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The mere mention of “quantum consciousness” makes most physicists cringe, as the phrase seems to evoke the vague, insipid musings of a New Age guru. But if a new hypothesis proves to be correct, quantum effects might indeed play some role in human cognition. Matthew Fisher, a physicist at the University of California, Santa Barbara, raised eyebrows late last year when he published a paper in Annals of Physics proposing that the nuclear spins of phosphorus atoms could serve as rudimentary “qubits” in the brain — which would essentially enable the brain to function like a quantum computer.

As recently as 10 years ago, Fisher’s hypothesis would have been dismissed by many as nonsense. Physicists have been burned by this sort of thing before, most notably in 1989, when Roger Penrose proposed that mysterious protein structures called “microtubules” played a role in human consciousness by exploiting quantum effects. Few researchers believe such a hypothesis plausible. Patricia Churchland, a neurophilosopher at the University of California, San Diego, memorably opined that one might as well invoke “pixie dust in the synapses” to explain human cognition.

Fisher’s hypothesis faces the same daunting obstacle that has plagued microtubules: a phenomenon called quantum decoherence. To build an operating quantum computer, you need to connect qubits — quantum bits of information — in a process called entanglement. But entangled qubits exist in a fragile state. They must be carefully shielded from any noise in the surrounding environment. Just one photon bumping into your qubit would be enough to make the entire system “decohere,” destroying the entanglement and wiping out the quantum properties of the system. It’s challenging enough to do quantum processing in a carefully controlled laboratory environment, never mind the warm, wet, complicated mess that is human biology, where maintaining coherence for sufficiently long periods of time is well nigh impossible.

Over the past decade, however, growing evidence suggests that certain biological systems might employ quantum mechanics. In photosynthesis, for example, quantum effects help plants turn sunlight into fuel. Scientists have also proposed that migratory birds have a “quantum compass” enabling them to exploit Earth’s magnetic fields for navigation, or that the human sense of smell could be rooted in quantum mechanics.

Fisher’s notion of quantum processing in the brain broadly fits into this emerging field of quantum biology. Call it quantum neuroscience. He has developed a complicated hypothesis, incorporating nuclear and quantum physics, organic chemistry, neuroscience and biology. While his ideas have met with plenty of justifiable skepticism, some researchers are starting to pay attention. “Those who read his paper (as I hope many will) are bound to conclude: This old guy’s not so crazy,” wrote John Preskill, a physicist at the California Institute of Technology, after Fisher gave a talk there. “He may be on to something. At least he’s raising some very interesting questions.”

Senthil Todadri, a physicist at the Massachusetts Institute of Technology and Fisher’s longtime friend and colleague, is skeptical, but he thinks that Fisher has rephrased the central question — is quantum processing happening in the brain? — in such a way that it lays out a road map to test the hypothesis rigorously. “The general assumption has been that of course there is no quantum information processing that’s possible in the brain,” Todadri said. “He makes the case that there’s precisely one loophole. So the next step is to see if that loophole can be closed.” Indeed, Fisher has begun to bring together a team to do laboratory tests to answer this question once and for all.

Courtesy of Matthew Fisher

Matthew Fisher has proposed a way for quantum effects to influence the workings of the brain.

Finding the Spin

Fisher belongs to something of a physics dynasty: His father, Michael E. Fisher, is a prominent physicist at the University of Maryland, College Park, whose work in statistical physics has garnered numerous honors and awards over the course of his career. His brother, Daniel Fisher, is an applied physicist at Stanford University who specializes in evolutionary dynamics. Matthew Fisher has followed in their footsteps, carving out a highly successful physics career. He shared the prestigious Oliver E. Buckley Prize in 2015 for his research on quantum phase transitions.

So what drove him to move away from mainstream physics and toward the controversial and notoriously messy interface of biology, chemistry, neuroscience and quantum physics? His own struggles with clinical depression.

