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Penrose & Hameroff 5


Penrose-Hameroff: 5

1.) The importance of quantum decoherence in brain processes - Max Tegmark

2.) Quantum Computation in Brain Microtubules - Response to famous Tegmark article

3.) Stuart Hameroff reply to Michael Shermer

4.) Meditators and Gamma Synchrony

5.) Hameroff v Koch Debate

6.) Orch OR Model for consciousness - Penrose & Hameroff

7.) Orchestrated space-time selection - Penrose and Hameroff

8.) Quantum computation in brain microtubules

9.) Consciousness, the brain and space-time geometry

10.) Quantum coherence in photosynthetic systems - Gregory Engel

11.) Inflationary theory & the early universe - Roger Penrose





The importance of quantum decoherence in brain processes

Max Tegmark

Institute for Advanced Studies, Princeton

Phys. Rev E, October 1999

This paper is often quoted as the definitive refutation of the Penrose/Hameroff model. Less frequently quoted is the response of Hameroff et al pointing out a number of deficiencies in its arguments.

Tegmark stresses that the crucial factor for quantum theories of consciousness is the ability to sustain quantum coherence in the conditions of the brain. This much is accepted by Hameroff. However, Tegmark says that the purpose of his paper is to calculate the rate of decoherence in the brain, which he boldly states as something that will settle the whole matter.

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.

In fact, the other main complaint against Tegmark’s paper is that he does not adequately discuss Hameroff’s proposals for how microtubules might be shielded from decoherence, or the proposals of other theorists for how their models might also evade decoherence. Hameroff accepts that even without Tegmark’s soliton model, decoherence would happen too quickly to be neurally useful. He suggests that shielding for microtubules could be provided by ordered water, that is water molecule dipoles aligned with the biomolecule dipoles of the microtubule tubulin protein, particularly during the gel part of the cytoplasmic cycle. This might be supplemented by energy pumping given the lack of thermal equilibrium in biological tissue and also by quantum error correction facilitated by the design of the microtubule lattice.

In the discussion section towards the end of his paper, Tegmark is drawn back to the idea of decoherence at the neuron level, an irrelevance in terms of modern quantum consciousness. Here he tries to argue that even if it turns out that there is quantum coherence in the brain, it must be irrelevant to consciousness, because decoherence would occur as soon as there was communication at the scale of a neuron. However, this fails to discuss suggestion that structures such as microtubules or ions in ion channels could carry out quantum processing, collapse their wave functions, and afterwards communicate classically with the synapses.

At the distance of nearly a decade, some aspects of Tegmark’s paper appear slightly old fashioned. Considerable faith is attached to work on computational neural networks, which boomed in the 1990s as a way of modelling brain processes on classical computers. The same faith is apparent in some of Patricia Churchland’s work. However, in the intervening years the neural network story appears to have fallen silent. To judge by the lack of striking progress on the artificial intelligence front, nothing has emerged from the neural network activities to allow any close artificial simulation of the brain. Bear in mind that in the late 1990s, some serious writers were forecasting a robot takeover of our planet in the early years of the present decade.





Quantum Computation in brain microtubules: Decoherence and biological feasibilty

S. Hagan

Dept. of Mathematics, British Columbia Institute of Technology

S.R. Hameroff,  Dept. of Anesthesiology and Centre for Consciousness Studies, University of Arizons

J. A. Tuszynski, Dept. of Physics, University of Alberta

Published in: Physical Review: vol 65, 10th June 2002.

This article is the authors reply to Tegmark’s claim that the speed of decoherence makes the Penrose/Hameroff or Orch OR model for consciousness implausible. Tegmark’s main criticism was that coherence would collapse in 10-13 seconds in the conditions of the brain, and this meant it could have no useful involvement in brain function.
 
The authors’ reply is that Tegmark did not look at the Penrose/Hameroff model involving protein superpositions, but at another model, apparently proposed by Sataric that involves a soliton in superposition along the whole length of the microtubule.

Tegmark also seems to have thought that the suggested superposition must cover the whole 24 nm of the microtubule, whereas Penrose/Hameroff are thinking in terms of separation at the level of atomic nuclei within the tubulins. Thus there is a seven orders of magnitude difference between the Tegmark model and the Penrose/Hameroff model.

The article sees the microtubules as mediating between the quantum computation of the tubulins and the classical behaviour of the rest of the neuron. The article sees the microtubule superposition as needing to survive for tens of milliseconds in order to usefully interact with brain functions. The Penrose/Hameroff model suggests that the cytoplasm around the microtubules alternates between a type of gel and a liquid. During the former stage the microtubule is screened from the environment and contains superpositions and quantum computing. During the latter there are classical events such as attachment of microtubule associated proteins, membrane activities and synaptic functions. On the inward route, synaptic activity is suggested as affecting the cytoskeleton. The arrangement of the MAPs following synaptic activity is suggested to have an impact on the subsequent microtubule states.

