I am replying to pevaquark but this has application to a lot of the issues including the difference of opinion between me and Mitchell about the nature of consciousness. Pevaquark sending a cartoon, which clearly indicates he might think my position is a loon bag position. I couldn’t sleep so let’s examine who else might be in that loon bag position.
Let’s start with a thing we can all agree on. Nature magazine is one of the most prestigious places in which to publish an article. My guess is 90% of the people on this forum have never had an article published there. Neither have I but I would like to have had one, and I bet most scientists here would like to have had one as well.
Given their reputation for excellence you should know that they published last fall an article by Frauchiger and Renner entitled, Quantum theory cannot consistently describe the use of itself. This paper had circulated for 3 years prior to its publication with reviewers finding nothing fatal. The paper passed peer-review with Nature’s editors, passed and was published. https://www.nature.com/articles/s41467-018-05739-8 Furthermore, as discussed below, there is experimental support just published for F&R’s position, that trying to model agents using quantum leads to contradictions, just like it did with Wigner’s friend.
The above in and of itself does not make their paper true, but it should make people think of the consequences if it is true.
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If a brain using quantum can’t be modeled using quantum mechanics, then that strongly implies that consciousness is something else that doesn’t arise from the laws of physics. It would mean that consciousness isn’t subject to the laws of quantum.
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If that is true, then this idea I am presenting is not such a loon bin idea if Nature is publishing something consistent with it.
The article shows that consciousness is not subject to the laws of quantum mechanics. The article extends Wigner’s friend paradox to four friends observing two labs. If you have read my post above, on Wigner’s friend, where one friend causes a paradox, you will not be surprised to see that more friends cause more problems. New Scientist says:
"The Frauchiger-Renner paradox hits a level of weirdness that exceeds the previous feline thought experiments. Previously there was a dead-and-alive cat that you never got to see, leaving room for doubt that it ever existed. In this experiment, all the measurements have been made and it is as if the dead-and-alive cat is right there in front of you. There is no single truth everyone involved in the measurements can agree on. "The resolutions of the old paradoxes of Schrodinger’s cat and Wigner’s friend don’t apply to this one,’ says Renner. That disturbing conclusion is writ large in the title of the paper that, after many refinements, Frauchiger and Renner finally published in 2018: "Quantum mechanics cannot consistently describe the use of itself’. Richard Webb, The Reality Paradox, New Scientist, March 23, 2019, p.31-32.
I will note here that Nature has published an article advocating Bohmian mechanics as the solution to the paradox Frauchiger and Renner present, but it may have as hard a sledding as I am here, since most think Bohmian mechanics has been disproven. Furthermore, Proietti et al, discussed below offer at least partial experimental support for Frauchiger and Renner’s paper.
Noting the controversiality of Frauchiger and Renner’s paper, New Scientist says"
"Since the paradox was first circulated, there has been lively discussion of its significance. Some think the result plain wrong, and that there is a faulty or hidden assumption that renders the thought experiment invalid.
"Scott Aaronson, a computational theorist at the University of Texas at Austin, doesn’t count himself in that camp. He thinks the thought experiment represents a clever new scenario, but rejects the assumption that quantum physics needs to be able to describe itself. ‘We already knew for a long time that quantum mechanics no longer really works in hypothetical scenarios where we ourselves are being manipulated as we try to make quantum-mechanical predictions,’ he says, Sure, the theory doesn’t work when observers are themselves in a superposition. But we aren’t, so who cares?"
"Hardy disagrees. ‘It is a significant theorem and it goes beyond the discussion we had before,’ he says. 'It’s undermining the absolute nature of truth–that is the problem here." Richard Webb, The Reality Paradox, New Scientist, March 23, 2019, p. 32.
Without going into the details of the paradox which would be tedious and I would invite interested parties to read the paper at https://www.nature.com/articles/s41467-018-05739-8.pdf Aaronson is correct. Wigner’s friend paradox already showed that quantum doesn’t work if we use it to model a conscious observer, but this work merely makes that conclusion more emphatic.
