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Introduction: 1Consciousness The Hard Problem Almost the only point of agreement on consciousness is that it is a property not detected in the universe except in the brains of humans and possibly animals. The hard problem, an expression coined by the philosopher David Chalmers, is to explain how the matter of the brain could generate a property not detected elsewhere in the universe. The nature of consciousness does not seem to have been viewed as a problem until perhaps the late nineteenth century. Before that the normal concept of consciousness was essentially dualistic. There was a spirit or soul, which roughly equated to the modern idea of consciousness or self, and there was the obvious material stuff of the body. In the seventeenth century, Descartes clarified this concept, with the idea of a purely mechanical body connected to the thinking and agency/freewill of the immaterial mind via the pineal gland. This was a politically convenient theory. It allowed scientists to investigate the body without trespassing on the Church's traditional monopoly of anything to do with the soul. The Weakness of Dualism Dualist concepts worked reasonably well until the nineteenth century, when the explanatory successes of science and increasing political liberalism began to crowd in on the dualistic preserve of the soul. The scientific understanding of matter and energy was becoming causally closed, leaving no room for a link to external non-physical entities. Dualism could now be seen to suffer from a crucial weakness. It was not apparent how the non-physical or spirit stuff could interact with the physical body or the rest of the physical universe without itself possessing some physical characteristics. Vitalism Vitalism arose in this period as a plausible explanation for life and consciousness. The theory suggested that living organism were composed of a different class of matter from the rest of the universe, and that they were energised by some form of life force. The theory was superficially attractive, because it accorded with everyday experience, where people and animals appeared to be quintessially different from the inanimate matter of furniture or rocks. However, before very long further scientific advances demonstrated that this theory was entirely false. For all its complexity, the chemistry of the body was not in principle different from the chemistry of other matter. The Hard Problem The failure of dualim and vitalism and an increasingly detailed knowledge of the brain brought to the fore the hard problem of consciousness. Despite the many explanatory triumphs of science, it was still not apparent how the physical material of the brain could produce the property of consciousness. The functioning of the brain as described by neuroscience can be summarised as depending on the fluctuation of electrical potentials in the brain cells or neurons, which act as signals for the release of neurotransmitter chemicals to other neurons, where the process of electrical signal and chemical release is repeated. This is reenacted countless times over in a system of a hundred billion neurons, linked by many trillions of synaptic connections. As described, this is a causally closed system for receiving and responding to information and as such has neither a requirement for consciousness or anyway of producing it. The nature of electricity and of the chemicals that form the neurotransmitters is well understood down to the sub-atomic level, and nothing in this knowledge suggests that they have the capacity to produce a new property not detected elsewhere in the universe. Functionalism & Identity Theory These two approaches can probably be viewed as the dominant ideas in mainstream consciousness theory. Functionalism proposes that consciousness is a function of the brain's information processing system rather than its biological material. Any system that operates in the same way as the brain will produce consciousness regardless of what it is made of. Therefore, a silicon computer of sufficient complexity would automatically flip into consciousness at a certain stage. This is because the system, rather than the stuff from which it is made, is seen as being the process that produces consciousness. The underlying weakness of functionalism is that it does not explain how consciousness arises in a brain in the first place, and why any particular brain process should generate consciousness, rather than performing its function non-consciously. This problem applies regardless of whether the brain in question is made biological tissue, silicon or anything else. Identity theory is similar in tone to functionalism. It simply says that consciousness is identical to the brain or at least parts of it. The problem with an identity theory is that it needs to specify a particular object, or more plausibly a particular process in the brain that is physically identical to consciousnesss. It is not enough to show that the axons of neurons spike, or that there is a gamma oscillation between the cortex and the thalamus, when conscious process occurs. These things are correlated to consciousness, but that is another thing from saying they are identical to consciousness. The distinction between identity and correlation is crucial. Thunder and lightning are correlated but they are not the same physical process, even though they have the same ultimate cause. However, the morning star and the evening star are identical, because they are both names given to the planet Venus, a single physical object. Astronomy has conclusively demonstrated this identity, but neuroscience has not demonstrated that any particular physical process in the brain is more than correlated to consciousness. Both functionalism and identity theory run contrary to the normal reductive strengths of the scientific method. This requires an explanation of how things work down to the most fundamental level. Thus, if someone