Quantum mind

Not to be confused with Quantum cognition.

The quantum mind or quantum consciousness is a group of hypotheses proposing that local physical laws and interactions from classical mechanics or connections between neurons alone cannot explain consciousness,^[1] positing instead that quantum-mechanical phenomena, such as entanglement and superposition that cause nonlocalized quantum effects, interacting in smaller features of the brain than cells, may play an important part in the brain's function and could explain critical aspects of consciousness. These scientific hypotheses are as yet unvalidated, and they can overlap with quantum mysticism. Empirical evidence is against the notion of quantum consciousness, experiments do not support hypotheses of quantum mind.^[2]

History

Eugene Wigner developed the idea that quantum mechanics has something to do with the workings of the mind.^[3] He proposed that the wave function collapses due to its interaction with consciousness. Freeman Dyson argued that "mind, as manifested by the capacity to make choices, is to some extent inherent in every electron".^[4]

Other contemporary physicists and philosophers considered these arguments unconvincing.^[5] Victor Stenger characterized quantum consciousness as a "myth" having "no scientific basis" that "should take its place along with gods, unicorns and dragons".^[6]

David Chalmers argues against quantum consciousness. He instead discusses how quantum mechanics may relate to dualistic consciousness.^[7] Chalmers is skeptical that any new physics can resolve the hard problem of consciousness.^[8][9][10] He argues that quantum theories of consciousness suffer from the same weakness as more conventional theories. Just as he argues that there is no particular reason why particular macroscopic physical features in the brain should give rise to consciousness, he also thinks that there is no particular reason why a particular quantum feature, such as the EM field in the brain, should give rise to consciousness either.^[10]

Approaches

Bohm

David Bohm viewed quantum theory and relativity as contradictory, which implied a more fundamental level in the universe.^[11] He claimed that both quantum theory and relativity pointed to this deeper theory, which he formulated as a quantum field theory. This more fundamental level was proposed to represent an undivided wholeness and an implicate order, from which arises the explicate order of the universe as we experience it.^[12]

Bohm's proposed order applies both to matter and consciousness. He suggested that it could explain the relationship between them. He saw mind and matter as projections into our explicate order from the underlying implicate order. Bohm claimed that when we look at matter, we see nothing that helps us to understand consciousness.^[13]

Bohm discussed the experience of listening to music. He believed that the feeling of movement and change that make up our experience of music derive from holding the immediate past and the present in the brain together. The musical notes from the past are transformations rather than memories. The notes that were implicated in the immediate past become explicate in the present. Bohm viewed this as consciousness emerging from the implicate order.^{[citation needed]}

Bohm saw the movement, change or flow, and the coherence of experiences, such as listening to music, as a manifestation of the implicate order. He claimed to derive evidence for this from Jean Piaget's work on infants.^[14] He held these studies to show that young children learn about time and space because they have a "hard-wired" understanding of movement as part of the implicate order. He compared this hard-wiring to Chomsky's theory that grammar is hard-wired into human brains.^{[citation needed]}

Bohm never proposed a specific means by which his proposal could be falsified, nor a neural mechanism through which his "implicate order" could emerge in a way relevant to consciousness.^[11] He later collaborated on Karl Pribram's holonomic brain theory as a model of quantum consciousness.^[15]

According to philosopher Paavo Pylkkänen, Bohm's suggestion "leads naturally to the assumption that the physical correlate of the logical thinking process is at the classically describable level of the brain, while the basic thinking process is at the quantum-theoretically describable level".^[16]

It was suggested by theoretical physicists David Bohm and Basil Hiley that mind and matter both emerge from an "implicate order".^[17] Bohm and Hiley's approach to mind and matter is supported by philosopher Paavo Pylkkänen.^[18] Pylkkänen underlines "unpredictable, uncontrollable, indivisible and non-logical" features of conscious thought and draws parallels to a philosophical movement some call "post-phenomenology", in particular to Pauli Pylkkö's notion of the "aconceptual experience", an unstructured, unarticulated and pre-logical experience.^[19]

Penrose and Hameroff

Main article: Orchestrated objective reduction

Theoretical physicist Roger Penrose and anaesthesiologist Stuart Hameroff collaborated to produce the theory known as "orchestrated objective reduction" (Orch-OR). Penrose and Hameroff initially developed their ideas separately and later collaborated to produce Orch-OR in the early 1990s. They reviewed and updated their theory in 2013.^[20][21]

Penrose's argument stemmed from Gödel's incompleteness theorems. In his first book on consciousness, The Emperor's New Mind (1989),^[22] he argued that while a formal system cannot prove its own consistency, Gödel's unprovable results are provable by human mathematicians.^[23] Penrose took this to mean that human mathematicians are not formal proof systems and not running a computable algorithm. According to Bringsjord and Xiao, this line of reasoning is based on fallacious equivocation on the meaning of computation.^[24] In the same book, Penrose wrote: "One might speculate, however, that somewhere deep in the brain, cells are to be found of single quantum sensitivity. If this proves to be the case, then quantum mechanics will be significantly involved in brain activity."^[22]: 400

Penrose determined that wave function collapse was the only possible physical basis for a non-computable process. Dissatisfied with its randomness, he proposed a new form of wave function collapse that occurs in isolation and called it objective reduction. He suggested each quantum superposition has its own piece of spacetime curvature and that when these become separated by more than one Planck length, they become unstable and collapse.^[25] Penrose suggested that objective reduction represents neither randomness nor algorithmic processing but instead a non-computable influence in spacetime geometry from which mathematical understanding and, by later extension, consciousness derives.^[25]

Hameroff provided a hypothesis that microtubules would be suitable hosts for quantum behavior.^[26] Microtubules are composed of tubulin protein dimer subunits. The dimers each have hydrophobic pockets that are 8 nm apart and may contain delocalized π electrons. Tubulins have other smaller non-polar regions that contain π-electron-rich indole rings separated by about 2 nm. Hameroff proposed that these electrons are close enough to become entangled.^[27] He originally suggested that the tubulin-subunit electrons would form a Bose–Einstein condensate, but this was discredited.^[28] He then proposed a Frohlich condensate, a hypothetical coherent oscillation of dipolar molecules, but this too was experimentally discredited.^[29]

In other words, there is a missing link between physics and neuroscience.^[30] For instance, the proposed predominance of A-lattice microtubules, more suitable for information processing, was falsified by Kikkawa et al.,^[31][32] who showed that all in vivo microtubules have a B lattice and a seam. The proposed existence of gap junctions between neurons and glial cells was also falsified.^[33] Orch-OR predicted that microtubule coherence reaches the synapses through dendritic lamellar bodies (DLBs), but De Zeeuw et al. proved this impossible^[34] by showing that DLBs are micrometers away from gap junctions.^[35]

In 2014, Hameroff and Penrose claimed that the discovery of quantum vibrations in microtubules by Anirban Bandyopadhyay of the National Institute for Materials Science in Japan in March 2013^[36] corroborates Orch-OR theory.^[21][37] Experiments that showed that anaesthetic drugs reduce how long microtubules can sustain suspected quantum excitations appear to support the quantum theory of consciousness.^[38]

In April 2022, the results of two related experiments at the University of Alberta and Princeton University were announced at The Science of Consciousness conference, providing further evidence to support quantum processes operating within microtubules. In a study Stuart Hameroff was part of, Jack Tuszyński of the University of Alberta demonstrated that anesthetics hasten the duration of a process called delayed luminescence, in which microtubules and tubulins re-emit trapped light. Tuszyński suspects that the phenomenon has a quantum origin, with superradiance being investigated as one possibility. In the second experiment, Gregory D. Scholes and Aarat Kalra of Princeton University used lasers to excite molecules within tubulins, causing a prolonged excitation to diffuse through microtubules further than expected, which did not occur when repeated under anesthesia.^[39][40] However, diffusion results have to be interpreted carefully, since even classical diffusion can be very complex due to the wide range of length scales in the fluid filled extracellular space.^[41] Nevertheless, University of Oxford quantum physicist Vlatko Vedral told that this connection with consciousness is a really long shot.