Fisher vividly remembers that February 1986 day when he woke up feeling numb and jet-lagged, as if he hadn’t slept in a week. “I felt like I had been drugged,” he said. Extra sleep didn’t help. Adjusting his diet and exercise regime proved futile, and blood tests showed nothing amiss. But his condition persisted for two full years. “It felt like a migraine headache over my entire body every waking minute,” he said. It got so bad he contemplated suicide, although the birth of his first daughter gave him a reason to keep fighting through the fog of depression.

Eventually he found a psychiatrist who prescribed a tricyclic antidepressant, and within three weeks his mental state started to lift. “The metaphorical fog that had so enshrouded me that I couldn’t even see the sun — that cloud was a little less dense, and I saw there was a light behind it,” Fisher said. Within nine months he felt reborn, despite some significant side effects from the medication, including soaring blood pressure. He later switched to Prozac and has continuously monitored and tweaked his specific drug regimen ever since.

His experience convinced him that the drugs worked. But Fisher was surprised to discover that neuroscientists understand little about the precise mechanisms behind how they work. That aroused his curiosity, and given his expertise in quantum mechanics, he found himself pondering the possibility of quantum processing in the brain. Five years ago he threw himself into learning more about the subject, drawing on his own experience with antidepressants as a starting point.

Since nearly all psychiatric medications are complicated molecules, he focused on one of the most simple, lithium, which is just one atom — a spherical cow, so to speak, that would be an easier model to study than Prozac, for instance. The analogy is particularly appropriate because a lithium atom is a sphere of electrons surrounding the nucleus, Fisher said. He zeroed in on the fact that the lithium available by prescription from your local pharmacy is mostly a common isotope called lithium-7. Would a different isotope, like the much more rare lithium-6, produce the same results? In theory it should, since the two isotopes are chemically identical. They differ only in the number of neutrons in the nucleus.

When Fisher searched the literature, he found that an experiment comparing the effects of lithium-6 and lithium-7 had been done. In 1986, scientists at Cornell University examined the effects of the two isotopes on the behavior of rats. Pregnant rats were separated into three groups: One group was given lithium-7, one group was given the isotope lithium-6, and the third served as the control group. Once the pups were born, the mother rats that received lithium-6 showed much stronger maternal behaviors, such as grooming, nursing and nest-building, than the rats in either the lithium-7 or control groups.

This floored Fisher. Not only should the chemistry of the two isotopes be the same, the slight difference in atomic mass largely washes out in the watery environment of the body. So what could account for the differences in behavior those researchers observed?

Fisher believes the secret might lie in the nuclear spin, which is a quantum property that affects how long each atom can remain coherent — that is, isolated from its environment. The lower the spin, the less the nucleus interacts with electric and magnetic fields, and the less quickly it decoheres.

Because lithium-7 and lithium-6 have different numbers of neutrons, they also have different spins. As a result, lithium-7 decoheres too quickly for the purposes of quantum cognition, while lithium-6 can remain entangled longer.

Fisher had found two substances, alike in all important respects save for quantum spin, and found that they could have very different effects on behavior. For Fisher, this was a tantalizing hint that quantum processes might indeed play a functional role in cognitive processing.

Lucy Reading-Ikkanda for Quanta Magazine

Quantum Protection Scheme

That said, going from an intriguing hypothesis to actually demonstrating that quantum processing plays a role in the brain is a daunting challenge. The brain would need some mechanism for storing quantum information in qubits for sufficiently long times. There must be a mechanism for entangling multiple qubits, and that entanglement must then have some chemically feasible means of influencing how neurons fire in some way. There must also be some means of transporting quantum information stored in the qubits throughout the brain.

This is a tall order. Over the course of his five-year quest, Fisher has identified just one credible candidate for storing quantum information in the brain: phosphorus atoms, which are the only common biological element other than hydrogen with a spin of one-half, a low number that makes possible longer coherence times. Phosphorus can’t make a stable qubit on its own, but its coherence time can be extended further, according to Fisher, if you bind phosphorus with calcium ions to form clusters.

In 1975, Aaron Posner, a Cornell University scientist, noticed an odd clustering of calcium and phosphorous atoms in his X-rays of bone. He made drawings of the structure of those clusters: nine calcium atoms and six phosphorous atoms, later called “Posner molecules” in his honor. The clusters popped up again in the 2000s, when scientists simulating bone growth in artificial fluid noticed them floating in the fluid. Subsequent experiments found evidence of the clusters in the body. Fisher thinks that Posner molecules could serve as a natural qubit in the brain as well.

