Gaaa…stop chattering on the Sean Henry thread! I set that up as a finely focused exercise in politely discussing his criticism of evolution, not for all that ongoing discussion about whether this is good or bad or complaining at each other about whether your answer is appropriate or chatting about how old he is. About 50% of the replies in that thread have been tossed out because you aren’t paying attention.
So talk about all that meta stuff here, not there, and stop cluttering up the thread, OK?
Except for you, Charlie Wagner. You’ve finally worn out your welcome. Goodbye, and good riddance—for spamming over 20 times, for whining that you have some sort of right to post here, for being an obnoxious, obtuse jerk, you’re finally banned from this site for good.
Or disemvoweled.
Oh, good, I don’t have to scroll past all of Charlie’s stuff anymore. Yeesh.
Digital Darwinism: Evolution for undergraduates
>Really?
get help
Don’t feed the ID troll. Banning means get lost. Scram. Beat it.
I’m really curious who exactly has filled Sean’s head with the anti-evolution crap.
He has a lot of siblings so I would doubt there’s a very dominating patriarch.
You would have to be with that many kids.
I wonder if he goes to a reilgious school. Do they have homeschooling where he’s from?
The journal Nature goes “meta”
EMBO reports 7, 10, 971-974 (2006)
doi:10.1038/sj.embor.7400802
A quantum leap in biology. One inscrutable field helps another, as quantum physics unravels consciousness
Philip Hunter
The most esoteric research field in the natural sciences is probably quantum physics. Despite the fact that Werner Heisenberg first proposed its central concepts nearly 80 years ago, it continues to baffle physicists and to cause headaches among non-physicists. Even Albert Einstein was unwilling to accept the central tenet that everything is just a matter of possibilities; he famously dismissed Heisenberg’s ideas by asserting that “God does not throw dice.” As quantum physics seems too mystical to be relevant to anything as real as a living organism, it might come as a surprise that its first applications have arrived in biology, rather than physics.
The seeds of contemporary quantum biology were sown as early as 1930, a mere three years after Heisenberg postulated his uncertainty principle describing the inability to measure related quantities exactly (see sidebar). At that time, Erich Hückel, a German chemist and physicist, developed simplified methods based on quantum mechanics (QM) for analysing the structure of unsaturated organic molecules, in particular to explain the state of electrons in aromatic compounds. But Hückel was too far ahead of his time, and his concepts went almost completely unrecognized until the 1950s, when the arrival of computers made it possible to perform more detailed calculations. It was not until the 1990s, however, that the field of quantum biology became established with the development of density functional theory (DFT), which allows accurate calculations of electronic structure (see sidebar). By that time, high-resolution structures of protein complexes obtained using X-ray crystallography and nuclear magnetic resonance produced sufficiently accurate descriptions of crucial molecules for QM methods to unravel the details of key reactions, such as ATP hydrolysis.
The seeds of contemporary quantum biology were sown as early as 1930, a mere three years after Heisenberg postulated his uncertainty principle…
A Background in Physics
In the early nineteenth century, physics faced a crisis, as researchers made a number of observations on the behaviour of single photons and electrons that could not be explained by Newton’s laws of mechanics. In 1926, the German physicist Werner Heisenberg finally solved these problems with his famous uncertainty principle, which has formed the cornerstone of quantum mechanics (QM) ever since. According to this principle, it is impossible to measure exactly all of a particle’s quantities (such as mass, energy, position or momentum), simply because they do not have absolutely fixed values. Instead, they have a range of possible values within a probability distribution, but at normal space and timescales this range is relatively small. In everyday life, it is therefore possible to make exact measurements limited only by the sensitivity of the equipment. However, at small space and timescales, such as those that operate at the submolecular level, the impact of the uncertainty becomes much greater.
If, for example, researchers wanted to predict the location of a particle at a given time, they would measure its current position and its rate of change in position expressed as its momentum. The uncertainty principle states that the more accurately researchers determine one of these quantities, the less accurately they will know the other, which imposes a deterministic limitation on the accuracy of prediction. This uncertainty becomes significant not only within small spatial dimensions, but also at short time intervals. This is relevant for biology, given that many processes at the molecular level occur over short timescales. For example, the operation of molecular motors is coupled to a chemical reaction that occurs over a few femtoseconds.
Explaining enzymatic reactions requires the analysis of quantum effects because the core processes usually take place just one molecule at a time and are not bulk chemical reactions in a test tube. As such, they rely on the precise alignment of molecules, for example, when water molecules are split by the catalytic actions of four manganese ions and one calcium ion in photosynthesis. The electrons involved govern the resulting molecular interactions, and QM can be used to resolve their energies and, thus, the outcome. Similarly, photoreception involves the excitation of orbital electrons, and calculating the resulting energy change requires QM.
The uncertainty principle is applied to such problems by determining the energy levels of atoms or molecules using the wave equation, which was developed by the Austrian physicist Erwin Schrödinger. It encapsulates the uncertainty in any system as the probability of finding a given particle at a particular place. Schrödinger’s equation is relevant for all chemical reactions or any interactions involving electrons, which can be described as an electromagnetic wave owing to the uncertainty of their position. When one electron interacts with another, such as in a chemical reaction, the waveform is said to collapse, as the electron assumes a definite position.
Density functional theory (DFT) replaces the individual electrons of a system, such as a molecule, with a single electronic density function to represent both the aggregate charge and the interactions between individual electrons. This means that the algorithm considers only three spatial dimensions when analysing quantum-level interactions between systems, irrespective of the number of electrons involved. Before DFT was first used in the 1990s, every electron had to be considered separately, restricting quantum-level analysis to the smallest interactions involving only a few atoms.
The Penrose-Hameroff model of consciousness uses the effect of quantum tunnelling to explain how several hundred neurons are able to simultaneously coordinate their firing rate. Quantum tunnelling exploits uncertainty about the position of an electron–with a high probability, it is near its atomic nucleus but it might also be at the far end of the galaxy, albeit with a much lower probability. By exploiting the uncertainty inherent in its wave nature, the electron appears to jump from one position on its probability wave to another, and seemingly hops over, or tunnels through, obstacles such as an atomic nucleus.