Also in 2022, a group of Italian physicists conducted several experiments that failed to provide evidence in support of a gravity-related quantum collapse model of consciousness, weakening the possibility of a quantum explanation for consciousness.^[42][43]

Although these theories are stated in a scientific framework, it is difficult to separate them from scientists' personal opinions. The opinions are often based on intuition or subjective ideas about the nature of consciousness. For example, Penrose wrote:^[44]

[M]y own point of view asserts that you can't even simulate conscious activity. What's going on in conscious thinking is something you couldn't properly imitate at all by computer.... If something behaves as though it's conscious, do you say it is conscious? People argue endlessly about that. Some people would say, "Well, you've got to take the operational viewpoint; we don't know what consciousness is. How do you judge whether a person is conscious or not? Only by the way they act. You apply the same criterion to a computer or a computer-controlled robot." Other people would say, "No, you can't say it feels something merely because it behaves as though it feels something." My view is different from both those views. The robot wouldn't even behave convincingly as though it was conscious unless it really was—which I say it couldn't be, if it's entirely computationally controlled.

Penrose continues:^[45]

A lot of what the brain does you could do on a computer. I'm not saying that all the brain's action is completely different from what you do on a computer. I am claiming that the actions of consciousness are something different. I'm not saying that consciousness is beyond physics, either—although I'm saying that it's beyond the physics we know now.... My claim is that there has to be something in physics that we don't yet understand, which is very important, and which is of a noncomputational character. It's not specific to our brains; it's out there, in the physical world. But it usually plays a totally insignificant role. It would have to be in the bridge between quantum and classical levels of behavior—that is, where quantum measurement comes in.

Umezawa, Vitiello, Freeman

Hiroomi Umezawa and collaborators proposed a quantum field theory of memory storage.^[46][47] Giuseppe Vitiello and Walter Freeman proposed a dialog model of the mind. This dialog takes place between the classical and the quantum parts of the brain.^[48][49][50] Their quantum field theory models of brain dynamics are fundamentally different from the Penrose–Hameroff theory.^{[citation needed]}

Quantum brain dynamics

In neuroscience, quantum brain dynamics (QBD) is a hypothesis to explain the function of the brain within the framework of quantum field theory.^{[citation needed]}

As described by Harald Atmanspacher, "Since quantum theory is the most fundamental theory of matter that is currently available, it is a legitimate question to ask whether quantum theory can help us to understand consciousness."

The original motivation in the early 20th century for relating quantum theory to consciousness was essentially philosophical. It is fairly plausible that conscious free decisions (“free will”) are problematic in a perfectly deterministic world, so quantum randomness might indeed open up novel possibilities for free will. (On the other hand, randomness is problematic for goal-directed volition!)^[51]

Ricciardi and Umezawa proposed in 1967 a general theory of quanta of long-range coherent waves within and between brain cells, and showed a possible mechanism of memory storage and retrieval in terms of Nambu–Goldstone bosons.^[52] This was later developed into a theory encompassing all biological cells and systems in the quantum biodynamics of Del Giudice and co-authors.^[53][54] Mari Jibu and Kunio Yasue later popularized these results and discussed the implications towards consciousness.^[55][56][57]

Umezawa emphasizes that macroscopic and microscopic ordered states are both of quantum origin according to quantum field theory and points out the shortcomings of classical neuronal models in describing them.^[58] In 1981, theoretical exploration of the Ising model in Cayley tree topologies and large neural networks yielded an exact solution on closed trees with arbitrary branching ratios greater than two, exhibiting an unusual phase transition in local-apex and long-range site-site correlations.^[59][60] This finding directly raises the possibility of multiple cooperative modes being present in ordering states long-range within neural networks and their constituents, with Barth cooperative effects of the closed tree Ising model (structurally and connectivity dependent, with critical point a function of branching ratio and site-to-site energies of interaction)^[61] and Umezawa ordering of states (less structure dependent and with significantly greater degrees of freedom)^[62] independently or collectively guiding overall long-range macroscopic ordering often associated with higher cognitive functions in QBD.

Pribram

Karl Pribram's holonomic brain theory (quantum holography) invoked quantum mechanics to explain higher-order processing by the mind.^[63][64] He argued that his holonomic model solved the binding problem.^[65] Pribram collaborated with Bohm in his work on quantum approaches to mind and he provided evidence on how much of the processing in the brain was done in wholes.^[66] He proposed that ordered water at dendritic membrane surfaces might operate by structuring Bose–Einstein condensation supporting quantum dynamics.^[67]

Stapp

Henry Stapp proposed that quantum waves are reduced only when they interact with consciousness. He argues from the orthodox quantum mechanics of John von Neumann^[clarify] that the quantum state collapses when the observer selects one among the alternative quantum possibilities as a basis for future action. The collapse, therefore, takes place in the expectation that the observer associated with the state. Stapp's work drew criticism from scientists such as David Bourget and Danko Georgiev.^{[68][69][70][71]}

David Pearce

British philosopher David Pearce defends what he calls physicalistic idealism ("the non-materialist physicalist claim that reality is fundamentally experiential and that the natural world is exhaustively described by the equations of physics and their solutions") and has conjectured that unitary conscious minds are physical states of quantum coherence (neuronal superpositions).^{[72][73][74][75]} This conjecture is, according to Pearce, amenable to falsification, unlike most theories of consciousness, and Pearce has outlined an experimental protocol describing how the hypothesis could be tested using matter-wave interferometry to detect nonclassical interference patterns of neuronal superpositions at the onset of thermal decoherence.^[76] Pearce admits that his ideas are "highly speculative", "counterintuitive", and "incredible".^[74]

Catecholaminergic Neuron Electron Transport (CNET)

CNET is a hypothesized neural signaling mechanism in catecholaminergic neurons that would use quantum mechanical electron transport.^[77][78] The hypothesis is based in part on the observation by many independent researchers that electron tunneling occurs in ferritin, an iron storage protein that is prevalent in those neurons, at room temperature and ambient conditions.^{[79][80][81][82]} The hypothesized function of this mechanism is to assist in action selection, but the mechanism itself would be capable of integrating millions of cognitive and sensory neural signals using a physical mechanism associated with strong electron-electron interactions.^[83][84][85] Each tunneling event would involve a collapse of an electron wave function, but the collapse would be incidental to the physical effect created by strong electron-electron interactions.^{[citation needed]}

CNET predicted a number of physical properties of these neurons that have been subsequently observed experimentally, such as electron tunneling in substantia nigra pars compacta (SNc) tissue and the presence of disordered arrays of ferritin in SNc tissue.^{[86][87][88][89]} The hypothesis also predicted that disordered ferritin arrays like those found in SNc tissue should be capable of supporting long-range electron transport and providing a switching or routing function, both of which have also been subsequently observed.^[90][91][92]

Another prediction of CNET was that the largest SNc neurons should mediate action selection. This prediction was contrary to earlier proposals about the function of those neurons at that time, which were based on predictive reward dopamine signaling.^[93][94] A team led by Dr. Pascal Kaeser of Harvard Medical School subsequently demonstrated that those neurons do in fact code movement, consistent with the earlier predictions of CNET.^[95] While the CNET mechanism has not yet been directly observed, it may be possible to do so using quantum dot fluorophores tagged to ferritin or other methods for detecting electron tunneling.^[96]

CNET is applicable to a number of different consciousness models as a binding or action selection mechanism, such as Integrated Information Theory (IIT) and Sensorimotor Theory (SMT).^[97] It is noted that many existing models of consciousness fail to specifically address action selection or binding. For example, O’Regan and Noë call binding a “pseudo problem,” but also state that “the fact that object attributes seem perceptually to be part of a single object does not require them to be ‘represented’ in any unified kind of way, for example, at a single location in the brain, or by a single process. They may be so represented, but there is no logical necessity for this.”^[98] Simply because there is no “logical necessity” for a physical phenomenon does not mean that it does not exist, or that once it is identified that it can be ignored. Likewise, global workspace theory (GWT) models appear to treat dopamine as modulatory,^[99] based on the prior understanding of those neurons from predictive reward dopamine signaling research, but GWT models could be adapted to include modeling of moment-by-moment activity in the striatum to mediate action selection, as observed by Kaiser. CNET is applicable to those neurons as a selection mechanism for that function, as otherwise that function could result in seizures from simultaneous actuation of competing sets of neurons. While CNET by itself is not a model of consciousness, it is able to integrate different models of consciousness through neural binding and action selection. However, a more complete understanding of how CNET might relate to consciousness would require a better understanding of strong electron-electron interactions in ferritin arrays, which implicates the many-body problem.