That’s the big picture scenario, but the devil is in the details that Fisher has spent the past few years hammering out. The process starts in the cell with a chemical compound called pyrophosphate. It is made of two phosphates bonded together — each composed of a phosphorus atom surrounded by multiple oxygen atoms with zero spin. The interaction between the spins of the phosphates causes them to become entangled. They can pair up in four different ways: Three of the configurations add up to a total spin of one (a “triplet” state that is only weakly entangled), but the fourth possibility produces a zero spin, or “singlet” state of maximum entanglement, which is crucial for quantum computing.

Next, enzymes break apart the entangled phosphates into two free phosphate ions. Crucially, these remain entangled even as they move apart. This process happens much more quickly, Fisher argues, with the singlet state. These ions can then combine in turn with calcium ions and oxygen atoms to become Posner molecules. Neither the calcium nor the oxygen atoms have a nuclear spin, preserving the one-half total spin crucial for lengthening coherence times. So those clusters protect the entangled pairs from outside interference so that they can maintain coherence for much longer periods of time — Fisher roughly estimates it might last for hours, days or even weeks.

In this way, the entanglement can be distributed over fairly long distances in the brain, influencing the release of neurotransmitters and the firing of synapses between neurons — spooky action at work in the brain.

Testing the Theory

Researchers who work in quantum biology are cautiously intrigued by Fisher’s proposal. Alexandra Olaya-Castro, a physicist at University College London who has worked on quantum photosynthesis, calls it “a well-thought hypothesis. It doesn’t give answers, it opens questions that might then lead to how we could test particular steps in the hypothesis.”

University of Oxford chemist Peter Hore, who investigates whether migratory birds’ navigational systems make use of quantum effects, concurs. “Here’s a theoretical physicist who is proposing specific molecules, specific mechanics, all the way through to how this could affect brain activity,” he said. “That opens up the possibility of experimental testing.”

Experimental testing is precisely what Fisher is now trying to do. He just spent a sabbatical at Stanford University working with researchers there to replicate the 1986 study with pregnant rats. He acknowledged the preliminary results were disappointing, in that the data didn’t provide much information, but thinks if it’s repeated with a protocol closer to the original 1986 experiment, the results might be more conclusive.

Fisher has applied for funding to conduct further in-depth quantum chemistry experiments. He has cobbled together a small group of scientists from various disciplines at UCSB and the University of California, San Francisco, as collaborators. First and foremost, he would like to investigate whether calcium phosphate really does form stable Posner molecules, and whether the phosphorus nuclear spins of these molecules can be entangled for sufficiently long periods of time.

Even Hore and Olaya-Castro are skeptical of the latter, particularly Fisher’s rough estimate that the coherence could last a day or more. “I think it’s very unlikely, to be honest,” Olaya-Castro said. “The longest time scale relevant for the biochemical activity that’s happening here is the scale of seconds, and that’s too long.” (Neurons can store information for microseconds.) Hore calls the prospect “remote,” pegging the limit at one second at best. “That doesn’t invalidate the whole idea, but I think he would need a different molecule to get long coherence times,” he said. “I don’t think the Posner molecule is it. But I’m looking forward to hearing how it goes.”

Others see no need to invoke quantum processing to explain brain function. “The evidence is building up that we can explain everything interesting about the mind in terms of interactions of neurons,” said Paul Thagard, a neurophilosopher at the University of Waterloo in Ontario, Canada, to New Scientist. (Thagard declined our request to comment further.)

Plenty of other aspects of Fisher’s hypothesis also require deeper examination, and he hopes to be able to conduct the experiments to do so. Is the Posner molecule’s structure symmetrical? And how isolated are the nuclear spins?

Most important, what if all those experiments ultimately prove his hypothesis wrong? It might be time to give up on the notion of quantum cognition altogether. “I believe that if phosphorus nuclear spin is not being used for quantum processing, then quantum mechanics is not operative in longtime scales in cognition,” Fisher said. “Ruling that out is important scientifically. It would be good for science to know.”

