and decohered and the thermal equilibrium state rho has been attained. This system (we should now call that, instead of qubit) is classical in the energy basis. No energy measurement will show any correlation between |R> and |L>. However, the superposition still exists in the computational basis {|^>,|v>} as shown by the nonzero off-diagonal elements, so the resulting equilibrium state can be highly quantum-mechanical!"
    Braun agrees:

    Quote Originally Posted by Daniel Braun, Dissipative Quantum Chaos and Decoherence," Springer, 2003, p. 53
    "Decoherence is a basis-dependent phenomenon. Obviously, if a reduced density matrix has become diagonal in a given basis, it will contain off-diagonal elements (i.e. 'coherences') in another basis. "
    Decoherence, even when it diagonalizes the matrix, doesn't provide an explanation of why we see those other 'coherences' in the other basis's. If part of the object is uncollapsed, we should observe multiple realities and we don't.
    The Feyngolds talk about how only special circumstances will allow all basis's to be classical.

    There are several basis's one can chose from, obviously from above, one can chose energy as the basis, or computation as the basis, there is positional basis etc. If decoherence only affects one aspect of the particle, that is a huge problem in my view.

    Problem 5. Time.

    To me this is one of the best arguments against decoherence. Td is the time of decoherence. Te is the time of the event/collapse of the wavefunction Pearle says that that time is chosen in an ad hoc manner.

    Quote Originally Posted by Pearle p. 7
    "In order to properly assess the meaning of Eq.(3.4), I believe it is salutary to avoid using the phrase “decoherence” time because that seems to imply that there is a physical process called decoherence which takes this amount of time to be completed. I suggest that the phrase “No One Will Ever kNow” time, or NOWEN time for short, is more apt for the following reason.
    "If the statevector evolution is as described in the previous section, then an event does not occur at any time." Pearle p. 7
    Pearle then lays out the mathematical argument and concludes:

    Quote Originally Posted by Pearle p. 7
    "The NOWEN time is, by definition, a time at which the last term in Eq.(3.5) is small enough to be beyond experimental resolution. Only if you chose Te to be equal to or greater than the NOWEN time will the experimental result be the same as if your claim were right. With this choice, No One Will Ever kNow that you were wrong." Pearle p. 7
    We conclude that decoherence does not replace the observer with a naturalistic collapse mechanism. Indeed, even strong advocates of decoherence admit that metaphysical bias' enter in to the choice to teach decoherence and admit that it is a bit of a sleight of hand:

    Quote Originally Posted by Tim Jones, [url
    https://www.physics.drexel.edu/~tim/open/main/node2.html[/url]]
    "Decoherence offers a theoretical framework in which the measurement problem can be swept under the carpet (pushed into a system larger than that which we can observe). The effect is that quantum mechanics can be studied and presented to a student without the need for the ad hoc ``wave collapse'' being presented as a primary tool of the theory. One can achieve, in many cases, the same apparent effect of a wave collapse without recourse to von Neumann's mysterious first intervention.
    Thus we clarify that decoherence is not a new theory unto itself, but is instead an efficient and fruitful repackaging of theory. It does not solve the measurement problem, and most certainly wouldn't have satisfied the reservations of Einstein in his later years"
    Similarly,Breuer and Petruccione, say the same thing:

    Quote Originally Posted by Heinz-Peter Breuer and Francesco Petruccione, The Theory of Open Quantum Systems, Oxford University Press, 2002 p. 270
    "Since decoherence, as it is understood here, is ultimately linked to the tracing over degrees of freedom of the environment, it cannot, of course, solve the measurement problem. This means that decoherence cannot be used to deduce the reduction of the state vector and the statistical intepretation of quantum mechanices from the unitary evolution given by the Schrodinger equation."
    Lurch, I stand by this statement: The observer remains as a ghost outside of the machinations of physics.


    Added for this forum is a quotes by Schlosshauer with the last quote describing the views of the founders vs what is claimed about decoherence https://arxiv.org/pdf/quant-ph/0312059.pdf:


    Quote Originally Posted by Maximilian Schlosshauer, Decoherence, the measurement problem, and interpretations of quantum mechanics , p. 30
    Physical collapse models that achieve reduction only “for all practical purposes” require a modification, namely, a weakening, of the orthodox e-e link to allow one to speak of the system’s actually being in a definite state, and thereby to ensure the objective attribution
    of determinate properties to the system.
    Quote Originally Posted by Maximilian Schlosshauer, Decoherence, the measurement problem, and interpretations of quantum mechanics , p. 37

    "We have argued that, within the standard interpretation of quantum mechanics, decoherence cannot solve the problem of definite outcomes in quantum measurement: We are still left with a multitude of (albeit individually well-localized quasiclassical) components of the wave function, and we need to supplement or otherwise to interpret this situation in order to explain why and how single outcomes are perceived."