asks, what is sunlight, a scientific explanation would discuss nuclear fusion in the sun and the emission of photons that travel through space between the Sun and the Earth. The explanation offered here extends right down to the quantum level of nuclear fusion and photons, that is at the most basic level of the universe. In contrast, an explanation on the same lines as functionalism or identity theory would say that sunlight was a function of being near a star or was the same thing as being near a star. This is true, but it leaves an explanatory gap as to how sunlight is generated and transmitted. These ideas were rooted in the mainstream philosophy of the 20th century. This appears to have had an agenda to minimise the importance of first person or subjective experience. To compensate for this, it had to increase the emphasis on the brain as a logic machine, which in turn made much of the recent mainstream thinking in consciousness studies look more plausible. However, some writers are now challenging this orthodoxy and advocating that recent neuroscience supports the idea of direct and subjective experience functioning without the intervention of some computer type machinery. The computer type machinery functions at a secondary stage, to sort and evaluate the initial data. Consciousness as an emergent property The idea of consciousness as an emergent property of the brain's complexity has been suggested as a method of dealing with the apparent explanatory gap in functionalism and identity. The concept of emergent properties is well known in physics. The classic example is that liquidity is an emergent property in water. Taken by themselves hydrogen and oxygen atoms do not possess this property of liquidity, and yet when they are combined together in a sufficient quantity of water molecules, the property of liquidity emerges from the initially non-liquid components. However, there is one problem with this explanation. Once a property such as liquidity has emerged, it is possible to describe its physical basis, even though it was not apparent in its original components. Thus the liquidity of water is a function of the electromagnetic force acting between the constituent molecules. But no such physically instantiated explanation has been put forward relative to consciousness as an emergent property in the brain. All three theories, functionalism, identity and emergent properties tend to have a degree of ambiguity as to whether their proposals apply to what neuroscience currently knows about the brain, or requires additional new discoveries promised for the future. Most in fact look for more light to be cast on the consciousness problem by future research, but the indignation with which any radical proposals such as quantum consciousness are rejected, implies that they are not expecting discoveries that will make an important difference to our present overall view of the brain. It is as well to keep in mind Noam Chomsky, who warns us not to be too deferential to expertise, and that claims by scientists in fields such as this often go well beyond anything that can be supported by experiment or observation. Four Questions 1.) Why is there something rather than nothing? 2.) What is mind? 3.) What are the quanta? 4.) What are space and time? Why Quantum Theory? The question is often put as to why quantum theory should be involved in discussions of consciousness at all, and also as to why it should be treated as something special. The features of quantum theory that make it special and also possibly relevant to consciousness can be summarised as follows: 1.) Quantum theory describes the fundamental level of energy and matter. In contrast to higher levels, the quantum level has aspects, such as mass, charge and spin that are given properties of the universe, not capable of further reduction or explanation. In quantum theories of consciousness, it is suggested that consciousness is such a fundamental property existing at this level. 2.) The other fundamental aspect of the universe is spacetime, as described by the special and general theories of relativity. Although both relativity and quantum theory have both been tested to very high degrees of accuracy, they are nevertheless incompatible with one another. The gravitational force is the main problems, since the smooth continous curvature of space which describes gravity in general relativity is incompatible with the discreteness of particles/waves that is fundamental to quantum theory. String theory and loop quantum gravity have attempted to bridge this gap, but neither are yet regarded as adequate. The significance of all this is that physics is incomplete, and its completion might be capable of involving aspects that are relevant to consciousness. 3.) In traditional versions of quantum theory, the wave form of the quanta is conceived as a superposition of the many possible positions of a quantum particle. When the wave function collapses the choice of a particular position for the particle is random. This choice of position is an effect without a cause. The property of randomness is not in itself particularly useful in theories of consciousness, but it does open a chink in the deterministic structure of the universe, which is exploited by the Penrose/Hameroff model. 