The article goes on to discuss the existence of quantum behaviour in protein. It quotes A. Roitberg et al in Science 268 (1), who reports substantial quantum effects. It also quotes J. Tejada  in Science 272 (2), who criticises Gidia et Al. The latter’s work claims to detect macroscopic quantum coherence in the protein ferritin. Tejada criticises their procedures, but Gidia defends the original conclusion in a response to Tejada. They also refer to a series of experiments involving brain scanning, by W.S. Warren et al, (3), R.R. Rizi et al (4) and W. Richter et al (5), which showed that quantum coherence between proton spins up to a micrometer apart could be artificially induced for tens of milliseconds. The length of the coherence periods allows it to be seen as possibly connected to the so-called 40Hz oscillation between the thalamus and the cortex and between other regions of the brain.
 
These experiments are seen as mainly important in demonstrating the possibility of quantum coherence within the brain. The argument that the brain could not sustain quantum coherence for a useful period has always been the most cogent argument against theories of quantum consciousness, and that argument is weakened by these experiments. However, it is stressed that the experiments did not involve entanglement, and the particular processes induced are not thought likely to be useful in brain function.

References:-

(1)  A. Roitberg et al, Science 268 1319 (1995)

(2)  J. Tejeda et al, Science 272 424 (1996)

(3)  W.S. Warren et al, Science 281 247 (1998)

(4)  R.R. Rizi et al, Magn Reson Med 43 627 (2000)

(5)  W. Richter et al, Magn Resonance Imaging 18 489 (2000)





Stuart Hameroff reply to Michael Shermers article in Scientific American (292)

Michael Shermer’s article refers to a book by Victor Stenger of the University of Colorado, which claims that for a system to be described quantum mechanically mass, speed and distance must be of the order of the Planck constant. Shermer says that neurotransmitter molecules are too large and slow in crossing the synapse to be quantum mechanical. Microtubules are dismissed as mere scaffolding for the cell in Shermer's view.

Hameroff has made a reply to Shermer that has not apparently been published by Scientific American. Hameroff stresses that the Orch OR model did not look for quantum activity at the synapses, which is what Shermer sought to disprove, but in microtubules within the neurons. He points out that in addition to their structural functions, microtubules are responsible for molecular transport within the cells and synaptic changes. They would appear to be the basis for the ability of single cell organism to survive in an environment without any brain or nervous system. Furthermore, the microtubule subunits are regulated by van der Waal forces in intra-protein non-polar pockets.

Hameroff goes on to put his case for thinking that the action of anaesthetic gases gives a clue as to the basis of consciousness. He points out that anaesthetic gases erase consciousness while many non-conscious processes in the brain continue. The action of the anaesthetics is thought to be related to the control of protein conformation, occurring  in brain structures including the cytoskeleton. For this reason Hameroff thinks that consciousness is related to one of the areas of the brain acted on by anaesthetic gases.

Hameroff further points out that he listed twenty testable predictions for his model, a testable prediction being effectively the distinction between a scientific theory and a mere speculation. He argues that mainstream theory has not made a testable prediction.





Meditators and Gamma Synchrony

Stuart Hameroff

Based on work of Antoine Lutz et al in Proceedings of the National Academy of Sciences USA 101, (46), pp. 16369-16373, 2004

Stuart Hameroff comments on a meditation experiment published in the ‘Proceedings of the National Academy of Sciences’, 2004. He cautions in discussing this material that the content of consciousness is not the same as consciousness. A seemingly obvious point, but one more often than not ignored in consciousness literature. He mentions the controversy over whether it is possible to be conscious of nothing, and the argument that meditators achieved this, clearing their minds’ of everything, but still being conscious of being.

Earlier studies of meditators had not found anything very notable in the EEGs of the subjects. However, these studies had not included the higher frequency gamma waves above 25Hz. The study commented on here showed that trained meditators produced a high level of gamma activity.

In the 1980s, these waves were found to correlate to cognition, attention, working memory, facial and linguistic recognition and consciousness itself. This was known as 40Hz oscillation and was initially accorded great importance as a correlate of consciousness.

Later mainstream attention moved away from this oscillation. Hameroff surmises that this was because the oscillation did not correlate to axonal action potentials, and these and the related synaptic junctions had always been given a central role in mainstream models of consciousness.

