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Quantum effects at the neurological level

  1. Sep 5, 2009 #1
    I had read that Roger Penrose and others (like Hameroff and Chalmers from Arizona) have been studying the possibility that quantum events may influence the way our nerves fire and our brains develop thought. Can anyone comment on the scientific progress of these studies?
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  3. Sep 6, 2009 #2


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    Sure: It's unwarranted speculation at best and pseudoscience at worst.

    It's not taken seriously by anyone in the field. And by 'the field' I mean people who actually know both quantum physics and chemistry: Theoretical chemists, quantum chemists, chemical physicists - in particular the ones studying biochemical systems.

    Penrose is a mathematician. Hameroff is an anesthesiologist. Neither are quantum chemists - despite that that's been an established field for about 80 years. If it doesn't strike you as odd that these ideas are being promoted by people completely outside the field, it should.
  4. Sep 6, 2009 #3
    Your point about the field is well taken. Yet, although it is odd, I still find it encouraging that some Nobel Prize winners like Penrose, Shrodinger, Crick, Polkinghorne, and others choose to exercise their minds beyond their disciplines to investigate what could be called "the moose on the table" i.e. the "mystery" of consciousness.

    Perhaps, I should have asked what are the latest scientific theories regarding consciousness?
  5. Sep 7, 2009 #4
    Mistery of consciousness? What are you talking about ?

    Ya mean why the wavelenght of red looks like red ? :smile: You should ask a color-blind person :wink: .
  6. Sep 7, 2009 #5
    I believe he is referring to the "hard problem."
  7. Sep 7, 2009 #6


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    Actually, only Crick and Schrödinger are Nobel laureates out of those. I don't know that either made any kind of direct connection between QM and neurology, though.
    Attributing mystery to consciousness is, IMO:
    1) Anthropocentric.. it strokes our egos to think that maybe our brains are really spectacular and not simple chemical machines. That kind of thinking has very consistently been wrong. We're not in the center of the solar system. We're not in the center of the universe. We're not really different from other animals. "Animal magnetism" and "life force" etc don't exist. Organic substances turned out not to be fundamentally different from other chemicals, and so far, biochemistry has not turned out to be fundamentally different from other chemistry. Many things in biology are unexplained, but I don't know of anything that's considered unexplainable in the current framework of things. (quasi-)Macroscopic quantum behavior is not part of that framework.

    2) Unwarranted, it's obviously a higher brain function and we've barely begun to understand the basics of how the brain works. There's no real reason to assume it'd be more difficult to understand than any other brain function, and even less reason to assume it'd be unexplainable by biochemistry, or chemistry, or anything short of a direct application of QM. I don't think anyone would ever have proposed such a far-fetched thing if it hadn't been for the reasons stated in (1).

    It's an excellent question. But it's absolutely a question for neurologists, cognitive neuroscientists, and the whole plethora of folks that study the brain. It's not a question for physicists. That would only happen if the neurologists eventually ran into something that in no way could be explained by existing biochemistry, which in turn could not be explained by existing theoretical chemistry. Which is a pretty tall order, given that nothing of the sort has turned up.

    (And again, there's no particular reason to think it'd turn up in connection with human consciousness)
  8. Sep 7, 2009 #7
    Well, in the July issue of Physics World, Paul Davies wrote an article "The quantum life", which gives a rather comprehensive overview of "quantum biology", even including a discussion on the issue of decoherence. You can view it here: http://physicsworld.com/cws/article/print/39669
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  9. Sep 7, 2009 #8
    Let me disagree with your philosophical points by quoting selectively from lectures given by Schrödinger in 1956 entitled What is Life, and Mind and Matter.

    From Schrödinger "He who accepts this brushing aside of the question ought to be told what an uncanny gap he thereby allows to remain in his picture of the world." Schrödinger argues that the brain "is the most elaborate and most ingenious of all mechanisms for adaptation to a changing environment."

    Schrödinger speaking of biology from the standpoint of entropy, "From all that we have learned about the structure of living matter, we must be prepared to find it working in a manner that cannot be reduced to the ordinary laws of physics" (italics mine) "In biology we are faced with an entirely different situation...events whose regular and lawful unfolding is guided by a mechanism entirely different from the 'probability mechanism' of physics...it is unknown anywhere else except in living matter."