4.) Non-locality is the remaining special feature of quantum theory. Classical physics comprises only so-called billiard ball relationships, with bits of matter and energy bumping into one another. These relationships are local, in that they involve immediate contact. Such relationships are also normal in quantum physics. However quantum physics also possesses non-local relationships. This applies where two particles have been in some close relationship, such as two electrons in the same orbital. In this case they can become correlated. For instance the spin on two particles may always be opposite, if one spins up, the other spins down. This is not a problem while the particles are in a wave form, as both will be in a superposition of up and down. However, if the wave function of one particles collapses, that particle chooses one or the other superposition. When that happens the other particle will choose the opposite position. In experiment, this is shown to happen when the two particles are out of range of a signal travelling at the speed of light. No matter or energy is transferred and the experiment is not regarded as a violation of relativity, but it is seen that quantum properties can correlate instantaneously over any distance. The Nature of Quantum Theory The Descent into the Quantum World Suppose one were to ask for a scientific description of your hand. Biology could describe it in terms of skin, bone, muscles, nerves, blood etc. and this might seem a completely satisfactory description. However, if you was just a bit more curious, you might ask what the muscle and blood etc were made of. Here you would descend to a chemical explanation in terms of molecules of protein, water etc. and the reactions and relations between these. If you were still not satisfied with this, you would have to descend into the quantum world. At this level, the solidity and continuity of matter dissolves. The molecules of protein etc. are made up of atoms, but the atoms themselves are mainly vacuum. Most of the mass of the atom lies in a small nucleus, comprised of protons and neutrons, which are themselves made up of smaller particles known as quarks. The rest of the mass of the atom resides in a cloud of electrons orbiting around the nucleus. The fundamental particles are bound together by the four forces of nature, which are gravity, electromagnetism and the strong and the weak nuclear forces. The strong nuclear force binds together the particles in the nucleus of the atom, and acts only over the very short range of the nucleus itself. Gravity is a long-range force that mediates the mutual attraction of all objects possessing mass. The electromagnetic force is perhaps the force most apparent in everyday life. We are familiar with it in the form of light, micowaves and X-rays. It holds together the atom through the attraction of the opposite electrical charges of the electron and the proton. It also governs the interactions between molecules. In contrast to the nuclear forces, gravity and elecromagnetism are conceived of as extending over infinite distance, but with their strength diminishing according to the inverse square law. That is, if you double your distance from an object, its gravitational attraction will be four times as weak. The quanta can be divided into two main classes, the fermions, which possess mass and the bosons which convey energy or the forces of nature. The most fundamental fermions are the quarks making up the nucleus and the circling electrons, while gluons and photons are the most prominent bosons. The gravitons, which may intermediate the gravitational force remain hypothetical. The Quantum Wave The quantum particles or quanta are unlike any particles or objects that are encountered in the large scale world. When isolated from their environment they are conceived as having the property of waves, but when they are brought into contact with the environment, there is a process of decoherence in which the wave function is described as collapsing into a particle. The wave form of the quanta is different from waves in matter in the large scale world, such as the familiar waves in the sea. These involve energy passing through matter. By contrast, the quantum wave can be viewed as a wave of probability for finding a particle in a specific position. While the quanta remains in its wave form it is viewed as a superposition of all the possible positions that the particle could occupy. At the peak of the wave, where the amplititude is greatest, there is the highest probability of finding a particle, when the wave eventually collapses. However, the choice of position for each individual particle is completely random, representing an effect without a cause. This comprises the first serious conceptual problem in quantum theory. The Two-Slit Experiment The physicist Richard Feynman said that this classic experiement contained all the problems of quantum theory. In this experiement, light is emitted from a source, and passes through a screen with two slits in it, before falling onto another screen on the far side of the barrier. Where two waves of ordinary matter, such as water, interact, an interference pattern arises such that in some places the heights of the waves are added together and in other places they cancel out. In the early nineteenth century an experiment by Thomas Young showed that when a light source shone through two slits in a screen onto a further screen, then a pattern of light and dark bands appeared on a further screen, indicating that the light was in some places intensified and in other reduced or eliminated. This phenomenon demonstrated that light was a wave. Later, the experiment was refined. It could now be performed with one or two slits open. If there was only one slit open, the photons or light quanta, or any other quanta used in the experiment behaved like particles. They passed through the one open slit, interacted with the screen beyond and left an accumulation of marks on that screen, signifying a shower of particles rather than a wave. But once the second slit was opened the traditional interference pattern, indicating interaction between two waves, reappeared on the screen. The ability to generate the behaviour of either particles or waves, simply according to how the experiement was set up, showed that the quanta had a perplexing wave/particle duality. The wave/particle duality was shocking enough, but there was worse to come. Technology advanced to the point where photons could be emitted one at a time, and therefore impacted the screen one at a time. What is remarkable is that with two slits open, but the photons impacting one at a time, the