Frauchiger and Renner lay out the assumptions that go into their calculations:
" It asserts that three natural-sounding assumptions, (Q), (C ), and (S), cannot all be valid. Assumption (Q) captures the universal validity of quantum theory (or, more specifically, that an agent can be certain that a given proposition holds whenever the quantum-mechanical Born rule assigns probability-1 to it). Assumption (C ) demands consistency, in the sense that the different agents’ predictions are not contradictory. Finally, (S) is the requirement that, from the viewpoint of an agent who carries out a particular measurement, this measurement has one single outcome. The theorem itself is neutral in the sense that it does not tell us which of these three assumptions is wrong. However, it implies that any specific interpretation of quantum theory, when applied to the Gedankenexperiment, will necessarily conflict with at least one of them." Daniela Frauchiger and Renato Renner, "Quantum Theory cannot consistently describe the use of itself" Nature, Sept 18, 2018
Let’s look at these assumptions. Assumption Q, Universal applicability of Quantum. Peterhouse says:
If a theory is universally valid in the absolute sense, it does not allow for an observer not described by the theory." Thomas Breuer Peterhouse, "Classical Observables, Measurement and Quantum Mechanics," Ph. D. Thesis, University of Cambridge, Sept 1994, p. 35
Most physicists and other scientists have used the materialistic assumption to assert that QM applies to all things inside this universe, including our consciousness/ mind/ soul. If our minds/souls are expressions of the workings of matter, QM and the other laws of physics and are some sort of epiphenomenon of complex matter, then mental states would be subject to the laws of quantum dynamics. Many suggestions have been made that consciousness is a quantum phenomenon.(Roger Penrose among them) But Frauchiger and Renner prove them wrong.
Others think it is ridiculous to think consciousness is a quantum phenomenon, but think consciousness arises from the complexity of the brain. The problem with this second group is that they don’t show how consciousness arises. We are left with no explanation of consciousness. What Sperry and Henry Stapp stated about consciousness remains true to this day:
“In a similar vein R. W. Sperry writes in 1952: 'The comment of Charles Sherrington remains as valid today as when he wrote it more than eighteen years ago: 'We have to regard the relation of mind to brain as still not merely unsolved but still devoid of a basis on which to begin.” Henry P. Stapp, “Mind, Matter and Quantum Mechanics,” Foundations of Physics, V. 12:4(1982), p.366
The problem seems insuperable. Searles puts it well (Qualia being the subjective sensation of pain we feel, the sensation of taste of an apple, the smell of rain or smoke, etc),
“Even for a system of whose qualia I have near-perfect knowledge, myself for example, the problem of qualia is serious. It is this: How is it possible for physical, objective, quantitatively describable neuron firings to cause qualitative, private, subjective experiences? How, to put it naively, does the brain get us over the hump from electrochemistry to feeling? That is the hard part of the mind-body problem that is left over after we see that consciousness must be caused by brain processes and is itself a feature of the brain.” John R. Searles, “Francis Crick, the Binding Problem, and the Hypothesis of Forty Hertz,” in John R. Searles, The Mystery of Consciousness, (New York: A New York Review Book, 1997), p. 28
This mind/body problem is consistent with the idea that our qualia are much more than mere neurons firing. A neural net computer tries to mimic our nerves. So far there is no evidence that such computers feel their existence. This places our consciousness in a special class and indicates that somehow mind/soul is " outside of the description provided by physics."
To me, assumption Q is the weak link in the set of assumptions. Mind is not subject to quantum mechanics, and that means it is something entirely different–something like a soul.
Assumption C–consistency. This is the real sine qua non of science and knowledge. If our theories are inconsistent, then all knowledge is impossible to obtain. If today when I measure the bounce of a ball and the height decreases with every bounce, then I know the laws of physics (friction and energy conservation) as we know them apply. But if tomorrow, the ball bounces higher and higher after each bounce, eventually shooting off into space, inconsistent with what we know of physics, then all we could do is shrug our shoulders and say we don’t understand nature. Consistency is the very touchstone of logic. As a professor once proved in my class, from any inconsistency he can prove that the Pope is protestant, and he did as we students peeled off one inconsistency after another. If C is not valid, shut your science books and start reading Tarot Cards.