Hammerof points out that the gamma oscillation has been found to correlate to dendritic activity. He takes the heightened activity during meditation as further support for both the link from dendritic activity through gap junctions to gamma oscillation, which is in its turn correlated to consciousness. He also thinks that heightened activity, at a time when external sensory input via the thalamus is at a low point, implies that the cortex is the driving end of the process.





Quest for Consciousness

by Christof Koch

Review by Stuart Hameroff and debate between Hameroff and Koch on Hameroff.
 
Hameroff says that Koch’s book acknowledges that there is a problem as to how qualia arise from the brain. However, he feels that the book somewhat sidesteps this central issue by concentrating on neural correlates of consciousness (NCC). As elsewhere, Hameroff expresses puzzlement as to the rapid taking up and dropping of 40Hz oscillation by Crick and Koch. They did not discover this oscillation, but they popularised it from 1990 onwards, then later downplayed it, possibly because it did not correlate with axonal spiking. Koch’s approach is very much focused on the axonal-dendritic synapses and the assemblies or coalitions of neurons that are driven by these. He sees this as the only possible basis of consciousness. Hameroff, however, queries how the spiking of an electrical potential is going to produce qualia/consciousness.

Hameroff also criticises Koch for his dismissive attitude to the linking of cortical interneurons to gap junctions. He claims that dozens of papers show that interneurons linked by gap junctions are responsible for the 40Hz oscillation. He further reminds us that the 40Hz oscillation is an NCC, so the interneuron/gap junction link is itself an NCC.

Koch and Hameroff also differ over the action of anaesthetic gases. Hameroff’s analysis is that anaesthetic gas molecules bind in hydrophobic pockets in a variety of brain proteins. The solubility of these gases in these hydrophobic correlates to their potentency as anaesthetics. Membrane ion channels are amongst the proteins to which anaesthetic gases bind, but the gases bind to many other proteins. Van de Waal forces in these pockets are claimed to control the conformation of protein. When anaesthetic gases get into the pockets they disrupt the conformational activity. Under anaesthesia consciousness is obliterated but many other body functions continue, so the gases must act on something that relates specifically to consciousness, and the something is connected to the hydrophobic pockets.

Connexin 36
In his reply to Hameroff’s criticisms, Koch moves on to discuss the question of the laboratory mice that were bred not to have one of the Connexin family of proteins called Cx36. Koch reports that in mice bred without Cx36 the 40Hz oscillation persists, albeit at a reduced amplitude. There are some deficits in their behaviour, but by and large they are not much different from normal mice. Koch and others have seen this as a knock out blow for the role given to gap junctions. 

In answer to this, Hameroff points out that there are at least ten types of connexin, with gap junctions often formed out of a mixture of connexin proteins. The reduction but persistence of gamma synchrony in the absence of Cx36 is consistent with it being one of a number of similar proteins involved in the effectiveness of the gap junctions.

The final discussion between Koch and Hameroff relates to the actual action of anaesthesia. Here Hameroff is on his own ground as an anaesthetist, and can reasonably be seen as authoritative relative to Koch. The latter claims that a host of body processes such a heart and breathing are effected, while Hameroff states that if the dose is correct patients routinely breathe on their own, unless separate muscle paralysing agents are used. This debate is significant relative to the debate as to whether consciousness is something physically distinct from other processes in the brain.





Quantum Computation in brain microtubules? The Penrose-Hameroff Orch Or Model of Consciousness

Stuart Hameroff

Some philosophers have suggested that qualia, the basic elements of subjective experience constitute a fundamental level of reality. To look at this from a scientific point of view, the nature of physical reality as described by relativity and quantum theory must be examined. In respect of this, Roger Penrose takes the position that the quantum wave function collapse is a real event rather than an abstract mathematical concept as in the orthodox Copenhagen interpretation. He has proposed a new version of the collapse of the quantum wave function known as objective reduction (OR). Objective reduction occurs if quantum superpositions do not interact with the environment for long enough for them to reach this alternative state. Penrose’s model suggests that OR connects to the fundamental level of spacetime, which is surmised by him to encode non-computable processing and possibly also the qualia of subjective experience.

In the Penrose/Hameroff model, the microtubules are the suggested site for OR activity in the brain. The microtubules are composed of subunits formed from the protein tubulin. Quantum superpositions are suggested to develop in these tubulins, with each of the tubulin, which are set in a hexagonal lattice recruiting other tubulins into a macroscopic quantum state. These quantum states are suggested to be orchestrated by microtubule associated proteins (MAPs) that influence the quantum processing. When the quantum superpositions collapse, they select states of the microtubule tubulins that in turn regulate synaptic functions.