pattern on the screen formed itself into the light and dark bands of an interference pattern. Somehow the photons 'knew' to arrange themselves into a pattern indicative on the interaction of waves. The question arose as to how the photons emitted later in time 'knew' how to arrange themselves relative to the earlier photons in such a way that there was a pattern of light and dark bands, indicative of interacting waves. The obvious solution was to place photon counters at the two slits in order to monitor what the photons were up to. However, as soon as a photon is registered by a counter, it collapses from being a wave into being a particle, and the wave related interference pattern is lost from the further screen. The most plausible way to look at it may be to say that the wave of the photon passes through both slits, or possibly that it tries out both routes, and after doing this the divided wave interfers with itself. The EPR Experiment & the Copenhagen Interpretation 'There is no Quantum World, there is no deep reality' Einstein disliked the inherent randomness involved in the collapse of the wave function. This was despite the fact that his revival of the idea of light in the form of discrete particles or quanta had contributed to the foundation of quantum theory. He sought repeatedly to show that it was flawed, and in 1935 he seemed to have produced a masterstroke in the form of the EPR (Einstein, Podolsky, Rosen) experiment. At the time this was only a 'thought experiement', a mental simulation of how a real experiment might proceed, but since 1982 it has been possible to perform this as a real experiment. The challenge to quantum theory presented by the EPR experiment hinges on the concepts of locality and non-locality. Locality comprises the idea of normal cause and effect under which objects or particles move or change as a result of being impacted by other objects or particles, or of being directly acted on by energetic forces such as the electromagnetic force. It is local because the object or force producing the action or change has to be in direct contact with the object or particle acted on. Morover where a force emitted by one object acts on another distant object such as light emitted from the Sun acting on the Earth, the force passes between the two objects at a speed not greater than that of light. By contrast, non-locality involves the ability of one particle to determine the behaviour of another distant particle instantaneously and without any matter or energy passing between the two. Einstein termed this 'spooky action at a distance'. With the EPR experiment it was shown, that as it stood, quantum theory violated the principle of locality, which is normally regarded as basic to scientific thinking and even to common sense. Quantum theory indicated that when two quanta had been closely related to one another, for instance in the same electron orbital, they could be regarded as quantum entangled. In this state certain aspects of their behaviour in relation to one another became fixed. For instance, quantum particles have a property of spin, which is partly analgous to the spinning of large-scale objects. Quanta can have the property of spin-up or spin-down. In an entangled state particles could have the relationship that when one had spin up, the other would always have spin down. However, as quanta, while they remained in a wave form, they both represented a superposition of spin-up and spin-down and therefore neither of them had a defined spin. The EPR experiment proposed that two such wave-form particles are moved apart. This could be a few metres along a laboratory bench or to the other side of the universe. The relevant consideration is that the two locations should be out-of-range of a signal travelling at the speed of light. Now, if an observation is made on one of the particles, its wave function collapses and it acquires a defined spin, let's say spin-up in this case. Now when an observation is made on the other particle, it will always be found to have the opposite spin. This defies the normal expectation of classical physics that a random choice of spin would produce approximately 50% the same spin and 50% different. Therefore, there is seen to be some non-local connection between the two particles, although it is not possible to describe or detect this in terms of a normal physical transfer of energy or matter. This non-locality and the randomness of the outcome of the wave function collapse constitute the two main puzzles in quantum theory. Copenhagen after the EPR Experiment The idea of non-locality, which appeared to deny much of what the science of the previous three hundred years had been trying to extablish, was as repugnant to the leaders of the quantum movement, such as Neils Bohr, as it was to Einstein as an opponent of quantum indeterminism. Some modern analysis suggests that Bohr changed his own view of the quantum world in a crucial manner after encountering the EPR challenge. Bohr's interpretation is known as the Copenhagen Interpretation and the form of this that emerged after 1935 essentially denied the objective existence or reality of the quantum wave. Bohr said that there was no quantum world, there was no deep reality. The quanta only achieved objective reality when they were the subject of an experiment or observation. The concept of reality or objective existence is here taken to mean that something exists even when it is not being observed by anyone. The Copenhagen Interpretation denies that sort of reality to the wave form of the quanta. The wave was to be seen only as an abstract mathematical expression allowing one to predict the likely position of a particle. If the wave form had no real existence, EPR type situations did not involve any physical action at a distance and the problem could be deemed to have gone away. The Aspect Experiment The question returned to the fore in the 1980's as technology overtook the orginal EPR thought experiement. In 