Experiments

See also: Consciousness § States of consciousness

In 2022, neuroscientists reported experimental MRI results that so far appear to imply nuclear proton spins of bulk water in the brains of human participants were entangled, suggesting brain functions that operate non-classically which may support quantum mechanisms being involved in consciousness as the signal pattern declined when human participants fell asleep. However, the results are far from unambiguous and if such brain functions indeed exist and are involved in conscious cognition, the extent and nature of their involvement in consciousness remains unknown.^{[further explanation needed][100][101]}

An experiment about wave function collapse led by Catalina Curceanu in 2022 suggests that quantum consciousness, as suggested by Roger Penrose and Stuart Hameroff, is highly implausible.^[2]

Criticism

These hypotheses of the quantum mind remain hypothetical speculation, as Penrose and Pearce admit in their discussions. Until they make a prediction that is tested by experimentation, the hypotheses aren't based on empirical evidence. In 2010, Lawrence Krauss was guarded in criticising Penrose's ideas. He said: "Roger Penrose has given lots of new-age crackpots ammunition... Many people are dubious that Penrose's suggestions are reasonable, because the brain is not an isolated quantum-mechanical system. To some extent it could be, because memories are stored at the molecular level, and at a molecular level quantum mechanics is significant."^[102] According to Krauss, "It is true that quantum mechanics is extremely strange, and on extremely small scales for short times, all sorts of weird things happen. And in fact, we can make weird quantum phenomena happen. But what quantum mechanics doesn't change about the universe is, if you want to change things, you still have to do something. You can't change the world by thinking about it."^[102]

The process of testing the hypotheses with experiments is fraught with conceptual/theoretical, practical, and ethical problems.

Conceptual problems

The idea that a quantum effect is necessary for consciousness to function is still in the realm of philosophy. Penrose proposes that it is necessary, but other theories of consciousness do not indicate that it is needed. For example, Daniel Dennett proposed a theory called multiple drafts model, which doesn't indicate that quantum effects are needed, in his 1991 book Consciousness Explained.^[103] A philosophical argument on either side isn't scientific proof, although philosophical analysis can indicate key differences in the types of models and show what type of experimental differences might be observed. But since there isn't a clear consensus among philosophers, there isn't conceptual support that a quantum mind theory is needed.^[104]

There are computers that are specifically designed to compute using quantum-mechanical effects. Quantum computing is computing using quantum-mechanical phenomena, such as superposition and entanglement.^[105] They are different from binary digital electronic computers based on transistors. Whereas common digital computing requires that the data be encoded into binary digits (bits), each of which is always in one of two definite states (0 or 1), quantum computation uses quantum bits, which can be in superpositions of states. One of the greatest challenges is controlling or removing quantum decoherence. This usually means isolating the system from its environment, as interactions with the external world cause the system to decohere. Some quantum computers require their qubits to be cooled to 20 millikelvins in order to prevent significant decoherence.^[106] As a result, time-consuming tasks may render some quantum algorithms inoperable, as maintaining the state of qubits long enough eventually corrupts the superpositions.^[107] Currently, there aren't any confirmed formal equivalencies between the functioning of quantum computers and the human brain. Some hypothetical models of quantum mind have proposed mechanisms for maintaining quantum coherence in the brain, but they have yet to be thoroughly demonstrated to operate as such.^{[citation needed]}

Quantum entanglement is a physical phenomenon often invoked for quantum mind models. This effect occurs when pairs or groups of particles interact so that the quantum state of each particle cannot be described independently of the other(s),^[108] even when the particles are separated by a large distance. Instead, a quantum state has to be described for the whole system. Measurements of physical properties such as position, momentum, spin, and polarization, performed on entangled particles are found to be correlated. If one particle is measured, the same property of the other particle immediately adjusts to maintain the conservation of the physical phenomenon. According to the formalism of quantum theory, the effect of measurement happens instantly, no matter how far apart the particles are.^[109][110] It is not possible to use this effect to transmit classical information at faster-than-light speeds^[111] (see Faster-than-light § Quantum mechanics). Entanglement is broken when the entangled particles decohere through interaction with the environment—for example, when a measurement is made^[112] or the particles undergo random collisions or interactions. According to Pearce, "In neuronal networks, ion–ion scattering, ion–water collisions, and long-range Coulomb interactions from nearby ions all contribute to rapid decoherence times; but thermally induced decoherence is even harder experimentally to control than collisional decoherence." He anticipated that quantum effects would have to be measured in femtoseconds, a trillion times faster than the rate at which neurons function (milliseconds).^[76]

Another possible conceptual approach is to use quantum mechanics as an analogy to understand a different field of study like consciousness, without expecting that the laws of quantum physics will apply. An example of this approach is the idea of Schrödinger's cat. Erwin Schrödinger described how one could, in principle, create entanglement of a large-scale system by making it dependent on an elementary particle in a superposition. He proposed a scenario with a cat in a locked steel chamber, wherein the cat's survival depended on the state of a radioactive atom—whether it had decayed and emitted radiation. According to Schrödinger, the Copenhagen interpretation implies that the cat is both alive and dead until the state has been observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; he intended the example to illustrate the absurdity of the existing view of quantum mechanics.^[113] But since Schrödinger's time, physicists have given other interpretations of the mathematics of quantum mechanics, some of which regard the "alive and dead" cat superposition as quite real.^[114][115] Schrödinger's famous thought experiment poses the question, "when does a quantum system stop existing as a superposition of states and become one or the other?" In the same way, one can ask whether the act of making a decision is analogous to having a superposition of states of two decision outcomes, so that making a decision means "opening the box" to reduce the brain from a combination of states to one state. This analogy about decision-making uses a formalism derived from quantum mechanics, but doesn't indicate the actual mechanism by which the decision is made. In this way, the idea is similar to quantum cognition. This field clearly distinguishes itself from the quantum mind, as it is not reliant on the hypothesis that there is something micro-physical quantum-mechanical about the brain. Quantum cognition is based on the quantum-like paradigm,^[116][117] generalized quantum paradigm,^[118] or quantum structure paradigm^[119] that information processing by complex systems such as the brain can be mathematically described in the framework of quantum information and quantum probability theory. This model uses quantum mechanics only as an analogy, but doesn't propose that quantum mechanics is the physical mechanism by which it operates. For example, quantum cognition proposes that some decisions can be analyzed as if there is interference between two alternatives, but it is not a physical quantum interference effect.^{[citation needed]}

Practical problems

Quantum mechanics is a mathematical model that can provide some extremely accurate numerical predictions. Richard Feynman called quantum electrodynamics, based on the quantum-mechanics formalism, "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen.^{[120]: Ch. 1} So it is not impossible that the model could provide an accurate prediction about consciousness that would confirm that a quantum effect is involved. If the mind depends on quantum mechanical effects, the true proof is to find an experiment that provides a calculation that can be compared to experimental measurement. It has to show a measurable difference between a classical computation result in a brain and one that involves quantum effects.^{[citation needed]}

The main theoretical argument against the quantum-mind hypothesis is the assertion that quantum states in the brain would lose coherency before they reached a scale where they could be useful for neural processing. This supposition was elaborated by Max Tegmark. His calculations indicate that quantum systems in the brain decohere at sub-picosecond timescales.^[121][122] No response by a brain has shown computational results or reactions on this fast of a timescale. Typical reactions are on the order of milliseconds, trillions of times longer than sub-picosecond timescales.^[123]