In terms of general relativity, each quantum superposition is conceived by Penrose to have its own spacetime geometry or relationships, so these geometries are themselves superpositions. In relativity, reality is four dimensional, meaning three spatial and one time dimension. This four-dimensional spacetime is curved in a way that encodes the gravitational fields of all the massive objects in spacetime. Where there are quantum superpositions within spacetime, they each have their own bit of spacetime or their own curvature, but relativity has no way of handling such a superposition, which thus puts it into conflict with quantum theory. If the spacetime geometries move too far apart from one another, they become unstable and collapse. In doing so they select one of the superpositions.

When the wave function collapses as a result of interaction with the environment, the selection of a particular state is random but in the case of OR the selection is suggested to be neither random nor deterministic, but the result of a non-computable process, which is claimed to be the basis of human understanding or judgement. Penrose believes that Gödel’s theorem shows that human brains include a form of processing that is non-computable. Such non-computability is in turn thought to only occur at the fundamental spacetime level, accessed by means of objective reduction of the wave function.

Objective reduction could occur in many places in the universe, but Penrose does not see this as an argument for some form of pan-psychism. The superpositions need to be large enough to collapse within a reasonable length of time, but not so large that collapse in a time shorter than is needed for neural processes. An electron or ion, if screened from the environment, would not collapse in a reasonable length of time, while something even as large a neuron would collapse much too quickly, to be relevant to neural processes. However, the quantum states of microtubules might occupy this middle ground. Thus the conditions under which objective reduction could provide a link to fundamental spacetime look to be very special, with brains so far the only suitable places detected in the universe.

Proteins, and particular tubulin protein in microtubules, are seen as the part of the brain that could support objective reduction. Proteins perform cell functions by means of conformational changes, which are in turn regulated by weak quantum forces known as van der Waal forces. The weakest type of these forces, known as London forces, act in hydrophobic pockets in proteins. Anesthetics also bind in these pockets and may disrupt existing processing when they do this.

The tubulin protein subunit is an 8 nm dimer comprising two 4 nm monomers. This can undergo conformational change putting the monomers at a 30? angle to the axis of the dimer. Crystallography studies show large hydrophobic pockets in which van der Waal forces can govern the action of the protein. Recent evidences indicates that there is signalling along microtubules. Microtubules interact with the cell membrane via linking proteins and second messengers. Microtubules are involved in forming and maintaining synaptic connections, while gelation of actin, another component of the cytoskeleton, regulates synaptic spines, and through them also affects synaptic connections. The conformational states of tubulin respond to London forces in hydrophobic pockets, and the tubulins interact with other tubulins. Quantum superposition in London forces leads to quantum superposition of tubulin and supports quantum computing. The tubulin proteins in the microtubules are viewed as qbits in a quantum computer.

The microtubules are suggested to be screened by gelation, ordered water, and coherent pumping of biochemical energy, as a function of being far from thermal equilibrium, so as to prevent decoherence for extended periods. The quantum states of microtubules in one neuron are communicated to other neurons via gap junctions. The paper distinguishes between quantum computation during the period of quantum coherence and consciousness, which comes when there is an objective reduction of the quantum event taking place in the tubulin.





Conscious Events as Orchestrated Space-Time Selection

Stuart Hameroff and Roger Penrose

This joint article discusses the authors views on the quantum wave function collapse and its possible involvement with microtubules. Penrose believes that the quantum wave reduction is a real event in physics. He thinks that non-computability in the brain is linked to non-computability in space-time. He argues that at least some conscious states cannot be derived from one another by algorithms. In this way they are distinct from the processing of computers.

Superpositions represent many possible states with complex number weighted values, which, when the wave function collapses reduce a single macroscopic eigenstate. The result is random but can be weighted according to probability. Schrödinger, Heisenberg, Dirac and von Neumann all considered the possibility that superpositions could continue indefinitely up to macroscopic size. Conscious observation was sometimes called in to collapse these superpositions, but the possibility of an unobserved superposition remained.

Penrose looks for an objective reduction (OR) to collapse the wave function when the separation of different possible space-time geometries reaches the Planck length, at which point the scale of separation between superpositions makes them unstable. Any attempt to persist with space-time separation brings general relativity and quantum theory into conflict.

Objective reduction of the wave function may be common in the universe, but individual reductions are not relevant for the processing of consciousness. The reduction needs to be on a macroscopic scale to be relevant. In the brain there would be a cascade of ORs to produce the perceived ‘stream of consciousness’. The brain ORs are described as ‘orchestrated ORs', because they are orchestrated by the MAPs

In looking for a site in the brain for this type of non-computable quantum activity, microtubules are seen as the most plausible candidates to support macroscopic quantum coherent activity, but clathrins, vesicular grids and neural membrane proteins are also considered to be possible sites. Microtubules possess a range of features that make them suitable for a combination of quantum coherence and information processing. They are widespread and common throughout the brain, they have functional effects, a periodic structure, a possible ability to be transiently isolated from their environment, and they contain a hollow core that could be a suitable location for a wave guide.