QM has also made a significant impact on the study of photoreception and the detection of colour, on research into the sensing of magnetic location and directional information by migratory birds, and, most controversially, in understanding the processes underlying consciousness. The last example relies on certain unprovable assumptions about the scientific basis of perception, whereas research on catalytic reaction centres (such as analysing substrate binding) hinges on solving the Schrödinger wave equation. Described in 1926, and central to the theory of QM, this equation describes the probability that a given electron is in a particular location at a certain time (see sidebar). Such QM-based applications calculate the sequence of events at the atomic level by analysing the electronic properties during the formation and breakage of chemical bonds or the orientation of electron orbitals, as determined by their quantum wave function.
The validity of QM methods is not seriously disputed, but their high computational intensity precluded their use until the 1990s. Although computers had been used to simulate the function of proteins and their chemical reactions since the mid-1960s, these calculations were based on molecular mechanics (MM) techniques derived from Newton’s laws of motion. These operate at the level of molecules rather than electrons, and describe the energy and forces associated with particular protein structures, by studying simpler model compounds that mimic the chemical groups in the constituent amino acids and other components.
The weakness of MM methods is that they rely on making simple assumptions. For example, electrons are not considered directly, but are assumed to be in an optimum position determined by the location of their atomic nuclei. This process, based on the Born-Oppenheimer approximation of the Schrödinger equation, treats a complex molecule like an assembly of weights connected by springs. Therefore, when the MM algorithm calculates the energy required to stretch or compress a chemical bond, it applies a formula similar to Hooke’s law of elastic springs under tension.
This works reasonably well for determining the geometry and total enthalpy of a molecule in isolation, but fails to describe reactions that involve binding or recognition in solution, as occurs in most crucial reactions in biology. Most reactions in nature involve bond formation and breakage, with associated changes in electron organization that cannot be described accurately by classical mechanics because of the uncertainties involved. Similarly, reactions involving docking or molecular recognition in solution require the calculation of polarization effects –how molecules orientate themselves as they approach each other–which are determined by the behaviour of their orbitals.
Whenever electrons and their associated energies need to be considered explicitly, QM steps in. The same is true for studying reactions that involve the recognition of light (such as in the retina) or stimulation by light (as in photosynthesis), because these processes involve the excitation of electrons. QM methods, which are often described as ab initio because they work from first principles without using empirical techniques, also reveal the dynamics of reactions as they are taking place. They make it possible to determine and analyse intermediates, such as radicals and oxidation states of metal ions, that exist transiently before the finished products of the reaction are formed.
Rapidly increasing computational power combined with new methods, notably DFT to simplify calculations, makes it possible to apply QM methods to analyse enzymatic reactions. Before scientists began to use DFT widely in the 1990s, every electron in a system being analysed using QM had to be dealt with separately in each of the three spatial dimensions, whereas DFT combines all electrons into a single density function. For a system with N electrons this reduces the number of variables from 3N to 3, without, in principle, introducing any approximations.
Rapidly increasing computational power combined with new methods … makes it possible to apply QM methods to analyse enzymatic reactions
Although DFT greatly reduces the degrees of freedom, QM calculations are still so computationally intensive that, even with contemporary supercomputers or computing grids, only a small number of atoms can be analysed at one time; the current maximum is around 100. Even more restrictive is the limit on the time-span of the simulation, according to Paolo Carloni, a professor at the International School for Advanced Studies in Trieste, Italy, who specializes in ab initio and MM simulations. “First-principle calculations of a system of, say, 100 atoms-can cover up to a few tens of picoseconds,” he said. However, most processes involving quantum effects occur over a much longer timescale, with many enzymatic reactions taking several milliseconds, for example. Researchers use statistical methods to extend the time range of QM methods, but this inevitably introduces errors.
…QM calculations are still so computationally intensive that even with contemporary supercomputers or computing grids, only a small number of atoms can be analysed at one time…
There has been considerable success combining QM with traditional MM techniques to circumvent the limited scaling of the former. Such hybrid methods are now widely deployed in the study of enzyme reactions. The crucial part of the system under study (such as the active site of an enzyme complex or a molecule in solution) is analysed using QM methods, whereas the energy and forces for the remainder (such as the non-reacting part of a protein complex or the solvent molecules) are calculated using the traditional MM model. The idea is to use MM approximations for those parts that are sufficiently far removed from the active reaction area so as not to contribute significantly to the overall system.
Inevitably, hybrid QM/MM methods represent a compromise, and so require judicious application if they are to be sufficiently accurate. “I would say that the reliability of any QM/MM simulation strongly depends on the skills and thoroughness of the researcher doing the work, particularly during the planning/testing phase of the simulations,” said Markus Dittrich from the University of Illinois at Urbana-Champaign, USA, who applies such methods to analyse ATP hydrolysis. “Once all the necessary steps have been taken, QM/MM simulations can give meaningful qualitative results, in some cases even quantitative ones, at least in my opinion.” However, this requires significant testing and benchmarking for each system, as well as describing the QM/MM interface and the size of the part treated with the high-precision QM methods, according to Dittrich.
Still, even hybrid methods require enormous computation power to analyse many biological structures and interactions, because of the large range of spatial dimensions and timescales involved. For example, molecular motor proteins coordinate chemical reactions over a few femtoseconds with mechanical motions taking place over microseconds or even milliseconds. Similarly, distances range from bond breaking in the catalytic binding site in a single angstrom to structural changes during molecular motion that span up to 10 nm.
No single computational approach can calculate over such ranges of time and distance; however, combining QM/MM with other classical techniques to focus on a small number of crucial variables has proved successful. Klaus Schulten and colleagues at the University of Illinois at Urbana-Champaign integrated a variety of methods, including QM/MM and molecular dynamics, to obtain new insights into the mechanism of the PcrA helicase molecular motor, which unwinds double-stranded DNA. PcrA uses the energy from ATP hydrolysis to skip along a single strand of DNA, one base pair at a time.
Schulten’s breakthrough lay in determining the link between the mechanical motion and the binding and unbinding of PcrA with ATP as it skips along the DNA (Yu et al, 2006). This link is mediated by a two-way conformational change in the protein. “When the protein binds, one part of the structure is a bit loose, and then the reverse happens when it unbinds,” said Schulten. This sequence of flexing allows the protein to traverse the DNA.