Daniel Dennett uses an experimental result in support of his multiple drafts model of an optical illusion that happens on a time scale of less than a second or so. In this experiment, two different-colored lights, with an angular separation of a few degrees at the eye, are flashed in succession. If the interval between the flashes is less than a second or so, the first light that is flashed appears to move across to the position of the second light. Furthermore, the light seems to change color as it moves across the visual field. A green light will appear to turn red as it seems to move across to the position of a red light. Dennett asks how we could see the light change color before the second light is observed.^[103] Velmans argues that the cutaneous rabbit illusion, another illusion that happens in about a second, demonstrates that there is a delay while modelling occurs in the brain and that this delay was discovered by Libet.^[124] These slow illusions that happen at times of less than a second don't support a proposal that the brain functions on the picosecond time scale.^{[citation needed]}

According to David Pearce, a demonstration of picosecond effects is "the fiendishly hard part – feasible in principle, but an experimental challenge still beyond the reach of contemporary molecular matter-wave interferometry. [...] The conjecture predicts that we'll discover the interference signature of sub-femtosecond macro-superpositions."^[76]

Penrose says:^[45]

The problem with trying to use quantum mechanics in the action of the brain is that if it were a matter of quantum nerve signals, these nerve signals would disturb the rest of the material in the brain, to the extent that the quantum coherence would get lost very quickly. You couldn't even attempt to build a quantum computer out of ordinary nerve signals, because they're just too big and in an environment that's too disorganized. Ordinary nerve signals have to be treated classically. But if you go down to the level of the microtubules, then there's an extremely good chance that you can get quantum-level activity inside them.

For my picture, I need this quantum-level activity in the microtubules; the activity has to be a large-scale thing that goes not just from one microtubule to the next but from one nerve cell to the next, across large areas of the brain. We need some kind of coherent activity of a quantum nature which is weakly coupled to the computational activity that Hameroff argues is taking place along the microtubules.^{[citation needed]}

There are various avenues of attack. One is directly on the physics, on quantum theory, and there are certain experiments that people are beginning to perform, and various schemes for a modification of quantum mechanics. I don't think the experiments are sensitive enough yet to test many of these specific ideas. One could imagine experiments that might test these things, but they'd be very hard to perform.

Penrose also said in an inverview:

...whatever consciousness is, it must be beyond computable physics.... It's not that consciousness depends on quantum mechanics, it's that it depends on where our current theories of quantum mechanics go wrong. It's to do with a theory that we don't know yet.^[125]

A demonstration of a quantum effect in the brain has to explain this problem or explain why it is not relevant, or that the brain somehow circumvents the problem of the loss of quantum coherency at body temperature. As Penrose proposes, it may require a new type of physical theory, something "we don't know yet."^[125]

Ethical problems

Deepak Chopra has referred a "quantum soul" existing "apart from the body"^[126] and human "access to a field of infinite possibilities".,^[127] and other quantum mysticism topics such as quantum healing or quantum effects of consciousness. Seeing the human body as being undergirded by a "quantum-mechanical body" composed not of matter but of energy and information, he believes that "human aging is fluid and changeable; it can speed up, slow down, stop for a time, and even reverse itself", as determined by one's state of mind.^[128] Robert Carroll states that Chopra attempts to integrate Ayurveda with quantum mechanics to justify his teachings.^[129] Chopra argues that what he calls "quantum healing" cures any manner of ailments, including cancer, through effects that he claims are based on the same principles as quantum mechanics.^[130] This has led physicists to object to his use of the term quantum in reference to medical conditions and the human body.^[130] Chopra said: "I think quantum theory has a lot of things to say about the observer effect, about non-locality, about correlations. So I think there’s a school of physicists who believe that consciousness has to be equated, or at least brought into the equation, in understanding quantum mechanics."^[131] On the other hand, he also claims that "[quantum effects are] just a metaphor. Just like an electron or a photon is an indivisible unit of information and energy, a thought is an indivisible unit of consciousness."^[131] In his book Quantum Healing, Chopra stated the conclusion that quantum entanglement links everything in the Universe, and therefore it must create consciousness.^[132]

According to Daniel Dennett, "On this topic, Everybody's an expert... but they think that they have a particular personal authority about the nature of their own conscious experiences that can trump any hypothesis they find unacceptable."^[133]

While quantum effects are significant in the physiology of the brain, critics of quantum mind hypotheses challenge whether the effects of known or speculated quantum phenomena in biology scale up to have significance in neuronal computation, much less the emergence of consciousness as phenomenon. Daniel Dennett said, "Quantum effects are there in your car, your watch, and your computer. But most things—most macroscopic objects—are, as it were, oblivious to quantum effects. They don't amplify them; they don't hinge on them."^[45]

See also

• Artificial consciousness
• Bohm interpretation of quantum mechanics
• Coincidence detection in neurobiology
• Critical brain hypothesis
• Electromagnetic theories of consciousness
• Evolutionary neuroscience
• Hameroff-Penrose Orchestrated Objective Reduction
• Hard problem of consciousness
• Holonomic brain theory
• Many-minds interpretation
• Mechanism (philosophy)
• Neuroplasticity
• Quantum cognition
• Quantum neural network