A number of features appear to point to the ability of microtubules to screen quantum coherence including the hollow core, internal hydrophobic pockets, ordered water close to the microtubules and the sol/gel fluctuation in the cytoplasm.

The article quotes a further experiment appearing to show quantum coherence in biological tissue. An experiment by Walleczek showed that biochemical radical pairs could retain the correlation of their quantum spin.





Quantum computation in Brain Microtubules

Stuart Hameroff

Philosophical Transactions Royal Society London: 356: 1869-1896 (1998)

Quantum computation has been shown to have a number of applications beyond those that can be achieved by a classical computer. A number of ways of building a quantum computer are being researched involving small entities such as trapped ions, or electron or nuclear spins. The main problem in quantum computing is decoherence.

Conventional theories of consciousness assume that consciousness emerges from brain processing that is analogous to a classical computer. The main flaw in this conventional theory is the apparent inability to account for the subjective experience of consciousness, as distinct from information processing and responses to information, neither of which require consciousness, plus an inability to explain the difference between conscious and unconscious processing, given an apparent lack of differences in electrophysiological activity across the brain.

Quantum computing requires either very low temperatures or energy pumping. At the same time as preserving coherence, the quantum computer needs to communicate with the external environment to produce an output. In the Penrose/Hameroff model there is a considerable difference between quantum computers and the conscious brain. This has been overlooked by some commentators. Presently planned quantum computers would have their wave functions collapse as a result of involvement with the environment. It is much more difficult to achieve objective reduction which is what is required for consciousness in this model. Furthermore the planned computers act only on small entities such as ions rather than macroscopic quantum entities that are felt to be relevant to consciousness. It is, however, suggested that the model does in principle open the door to the building of quantum computers/robots at some time in the future.

The output are presently planned quantum computers, with wave functions collapsing due to involvement with the environment, would reflect a mixture of deterministic processing and random collapse but they would not involve non-computability.

Proteins are versatile macromolecules that perform a variety of functions by changing their conformation. This is important for a wide variety of functions such as muscle movement, opening and closing of ion channels in the cell membrane, and in fact most of life is organised by the conformation of proteins. Proteins are composed of hundreds of amino-acids. The main driver in the folding or conformation of protein is a non-polar group of amino-acids acting in hydrophobic pockets. Hydrophobic pockets may be critical to the functioning of protein. Anaesthetic gases exert effects in hydrophobic pockets by means of van der Waals forces. Protein is only marginally stable and conformation is a delicate balance between different forces. The timescale of conformation can be up to a nanosecond.

Dipole to dipole forces are known as van der Waals forces. They can be permanent to permanent dipole, permanent to induced dipole or induced to induced. These last are called London or London dispersion forces and are the weakest type of Van der Waals force. They are 40x weaker than the hydrogen bonds. The London forces arise as a result of instantaneous dipoles in electrically neutral areas and they may couple to zero point fluctuations in the vacuum.

It is also suggested that proteins may utilise superpositions of possible conformations. An experiment by Roitberg et al tended to confirm the existence of superpositions in protein.

The interiors of living cells are organised by the cytoskeleton. They govern a number of functions including movement, maintenance of functions, extension of axons and dendrites, the formation of synapses and the regulation of synaptic strength. More recent signalling has been detected within the cytoskeleton. Proteins called fodrin and ankryn link the cytoskeleton to the cell membrane.

Microtubules and the rest of the cytoskeleton are embedded in the cytoplasm. This can switch periodically between being a liquid and a gel and this may help to shield the microtubules. The MAPs are seen as setting the probabilities for the outcome of quantum computation.

There is a high concentration of gap junctions in the cortex and the thalamus.

Appendix 2 of this article outlines 20 ways in which the Penrose/Hameroff model could be tested. Nineteen of these refer to microtubules and one to Penrose’s objective reduction, but Penrose has mentioned further work on objective reduction in 2004 and 2006

References:-

Wallaczek J. (1995) Chemistry no 250: American Chemical Society Books





Consciousness, the Brain and Spacetime Geometry

Stuart Hameroff

Annals of the New York Academy of Sciences

The Orch OR model of consciousness differs significantly from current ideas for the construction of quantum computers. Plans for quantum computers rely on decoherence as a result of interaction with the environment and are deterministic. The Penrose/Hameroff proposal for quantum computing in the brain involves objective reduction as a result of the quanta’s relation to fundamental spacetime and a non-computable process for selecting the outcome of the wave reduction.