As protein motors go, PcrA helicase is relatively simple, as it moves in a linear direction. Other motors involve more complex rotary motion. One of the best known and most sophisticated examples is the combination of Fo and F1 motors that work in tandem to synthesize or hydrolyse ATP. These motors convert energy between the two forms in which it is stored in cells: as a transmembrane electrochemical gradient or in a chemical bond, such as the gamma phosphate bond in ATP. Fo and F1 act reversibly, with the former using the transmembrane electrochemical gradient to generate a rotary torque to drive ATP synthesis in the latter. The system can operate in reverse when F1 hydrolyses ATP instead of producing it, generating torque that can then be harnessed by Fo to pump ions ‘uphill’ against their transmembrane electrochemical gradient. As Schulten noted, this complex motion has yet to be fully explained, but the work on PcrA helicase will provide some clues. “When you look at the binding sites of ATPase and PcrA, you see that they are the carbon image of each other,” said Schulten.
Another fundamental process that has benefited from the use of QM is photoreception. For years, researchers have been puzzled by how some animals, particularly migratory birds, use their retinal receptors not only for normal vision, but also to ‘see’ longer distances by measuring the direction and strength of the Earth’s geomagnetic field. QM theories have been used to describe two mechanisms for this magnetoreception: the radical-pair mechanism and the magnetite-based mechanism. Originally believed to be competing, the two explanations have since been found to be complementary.
In the radical-pair mechanism, a light-induced electron transfer in photopigments in a receptor in the eye creates a pair of excited electrons with a particular magnetic orientation or quantum spin state. The Earth’s magnetic field affects the transition between these spin states, thus altering how the bird perceives colours. These radical-pair receptors amplify the Earth’s weak magnetic signal using magnetic resonance, thus allowing the bird to detect it.
Under the magnetite-based mechanism, the Earth’s field exerts a mechanical force on magnetite particles in the upper beaks of migrating birds. An increasing number of researchers now believe that the radical-pair mechanism provides directional information that is comparable to that from a magnetic compass, whereas the magnetite-based mechanism provides positional information as it measures the strength of the signal, which varies with location (Wiltschko & Wiltschko, 2006). However, further work will be needed to elucidate fully how the brain reconciles and processes information from the two magnetic sources alongside normal vision.
The debate over magnetoreception might not be settled, but there is broad agreement over the applicability of QM to this field. What is still disputed is its application to the study of consciousness. QM has always been inextricably linked to consciousness, given the vital role of the observer in making measurements and defining events, and consciousness itself can be explained with reference to QM according to a number of researchers. “It seems that consciousness operates very well in the classical realm,” said Koichiro Matsuno, a professor in the Department of Bioengineering at Nagaoka University of Technology in Japan, and a leader in the QM field. “But one serious question would arise at this point. That is, how could one guarantee the robustness of such seemingly classical phenomena including our brain activities.”
QM has always been inextricably linked to consciousness, given the vital role of the observer in making measurements and defining events, and consciousness itself can be explained with reference to QM…
The most celebrated theory of quantum consciousness–linking events at the sub-atomic level with our perception of consciousness–was developed by the British mathematician and physicist Roger Penrose, and by Max Hameroff, a physician at the University of Arizona Medical Center in Tucson, USA (Hameroff & Penrose, 1996). In the quantum world, matter exists only as a set of possibilities. ‘Reality’ emerges when the Schrödinger equation used to describe these possibilities ‘collapses’–or moves from a probability wave form to a fixed state–which translates into a classical event, obeying rules such as Newton’s laws of motion.
According to the Penrose-Hameroff model, such quantum states of infinite possibilities exist in the tubulin subunits of microtubules in brain neurons and glia cells, in which they are isolated from their environment to prevent them from collapsing as a result of interacting with each other. Furthermore, the proteins and their associated quantum states are linked through quantum tunnelling, which allows particles to overcome energy and space-time barriers. Consciousness then occurs whenever a series of quantum states connected across neurons can no longer be preserved, and interact to yield a signal that the brain can recognize and respond to. This model explains the observation that consciousness seems to involve the simultaneous coordination of multiple neuronal signals.
The Penrose-Hameroff model has attracted criticism. Max Tegmark, an astrophysicist at the Massachusetts Institute of Technology in Boston, USA, suggested that the model could not work as the brain is simply too warm for quantum effects to occur (Tegmark, 2000). However, like Matsuno, Hameroff insists that no classical theory of consciousness has stood up to scrutiny. “Classical theories based on complexity, emergence, and so forth, have yet to make any testable predictions, and are not, as far as I can tell, falsifiable,” he said. “Thus, although we are often criticized, we have a theory and our critics do not”–at least, that is, no theory that can be proved or disproved.
Hameroff has further attempted to define the relationship between complexity and consciousness, given that the phenomenon did not exist at the beginning of evolution and must have emerged at some point, either gradually or abruptly. His explanation depends to some extent on the Penrose-Hameroff theory, and posits that consciousness arises at the boundary between classical states–events, such as neural signals, which can be recognized or processed as information–and the underlying quantum processes that generated them. On this basis, the threshold of complexity for consciousness was passed 540 million years ago in small worms, such as nematodes. Their neuronal network was sufficient to create quantum tunnel effects involving 100-1,000 neurons, which Hameroff considers enough to generate a single conscious event. This single event was defined by Libet et al. (1991) to have a pre-conscious time of 500 ms–the time between the formation of a new waveform and its subsequent collapse. The basis for magnetoperception might have evolved even earlier, given that plants and animals have been shown to suffer when shielded from the Earth’s magnetic field (Galland & Pazur, 2005).
Although the debate on the role of QM in consciousness persists, quantum physics has nevertheless made inroads into biology, and will further help biologists to understand other phenomena and mechanisms. If QM is the basis of reality, as some researchers believe, it should come as no surprise that it is intimately involved in all kinds of biological processes, even sensation and cognition.
References
Galland P , Pazur A (2005) Magnetoreception in plants. J Plant Res 118: 371-389 | Article | PubMed |
Hameroff SR , Penrose R (1996) Orchestrated reduction of quantum coherence in brain microtubules: a model for consciousness. In Hameroff SR, Kaszniak AW, Scott AC (eds) Toward a Science of Consciousness: The First Tucson Discussions and Debates, pp 507-540. Cambridge, Massachusetts, USA: MIT Press
Libet B , Pearl DK , Morledge DE , Gleason CA , Hosobuchi Y , Barbaro NM (1991) Control of the transition from sensory detection to sensory awareness in man by the duration of a thalamic stimulus. The cerebral ‘time-on’ factor. Brain 114: 1731-1757 | PubMed |
Tegmark M (2000) Importance of quantum decoherence in brain processes. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 61: 4194-4206 | PubMed | ChemPort |
Wiltschko R , Wiltschko W (2006) Magnetoreception. Bioessays 28: 157-168 | Article | PubMed | ChemPort |
Yu J , Ha T , Schulten K (2006) Structure-based model of the stepping motor of PcrA helicase. Biophys J (published online) doi:10.1529/biophysj.106.088203 | Article |
PZ: Excellent idea to have a meta-thread, thanks!