References

1. "Quantum Approaches to Consciousness". Stanford Encyclopedia of Philosophy. May 19, 2011 [First published Tue Nov 30, 2004].
2. Derakhshani, Maaneli; Diósi, Lajos; Laubenstein, Matthias; Piscicchia, Kristian; Curceanu, Catalina (September 2022). "At the crossroad of the search for spontaneous radiation and the Orch OR consciousness theory". Physics of Life Reviews. 42: 8–14. doi:10.1016/j.plrev.2022.05.004.
3. Wigner, Eugene (1961). "Remarks on the Mind-Body Question". In Good, Irving John (ed.). Philosophical Reflections and Syntheses. London: Heinemann. pp. 284–302. doi:10.1007/978-3-642-78374-6_20. ISBN 978-3-540-63372-3.
4. Dyson, Freeman (2004). Infinite in All Directions: Gifford Lectures Given at Aberdeen, Scotland April–November 1985 (1st Perennial ed.). New York: Perennial. p. 297. ISBN 0060728892.
5. Searle, John R. (1997). The Mystery of Consciousness (1st ed.). New York: New York Review of Books. pp. 53–88. ISBN 9780940322066.
6. Stenger, Victor (May–June 1992). (PDF). The Humanist. Vol. 53, no. 3. pp. 13–15. Archived from the original (PDF) on 2008-05-17.
7. Stephen P. Stich; Ted A. Warfield (15 April 2008). The Blackwell Guide to Philosophy of Mind. John Wiley & Sons. p. 126. ISBN 9780470998755. {{cite book}}: |work= ignored (help)
8. Chalmers, David J. (1995). "Facing Up to the Problem of Consciousness". Journal of Consciousness Studies. 2 (3): 200–219.
9. Chalmers, David J. (1997). The Conscious Mind: In Search of a Fundamental Theory (Paperback ed.). New York: Oxford University Press. ISBN 978-0-19-511789-9.
10. Chalmers, David (1996). The Conscious Mind: In Search of a Fundamental Theory. Oxford University Press. ISBN 978-0-19-510553-7.
11. Bohm, David (2002). Wholeness and the Implicate Order (Online-Ausg. ed.). Hoboken: Routledge. ISBN 0203995155.
12. Bohm, David (1980). Wholeness and the implicate order (Repr. ed.). London, England: Routledge & Kegan Paul. ISBN 9780415289795.
13. Raggett, Simon. "https://www.facebook.com/QuantumMind". Quantum Mind. Retrieved 11 September 2023. {{cite web}}: External link in |title= (help)
14. Piaget, Jean (1997). Jean Piaget: selected works. (The Origin of Intelligence in the Child) (Repr. ed.). London, England: Routledge. ISBN 9780415168861.
15. Wade, Jenny (1996). Changes of Mind: A Holonomic Theory of the Evolution of Consciousness. Albany, New York: State University of New York Press. ISBN 9780791428498.
16. Pylkkänen, Paavo. "Can quantum analogies help us to understand the process of thought?" (PDF). Mind & Matter. 12 (1): 61–91 [75].
17. Basil J. Hiley. Particles, fields, and observers, Volume I The Origins of Life, Part 1 Origin and Evolution of Life, Section II The Physical and Chemical Basis of Life, pp. 87–106 (PDF).
18. Basil J. Hiley, Paavo Pylkkänen: Naturalizing the mind in a quantum framework. In Paavo Pylkkänen and Tere Vadén (eds.): Dimensions of conscious experience, Advances in Consciousness Research, Volume 37, John Benjamins B.V., 2001, ISBN 90-272-5157-6, pages 119–144
19. Paavo Pylkkänen. "Can quantum analogies help us to understand the process of thought?". Mind & Matter. 12 (1): 61–91. p. 83–84.
20. "Discovery of quantum vibrations in 'microtubules' inside brain neurons supports controversial theory of consciousness". ScienceDaily. 2014-01-16. Retrieved 2017-12-28.
21. "Discovery of Quantum Vibrations in "Microtubules" Inside Brain Neurons Corroborates Controversial 20-Year-Old Theory of Consciousness". Elsevier. 2014-01-16. Retrieved 2017-12-28.
22. Penrose, Roger (1989). The Emperor's New Mind. New York, New York: Penguin Books. ISBN 0-14-01-4534-6.
23. Gödel, Kurt (1992). On Formally Undecidable Propositions of Principia Mathematica and Related Systems (Reprint ed.). New York: Dover Publications. ISBN 0486669807.
24. Bringsjord, S. and Xiao, H. 2000. A Refutation of Penrose's Gödelian Case Against Artificial Intelligence. Journal of Experimental and Theoretical Artificial Intelligence.
25. Penrose, Roger (1999). The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics (New ed.). Oxford, England: Oxford University Press. ISBN 0192861980.
26. Penrose, Roger (1995). Shadows of the Mind: A Search for the Missing Science of Consciousness (Repr. (with corrections) ed.). Oxford [u.a.]: Oxford University Press. ISBN 0198539789.
27. Hameroff, Stuart (2008). "That's life! The geometry of π electron resonance clouds" (PDF). In Abbott, D.; Davies, P.; Pati, A. (eds.). Quantum Aspects of Life. World Scientific. pp. 403–434. Retrieved Jan 21, 2010.
28. Penrose, Roger & Hameroff, Stuart (2011). . Journal of Cosmology. 14. Archived from the original on February 7, 2014.
29. Reimers, Jeffrey R.; McKemmish, Laura K.; McKenzie, Ross H.; Mark, Alan E.; Hush, Noel S. (17 March 2009). "Weak, strong, and coherent regimes of Fröhlich condensation and their applications to terahertz medicine and quantum consciousness". PNAS. 106 (11): 4219–4224. Bibcode:2009PNAS..106.4219R. doi:10.1073/pnas.0806273106. PMC 2657444. PMID 19251667.
30. van den Noort, Maurits; Lim, Sabina; Bosch, Peggy (2016-10-28). "Towards a theory of everything: The observer's unconscious brain". Nature. 538 (7623): 36–37. Bibcode:2016Natur.538...36D. doi:10.1038/538036a.
31. Kikkawa M, Ishikawa T, Nakata T, Wakabayashi T, Hirokawa N (1994). "Direct visualization of the microtubule lattice seam both in vitro and in vivo". Journal of Cell Biology. 127 (6): 1965–1971. doi:10.1083/jcb.127.6.1965. PMC 2120284. PMID 7806574.
32. Kikkawa M, Metlagel Z (2006). "A molecular 'zipper' for microtubules". Cell. 127 (7): 1302–1304. doi:10.1016/j.cell.2006.12.009. PMID 17190594. S2CID 31980600.
33. Binmöller, F. J. & Müller, C. M. (1992). "Postnatal development of dye-coupling among astrocytes in rat visual cortex". Glia. 6 (2): 127–137. doi:10.1002/glia.440060207. PMID 1328051. S2CID 548862.
34. De Zeeuw CI, Hertzberg EL, Mugnaini E (1995). "The dendritic lamellar body: A new neuronal organelle putatively associated with dendrodentritic gap junctions". Journal of Neuroscience. 15 (2): 1587–1604. doi:10.1523/JNEUROSCI.15-02-01587.1995. PMC 6577840. PMID 7869120.
35. Hameroff, S. (2013-08-12). "Consciousness, the brain, and spacetime geometry". Annals of the New York Academy Sciences. 929 (1): 74–104. Bibcode:2001NYASA.929...74H. doi:10.1111/j.1749-6632.2001.tb05709.x. PMID 11349432. S2CID 12399940.
36. Sahu S, Ghosh S, Ghosh B, Aswani K, Hirata K, Fujita D, Bandyopadhyay A (2014-05-14). "Atomic water channel controlling remarkable properties of a single brain microtubule: correlating single protein to its supramolecular assembly". Biosens Bioelectron. 47: 141–148. doi:10.1016/j.bios.2013.02.050. PMID 23567633.
37. Osborne, Hannah (2014-01-16). "Quantum Vibrations in Brain Opens 'Pandora's Box' of Theories of Consciousness". Yahoo News UK. Retrieved 2014-08-04.
38. Lewton, Thomas (18 April 2022). "Quantum experiments add weight to a fringe theory of consciousness". New Scientist. Retrieved 20 April 2022.
39. Lewton, Thomas (18 April 2022). "Quantum experiments add weight to a fringe theory of consciousness". New Scientist. Retrieved 23 April 2022.
40. Tangermann, Victor. "Experiment Suggests That Consciousness May Be Rooted in Quantum Physics". www.futurism.com. Camden Media Inc. Retrieved 24 April 2022.
41. Nicholson, Charles (May 2022). "The Secret World in the Gaps between Brain Cells". Physics Today. 75 (5): 26–32. Bibcode:2022PhT....75e..26N. doi:10.1063/PT.3.4999. S2CID 248620292.
42. "Collapsing a leading theory for the quantum origin of consciousness". phys.org. 13 June 2022.
43. Derakhshani, Maaneli; Diósi, Lajos; Laubenstein, Matthias; Piscicchia, Kristian; Curceanu, Catalina (1 September 2022). "At the crossroad of the search for spontaneous radiation and the Orch OR consciousness theory". Physics of Life Reviews. 42: 8–14. Bibcode:2022PhLRv..42....8D. doi:10.1016/j.plrev.2022.05.004. PMID 35617922. S2CID 248868080.
44. Daniel, Dennett. "Edge Conversation Chapter 10: Intuition Pumps, and response by Roger Penrose". Edge.com. Retrieved 20 Feb 2018.
45. Penrose, Roger. "Edge Conversation Chapter 14: Consciousness Involves Noncomputable Ingredients". Edge.com. Retrieved 20 Feb 2018.
46. Ricciardi L. M.; Umezawa H. (1967). "Brain physics and many-body problems". Kibernetik. 4 (2): 44–48. doi:10.1007/BF00292170. PMID 5617419. S2CID 29289582.
47. Ricciardi, L. M.; Umezawa, H. (2004) [1967]. Gordon, G. G.; Pribram, K. H.; Vitiello, G. (eds.). "Brain physics and many-body problems". Brain and Being. Amsterdam: John Benjamins Publishing Company: 255–266.
48. G. Vitiello, My Double Unveiled. John Benjamins, 2001.
49. Freeman, W.; Vitiello, G. (2006). "Nonlinear brain dynamics as macroscopic manifestation of underlying many-body dynamics". Physics of Life Reviews. 3 (2): 93–118. arXiv:q-bio/0511037. Bibcode:2006PhLRv...3...93F. doi:10.1016/j.plrev.2006.02.001. S2CID 11011930.
50. Atmanspacher, H. (2006), "Quantum Approaches to Consciousness", Quantum Approaches to Consciousness. A critical survey article in Stanford University Encyclopedia of Philosophy, Metaphysics Research Lab, Stanford University