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  • First, what trouble did Penrose and Hameroff have with microtubules? You just said they had trouble but didn't explain why. In fact, Penrose and Hameroff predicted quantum vibrations in microtubules which has been confirmed by experiment. So I don't see any problems with Penrose and Hameroff and when you look at photosynthesis, it's microtubules that help transmit information to the reaction sites via a quantum walk which makes it more efficient.

    I think this is a good thing as well because if you ask me quantum consciousness is a no brainer. Nature has figured out how to shield coherence long enough to use things like quantum superposition to be more efficient. Why would this efficiency be prohibited from the human brain? The too wet and warm excuse went out the door with quantum biology.

    The brain seems to work on a classical and quantum level. I was reading a published paper that said true artificial intelligence will need quantum circuitry added so A.I. can do what's called a quantum walk. So A.I. will need a quantum aspect to try and mimic the human brain.

  • We have evolved FPGA chips that utilize the noise inside themselves. We have also found some classical theories as strange as quantum ones, in addition to finding some quantum ones much like chaotic others.

    The problem is that some of Bayesianism and randomness overlap. So determinism, objectivity, and dependence become a choice. The solution won't be all-or-nothing. Some mechanisms of olfaction use quantum properties, yet some aspects of psychology probably just have noise. Now which Markov processes are bootstrapped or emulated because a more interesting inquiry. Where are maps, references, reactions, and faithful mirrorings of the territory used and for what kind of real time contexts are we still learning shortcuts? We are cognitively lazy in automation, yet forever curious and exploratory to the point of neuroticism.

  • Tvery very importantant devopment in human history thank you for all hard wok done by concern ed scientist and supprting staff

  • Interesting idea. I talked to Matt a fair bit some time ago when he proposed it and would be curious to know if any progress has been made since as far as his intent to re-explore the older Li isotope work and further refine the mechanisms and any potential shortfalls of the Posner conception.
    Specifically, Fisher proposed that these VGLUTs have dual role first in taking up presumptive Posner molecules during brief exposures of the fusion pore during classical exocytosis, and then later operate much in reverse to express decomposed phosphorus into the larger presynaptic space.

  • The ability to live in coherent superpositions is a signature trait of quantum systems and constitutes an irreplaceable resource for quantum-enhanced technologies. However, decoherence effects usually destroy quantum superpositions. It has been recently predicted that, in a composite quantum system exposed to dephasing noise, quantum coherence in a transversal reference basis can stay protected for indefinite time. This can occur for a class of quantum states independently of the measure used to quantify coherence, and requires no control on the system during the dynamics. Here, such an invariant coherence phenomenon is observed experimentally in two different setups based on nuclear magnetic resonance at room temperature, realising an effective quantum simulator of two- and four-qubit spin systems. Our study further reveals a novel interplay between coherence and various forms of correlations, and highlights the natural resilience of quantum effects in complex systems.
    https://arxiv.org/pdf/1511.01971v3.pdf

  • This video contains an experiment with the qubit made from the phosphorus nucleus (and from the electron of the phosphorus atom in the first part of the video).
    https://www.youtube.com/watch?v=zNzzGgr2mhk&index=6&list=PLkahZjV5wKe_dajngssVLffaCh2gbq55_

    I am skeptical about the quantum computing in the brain, but I support the works on this topic. Roughly speaking, quantum information is unique: you cannot destroy it, you can teleport it, but you cannot clone it. The superposition of quantum states has a range from zero to fully entangled in the context of many measurements. The states are associated with the range of energies. The superposition speaks about the collective, correlated dynamics of the states in the context in which the energies of the states are defined. A thing or two on the unknowns: sometimes, physicists don't know what these particle really do from the mechanics perspective, but they have energy levels and fall to the lowest states. A correlated state may be additionally unstable (more dynamical). The description of that dynamics (the system as a whole) is so huge, that this amount of information cannot be used by itself. Finally, when an interaction occurs, randomness is combined with the states of particles, so you may not obtain any relevant calculation from the quantum computer. In addition, entanglement goes beyond the classical space and time, while this window into weirdness closes exponentially nonetheless.