    Schrödinger didn't believed QM played a significant role in the biology of the mind for he says, " the space-time events in the body of a living being, which correspond to the activity of its mind, to its self-conscious or any other actions, are...if not strictly deterministic at any rate statistico-deterministic". He makes an interesting logical point of why consciousness cannot be confined within the physical bounds of the brain. He hypothesizes the state of the world if consciousness were linked to the brain, and the brain never evolved "Would it (the world) otherwise have remained a play before empty benches, not existing for anybody, thus quite properly speaking not existing?" (italics mine)

    He states the problem as the need to draw a correct, non-contradictory conclusion from the following two premises:
    "1) My body functions as a pure mechanism according to the Laws of Nature
    2) Yet I know, by incontrovertible direct experience, that I am directing its motions, of which I forsee the effects, that may be fateful and all-important, in which case I feel and take full responsibility for them."

    I believe he takes the stance that consciousness must exist outside the body because of his very strong personal belief that an observation is required to separate existence from possibility via the collapse of the wavefunction.
    Your comments?
  10. Sep 7, 2009 #9
    This is an old question. I was just wondering if there are some new answers.
    Schrodinger wrote in Mind and Matter in 1956 "the sensation of color cannot be accounted for by the physicists objective picture of light waves." Yellow is produced by a certain numerical wavelength. Yet an indistinguishable sensation of yellow can be produced by mixing green and red of different wavelengths. "Is there a numerical connection between these physical objective characteristics of these waves? No".
  11. Sep 7, 2009 #10


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    Yes, Schrödinger did not know enough of neither neurology nor quantum physics to be considered an authority in this matter.

    Remember that he died in 1961 and did most of his important work in the very early days of QM when it was still being developed. Most of the physics and biology that is relevant here simply did not exist when he was active.

    Peter Knight likes to illustrate how much our view and understanding of QM has changed over the past few decades by using the following quote from Schrödinger:

    Which is of course now incorrect; and we also know that those "ridiculous" consequences are real.
    Last edited: Sep 7, 2009
  12. Sep 7, 2009 #11
    Thanks for the reference, which was enlightening regarding biology in general, although it didn't say much regarding neuroscience. I admire Davies' strong stance on the incredibility of random events explaining the origin of life.
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  13. Sep 7, 2009 #12
    You say yes, meaning there are new developments in relating the subjective quality of conscious experience to the physical phenomenon? Can you reference them?
  14. Sep 7, 2009 #13


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    I'd say you are starting from the wrong end here. We are not even sure there IS such as thing as a "consciousness" in the traditional sense (as far as I can tell modern research seems to indicate that there isn't). Much less any reason to expect it to be related to "physics" beyond the normal (or at least well known) physics you need to understand chemistry.
    I don't know much about neurology (although I have an "indirect" interest since some of the potential applications of some of work is in that field); but I'd say it might be worth starting with one of Dennet's books. You should also look up some references on fMRI and other modern experimental methods.
  15. Sep 7, 2009 #14
    There is NO traditional sense of consciousness. Only an ostrich with its head in the sand would say there is no consciousness. Perhaps you'd be happier with the term awareness.

    There are NO working theories of consciousness on a physics or chemical basis as far as I know. And there are unique qualities of consciousness that make it different than most neurological events, and which lead researchers to postulate exotic theories like emergence from organizational complexity or QM.
  16. Sep 7, 2009 #15


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    I mean "traditional" as in how the term was used be e.g. Decartes.

    There are definitely at least fragments of theories for what we perceive as consciousness; but you are right that there are no fully developed theory yet.

    btw, which "unique qualities" are you refering to that can NOT be explanined without using "exotic" physics?

    Note that neither QM nor complex system (or emergence) are very "exotic", the former has been around for over a 100 years now and although there are many unanswered questions we do know quite a lot about how QM applies to essentially classical systems such as the brain.
    Emergence and more generally the study of complex systems has also been around for quite a while and there are plenty of applications; e.g. much of modern condensed matter theory uses concepts from these fields (it is hardly a coincidence that e.g. Laughlin is a big proponent of emergence). It is likely that any theory for how the brain works will use elements of these fields, but that does not make such a theory "exotic".
  17. Sep 7, 2009 #16
    Some "traditional" questions of consciousness go back before Descartes and are still viable. Descartes divided the world into thinking substances "res cognita" and extended substances "res extensa". In the 5th century BC Democritus wrote a play in which the intellect, "res cognita", argues with the senses, "res extensa", about what is real. The former says, " Ostensibly there is color, ostensibly sweetness, ostensibly bitterness, actually only atoms and the void. . To which the senses retorted,'Poor intellect, do you hope to defeat us while from us you borrow your evidence?'