51. Atmanspacher, Harald (2 June 2015) [30 November 2004]. "Quantum Approaches to Consciousness". Stanford Encyclopedia of Philosophy. Center for the Study of Language and Information (CSLI), Stanford University. Retrieved 17 February 2016.
52. Ricciardi LM, Umezawa H (1967). "Brain and physics of many-body problems". Kybernetik. 4 (2): 44–48. doi:10.1007/bf00292170. PMID 5617419. S2CID 29289582.
53. Del Giudice E, Doglia S, Milani M, Vitiello G (1986). "Electromagnetic field and spontaneous symmetry breaking in biological matter". Nucl. Phys. B. 275 (2): 185–199. Bibcode:1986NuPhB.275..185D. doi:10.1016/0550-3213(86)90595-x.
54. Del Giudice E, Preparata G, Vitiello G (1988). "Water as a free electric dipole laser". Physical Review Letters. 61 (9): 1085–1088. Bibcode:1988PhRvL..61.1085D. doi:10.1103/physrevlett.61.1085. PMID 10039515.
55. Jibu M, Yasue K (1995). Quantum Brain Dynamics: An Introduction. Amsterdam: John Benjamins.
56. Jibu M, Yasue K (1997). "What is mind? Quantum field theory of evanescent photons in brain as quantum theory of consciousness". Informatica. 21: 471–490.
57. Yasue, Kunio. . Toward a Science of Consciousness. Archived from the original on June 25, 2014.
58. Umezawa, Hiroomi (1993). Advanced Field Theory: Micro, Macro, and Thermal Physics. American Institute of Physics Press. ISBN 1-56396-456-2.
59. Barth, Peter F. (1981). Cooperativity and the Transition Behavior of Large Neural Nets (M.Sc. Thesis). University of Vermont. pp. 1–118. OCLC 8231704.
60. Krizan, J. E.; Barth, P. F.; Glasser, M. L. (1983). "Exact Phase Transitions for the Ising Model on the Closed Cayley Tree". Physica. 119A. North-Holland Publishing Company: 230–242. doi:10.1016/0378-4371(83)90157-7.
61. Barth, Peter F. (1981). Cooperativity and the Transition Behavior of Large Neural Nets (M.Sc. Thesis). University of Vermont. pp. 58–59, 99. OCLC 8231704.
62. Umezawa, Hiroomi (1993). Advanced Field Theory: Micro, Macro, and Thermal Physics. AIP (American Institute of Physics) Press. ISBN 1563964562.
63. Pribram, K. H. (1999). "Quantum holography: Is it relevant to brain function?". Information Sciences. 115 (1–4): 97–102. doi:10.1016/s0020-0255(98)10082-8.
64. Pribram, K. H. (2004). "Consciousness Reassessed". Mind and Matter. 2: 7–35.
65. Pribram, K. (1999) Status Report: Quantum Holography and the Braln. Acta Polyiechnica Scandinavica: Emergence Complexity, Hierarchy, Organization, Vol. 2, pp. 33–60.
66. Pribram, K. H. Holography, holonomy and brain function. Elsevier's Encyclopedia of Neuroscience, 1999.
67. Jibu, M.; Pribram, K. H.; Yasue, K. (1996). "From conscious experience to memory storage and retrieval: The role of quantum brain dynamics and boson condensation of evanescent photons". International Journal of Modern Physics B. 10 (13n14): 1735–1754. Bibcode:1996IJMPB..10.1735J. doi:10.1142/s0217979296000805.
68. Bourget, D. (2004). "Quantum Leaps in Philosophy of Mind: A Critique of Stapp's Theory". Journal of Consciousness Studies. 11 (12): 17–42.
69. Georgiev, D. (2012). "Mind efforts, quantum Zeno effect and environmental decoherence". NeuroQuantology. 10 (3): 374–388. doi:10.14704/nq.2012.10.3.552.
70. Georgiev, D. (2015). "Monte Carlo simulation of quantum Zeno effect in the brain". International Journal of Modern Physics B. 29 (7): 1550039. arXiv:1412.4741. Bibcode:2015IJMPB..2950039G. doi:10.1142/S0217979215500393. S2CID 118390522.
71. Georgiev, Danko D. (2017). Quantum Information and Consciousness: A Gentle Introduction. Boca Raton, Florida: CRC Press. ISBN 9781138104488. OCLC 1003273264.
72. Pearce, David. "Non-Materialist Physicalism: An experimentally testable conjecture". Retrieved 15 Feb 2018.
73. Pearce, David. "Quantum computing: the first 540 million years: Abstract of talk given at Tucson conference 'Toward a Science of Consciousness' (2010)". Retrieved 18 Feb 2018.
74. Pearce, David. "The Binding Problem of Consciousness". YouTube.com. Archived from the original on 2021-12-13.
75. Pearce, David. "Schrödinger's Neurons: David Pearce at the '2016 Science of Consciousness' conference in Tucson". YouTube.com. Archived from the original on 2021-12-13. Retrieved 18 Feb 2018.
76. Pearce, David. "Non-Materialist Physicalism: An experimentally testable conjecture, Section 6". Retrieved 15 Feb 2018.
77. Rourk, Christopher John (September 2018). "Ferritin and neuromelanin "quantum dot" array structures in dopamine neurons of the substantia nigra pars compacta and norepinephrine neurons of the locus coeruleus". Biosystems. 171: 48–58. doi:10.1016/j.biosystems.2018.07.008. ISSN 0303-2647. PMID 30048795. S2CID 51722018.
78. Rourk, Christopher J. (2020), "Functional neural electron transport", Quantum Boundaries of Life, Advances in Quantum Chemistry, vol. 82, Elsevier, pp. 25–111, doi:10.1016/bs.aiq.2020.08.001, ISBN 9780128226391, S2CID 229230562, retrieved 2022-10-23
79. Xu, Degao; Watt, Gerald D.; Harb, John N.; Davis, Robert C. (2005-03-25). "Electrical Conductivity of Ferritin Proteins by Conductive AFM". Nano Letters. 5 (4): 571–577. Bibcode:2005NanoL...5..571X. doi:10.1021/nl048218x. ISSN 1530-6984. PMID 15826089.
80. Kumar, Karuppannan Senthil; Pasula, Rupali Reddy; Lim, Sierin; Nijhuis, Christian A. (2015-12-28). "Long-Range Tunneling Processes across Ferritin-Based Junctions". Advanced Materials. 28 (9): 1824–1830. doi:10.1002/adma.201504402. ISSN 0935-9648. PMID 26708136. S2CID 2238319.
81. Kolay, J.; Bera, S.; Rakshit, T.; Mukhopadhyay, R. (2018-02-07). "Negative Differential Resistance Behavior of the Iron Storage Protein Ferritin". Langmuir. 34 (9): 3126–3135. doi:10.1021/acs.langmuir.7b04356. ISSN 0743-7463. PMID 29412680.
82. Gupta, Nipun Kumar; Karuppannan, Senthil Kumar; Pasula, Rupali Reddy; Vilan, Ayelet; Martin, Jens; Xu, Wentao; May, Esther Maria; Pike, Andrew R.; Astier, Hippolyte P. A. G.; Salim, Teddy; Lim, Sierin; Nijhuis, Christian A. (2022-09-23). "Temperature-Dependent Coherent Tunneling across Graphene–Ferritin Biomolecular Junctions". ACS Applied Materials & Interfaces. 14 (39): 44665–44675. doi:10.1021/acsami.2c11263. ISSN 1944-8244. PMC 9542697. PMID 36148983.
83. Kouwenhoven, Leo P.; Marcus, Charles M.; McEuen, Paul L.; Tarucha, Seigo; Westervelt, Robert M.; Wingreen, Ned S. (1997), "Electron Transport in Quantum Dots", Mesoscopic Electron Transport, Dordrecht: Springer Netherlands, pp. 105–214, doi:10.1007/978-94-015-8839-3_4, ISBN 978-90-481-4906-3, retrieved 2022-10-23
84. Basov, D. N.; Averitt, Richard D.; van der Marel, Dirk; Dressel, Martin; Haule, Kristjan (2011-06-02). "Electrodynamics of correlated electron materials". Reviews of Modern Physics. 83 (2): 471–541. arXiv:1106.2309. Bibcode:2011RvMP...83..471B. doi:10.1103/revmodphys.83.471. ISSN 0034-6861. S2CID 118437353.
85. Dykman, M. I.; Fang-Yen, C.; Lea, M. J. (1997-06-15). "Many-electron transport in strongly correlated nondegenerate two-dimensional electron systems". Physical Review B. 55 (24): 16249–16271. Bibcode:1997PhRvB..5516249D. doi:10.1103/physrevb.55.16249. ISSN 0163-1829.
86. Rourk, Christopher J. (May 2019). "Indication of quantum mechanical electron transport in human substantia nigra tissue from conductive atomic force microscopy analysis". Biosystems. 179: 30–38. doi:10.1016/j.biosystems.2019.02.003. ISSN 0303-2647. PMID 30826349. S2CID 73509918.
87. Sulzer, David; Cassidy, Clifford; Horga, Guillermo; Kang, Un Jung; Fahn, Stanley; Casella, Luigi; Pezzoli, Gianni; Langley, Jason; Hu, Xiaoping P.; Zucca, Fabio A.; Isaias, Ioannis U.; Zecca, Luigi (2018-04-10). "Neuromelanin detection by magnetic resonance imaging (MRI) and its promise as a biomarker for Parkinson's disease". npj Parkinson's Disease. 4 (1): 11. doi:10.1038/s41531-018-0047-3. ISSN 2373-8057. PMC 5893576. PMID 29644335.
88. Friedrich, I.; Reimann, K.; Jankuhn, S.; Kirilina, E.; Stieler, J.; Sonntag, M.; Meijer, J.; Weiskopf, N.; Reinert, T.; Arendt, T.; Morawski, M. (2021-03-22). "Cell specific quantitative iron mapping on brain slices by immuno-µPIXE in healthy elderly and Parkinson's disease". Acta Neuropathologica Communications. 9 (1): 47. doi:10.1186/s40478-021-01145-2. ISSN 2051-5960. PMC 7986300. PMID 33752749.
89. Xiong, Nian; Huang, Jinsha; Zhang, Zhentao; Zhang, Zhaowen; Xiong, Jing; Liu, Xingyuan; Jia, Min; Wang, Fang; Chen, Chunnuan; Cao, Xuebing; Liang, Zhihou; Sun, Shenggang; Lin, Zhicheng; Wang, Tao (2009-11-18). "Stereotaxical Infusion of Rotenone: A Reliable Rodent Model for Parkinson's Disease". PLOS ONE. 4 (11): e7878. Bibcode:2009PLoSO...4.7878X. doi:10.1371/journal.pone.0007878. ISSN 1932-6203. PMC 2774159. PMID 19924288.
90. Bera, Sudipta; Kolay, Jayeeta; Pramanik, Pallabi; Bhattacharyya, Anirban; Mukhopadhyay, Rupa (2019). "Long-range solid-state electron transport through ferritin multilayers". Journal of Materials Chemistry C. 7 (29): 9038–9048. doi:10.1039/c9tc01744e. ISSN 2050-7526. S2CID 198849306.