1969 John Bell's Theorem had shown mathematically how EPR could be tested, and in 1982 Alain Aspect's experiment demonstrated the physical reality of EPR. The Aspect experiment did not invalidate Copenhagen, but it transferred the whole debate fom the hypothetical to the scientifically tested level. It presented physics with a stark choice. Either one could accept the Copenhagen Interpretation in which the locality of interactions was preserved, but the components of matter and energy were unreal, or one could have a world that was real but in part governed by non-local influences, Einstein's dreaded 'spooky action at a distance'. In fact, recent decades have seen a growing challenge to the orthodoxy of Copenhagen. This leaves us without a generally agreed interpretation of quantum theory. The Copenhagan Interpretation preserved us from non-locality but the concept of the quanta as mathematical abstractions that suddenly produced physical particles was troubling. It seems to propose a sort of dualism. How could mental constructs such as mathematical formula become physcial without having had some physical reality in the first place. Other interpretations have come more to the fore in recent decades. Decoherence has become particularly popular as a substitute for the traditional 'measurement' always referred in the Copenhagen version. In decoherence the collapse happens of its own accord as a result of the wave becoming entangled with the rest of the environment. In some recent versions it is suggested that there is no collapse, the information simply gets lost with the larger scale environment. In some quarters this is argued to provide a connection to the 'Many Worlds' interpretation. In this there is also no collapse, but a branching of reality into separate universes. So in the Schrodinger cat paradox, the universe splits into one universe with a live cat and one with a dead cat. Quantum Gravity & the Search for Reality The success of quantum theory, which describes matter and energy and relativity, which describes space and time has been marred by the incompatibility of these two key theories. Relativity describes gravity as the smooth, continuous curvature of space under the influence of massive objects, while quantum theory is based on the idea of energy and matter coming in discreet discontinous units. Mathematically these contrasting features lead to infinities, indicating that something is wrong. The attempt to overcome these problems has led to new theories, such as string theory, and loop quantum gravity. String theory proposes that the fundamental particles are not point particles, as had been assumed, but one-dimensional strings extending into higher dimensions, beyond the normal four dimensions. The extra dimensions are usually deemed to have been rolled up very small in the Big Bang, which accounts for them never having been detected. The manner in which the strings vibrate determines the nature of the particle involved. The analogy is that of the strings of a violin, where the vibration of the string determines the nature of the note. While this may appear both speculative and improbable, it has the advantage of being described by mathematics that would allow quantum theory and relativity to be compatible. The two main criticisms of string theory are that it produces 10^500 possible universes, and that it operates against the background of a fixed space-time, a concept that relativity showed to be invalid. An alternative approach is provided by loop quantum gravity (LQG). This approaches the problem from the direction of relativity and concepts of space-time, in contrast to string theory, which approaches from the the point of view of particles and quantum theory. LQG proposes that space-time is quantised or in discrete units. Space-time is suggested to be created out of a network or lattice or loops. This theory has drawn on the earlier spin network theory developed by Roger Penrose, and moves towards viewing particles and spacetime as dual aspects of the same thing. Problems & Opportnities in Quantum Theory We have emphasised three problematic aspects of the theory, acausality in the randomness of the wave function collapse, acausality in the non-local influences demonstrated by EPR type of experiments, and the resulting lack of agreement as to underlying reality of the physical universe. On the other hand, the theory successfully describes what appear to be the fundamental components of the universe. The arrow of explanation heads for ever downwards, from the manifest level of our everyday experience, through biology and chemistry, and finally to the level of the quantum world, and here the arrow strikes ground, for the quantum world manifests properties for which there is no explanation and cause. At the quantum level, we find properties of mass, charge and spin that are given properties of the universe lacking cause or explanation. If we ask, what is the charge on the electron, what is it, not what does it do, the answer will be a resounding silence. This is the only level of the physical universe where it might be possible for science to insert consciousness as an additional fundamental. The existence of such fundamental properties opens up the possibility that consciousness is another such fundamental, a possibility strengthen by the apparent inability of science to explain consciousness in terms of less fundamenetal aspects of matter. In this site we look particularly at Penrose's theory which suggests that consciousness is derived from interaction with the fundamental spacetime geometry. The Penrose/Hameroff Model of Quantum Consciousness Godel's Theorem Several models of quantum consciousness have emerged in recent decades. The Penrose/Hameroff model also referred to as the ORCH OR model looks to be the most developed and specific both in terms of how consciousness arises and how it is generated by the brain. Penrose developed his theory from a mathematical angle. The