Spacetime is suggested to be not continuous but to comprise some form of web or network, such as Penrose’s proposed spin networks, where a spin network codes for each quantum state of spacetime. These networks operate at the Planck length, where the continuity of spacetime is perceived to break up. The spin networks define volumes and configurations that evolve dynamically. The blisters that Penrose predicts in spacetime as a result of superpositions extend down to the fundamental level of the spin networks.

In proposing objective reduction (OR) Penrose takes the general relativity notion that mass is equivalent to spacetime curvature, and curvatures in different directions, as with two quantum superpositions with different spacetimes, result in separations, bubbles or blisters in spacetime. These become unstable above the scale of the Planck length resulting in objective reduction and a reconfiguration of spacetime geometry. The length of time to objective reduction for a system is a function of mass or energy, the larger the size, the greater the speed of reduction.

Protein, specifically tubulin in microtubules, is seen as the basis for objective reductions in the brain. Proteins are only marginally stable and undergo frequent changes. Proteins are macromolecules that perform a variety of functions by changing their configuration. The driving force of protein is seen as non-polar groups of amino-acids that form into hydrophobic pockets in the protein interiors by means of van der Waal forces. Anesthetic gases have their effects in such pockets. London forces, which are the weakest form of van der Waal force, are important to the action of proteins. London forces depend on the instantaneous formation of dipoles in atoms or molecules that are otherwise electrically neutral. Fröhlich was the first to suggest dipole oscillations in hydrophobic pockets in the 1960s. Such excitation within microtubules is suggested to allow interaction with other tubulins, and to support information processing. Quantum tunnelling is proposed to allow quantum states to spread between neurons.

The folding of protein, by which proteins change their configuration is known as ‘the protein folding problem’ because it has not proved possible to predict the folding process on computers, suggesting to some that this is a non polynomial problem that can only be solved by quantum computing,

The driving force of protein is seen as non-polar groups of amino-acids that form into hydrophobic pockets in the protein interiors by means of van der Waal forces. Anesthetic gases have their effects in such pockets. London forces, which are the weakest form of van der Waal force, are important to the action of proteins. London forces depend on the instantaneous formation of dipoles in atoms or molecules that were otherwise electrically neutral. Fröhlich was the first to suggest dipole oscillations in hydrophobic pockets in the 1960s. Such excitation within microtubules is suggested to allow interaction with other tubulins and to support information processing. Quantum tunnelling is proposed to allow quantum states to spread between neurons.

Roitberg et al (1995) showed protein vibrations centred on quantum effects in hydrophobic regions and Gidia (1996) suggested coherence in the protein ferritin. In tubulin, one monomer of the tubulin dimer can move as much as 30? out of the axis of the dimer. The protein can switch between states governed by an electron pair in a hydrophobic pocket regulated by London forces.





Brian Josephson

Review of Penrose's 'The Large, the Small and the Human Mind' in the Journal of Consciousness Studies

Brian Josephson’s review of Penrose’s third consciousness book is disappointing in the lack of depth of argument. In discussing Penrose’s hypothesis that objective reduction of the wave function provides access to mathematical understanding and possibly qualia, which are supposed to be coded into fundamental time, he can only claim that Penrose does not give reasons to justify this belief sufficient to satisfy the reviewer.

Brian Josephson’s review of Penrose’s third consciousness book is disappointing in the lack of depth of argument. In discussing Penrose’s hypothesis that objective reduction of the wave function provides access to mathematical understanding and possibly qualia, which are supposed to be coded into fundamental time, he can only claim that Penrose does not give reasons to justify this belief sufficient to satisfy the reviewer.

Penrose’s ideas are very speculative, but the review ought to discuss the ideas rather, than merely stating that they are insufficient. Penrose’s reason for advancing objective reduction as such is to resolve the well known problems with the en reduction of the wave function, which Josephson himself discusses earlier in his review. Objective reduction is viewed by Penrose as the one candidate in the entire universe for a process that is both non-algorithmic and non-random. Speculative indeed, but it should at least be stated or discussed rather than shuffled away as some unknown thing that doesn’t satisfy the reviewer.

In dealing with the arguments relative to Gödel and non-computability, Josephson relies more on the appeal to majority opinion than on detailed argument. It does appear that a large number of logicians oppose Penrose, but there is at least an impression that this represents an en bloc rallying to the traditional Newtonian paradigm, rather than a large number of really different lines of thought.