91. Rourk, Christopher; Huang, Yunbo; Chen, Minjing; Shen, Cai (2021-06-16). "Indication of Highly Correlated Electron Transport in Disordered Multilayer Ferritin Structures". doi:10.31219/osf.io/7gqmt. S2CID 241118606. Retrieved 2022-10-23. {{cite journal}}: Cite journal requires |journal= (help)
92. Labra-Muñoz, Jacqueline A.; de Reuver, Arie; Koeleman, Friso; Huber, Martina; van der Zant, Herre S. J. (2022-05-15). "Ferritin-Based Single-Electron Devices". Biomolecules. 12 (5): 705. doi:10.3390/biom12050705. ISSN 2218-273X. PMC 9138424. PMID 35625632.
93. Schultz, Wolfram (1998-07-01). "Predictive Reward Signal of Dopamine Neurons". Journal of Neurophysiology. 80 (1): 1–27. doi:10.1152/jn.1998.80.1.1. ISSN 0022-3077. PMID 9658025. S2CID 52857162.
94. Schultz, Wolfram (2016-02-02). "Reward functions of the basal ganglia". Journal of Neural Transmission. 123 (7): 679–693. doi:10.1007/s00702-016-1510-0. ISSN 0300-9564. PMC 5495848. PMID 26838982.
95. Liu, Changliang; Goel, Pragya; Kaeser, Pascal S. (2021-04-09). "Spatial and temporal scales of dopamine transmission". Nature Reviews Neuroscience. 22 (6): 345–358. doi:10.1038/s41583-021-00455-7. ISSN 1471-003X. PMC 8220193. PMID 33837376.
96. Garg, Mayank; Vishwakarma, Neelam; Sharma, Amit L.; Singh, Suman (2021-07-08). "Amine-Functionalized Graphene Quantum Dots for Fluorescence-Based Immunosensing of Ferritin". ACS Applied Nano Materials. 4 (7): 7416–7425. doi:10.1021/acsanm.1c01398. ISSN 2574-0970. S2CID 237804893.
97. Rourk, Chris (2022-01-06). "Application of the Catecholaminergic Neuron Electron Transport (CNET) Physical Substrate for Consciousness and Action Selection to Integrated Information Theory". Entropy. 24 (1): 91. Bibcode:2022Entrp..24...91R. doi:10.3390/e24010091. ISSN 1099-4300. PMC 8774445. PMID 35052119.
98. O'Regan, J. Kevin; Noë, Alva (October 2001). "A sensorimotor account of vision and visual consciousness". Behavioral and Brain Sciences. 24 (5): 939–973. doi:10.1017/s0140525x01000115. ISSN 0140-525X. PMID 12239892.
99. Volzhenin, Konstantin; Changeux, Jean-Pierre; Dumas, Guillaume (2022-01-25). "Multilevel Development of Cognitive Abilities in an Artificial Neural Network". Proceedings of the National Academy of Sciences of the United States of America. 119 (39): e2201304119. Bibcode:2022PNAS..11901304V. bioRxiv 10.1101/2022.01.24.477526. doi:10.1073/pnas.2201304119. PMC 9522351. PMID 36122214. Retrieved 2022-10-23.
100. Firtina, Nergis (20 October 2022). "Our brains could use quantum computation – here's how". interestingengineering.com. Retrieved 17 November 2022.
101. Kerskens, Christian Matthias; López Pérez, David (1 October 2022). "Experimental indications of non-classical brain functions". Journal of Physics Communications. 6 (10): 105001. arXiv:1806.07998. Bibcode:2022JPhCo...6j5001K. doi:10.1088/2399-6528/ac94be. ISSN 2399-6528.
102. Boyle, Alan (20 September 2010). "How to Spot Quantum Quackery". NBC News Science News. Retrieved 8 Mar 2018.
103. Dennett, Daniel C. (1991). Consciousness Explained. Little, Brown & Company.
104. Myrvold, Wayne (2022). "Philosophical Issues in Quantum Theory". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 11 September 2023.
105. Gershenfeld, Neil; Chuang, Isaac L. (June 1998). "Quantum Computing with Molecules" (PDF). Scientific American. 278 (6): 66–71. Bibcode:1998SciAm.278f..66G. doi:10.1038/scientificamerican0698-66.
106. Jones, Nicola (19 June 2013). "Computing: The quantum company". Nature. 498 (7454): 286–288. Bibcode:2013Natur.498..286J. doi:10.1038/498286a. PMID 23783610.
107. Amy, Matthew; Matteo, Olivia; Gheorghiu, Vlad; Mosca, Michele; Parent, Alex; Schanck, John (November 30, 2016). "Estimating the cost of generic quantum pre-image attacks on SHA-2 and SHA-3". arXiv:1603.09383 [quant-ph].
108. Georgiev, Danko D. (2021). "Quantum information in neural systems". Symmetry. 13 (5): 773. arXiv:2105.01410. Bibcode:2021Symm...13..773G. doi:10.3390/sym13050773. S2CID 233714776.
109. Matson, John (13 August 2012). "Quantum teleportation achieved over record distances". Nature. doi:10.1038/nature.2012.11163. S2CID 124852641.
110. Griffiths, David J. (2004), Introduction to Quantum Mechanics (2nd ed.), Prentice Hall, ISBN 0-13-111892-7.
111. Roger Penrose, The Road to Reality: A Complete Guide to the Laws of the Universe, London, England, 2004, p. 603.
112. Asher Peres, Quantum Theory: Concepts and Methods, Kluwer, 1993; ISBN 0-7923-2549-4 p. 115.
113. Schrödinger, Erwin (November 1935). "Die gegenwärtige Situation in der Quantenmechanik (The present situation in quantum mechanics)". Naturwissenschaften (in German). 23 (48): 807–812. Bibcode:1935NW.....23..807S. doi:10.1007/BF01491891. S2CID 206795705.
114. Polkinghorne, J. C. (1985). The Quantum World. Princeton University Press. p. 67. ISBN 0691023883. from the original on 2015-05-19.
115. Tetlow, Philip (2012). Understanding Information and Computation: From Einstein to Web Science. Gower Publishing, Limited. p. 321. ISBN 978-1409440406. from the original on 2015-05-19.
116. Khrennikov, A. (2006). "Quantum-like brain: Interference of minds". Biosystems. 84 (3): 225–241. arXiv:quant-ph/0205092. doi:10.1016/j.biosystems.2005.11.005. PMID 16427733.
117. Khrennikov, A. Information Dynamics in Cognitive, Psychological, Social, and Anomalous Phenomena (Fundamental Theories of Physics) (Volume 138), Kluwer, 2004.
118. Atmanspacher, H.; Römer, H.; Walach, H. (2002). "Weak quantum theory: Complementarity and entanglement in physics and beyond". Foundations of Physics. 32 (3): 379–406. doi:10.1023/a:1014809312397. S2CID 118583726.
119. Aerts, D.; Aerts, S. (1994). "Applications of quantum statistics in psychological studies of decision processes". Foundations of Science. 1: 85–97. doi:10.1007/BF00208726.
120. Feynman, Richard (1985). QED: The Strange Theory of Light and Matter. Princeton University Press. ISBN 978-0-691-12575-6.
121. Tegmark, M. (2000). "Importance of quantum decoherence in brain processes". Physical Review E. 61 (4): 4194–4206. arXiv:quant-ph/9907009. Bibcode:2000PhRvE..61.4194T. doi:10.1103/PhysRevE.61.4194. PMID 11088215. S2CID 17140058.
122. Seife, Charles (4 February 2000). "Cold Numbers Unmake the Quantum Mind". Science. 287 (5454): 791. doi:10.1126/science.287.5454.791. PMID 10691548. S2CID 33761196.
123. Yuhas, Daisy (May 24, 2012). "Speedy Science: How fast can you react?". Scientific American. Retrieved 18 Feb 2018.
124. Velmans, M. (1992). "Is Consciousness Integrated?". Behavioral and Brain Sciences. 15 (2): 229–230. doi:10.1017/s0140525x00068473. S2CID 145232451. (Commentary on Dennett & Kinsbourne "Time and the observer", BBS, 1992, 15(2): 183–201.)
125. Brooks, Michael (Autumn 2023). "Cosmic Thoughts". New Scientist. 256 (3413): 34–37. Bibcode:2022NewSc.256...46P. doi:10.1016/S0262-4079(22)02094-2. S2CID 253724922. Retrieved November 3, 2023.
126. Hameroff, Stuart R.; Chopra, Deepak (2012). "The "Quantum Soul": A Scientific Hypothesis". In Moreira-Almeida, Alexander; Santos, Franklin Santana (eds.). Exploring Frontiers of the Mind-Brain Relationship. New York: Springer. pp. 79–93. doi:10.1007/978-1-4614-0647-1_5. ISBN 978-1-4614-0647-1. When the blood stops flowing, energy and oxygen depleted and microtubules inactivated or destroyed (e.g., near death experience (NDE)/out-of-body experience (OBE), death), it is conceivable that the quantum information which constitutes consciousness could shift to deeper planes and continue to exist purely in space-time geometry, outside the brain, distributed nonlocally. Movement of consciousness to deeper planes could account for NDEs/OBEs, as well as, conceivably, a soul apart from the body.
127. Chopra, Deepak (2021). "What is wholeness? The consciousness view". Global Advances in Health and Medicine. 10: 21649561211043794. doi:10.1177/21649561211043794. PMC 8419538. PMID 34497737. The snake biting its tail solves the problem of consciousness, but you have to look at it closely and let its meaning sink in. The snake biting its tail symbolism points to something that has no beginning or end, is immune to death, extends infinitely in all directions, and gives humans access to a field of infinite possibilities.
128. Chopra, Deepak (1997). Ageless Body, Timeless Mind: The Quantum Alternative to Growing Old. Random House. p. 6. ISBN 9780679774495.
129. Carroll, Robert Todd (May 19, 2013), "Deepak Chopra", The Skeptic's Dictionary.
130. Park, Robert L. (September 1, 2005). "Chapter 9: Voodoo medicine in a scientific world". In Ashman, Keith; Barringer, Phillip (eds.). After the Science Wars: Science and the Study of Science. Routledge. pp. 137–. ISBN 978-1-134-61618-3.
131. Chopra, Deepak (2013-06-19). "Richard Dawkins Plays God: The Video (Updated)". Huffington Post. Retrieved 5 Mar 2018.
132. O'Neill, Ian (May 26, 2011). "Does Quantum Theory Explain Consciousness?". Discovery News. Discovery Communications, LLC. Retrieved August 11, 2014.
133. Dennett, Daniel (Feb 2017). From Bacteria to Bach and Back: The Evolution of Minds (1st ed.). New York: W. W. Norton and Company. ISBN 978-0393242072.