    Maybe I piled up some facts at random and this makes no sense at all, so I apologize. I find the quantum information to be so special, to the extent that it looks entirely inconvenient for parallel computing in the brain (e.g. following a single sensory input, the information is branching in the brain and the response is ready in 0.3 seconds).

  • Microtubules are ubiquitous biological structures in most organisms with a variety of roles and are not at all mysterious and haven't been mysterious for many years prior to 1989.

  • Jay B.
    Totally agree. Penrose & Hameroff adressed all criticism in the decades since their theory came out.

  • A good time to re-read Tegmark's paper on the importance of quantum decoherence in brain processes http://journals.aps.org/pre/pdf/10.1103/PhysRevE.61.4194

  • That Tegmark paper is old and has been asnswered numerous times. It's a reason Tegmark hasn't updated this paper since 1999.

    "An unexpectedly long section in the paper is devoted to discussing the speed of decoherence at the level of neurons, which is not the basis for any of the main theories of quantum consciousness. However, Tegmark finally goes on to examine the more rellevant matter of decoherence on the scale of microtubules, which is central to the Penrose/Hameroff model. Tegmark arrived at a decoherence time of 10-13 seconds, which would be too short to be of use in neural processes. However, Tegmark assumed a model involving a superposition of solitons 24 nm apart, whereas Penrose/Hameroff are working on the basis of the much smaller separation of nuclei within the tubulin protein subunits of the microtubules. It remains a mystery as to why Tegmark selected a model that is not only different from the Penrose-Hameroff model, but does not resemble any of the principal modern quantum consciousness models. Whatever the reason, it certainly makes his particular calculation irrelevant, although it remains true that decoherence would obliterate quantum coherence, unless such coherence is shielded from the environment in some way."

    I think cytoplasm might have something to do with shielding coherence. Nature has figured out how to shield coherence in order to use quantum properties to be more efficient. I don't know why that sounds surprising at all. I think some object to a quantum mind because a quantum mind can open the door to things we label Psi because of entanglement and superposition.

  • Jennifer – It's so great to see you on Quanta! I have long followed your Twitter feed for science news and loved your work at Gizmodo. It was a great surprise to see you pop up on Quanta. Keep it up!
    Also, nice to see a return to articles focused on science/math rather than education on Quanta.

  • A Quantum brain , WOW ! I don't think evolution would have ever be able to produce such a complex computer, made of tissue . !!!! Think about a Quantum computer works , you talk about spooky action at a distance , it's happening in our heads ! I agree with the logic discussed in this article.

  • Lithium-7 is 17% more massive than Lithium-6: not exactly a 'slight' amount. Such a difference in mass will lead to different reaction rates, a phenomenon known as the 'kinetic isotope effect'. Generally speaking, the lighter isotope has a higher reaction rate than the heavier one. This is consistent with the observation that the rats fed the Lithium-6 appeared to be 'livelier'.

  • What a great article! Very exciting It will be momentous if it can be demonstrated that the Human brain has evolved to take advantage of some form of quantum computation. It will also provide the lie to folks like Ray Kurzweil, who believe that silicon computers will develop conciousness in the next twenty years or so. I really hope Matthews hypothesis works!

  • The claim of quantum effects in photosynthesis have been disproved. Quantum coherence in the most studied system where this was first claimed has been demonstrated to live for 100 femto seconds. Exactly as long as expected in a wet and dirty biological environment.

  • From a layperson's perspective, the question can be approached from a less technical perspective. The brain's evolution is clearly a product of adaptation to the environment. So, on what basis should QM not considered to be part of the natural environment? Why should the molecular components of a cell only adapt to the macro environment? Given the propensity for "life finds a way", the question becomes a matter of degree. Considering the complexity of biological systems, it would be more remarkable if it didn't evolve to include principles of QM. To argue that evolution has not adapted to these environmental realities, even as strange as they are, is simply wrong headed. Instead, the question should be turned around, let the physicist and philosophers explain their reason for the exclusion of QM from the principles of evolution. Why should a QM environment be excluded from the principles of evolution? It is easy to sick back and scoff at the hard work of others. Maybe they should provide empirical evidence for their views instead? It seems rather obvious that the objection is rooted in the fear of a reality that has "meta-physical" implications.