    One unique characteristic of consciousness is just this. That all knowledge of the external world, observations, quantum and other wise must eventually pass though our senses.

  18. Sep 7, 2009 #17
    I could go on and on about Dennet and these arguments, but perhaps it would be better to move this thread?
  19. Sep 7, 2009 #18
  20. Sep 8, 2009 #19


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    For what is worth, even though it's from a superb scientist who also has fun being an occasional crackpot, here is a rebuttal of QM having anything to do with consciousness: http://arxiv.org/abs/quant-ph/9907009

    My own view is that the difficulty with "consciousness" is defining it operationally - like "long range entanglement" - a concept which theorists don't understand well enough yet to tell experimentalists what they should measure to determine whether the property is absent or present in the sample: http://pirsa.org/08110003/ (try 58:30).
  21. Sep 8, 2009 #20
  22. Sep 8, 2009 #21
    Thanks to all who have replied. I got what I wanted from this thread, which is an update to my knowledge. I haven't read all the references yet but I will. So for now adios.

    Can't resist one last question. Anyone have an opinion on Henry Stapp's work on quantum computing?
  23. Sep 8, 2009 #22
    Stapp seems like Penrose-Hameroff gone holistic. And since you're still around and receptive to speculative input, here's Johnjoe McFadden, a reputable molecular biologist who believes the brain and consciousness need to be understood in terms of electromagnetic fields:

    http://machineslikeus.com/MLU-interviews-johnjoe-mcfadden.html [Broken]
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  24. Sep 8, 2009 #23


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    Sure, we can be 'prepared' to find it working in a matter that defies 'ordinary' laws of physics. But we have no reason to expect it to do so. None at all, especially given that - as I said- every time an "outside of ordinary physics" mechanism has been proposed in biology, it's turned out to be false. (Oh and I forgot another one: Newton, in Opticks, thought "That which causes fermentation" was a fundamental force of nature, like gravity.) Every day, more and more aspects of biology are being explained in terms of the physics and chemistry we all know.
  25. Sep 9, 2009 #24


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    I don't think anyone said I never said that processes in biology don't sometimes require quantum-mechanical treatment. If you think I did, perhaps I took it for granted that as obvious. Just to take an example: Eyesight, the absorption of (down to) individual photons, is not something chemistry has traditionally dealt with. Neither is the nature of most electron transfer.

    The point I was making was that, none of this is unique or specific to biochemistry.

    Yup, they work with similar stuff to what I do. I've used their software, VMD, as well.
    I could say that I work in "quantum biology", only I despise that term exactly because of this - getting conflated with all this unserious Deepak Chopra stuff. (A misguided acquaintance gave me a book of his, "I heard you did quantum physics, so I thought you'd find this interesting..")

    Yet another person way out of their field. You don't need to know anything about quantum mechanics to get a degree in molecular biology, you know. Wonder why the actual quantum chemists studying biological systems you linked to aren't advocating any such things... hmm?

    (Just to be nice I'll give an example of the reverse: Henry Schaefer is very reputable quantum chemist. He's also an outspoken creationist, meaning he believes complete nonsense about biology)

    Ridiculous, he's got no calculations there. The physics is all hand-waving. There's no model of the brain. It's idle speculation.

    Seriously, if anyone thinks they know how the brain works, they should go explain the causes of schizophrenia, and all the many, many, many other neurological disorders. Help the sick.

    There will never be a problem with explaining consciousness until every other aspect of the brain is understood. Because until then: How do you know it's not due to one of the things you don't understand yet?

    That's how science works. You don't put the cart in front of the horse, and you don't try to solve problems until you know what the problem is.
    Last edited: Sep 9, 2009
  26. Sep 14, 2009 #25
    To the extent that this responds to my post: I wasn't aware I was talking to you. Why would I want to do that?
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