In attempting a more specific argument, Josephson distinguishes between how a process can be executed, and how it can be simulated. Presumably this should be taken as a distinction between mathematical understanding in the brain, and the simulation of mathematical understanding by a computer. Josephson suggests that this could be the difference between an idealisation of a theory and the approximation achieved by an actual and therefore finite computer. However, Josephson also refers to the first process being performed by networks of neurons in the brain. Clearly, any system of neurons is also finite, so the comparison does not look valid.

Like many commentators, Josephson places a puzzling amount of reliance on a 1995 article by Grush & Churchland, which attacked the Penrose/Hameroff model. The core part of their argument refers to the soundness of mathematical procedures and their underlying brain processes. They argue that mathematicians can make mistakes, and because of the complexity of their work, it may be a long time before these are detected. From this they argue that there are no sound procedures, but only ones that are usually reliable or useful on a trial and error basis. Penrose’s reply to this was that while it is obvious that mathematicians sometimes make mistakes, it is nevertheless eventually possible to arrive at an incontrovertibly sound argument, examples being the so called Pi 1 sentences that state that certain computation, such as Goldbach’s conjecture, do not halt.

Josephson views Penrose’s response to G&C as unconvincing, but does not go onto discuss their views instead, entering on a digression on his own. He argues that if mathematical understanding derived from gradual familiarisation and confidence in mathematical ideas, it would be an error to view such a system as totally reliably. This is true in itself, but rather begs the question. The system he describes would appear to be the product, or at least capable of being the product, of an algorithm, while Penrose is postulating the existence of a non-algorithmic process. This may not exist, but the reliability or otherwise of a series of algorithmic processes does not throw much light on this.

At the end of his review, Josephson does something of a volte face, in coming down in favour of a Platonic realm manifesting itself in such areas as musical appreciation. Approximations are suggested to point us towards ideals in the Platonic realm, and this could apply to both maths and music. Penrose, it is suggested, may be correct after all, but not on the basis of the arguments in his books. One suspects that such a notion would excite even greater ridicule on the part of Grush and Garland.





Inflationary theory and the early universe
 
From Roger Penrose's 'Road to Reality'

The concept of inflation in the early universe is an important theme in recent cosmology. The inflationary period is seen as a time in which a multiverse of different universes could have been spun off, with our universe being just one of many or even an infinity of universes.
 
The idea appears to recommend itself to much of the scientific establishment, possibly because it is seen as allowing us to do away with the concept of a God or prime mover at the beginning of the universe. The observed 'fine tuning' of our universe creates impossible odds against this universe having arisen by chance from a single fluctuation of the vacuum without some form of design or prime mover. The idea of a multiverse gets round this, by allowing up to an infinity of universes and therefore up to an infinity  of shots at getting a universe like ours. An inflationary period in the early universe is a favoured way of creating the conditions in which a multiverse could arise.

As so often, we find Penrose at odds with fashionable theory, and here arguing against the idea of inflation in his most recent book 'The Road to Reality'. Much of his discussion deals with the second law of thermodynamics, by which the entropy or disorder of closed systems always increases with time. There is a problem in physics here. It is easy to see entropy as increasing into the future. But the laws of physics as expressed in the Maxwell and Schrodinger equations are time symmetric, so if entropy increases into the future, it should also increase into the past. This is contrary to experience, and would require that at the present moment the universe was at a unique point of low entropy, with entropy increasing from here into both the past and the future.

Penrose conceives entropy as different sizes of phase space, which is seen as containing six dimensions, three for position and three for momentum. The amount of entropy and therefore of phase space gets smaller and smaller as we go back towards the Big Bang. The source of the second law, by which entropy increases, lies in a tiny volume of phase space at the Big Bang. Uniformity at the Big Bang corresponds to very low entropy. This is not a function of the actual size of the universe, otherwise a collapsing universe would have declining entropy, whereas the reverse is forecast for this type of universe.

A number of observations indicate that there was thermal equilibrium in the early universe. Penrose argues that it is wrong to take this as an indication that entropy was high rather than low in the early universe. The lack of gravitational clumping in the early universe represents low entropy, which more than offsets the thermal equilibrium. Penrose again argues that there are absurdly high odds against getting a universe with such low entropy simply by chance.

In discussing inflationary theory, Penrose looks first at the 'horizon problem', the fact that the observed temperature of the universe is nearly the same in all directions. This can be explained by thermalisation, but this carries the problem that the original models for the Big Bang did not allow for all parts of the early iniverse to have been in contact with one another. This is however possible if there was an inflationary period after an early thermalisation.
 