  • What intrigues me even more than this specific quantum mechanism in our wet brain, is the mechanism that makes some brain neurons entangled with molecules (structures?) of a remote object, which is being observed by this mind. I simply don't see this possible without rethinking the whole quantum theory.

  • The idea is to tag (or label) a set if molecules which later will propagate throughout the brain in order to transmit some information. If these molecules were tagged by binding with other molecules (i.e., just chemically), once these have propagated to different sites, any change in state of a single one will not affect the rest. And this is where QE (quantum entanglement) gets interesting, because if one of these changes its label, then the rest of the set also will change it, because of entanglement. There is no need for an explicit connection (axon, dendrite,APs code) to do that, what implies that QE would propagate any change in state immediately. Thus, different mechanisms can be switched on or off almost instantaneously (assuming a two state entangled system). This adds another dimension to information processing in the brain, certainly worthwhile to investigate, IMO.

  • Micocroscopic reversibility and isotope effects are well-known in physical organic Chen studies of reaction rates but usually study hasn't gone further beyond the "curtain" of a kind of 'macro' observation. It is significant that Fisher seems to have pushed aside the curtain to reveal a potentially new 'chemistry' that integrates 'macro' rate studies with quantum spin, entanglement and even a fresh insight into the mechanics of sub-macro conformal effects. Where this is leading to might eventually be a new way of 'quantum'-parsing thermodynamic entropy…is, entropy effects being macro-shadows of spin entanglement.

  • All this speculation about phosphate, pyrophosphate, and lithium would suggest to me that a look at phosphoinositide metabolism would be an interesting creek to drop a hook into. Particularly since Lithium seems to function via modulation of phosphoinositide metabolism.

  • What could be the evolutionary advantage to use some qubits? To run shors algorithm in order to factor integers into their primes?

  • It would be nice (and responsible) if there were some reference to or basis in biology or neuroscience for what are essentially unfounded, irrelevant, unnecessary, or just plain silly speculations.

    Calling on "quantum" effects is either trivial (all chemical reactions and molecular structures are based on the quantum mechanical properties of atoms – think about carbon's tendency to form four tetrahedrally organized bonds) or they are meant to conjure up some mystical (often actively anti-scientific and as far as one can tell unnecessary) forces at play.

    More to the point, there is no "theory" here, if by theory one means a set of tested explanatory and predictive ideas that address well established observations.

    The statement by Dave S. captures it all, there is nothing mysterious about microtubules. Similarly lithium acts by interacting with various molecules – in particular enzymes (kinases) involved in protein phosphorylation. A PubMed search for "lithium inhibition" yields over 2000 papers; many lithium-binding proteins play important roles in the brain [see https://www.ncbi.nlm.nih.gov/pubmed/?term=lithium+inhibition ]

    The complexity of lithium's effects arises from its effects on the dynamic interaction networks responsible for cell and neural system behaviors, a system which, in humans, involves billions of neurons and non-neuronal cells, connected by trillions of synapses.

  • why is important to keep coherence to explain quantum effects in the brain?
    why are quantum effects important to explain conciousness?

  • Fisher has ruled his unnecessary hypothesis out himself:

    "Experimental testing is precisely what Fisher is now trying to do. He just spent a sabbatical at Stanford University working with researchers there to replicate the 1986 study with pregnant rats. He acknowledged the preliminary results were disappointing, …"

    Besides that the Posner cluster doesn't seem to take his proposed interactions kindly:

    "Considering separated clusters, energy criteria favor the so-called Posner's cluster Ca9(PO4)6, which is the core of the actual structural model of amorphous calcium phosphate. This is rationalized through the existence of a distinct CaO bonding pattern in this cluster. Considering aggregated clusters as a possible model for amorphous calcium phosphate, the aggregation of Ca3(PO4)2 clusters appears as an alternative to Posner's hypothesis."