Quork: Dang! Nice! Lunchtime reading for me…
Charlie: Puppeting is reprehensible and destroys what respect I had left for you (and I did have some.) Bow out now and salvage at least a little of it. Not that I suppose you care what I think of you.
As for Wagner, quoting Nanci Griffith lyrics in support of his obtuseness ought to have been enough to ban the guy some time ago.
You won’t mind at all if I bust down your door and come into your house, right? Will you make some tea in advance?
(What part of “You are not welcome here.” is so hard to understand?)
Nice one, Drew – why not just copy and paste the entire woo portion of the internet into one damn comment next time?
He’s like that annoying guy that keeps trying to talk to you while you’re reading a book at a Cafe or in the park.
No one respects you. You don’t deserve it.
I thought you were going to sign every post.
Putz from Hawaii, sounds appropriate.
I think drew has earned the nickname dwoo now.
Yes you do. The childish whining that followed that sentence is evidence of that.
And apparently mentioning “onoxious spammers”, attracted hempel again.
I don’t need help. I need respect.
if you think behavior like this is going to do anything to increase anybody’s respect for you, you need more help than i suspected.
/yawn
I’m sorry — it’s not the journal Nature exactly — just their website. The source for quantum biology and consciousness — Oct. 2006: the European Molecular Biology Organization — definite WOO territory
Hempel, you do know the difference between an opinion piece (like the one you posted fully, violating NPG’ copyright, probably) and a scientific paper, right? Right?
dwoo, just post links. They’re easier to ignore. Eating up that much post space is obnoxious.
Quantum is simply the new electricity, magnetism, radioactivity, etc, etc, etc… Every time we discover something new a whole bunch of chancers and weirdos tries to hide in this new field. Because it is all unproven everything is possible bla bla bla….
Oooh! A prediction from ID!!!
http://www.uncommondescent.com/archives/1839
In a nutshell: “If science can’t prove exactly how life started, then ID is true.”
Ha! And if you’re weak in the stomach, don’t read the comments.
Dr. Myers, care to comment on this bold prediction? :)
There’s a damn good reason we don’t have a “classical theory of consciousness”, and that’s because “consciousness” is such an ill-defined concept that one cannot even specify what one is trying to explain. Might as well complain about our lacking a “classical theory of metaphor,” a “classical theory of beauty” or “a classical theory of why the Beatles rock”.
What we do have is a flourishing field of neuroscience. With models like “dendritic computation”, we can explain why neurons do the things they do in the circumstances where they find themselves — at least in many cases. And guess what? These models are fundamentally classical in nature.
People have done fascinating research on the barn owl and its ability to find prey via auditory location. Masakazu Konishi and his colleagues discovered that neurons in the barn owl’s inferior colliculus act as AND gates, firing only when they receive simultaneous inputs on two different channels. Does this marvelous evolutionary example of coincidence detection require a quantum mechanism?
No.
Obviously, coincidence detection is not “consciousness”. To explain any of the human abilities which the word consciousness so fuzzily embraces, we’ll need a great deal more understanding of how neurons work in combination. Nevertheless, we have been able to find instances where an animal’s brain needs to do a specific task, and we can identify the neural structure which performs this task. Studying these structures at the level of neurons and even parts of neurons — axons, dendrites — we have never found a place where quantum theory is necessary to understand the result.
Never.
Nerve cells — like all other material objects — are built out fundamental particles which obey quantum-mechanical rules. But a puzzling feature of quantum mechanics comes into play: when we assemble a large amount of quantum particles, the aggregate no longer behaves in an obviously quantum way. This is different from the older, Newtonian mechanics, in which a pile of classical rocks can stick together to make a classical planet. Unlike the laws of Newtonian physics, the quantum laws do not reproduce themselves at higher scales.
What causes this odd dissimilarity, and at what scale does it become relevant? Well, that’s the domain of quantum decoherence. It’s not a philosophical question anymore, but one which we answer using experiments and equations.
Tegmark showed that decoherence makes the specific quantum-brain model proposed by Penrose and Hameroff quite implausible. Later calculations have not significantly changed this result, and as Tegmark has justly pointed out, nothing in our observations of the brain makes quantum theory necessary. Large-scale correlations at a distance are familiar features of classical physics. Quoting his lucid paper on the subject,
Penrose’s claims about some kind of super-classical computation being necessary to do the types of reasoning our brains can do have also been debunked.
The “quantum mind” is bad physics and bad neuroscience but an excellent fuel for woo.
Drew –
It should not come as a surprise to most, that biological structures rely on quantum mechanics in some manner, since they are made of molecules which are quantum mechanical objects. Therefore, it is interesting to pontificate on whether the finer structures of the brain (proteins, etc.) can take advantage of the properties of quantum objects (e.g. molecules) in order to create consciousness. Some of the ideas of Hameroff et al. are kind of “cool,” because they begin to look at whether or not this is possible.
Still, in the end, they are still just interesting ideas. Maybe in the future we will be able to manipulate proteins in vivo down to the nano-scale necessary to begin looking for the ramifications of these predictions, but until then, they are what is commonly known (around here) as Woo.
Still, pretty cool though. :)
I have to add, however, that none of this crap has anything to do with an all-encompassing God field or whatever (see Chopra), which is usually the topic at hand when we find you pulling this stuff out and shoving it in people’s faces like it means something. Trust me, that will never get a warm response here, as it doesn’t have shit to do with actual science.
For more details on the Penrose angle, see “Penrose’s Gödelian Argument” (1995) by Solomon Feferman.
In _Shadows of the Mind_ , Penrose and Hameroff argued that everything which had microtubules had a kind of non-deterministic consciousness. Now Penrose and Hameroff argue that everything which has chemical reactions has non-deterministic consciousness. Folks, when you are drunk, and staring into the fire, and it seems to be talking to you, it may not be talking to you, but it is thinking about you.
We all like to make fun of ‘Dr.’ Chopra, but Penrose has taught us that he, a top-echelon physicist was taken to the cleaners by Deepak’s ilk, and bilked so thoroughly he came back without any clothes.
It’s his blog he doesn’t have to respect you or listen to your crap.