    Quote Originally Posted by Maximilian Schlosshauer, Decoherence, the measurement problem, and interpretations of quantum mechanics, p. 2,3

    In his monumental book on the foundations of quantum mechanics (QM), Auletta (2000, p. 791) concludes that

    the Measurement theory could be part of the interpretation of QM only to the extent that it would still be an open problem, and we think that this is largely no longer the case.

    This is mainly so because, according to Auletta (2000, p. 289),

    decoherence is able to solve practically all the problems of Measurement which have been discussed in the previous chapters.

    On the other hand, even leading adherents of decoherence have expressed caution or even doubt that decoherence has solved the measurement problem. Joos (2000, p. 14) writes

    Does decoherence solve the measurement problem? Clearly not. What decoherence tells us, is that certain objects appear classical when they are observed. But what is an observation? At some stage, we still have to apply the usual probability rules of quantum theory.

    Along these lines, Kiefer and Joos (1999, p. 5) warn that

    One often finds explicit or implicit statements to the effect that the above processes are equivalent to the collapse of the wave function (or even solve the measurement problem). Such statements are certainly unfounded.

    In a response to Anderson’s (2001, p. 492) comment, Adler (2003, p. 136) states

    I do not believe that either detailed theoretical calculations or recent experimental results show that decoherence has resolved the difficulties associated with quantum measurement theory.

    Similarly, Bacciagaluppi (2003b, p. 3) writes

    Claims that simultaneously the measurement problem is real [and] decoherence solves it are confused at best.

    Zeh asserts (Joos et al., 2003, Ch. 2)

    Decoherence by itself does not yet solve the measurement problem (...). This argument is nonetheless found wide-spread in the literature. (...) It does seem that the measurement problem can only be resolved if the Schrodinger dynamics (...) is supplemented by a nonunitary collapse (...)."

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    tWebber
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    Quote Originally Posted by shunyadragon View Post
    The Quantum World is very natural world that our macro-world arises from the quantum world and not supernatural.
    Frank, go read the OP. I had asked you not to be here--and you clearly didn't read the OP so are unprepared to really deal with the issues as Lurch is. You hijacked my last thread and I don't want you doing that again. While this post doesn't hijack it, it still lacks any supporting data for your position, and that means, you are not discussing science but merely saying what you believe and I don't care what you believe. I want to know what people know.

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    Quote Originally Posted by JimL View Post
    I'm wondering if consciousness, i.e. conscious observation, has anything at all to do with the so called wave function collapse, or if there is even any such thing as a wave function collapse.
    that is what I am claiming, that consciousness is the only thing that can collapse the wavelet. Today I posted a reasons why the decoherence view is totally misunderstood and doesn't allow a naturalistic collapse of the wavelet. And if consciousness is the only thing that can cause collapse, then consciousness is apart from and something different than matter. i.e. doesn't arise from matter.

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    Quote Originally Posted by grmorton View Post
    We conclude that decoherence does not replace the observer with a naturalistic collapse mechanism.
    I wasn't claiming that it does. If you'd read my post carefully, i was arguing that it explains why, contra one of your statements, the interaction of a quantum system with another object does not necessarily result in the two becoming entangled.

    As far as i can tell, your argument here is that decoherence doesn't explain why we get a single measurement result when we do measure. Decoherence would seem to provide a tidy solution, given that we know decoherence exists, but I'm more than happy to acknowledge we don't have any evidence that it is involved at all. More generally, I'll happily admit that nobody knows scientifically what's involved with a wavefunction collapse other than in terms of phenomenology - because that's been my point the whole time.

    But: none of that means that decoherence does not exist as a phenomenon, or that it doesn't explain other quantum behaviors. We'd all have quantum computers now if it didn't exist, after all. And one of the things it explains is why simple interactions don't end up with everything being entangled with everything else.
    "Any sufficiently advanced stupidity is indistinguishable from trolling."

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