    [ https://www.ncbi.nlm.nih.gov/pubmed/11561898 ; from 2001, later that the article references.

    Moreover Fisher's proposed 'qubits' seems to be nothing of the kind. His paper describes a possible prolonging in the inherently stochastic operation of Na/K pores in neuron cell membranes. And similar to the quantum effect in antenna complexes, that seems reasonable since organisms are foremost biochemical machines and important phenotypes evolves on that substrate.

    Finally, re the (unrepeatable) 6/7Li experiment, isotope fractionation is common and especially in organisms. Lithium is especially known for substantial fractionation everywhere:

    "Lithium has two naturally-occurring stable isotopes, 6Li (7.5 %) and 7Li (92.5 %). Lithium isotopes fractionate substantially during a wide variety of natural processes, including mineral formation (chemical precipitation), <b>metabolism</b>, ion exchange (Li substitutes for Mg and Fe in octahedral sites in clay minerals, where 6Li is preferential over 7Li), hyperfiltration, and rock alteration (Morozova and Alferovskiy, 1974; Chan and Edmond, 1988; Fritz and Whitworth, 1994)."

    So while this could be something, the odds are really long at this time.

  • @Lazlo Z: "Penrose & Hameroff adressed all criticism in the decades since their theory came out."

    No, they haven't answered Tegmark's analysis what I know of, and I note you don't give references. As JayB cites on an irrelevant (and unreferenced) criticism of the use of Tegmark's toy model, the critics admit P&H idea wouldn't work (and indeed still has no observational evidence after 30 years): "it remains true that decoherence would obliterate quantum coherence, unless such coherence is shielded from the environment in some way."

    Really, need this be rehashed every time someone believes there is a possibility for quantum physics phenomena outside of chemistry being relevant for evolution in biochemical organisms? Selection happens on that substrate of functional biochemistry. Besides there being a minuscule likelihood for rare quantum phenomena being used and in the case of brain function no obvious difference between ancestral and derived neurons and their function, there is the continued lack of evidence. It should be easy enough to pay that up seeing the enthusiasm from some quarters that reminds of "the vague, insipid musings of a New Age guru." The usual order of science is first evidence, *then* back slaps.

  • Any workable theory of the physical basis of consciousness must account for the way small-molecule gases (the general anesthetics, CO2, NO2, etc.) can so dramatically interfere with it.

  • I'm not qualified to have an opinion on whether the specific proposed mechanisms are good suspects for some form of quantum processing in the brain but I am delighted someone is not only thinking about this but also proposing experiments which may get us closer to an answer.

    The sheer power of mind has been troubling me for a while. In the absence of supernatural explanations (which of course are exactly the opposite of explanations: sorry) I've wondered whether we're missing a trick, perhaps tempted into reductionist thinking and a therefore doomed attempt to map all 'mind' onto squishy biochemistry. My personal, inconsequential musings have fruitlessly circled the concept of compact extra dimensions as a candidate for the 'secret sauce'. Evolution, after all, has produced some extraordinary effects even at the microscale—right where some hypothesised compactification models of some string and brane theories could conceivably influence what we have heretofore regarded as 'merely' chemical interactions.

    But there's no explicit evidence for any such thing, nor even a good model for how this might work: and worse still, no apparent means of testing it—so it's fair to ask, what would be the point?

    For me, the point in a nutshell is that it took an extremely powerful computing system, with unfathomably complex deep learning algorithms, built from thousands of hours and millions of moves of 'training', just to get to the point of beating a human player at the game of Go. Now I do not mean to denigrate Go's intrinsic potential for great complexity, but still, just think about that: even in the absolutely restricted universe of a score¹ of simple rules confined within a domain of 361 loci, it takes the horsepower of over 1,200 CPUs and 170-plus GPU cores to beat a pint and a half of blue jelly.

    Every time we use our ever-growing, increasingly awesome computing power to compete with the human mind, we are left amazed by how powerful the mind is … and no closer to explaining how it does what it does. You might have thought that building 'smart' machines would have provided some insights into how the mind works: yet, strangely, that is not happening. It is surely reasonable to wonder whether all of the mind's extraordinary capability arises only from biochemistry, or if evolution has sprung another of her astonishing achievements on us.