No one else cares.
Shove off.
It’s not God’s earth. It’s ours.
“As quantum physics seems too mystical to be relevant to anything as real as a living organism, it might come as a surprise that its first applications have arrived in biology, rather than physics.”
Well, this is just patently false. Quantum physics has found more than a few applications in electrical engineering, particularly in the field of semiconductors. Hell, semiconductors make virtually no sense at all without at least some basic concepts from quantum physics. And that says nothing of the cutting edge of the field, where elements are small enough — unlike in the brain, I should point out — that quantum effects actually become important.
The very first sentence of that long, mostly worthless opinion piece which D. H. quoted calls quantum mechanics the “most esoteric research field in the natural sciences”. It’s not. Rule of thumb: anything which is mentioned in a high-school chemistry class is not esoteric. Difficult to understand, perhaps. . . but half the problem the layman faces is getting through the thicket of woo to reach the actual science! If you had no prior information, and you visited your friendly local Barnes and Borders-A-Million to buy a science book, would you be any more likely to pick up Richard Feynman’s QED than, say, Deepak Chopra’s Ageless Body, Timeless Mind?
There is one other person I know of who persists on getting around killfiles (can’t ban in this case) even though he is not welcome, and has not been for longer than most people have been online.
Daniel Min – do you really want to associate yourself with him? ;)
(Min also happens to be a rabid creationist, when he’s not failing to predict the end of the world.)
Penrose’s model is a solution looking for a problem. Perhaps if ordinary biological processes were actually inadequate, we might sneak a glance at the oddities of quantum physics.
Neuroscience hasn’t really run into such big gaping holes where mechanics, chemistry and electromagnetism cannot tread, though.
He’s a smart man, as evidenced by some of his other writing (the quantum physics book Road to Reality in particular), but biology is not his forté. Hawking, too, succumbs to weird beliefs about biology, like one of his quotes in Universe in a Nutshell, “I think that the human race, and its DNA, will increase in complexity quite rapidly.”, as though increasing the complexity of our DNA is somehow the way, and the only way, for humans to get smarter.
…
Now, if only I could sense the disturbance in the force when poor Sean comes back to the oodles of messages. There didn’t seem to be that many messages before mine when I started posting. I might have cut back a little if I knew everyone was up that late and/or was in Europe :)
I hope he receives the messages well. I had a pretty good exchange with someone with the handle “high school student” once upon a time on the Sounding The Trumpet blog. They sure knew more than when they started; it was pretty productive, and he had started out basically citing the entire creationist handbook as well.
Re: the ID prediction (Jeebus),
I love how their “prediction” could also be caused by forgetting to flip a switch or something. Nice to know they have such a high opinion of their Go–excuse me, Intelligent Designer.
As a pretty sound rule of thumb, think “woo” if you read “quantum blah blah” and it’s written by:
1) A non-physicist.
2) A physicist talking about any subject other than physics.
Erm …
Lasers are, at least in part, QM machines.
They are certainly not driven by “classical” physics.
And there is a laser in every CD drive in everybody’s computer.
A very parctical application.
That’s why it is called Quantum MECHANICS.
You may not be able to understand the “philosophical” implications, but it makes some very specific, testable, reliable predictions.
Charlie- you are officially a mental case. What you think you’re “winning”, I can’t imagine. Very, very sad.
I do understand. You fancy yourself some kind of Internet gang-banger and you feel dissed. As I said, very, very sad.
Damn, that disemvowling really gets to me! I enjoy reading the ridiculous creationist comments, and I don’t have the energy to piece them together after they’ve been eviscerated. :)
You know, respect has to be earned, not demanded. Acting like a petulant child because people do not behave exactly as you insist they must is not a good way to earn that respect.
The more you post, insisting that PZ respect you, the less likely he is to do so.
I know I respect you less than I did at the top of this thread.
The respectable thing to do would be to understand that PZ does not wish to converse with you, and respect his desires on this point.
It’s his blog, and his call who is welcome on it. And you are a disgusting, pathetic little moron.
Sorry, got a little angry there. It would be appropriate to delete my responses as well as the now-deleted comments they responded to.
Certainly, and quantum mechanics does make very testable predictions in the case of lasers, and indeed many parts of optics.
What the quantum “woo” masters rely on for their explanations of consciousness, however, is not the wonderful predictable parts that give us coherent light, but throwing around the more ‘mystical’ parts, like the Heisenberg Uncertainty Principle, superposition and entanglement, where the former certainly is vastly overshadowed by the chaos of plain old thermal effects, and the latter two decohere pretty quickly with isolated quantum objects, never mind the billions of atoms that they would interact with in a biological system :)
[snark]
Wrong on both ends! Well, no one can say he’s not consistent. I leave it to you, Gentle Reader, to ponder the implications of such consistency. Did I just hear someone say something about a hobgoblin? Or were you just thinking it very loudly?
[/snark]
Steve LeBonne: I believe your insight re: ‘quantum’ pronouncements is dead-on. In fact, it’s something of a quantum leap in terms of analysis of ‘pop’ science….but I see that I am making your point.
Seriously, though, your litmus test is dead-on. If I had a dollar for every piece of nonsense I’ve heard that follows the word ‘quantum’, I could buy a cat and stick ’em in a box with some cyanide, etc.
Cheers…SH
Did Charlie Wagner just post as “Mimi Farina”?
And how do you intend to enforce that ban?
Oh, I know: swallow your pride and ask me nicely? It just might work! Or you could just continue to delete my messages
as fast as I post them.- Charlie Wagner
I suppose an IP Ban will have to do. There are ways around that too, but you’ll just keep getting deleted. Is it really that amusing to keep posting here, when you’re really just showing how childish you are?
Ah! You’ve got me pegged. I’m really a 17 year old trapped in a 62 year old body. That’s what the drugs are for ;-)
then why did you stop taking them?
admitting your insanity is only the first step on the road to recovery, CW.
…you should apply as a volunteer for the Dawkins Institute as a representative sample to study how underlying psychological malfunction produces science deniers such as yourself.
seriously, I bet they would be interested in including you in a study or two.
If I had a dollar for every piece of nonsense I’ve heard that follows the word ‘quantum’, I could buy a cat and stick ’em in a box with some cyanide, etc.
Heh. Bravo, as well as to S. LaBonne.
The term I’m fond of is ‘quantum quackery’. Just for the alliteration.