Assumption S–singular results. Frauchiger and Renner say " from the viewpoint of an agent who carries out a particular measurement, this measurement has one single outcome" This is totally consistent with our experience. We never experience multiple outcomes of a quantum experiment–it is one or the other, but not both. It is hard to see how this can be the problematical assumption.
This leaves us solely with the idea that quantum is not universally applicable. It isn’t applicable to consciousness. This all says one thing, there is something in the situation to which quantum doesn’t apply.
Maybe it doesn’t apply to macroscopic objects, but already objects large enough to be seen have been placed in superposition. But macroscopic objects with trillions of atoms, which can be seen by the naked eye have already been placed in quantum states, so a possible limit of quantum due to size seems unlikely. Furthermore as Proietti et al observe:
"Notably, the formalism of quantum mechanics does not make a distinction between large (even conscious) and small physical system, which is sometimes referred to as universality." Massimiliano Proietti et al, Experimental rejection of observer-independence in the quantum world https://arxiv.org/pdf/1902.05080.pdf, p.3
But if quantum doesn’t apply to consciousness, then quantum is not a universal theory and consciousness does not arise as a phenomenon of the material brain either. These issues have tremendous implications for the nature of man and the nature of this universe. Materialism has reigned in our secular, technological society, but that doesn’t mean that materialism is true.
Renner sees his work as disproving the Everett multiverse. He says:
"Take Renner’s favoured many-worlds interpretation, which forgoes the part about alternative facts not being allowed–they are allowed, just in another universe. Renner initially thought this might work. But further investigation showed that there is no branch of the universe after the measurement where the answers of all four observers are consistent. ‘Before this thought experiment, I was relatively convinced that certain interpretations make sense,’ says Renner. 'Now I think none of them can.'" Richard Webb, The Reality Paradox, New Scientist, March 23, 2019, p.32-33
Amazingly, a recent experiment by Proietti et al has been placed out on arxiv which uses an extended Wigner’s friend model to design their experiment. They too came up with the now familiar problem that quantum predicts that the different observers see different answers. It clearly shows a problem of consistency (Assumption C above). But in almost all cases different experimenters in our world do NOT report different results from similar or identical experiments. So if assumption C is the problem and is real, as Proietti et al suggest, why don’t we see more inconsistency in our observations of nature?
These experimenters seem to be committed many worlds advocates and their conclusion on how to avoid the problems their experiment generates borders on the theological–shoot, it doesn’t border on it, it marches boldly into theology… Proietti et al, assume the universality of quantum theory and when applied to their favored interpretation of quantum, they run into another immaterial being–God.
If different observers of the identical experiments see different things, what is it that rectifies all the different observations in our world, so that we generally see consistent experimental results? They make a suggestion.
" Modulo the potential loopholes and accepting the photons’ status as observers, the violation of inequality (2) implies that at least one of the three assumptions of free choice, locality, and observer-independent facts must fail. Since abandoning free choice and locality might not resolve the contradiction [5] , one way to accommodate our result is by proclaiming that “facts of the world” can only be established by a privileged observer—e.g., one that would have access to the “global wavefunction” in the many worlds interpretation"
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other options "…however, requires us to embrace the possibility that different observers irreconcilably disagree about what happened in an experiment ." Massimiliano Proietti et al, Experimental rejection of observer-independence in the quantum world https://arxiv.org/pdf/1902.05080.pdf, p.4
As Lee Smolin says of the multiverse in general but is quite applicable to Proietti et al’s 'privileged observer":
"It seems to me that the only possible name for such an observer is God…" Lee Smolin, The Life of the Cosmos Oxford University Press, 1997, p. 264
It seems that quantum invariably leads to something existing that is immaterial. Some try to avoid this by holding the decoherence view of quantum but as Gordie and I show in our paper, [The Migrant Mind: Quantum Soul]
So prevaquark, to answer your earlier questions, I get these quotations by reading and paying attention to the literature. And maybe Nature magazine is also hijacking quantum to lobby for the existence of the immaterial. The Nature article has major implications to the nature of humans–and it isn’t just me flapping my arms; Nature magazine is flapping right beside me.