    So this quote from the article (which may ultimately be correct in terms of fact) is dead wrong in terms of attitude:

    "'The evidence is building up that we can explain everything interesting about the mind in terms of interactions of neurons,' said Paul Thagard, a neurophilosopher at the University of Waterloo in Ontario, Canada, to New Scientist."

    That sounds glib, and possibly defensive, and it is absolutely no kind of reason not to do what scientists do: poke, prod, challenge—and keep looking. Even finding out that Matt Fisher's theory was completely wrong would still teach us plenty: so keep at it!

    ¹ Sure, it's arguable precisely how many rules Go has, but surely fair enough to say 'Not many, nor complicated'.

  • What if we all create our own reality through our thoughts, expectations, beliefs, intentions, desires, etc.?

    But we are all "entangled", connected in some deep way, so that our desires, intentions, beliefs, etc. interfere and exert force on each other's realities?

    This may be what makes the next state of reality chaotic, indeterminate, and probabilistic.

    Is reality some type of de-coherence, in which one unified, coherent reality is de-cohering and experiencing the inevitable conflict?

  • I think Fischer has explored something on the behavior of the brain whether his hypotheses is true or not, it points out an idea of quantum mechanics of either Posner molecules or other molecules that are relevant in brain functioning.

  • @Torbjorn L – Consciousness in the universe: A review of the ‘Orch OR’ theory
    http://www.sciencedirect.com/science/article/pii/S1571064513001188

    See section 5.6 – Orch OR criticisms and responses

  • I read the ideas in the comments and again, I find them in conflict with other articles, roughly speaking. 1. The entanglement does not represent the means of communication at any distance. This is not the way to promote the idea of a common information space. 2. Even if you consider the "space" that the entangled ensemble captures, it escapes the boundaries of common space and time, so the phenomenon cannot be quite matched with the shape and function of the brain. 3. The presence of fully entangled qubits, would imply that the qubits contain a lot of information like a closed-off memory device. The information is humongous, so the 300 qubits could encode enough information to fill the universe. 4. The quantum theory is considered in a gimmicky fashion. It is a limited theory that considers particles in certain situations. A particle can transform into another particle or collide with another particle… and all these are accounted for by the quantum field theory. People consider a limited view, while the particle states are being "interrupted" everywhere. 5. The quantum information is analogous to the zero-energy entropy. It is a conserved quantity, similar to energy. You can't heat up or cool down the universe, hence it's a kind of a constant. The living beings process information classically – by using fuel and seemingly going against the entropy (by making order). 6. A quantum information network would be easier to make, experiments show, because you just need single polarized photons in a fiber-optics network (as in https://arxiv.org/ftp/arxiv/papers/1203/1203.4940.pdf). However, an analogous photon would need to go from the eyes to the brain and clone its quantum information encoded in the qubit polarization across all the boundaries at which it transforms into other forms of energy (a "digital" temporally-encoded signal = spike train, because the photons modulate the inhibitory neurons in retina, before an electrical signal is created). Also, something would need to prepare any information and encode it in the qubit states specifically.

    It is still good to study living beings, because everything of value is found there. Maybe Matthew Fisher wanted to get the hunch for the information that the biomolecules contain. There is some kind of motion that the molecules perform, which no one noticed probably. There would be a quantum field theory for this, but this news magazine is telling me that QFT is too difficult for anyone to handle. 🙂

  • I wonder if it would be informative to influence the spin states of phosphorus externally to see if that affects brain function. If you were to tune a MRI to the resonance frequency of P-31 you could “flip” the phosphorus spin states, perhaps even target specific areas of the brain. You might even be able to image the phosphorus in the brain if there is enough sensitivity to do so. Just a humble old organic chemist putting in a half baked idea, so go easy on me!

  • Studies of 31P MRI (MRS) imaging have already been done:

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4029084/

  • In light of recent studies which use magnetic fields to activate 'trace memories' there must be a correlation to the quantum.

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