My own explanation of the phenomenon is, roughly:
1. Quantum physics is something which is generally poorly understood by the average layman…
2. And generally somewhat difficult to explain…
3. But the average layman tends to know it’s fundamental science…
3. And they tend to know it’s newish science…
4. Thus quacks pushing woo readily fasten upon it as a useful tool. Because:
4a. They know they can generally safely say ‘fascinating new discoveries in the field of quantum physics are further proof of my woo’… and generally not fear being caught outright, since it is unlikely there’s anyone in shouting distance who knows a lot of quantum physics, or, for that matter, what might be going on in the field…
4b. Better still, even if someone who does know quantum physics fairly well is in the room, they’re going to have an uphill climb just explaining it to the rest of the room, to get far enough to where they can demonstrate said quack is a quack.
Anyway: I would therefore like to propose that the appropriate response to all quantum quackery should be: ‘Well, look what Schrödinger’s cat dragged in…’
… or not.
But,but … I have come to *expect* the Wagnerian Inquisition!
Oh, well then. I always suspected there was a low streak in his character. At times he seemed like he had floated here from some other world, with behavior frontloaded sometime in the indefinite past.
…
As may be noticeable elsewhere I’m quite tired of consciousness models floated around who are like that; quantum, electrical, what have you. Debunked or not, it is not as if studying the biological systems themselves have failed yet.
Blake made an excellent job on the quantum woo side. There are also positive findings. Abstract thinking is part of consciousness, and there are now biologically based models for symbolic thinking:
“In this article from the Proceedings of the National Academy, Rougier et al. demonstrate how a specific network architecture – modeled loosely on what is known about dopaminergic projections from the ventral tegmental area and the basal ganglia to prefrontal cortex – can capture both generalization and symbol-like processing, simply by incorporating biologically-plausible simulations of neural computation [bold added].
…
This is the first time (to my knowledge) that such abstract, symbol-like representations have been observed to self-organize within a neural network.
Furthermore, this network also showed powerful generalization ability. If the network was provided with novel stimuli after training – i.e., stimuli that had particular conjunctions of features that had not been part of the training set – it could nonetheless deal with them correctly. This demonstrates clearly that the network had learned sufficiently abstract rule-like things about the tasks to behave appropriately in a novel situation. Further explorations involving parts of the total network confirmed that the “whole enchilada” was necessary for this performance; [bold added]”
( http://develintel.blogspot.com/2006/10/generalization-and-symbolic-processing.html )
Fascinating stuff, emerging from being faithful to the observations in making the models. It is unfortunate that the likes of D.H. or C.W. can’t see the beauty of that.
But,but … I have come to *expect* the Wagnerian Inquisition!
Oh, well then. I always suspected there was a low streak in his character. At times he seemed like he had floated here from some other world, with behavior frontloaded sometime in the indefinite past.
…
As may be noticeable elsewhere I’m quite tired of consciousness models floated around who are like that; quantum, electrical, what have you. Debunked or not, it is not as if studying the biological systems themselves have failed yet.
Blake made an excellent job on the quantum woo side. There are also positive findings. Abstract thinking is part of consciousness, and there are now biologically based models for symbolic thinking:
“In this article from the Proceedings of the National Academy, Rougier et al. demonstrate how a specific network architecture – modeled loosely on what is known about dopaminergic projections from the ventral tegmental area and the basal ganglia to prefrontal cortex – can capture both generalization and symbol-like processing, simply by incorporating biologically-plausible simulations of neural computation [bold added].
…
This is the first time (to my knowledge) that such abstract, symbol-like representations have been observed to self-organize within a neural network.
Furthermore, this network also showed powerful generalization ability. If the network was provided with novel stimuli after training – i.e., stimuli that had particular conjunctions of features that had not been part of the training set – it could nonetheless deal with them correctly. This demonstrates clearly that the network had learned sufficiently abstract rule-like things about the tasks to behave appropriately in a novel situation. Further explorations involving parts of the total network confirmed that the “whole enchilada” was necessary for this performance; [bold added]”
( http://develintel.blogspot.com/2006/10/generalization-and-symbolic-processing.html )
Fascinating stuff, emerging from being faithful to the observations in making the models. It is unfortunate that the likes of D.H. or C.W. can’t see the beauty of that.
Torbjörn Larsson wrote:
Thank you! Someday, I will get all the anti-woo scraps I’ve written here and there together into a big essay. Given all the time I waste procrastinating on the Internet, tapping out these comments, I might have enough for a whole darn book. Quantum Quackery: How to Abuse Science for Fun and Profit.
(Thanks also to AJ Milne for the phrase “quantum quackery”. Alliteration is always alluring.)
AJ Milne: OK, I laughed out loud (in the middle of a DNA extraction lab) when I read your post. I think I will use that line the very next chance I get!…SH
The worst part of Penrose’s quantum quackery is that he perists in insisting that Turing machines cannot replicate human consciousness, so therefore quantum mechanics must be responsible. The problem is that quantum mechanics doesn’t actually permit any kind of computation that classical computers can’t also do. It may someday allow parallel computation to occur far faster than our current designs permit, but that’s it. If it turned out that quantum effects were important to human consciousness, we still wouldn’t have anything that a properly-programmed computer wouldn’t have.
When you get right down to it, Penrose just wants to prove that humans have souls.
Ichthyic wrote:
“then why did you stop taking them?”
Stop taking them? Bite your tongue.
What makes you think I stopped taking them?
I think that anyone over the age of 50 should be automatically exempt from all laws concerning the possession and use of drugs. That includes heroin, which just happens to be the perfect comfort drug for old people.
quork:
Do you know whether they’ve published anything about that? The linked article isn’t very imformative.
Blake and Torbjorn –
I totally agree that Penrose and Hameroff’s ideas are implausible, but would I argue that Tegmark’s comments and ideas are in error as well.
Blake, in Tegmark’s calculations for determining whether microtubules would be able to take advantage of quantum properties – that is, that microtubules represent a quantum system – he makes a rather egregious error. When figuring the ratio of the dynamical timescale of the system to the dissipative timescale of the system, he incorrectly substitutes membrane firing as the representative timescale of the dynamics of the system, while simultaneously plugging in the decoherence timescale for microtubules. Do you see the error here? What he needs to compare in order to find out if the system is truly quantum, he must compare the timescale of a microtubule’s dynamics, to the decoherence timescale for microtubules (that is, as opposed to the timescale of an entire neuron).