Further reading

• Georgiev, Danko D. (2017). Quantum Information and Consciousness: A Gentle Introduction. Boca Raton, Florida: CRC Press. ISBN 9781138104488. OCLC 1003273264.
• Hodgson, David (1993). The Mind Matters: Consciousness and Choice in a Quantum World. Clarendon Press. ISBN 978-0-19-824068-6.
• Koch, Christof; Hepp, Klaus (2006). "Quantum mechanics in the brain". Nature. 440 (7084): 611–612. Bibcode:2006Natur.440..611K. doi:10.1038/440611a. PMID 16572152. S2CID 5085015.
• Litt, Abninder; Eliasmith, Chris; Kroon, Frederick W.; Weinstein, Steven; Thagard, Paul (2006). "Is the brain a quantum computer?" (PDF). Cognitive Science. 30 (3): 593–603. doi:10.1207/s15516709cog0000_59. PMID 21702826.
• Lockwood, Michael (1995). Mind, Brain, and the Quantum: The Compound 'I'. Basil Blackwell.
• McFadden, Johnjoe (2000) Quantum Evolution HarperCollins. ISBN 0-00-255948-X; ISBN 0-00-655128-9 . Final chapter on the quantum mind.
• Musser, George (17 January 2024). "Can quantum hints in the brain revive a radical consciousness theory?". New Scientist. Retrieved 2024-01-19.
• Rosenblum, Bruce; Kuttner, Fred (2011). Quantum Enigma: Physics Encounters Consciousness (2nd ed.). Oxford University Press. ISBN 9780199753819.
• Schrödinger, Erwin (2012). What is Life?: With Mind and Matter and Autobiographical Sketches (PDF). Canto Classics. Cambridge: Cambridge University Press. ISBN 978-1107604667.
• Weyl, Hermann (1934). Mind and Nature. Philadelphia, Pennsylvania: University of Pennsylvania Press.
• Wigner, Eugene P. (1970). "Physics and the explanation of life". Foundations of Physics. 1 (1): 35–45. Bibcode:1970FoPh....1...35W. doi:10.1007/bf00708653. S2CID 121081834.

External links

• Center for Consciousness Studies, directed by Stuart Hameroff
• PhilPapers on Philosophy of Mind, edited by David Bourget and David Chalmers
• Quantum Approaches to Consciousness, entry in Stanford Encyclopedia of Philosophy
• Quantum-Mind, founded by Simon Raggett