Penrose's criticism of this relates to the second law. If there was thermalisation at this stage, this represents an increase in entropy from some earlier stage, meaning that the universe initiated with even lower entropy and there is an even lower chance of it having risen from a single chance fluctuation in the vacuum. Inflationary theory deals with this fine tuning process by the creation of a multiverse during the inflationary period, but earlier thermalisation creates an initial element of fine tuning that is not explained by the later bout of inflation.

Inflation is also supposed to provide an explanation for the evenness of distribution of matter and the near flatness of the overall curvature of the universe. In this view, the period of inflation is suggested to have smoothed out the irregularities of the pre-inflationary universe, which is here thought of as being irregular as a result of the chance state in which it emerged from Big Bang. Penrose also criticises this approach. He points to the conditions that would arise in the later stages of a collapsing universe, suggesting that the irregularities that would arise here would be fractal, and therefore incapable of being smoothed out by an inflationary process. If there were irregularities near the Big Bang, it is suggested that these would also be fractal and incapable of being smoothed out by inflation. However, he appears to think that low entropy precludes such irregularities from the early universe, which might also prevent inflation from arising.

The concept of inflation in the early universe is an important theme in recent cosmology. The inflationary period is seen as a time in which a multiverse of different universes could have been spun off, with our universe being just one of many or even an infinity of universes. The idea appears to recommend itself to much of the scientific establishment, possibly because it is seen as allowing us to do away with the concept of a God or prime mover at the beginning of the universe. The observed 'fine tuning' of our universe creates impossible odds against this universe having arisen by chance from a single fluctuation of the vacuum without some form of design or prime mover.
 
The idea of a multiverse gets round this, by allowing up to an infinity of universes and therefore up to an infinity  of shots at getting a universe like ours. An inflationary period in the early universe is a favoured way of creating the conditions in which a multiverse could arise.As so often, we find Penrose at odds with fashionable theory, and here arguing against the idea of inflation in his most recent book 'The Road to Reality'.
 
Much of his discussion deals with the second law of thermodynamics, by which the entropy or disorder of closed systems always increases with time. There is a problem in physics here. It is easy to see entropy as increasing into the future. But the laws of physics as expressed in the Maxwell and Schrodinger equations are time symmetric, so if entropy increases into the future, it should also increase into the past. This is contrary to experience, and would require that at the present moment the universe was at a unique point of low entropy, with entropy increasing from here into both the past and the future.Penrose conceives entropy as different sizes of phase space, which is seen as containing six dimensions, three for position and three for momentum. The amount of entropy and therefore of phase space gets smaller and smaller as we go back towards the Big Bang. The source of the second law, by which entropy increases, lies in a tiny volume of phase space at the Big Bang. Uniformity at the Big Bang corresponds to very low entropy. This is not a function of the actual size of the universe, otherwise a collapsing universe would have declining entropy, whereas the reverse is forecast for this type of universe.A number of observations indicate that there was thermal equilibrium in the early universe.
 
Penrose argues that it is wrong to take this as an indication that entropy was high rather than low in the early universe. The lack of gravitational clumping in the early universe represents low entropy, which more than offsets the thermal equilibrium. Penrose again argues that there are absurdly high odds against getting a universe with such low entropy simply by chance.In discussing inflationary theory, Penrose looks first at the 'horizon problem', the fact that the observed temperature of the universe is nearly the same in all directions. This can be explained by thermalisation, but this carries the problem that the original models for the Big Bang did not allow for all parts of the early iniverse to have been in contact with one another. This is however possible if there was an inflationary period after an early thermalisation. Penrose's criticism of this relates to the second law. If there was thermalisation at this stage, this represents an increase in entropy from some earlier stage, meaning that the universe initiated with even lower entropy and there is an even lower chance of it having risen from a single chance fluctuation in the vacuum.

Inflationary theory deals with this fine tuning process by the creation of a multiverse during the inflationary period, but earlier thermalisation creates an initial element of fine tuning that is not explained by the later bout of inflation.Inflation is also supposed to provide an explanation for the evenness of distribution of matter and the near flatness of the overall curvature of the universe. In this view, the period of inflation is suggested to have smoothed out the irregularities of the pre-inflationary universe, which is here thought of as being irregular as a result of the chance state in which it emerged from Big Bang. Penrose also criticises this approach. He points to the conditions that would arise in the later stages of a collapsing universe, suggesting that the irregularities that would arise here would be fractal, and therefore incapable of being smoothed out by an inflationary process. If there were irregularities near the Big Bang, it is suggested that these would also be fractal and incapable of being smoothed out by inflation. However, he appears to think that low entropy precludes such irregularities from the early universe, which might also prevent inflation from arising.
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