Tegmark pegs the decoherence time of microtubules as 10^-13, while Georgiev 2003 (see link below), the dynamical timescale of microtubules comes to about 10^-11. For a system to be truly quantum (Tegmark’s definition), decoherence time must be greater than the dynamical timescale. Obviously, by the above numbers, the microtubule doesn’t seem to be a truly quantum system, but:
Thus, Georgiev concludes that it is plausible that the microtubule system – as proposed in their “quantum mind” hypothesis (yes, it sounds woo as hell) – could be a quantum system.
Now, why this is important, will be answers in the following response to Torjborn’s remarks:
I agree that Rougier’s argument is plausible, but it is not necessarily incompatible with the hypothesis that microtubules are quantum systems. One of the primary reasons, in my opinion, to commit to some sort of quantum system in the brain, is not because it is the only type of system that can incorporate symbol-like processing (i.e. with neural computation, dendritic processing, or other classical processes). It is because it is the only mechanism that could fully explain what I’m sure you would recognize as “The Binding Problem.”
And that is where the fuzzy concept of consciousness comes in. In many quantum brain models, consciousness refers to the fact that our brain somehow lets us experience things. The most important aspect of this experience, is what I’m also sure you would recognize as the “unity” of consciousness – nothing crazy, but just the binding of information in the brain, such that it behaves as one “unitary quantum system” (again, Tegmark’s language). The binding problem will never be solved with purely classical systems.
And Blake, I did read your quote from Tegmark where he cites that there are other way’s for biological systems to utilize non-locality. That is extremely interesting for sure, but even if they were true, again they would not necessarily be at odds with a quantum theory of mind. Why? Because, if the mind could be represented by “highly non-local excitation patterns in the neural network of our brain, except of a non-linear and much more complex nature,” where does that get is in regards to the binding problem? The binding problem is a problem about experience. It’s all well and good if we could point to a brain and model it accurately in Fourier space, it does not explain how a non-linear function could be experienced as “unitary,” (bound), since classical physics could not explain how information could be bound considering the physical dimensions of the system itself.
I’m just saying that Tegmark isn’t exactly correct, and that the quantum model can be compatible with current classical hypotheses.
And, I’m glad we can at least agree that Penrose’s model is off the mark. :)
http://cogprints.org/3318/01/time.pdf
Well then, I can pitch in with “consciousness con” and “soul soup”.
What about other kookery, like on “disproving” (special) relativity or evolution? It doesn’t look as promising.
Well then, I can pitch in with “consciousness con” and “soul soup”.
What about other kookery, like on “disproving” (special) relativity or evolution? It doesn’t look as promising.
That is because nerve signals is the main dynamic that is to be affected. But he also compares with the kink-like microtubule excitation in the discussions (p 8) and find that the classical timescale of 10{-7} s is far from the microtubule decoherence time of 10{-13} s. Exactly what you asked for.
It is not an argument, it is a verifiable model.
No, I have never heard about the binding problem. “”The binding problem is, basically, the problem of how the unity of conscious perception is brought about by the distributed activities of the central nervous system.”” ( http://en.wikipedia.org/wiki/Binding_problem )
This is a curious question to put in times when programs can abstract objects by the distributed activities of the computer.
It is also exactly what Rougier et al have solved regarding the part that is symbolic processing:
“After this training, the prefrontal layer had developed peculiar sensitivities to the output. In particular, it had developed abstract representations of feature dimensions, such that each unit in the PFC seemed to code for an entire set of stimulus dimensions, such as “shape,” or “color.”” ( http://develintel.blogspot.com/2006/10/generalization-and-symbolic-processing.html )
Rougier et al’s model is also mimicing the biological behaviour closely:
“Furthermore, Fig. 4b shows that simulated lesions to the model’s PFC layer (30% unit removal, post training) replicate the color-naming impairments observed from PFC lesions (predominantly dorsolateral areas of PFC) in human patients (30), consistent with the observation that this PFC area supports abstract color dimension representations (29).” ( http://www.pnas.org/cgi/content/full/102/20/7338 )
So your consistent efforts to argue for your nonexistent model by claims on other models (“it is the only mechanism that could fully explain”) falls flat.
I am not saying that this solves the full binding problem, since there are many more characteristics of consciousness to explain. But it shows that some is already modelled by biological models in the classical regime. So there is no reason to think that any mystical phyiscal effects will be needed as the work progresses.
As the biologically models are quite intricate, they are also much more fascinating than quantum woo.
That is because nerve signals is the main dynamic that is to be affected. But he also compares with the kink-like microtubule excitation in the discussions (p 8) and find that the classical timescale of 10{-7} s is far from the microtubule decoherence time of 10{-13} s. Exactly what you asked for.
It is not an argument, it is a verifiable model.
No, I have never heard about the binding problem. “”The binding problem is, basically, the problem of how the unity of conscious perception is brought about by the distributed activities of the central nervous system.”” ( http://en.wikipedia.org/wiki/Binding_problem )
This is a curious question to put in times when programs can abstract objects by the distributed activities of the computer.
It is also exactly what Rougier et al have solved regarding the part that is symbolic processing:
“After this training, the prefrontal layer had developed peculiar sensitivities to the output. In particular, it had developed abstract representations of feature dimensions, such that each unit in the PFC seemed to code for an entire set of stimulus dimensions, such as “shape,” or “color.”” ( http://develintel.blogspot.com/2006/10/generalization-and-symbolic-processing.html )
Rougier et al’s model is also mimicing the biological behaviour closely:
“Furthermore, Fig. 4b shows that simulated lesions to the model’s PFC layer (30% unit removal, post training) replicate the color-naming impairments observed from PFC lesions (predominantly dorsolateral areas of PFC) in human patients (30), consistent with the observation that this PFC area supports abstract color dimension representations (29).” ( http://www.pnas.org/cgi/content/full/102/20/7338 )
So your consistent efforts to argue for your nonexistent model by claims on other models (“it is the only mechanism that could fully explain”) falls flat.
I am not saying that this solves the full binding problem, since there are many more characteristics of consciousness to explain. But it shows that some is already modelled by biological models in the classical regime. So there is no reason to think that any mystical phyiscal effects will be needed as the work progresses.
As the biologically models are quite intricate, they are also much more fascinating than quantum woo.
“biological models” – biological-like models
(Since this is a biological blog, and IIRC biological model is something entirely else here.)
“biological models” – biological-like models
(Since this is a biological blog, and IIRC biological model is something entirely else here.)
But, the kink-like microtubule excitations are not what is relevant when considering the dynamical timescale of microtubules. The correct timescale is that of “tubulin conformational transitions” (Georgiev, 2003). Like I mentioned earlier, this comes out to be on the order of about 10^-11. You are right in that this is still too slow compared to the calculated microtubule decoherence time of 10^-13. But, I don’t think this necessarily rules out the system being quantum (in Tegmark’s sense), because as I mentioned above, Tegmark admits that the decoherence time could be reduced by 1-2 orders of magnitude.
Sorry, that was bad terminology on my part. I meant to acknowledge his model’s efficacy in mimicing biological behavior, but also to dispute whether or not it solved the binding problem and present the possibility that it could be compatible with a quantum model.
Rougier:
So, as a solution to the binding problem, you (and Rougier) are implying that individual units or small structures in the brain are responsible for creating the unity of consciousness? I understand that individual units/neurons/groups of neurons can represent large amounts of distributed information (as in Rougier’s model), but that does not mean that these units are themselves able to produce a bound conscious experience. Presumably, these units are found all over the brain, representing different aspects of experience. They may, individually, be able to be modelled classically, and may be able to produce its own aspects of conscious experience, but again – how are they bound together? Is there one “Super-unit” that ends up representing all the individual units of the brain, which then produces the big picture? There are structures in the brain that receive inputs from all over the cortex, but done classically, the time it would take is too long to accurately mimic the (millisecond) timescale of biological behavior.
What I am saying, is that no classical model can explain the binding problem, and that plausible quantum models have been put forth. I’ll first start by quoting something I said above in this thread, as a disclaimer:
I am firmly anti-woo, and I know that neuroscience hasn’t had any problems explaining what we generally see in the behavior of the brain. But, I still think that the binding problem is worth investigating, even if only hypothetically. That being said, Georgiev, who has done extensive (non-quantum related) work on the biophysical nature of microtubules and the synapse, has presented a quite detailed quantum model in a number of publications that follows Jibu and Yasue’s (and Umezawa’s) quantum field theoretical models. They are quantum physicists who understand the physics as well as the biology, and have no motivation to present woo.
I understand that woo is a terrible thing, and that these quantum brain models are not (directly) testable, etc. Still, there are arguments for why they should exist, and models that present plausible ideas for how they could exist. Again, they are just interesting ideas, and nothing more. Thank you for your input, and I appreciate your educating me on the current classical models being presented, which are obviously more relevant to the goals as they stand in today’s neuroscience.
You’ve been watching “Little Miss Sunshine”, haven’t you. ;) Great movie.
Is there one “Super-unit” that ends up representing all the individual units of the brain, which then produces the big picture?
Yes. Lets put it more clearly. If you read a lot of the most recent papers (or just any) on the subject, what you get is something like this:
1. Multiple (independent) systems parse information and produce data points.
2. This data is handed off the conceptual systems as it is produced, which produces “multiple” responses. Not just “one” person, if you will, parses the information, but many simpler ones (think like a hundred disimilar programs running on seperate computers, which all process incomplete copies of shared data).
3. Some level of filters determine the “likely” optimal response, if its a fight/flight situation, you “start” to act, even before you become aware of doing so.
4. More filters cut out all but the most rational of the responses produced.
5. The “ME!” filter sets in, organizes the results and reaches a concensus with itself about “which” of the now dozen or so responses makes the most sense, socially and logically.
Just as a computer that massively parallel processes parts of a complex task, where the only delays are in syncronization between the data when needed, can out perform the most complex *single* microprocessor, the human brain seems, according to those recent studies, to work the same way. It doesn’t process everything in one linear path, but hundreds, maybe thousands of paths, none of them necessarilly having 100% of the information, none necessarilly having identical means to determine results, but where more specialized and higher level systems parse out the first the completely invalid, then the mostly invalid, then socially invalid, parts, before deciding what of a set of limited possibilities from that final set “is” the correct response. In fact, scitzophrenia seems to be a malfunction in this final filter. The voices people hear, depending on how severe the malfunction, can be one to many vioces, all with very different “opinions” about what is going on, but all of them are “you”. One study on the subject even determined that something like 1 on 8 (not sure of that number) people “hear” such voices, but that it takes additional faults in the brain to produce scitzophrenic behaviours. In other words, lots of people hear them, but only “some” are bothered by them or react to them in a self destructive fashion. And, depending on how their brains are wired, they might have just one phantom voice, or many.
In any case, you are assuming a system that “needs” to be fast. The problem is, most of the stuff we do, we start to do “before” consciously aware of it. This cuts the “time” needed to do a thing in half, or more, depending on what kind of response it is and one what level the brain decides “this is critical and I need to act!”. Snatching your hand away from something about to burn it is very fast, since the reaction happens on the “lowest” level. Jumping out of the way of a car requires running more threat analysis, so its a hair slower, etc. On average, the tests done on the subject showed a delay between response and awareness of anything from a half second up, depending on how complex the reaction needed to be. You seem to think our brains are working at milisecond speeds or something, but all the evidence points to “slow” multipath processing, with different levels of critical reactions, that can side step awareness if needed, to handle something, even before we “know” we are doing it. Conscious awareness is merely the finally arbiter, the point where we can derail something “already” in progress and rethink, based on more careful consideration. But even that is happening “prior” to us being aware that we “thought” of it.
Yes, the paper mentions that tubulins interact with MAP’s, which reactions work on those timescales.
But that should change the decoherence time. Tegmark’s result that I quoted are the slowest case for near non-interacting tubulins (distant ions). MAP’s are proteins, so contains ions. Tegmark’s result for nearby ions are 10{-19} s, so the tubulin should decohere before reaction commences. Georgiev doesn’t do any such modeling.
They are observed to be; I recommend reading the paper, perhaps it answers why.
I suspect that if they haven’t adjusted the timing, the neuron-net answers much faster than that. But this is a proof of principle.
Yes, the paper mentions that tubulins interact with MAP’s, which reactions work on those timescales.
But that should change the decoherence time. Tegmark’s result that I quoted are the slowest case for near non-interacting tubulins (distant ions). MAP’s are proteins, so contains ions. Tegmark’s result for nearby ions are 10{-19} s, so the tubulin should decohere before reaction commences. Georgiev doesn’t do any such modeling.
They are observed to be; I recommend reading the paper, perhaps it answers why.
I suspect that if they haven’t adjusted the timing, the neuron-net answers much faster than that. But this is a proof of principle.