first stage of his argument considers Godel's Theorem. The mathematician and logician Kurt Goedel demonstrated that with any set of axioms, it was possible to produce a statement that was obviously true, at least to mathematicians, but could not be proved by means of the axioms. This much is accepted and uncontroversial in modern logic and mathematics. What is, however, highly contentious is the use that Penrose made of Godel's theorem. He claimed that the ability of the human mind to go beyond what could be demonstrated by the mathematical axioms showed that the functioning of the human brain had to include some process that was not based on an algorithm (system of calculations). The functioning of a computer is based on algorithms, and Penrose therefore claimed that Godel had demonstrated that human brains could do something that no computer would ever be able to do. Penrose went on to ask, what it was in the human brain that was not based on algorithms. The physical law is described by mathematics, so it is not easy to come up with a process that is not governed by algorithms. The only plausible candidate that Penrose could find was the collapse of the wave function, where the choice of the position of a particle is random, and therefore not the product of an algorithm. However, the very randomness of the wave collapse disqualifies it as a useful basis either for mathematical judgement or for the useful exercise of any free will that might be thought to be linked to consciousness. Objective Reduction Penrose attempted to deal with this by proposing that in certain circumstances there could be an alternative form of wave function collapse. Penrose called this Objective Reduction (OR). The collapse or reduction was originally viewed as the result of an experiment or observation, and more recently it has been associated with the wave become involved with its environment, so-called decoherence. However, Penrose proposes a further possibility for collapse not involving measurement or entanglement with the environment. The quantum wave is seen as a superposition of the possible positions that a particle might occupy once the wave function collapses. Penrose suggests that each superposition has its own spacetime geometry, its own relationship to whatever form of lattice or network is assumed to comprise the quantised structure of space itself. The separation of the superpositions, each with its own space-time geometry constitutes a form of blister in space-time. However once the blister or separation grows to more than the Planck length of 10^-35 metres the separations begin to be affected by the gravitational force, the superposition becomes unstable, and soon collapses under the pressure of its gravitational self-energy, and as it does so chooses one of the possible positions for the particle. Penrose argues that, in contrast to the normal form of collapse, there are indications that in this case there is a decision process that is neither random nor computationally/algorithmically based, but is more akin to the 'understanding' by which Penrose claims the human brain goes beyond what can be achieved by a computer. Some support for this speculative hypothesis is given by the work of Geroch and Hartle. Working on quantum gravity in the 1980s by the physicists, Robert Geroch and James Hartle ran up against a problem in deciding whether two space times were the same. The problem was solvable in two dimensions but intractable in the four dimensions that accord with the four dimensional space time in which the superposition of quantum particles needs to be modelled. It has been shown that there is no algorithm for solving this problem in four dimensions. Penrose takes this to suggest that the geometry of space-time, the most fundamental level of the universe is non-computable. Hameroff & the Quantum Brain When Penrose first launched his theory in 1989, he faced a considerable explanatory gap as to how his type of wave function could occur in the brain, and if they did occur how they would combine together to influence the large scale activity of the brain. Stuart Hameroff had approached the question of consciousness from an entirely different angle through a career in anaesthesia. Hameroff stressed that the anaesthetic process obliterated consciousness, but leaves many other body functions that require activity in the brain substantially unaffected. This suggests that the physical basis of consciousness in the brain is distinct from many other brain activities. Hameroff developed the theory that consciousness in the brain was based on structures known as microtubules. Neurons contain a supportive skeleton known as the cytoskeleton. Microtubules form the core of the cytoskeleton. As neuroscience has progressed the role of the cytoskeleton and microtubules has assumed increased importance. In addition to providing a supportive structure for the cell, the cytoskeleton is important for transporting molecules such as neurotransmitter molecules within the cell, for cell movement, growth, shape and division. Hameroff suggested that the microtubules could support large scale quantum features known as Bose-Einstein condensates. These can occur when large numbers of bosons, massless particles such as photons, become locked in phase, and exist as a single quantum object, which can extend to the macroscopic scale. The existence of such objects in the brain would make it easier for quantum features, which are normally extremely tiny, to have an influence over the macroscopic scale of the brain. Microtubules can be extensive within individual neurons, but Hameroff suggested that it might be possible for condensates to link to other neurons by means of gap junctions between neurons. In recent years, gap junctions have been discovered to be common in areas of the brain assocociated with consciousness. In this way, the condensates could extend over large areas of the brain. Hameroff also claims that there a now dozens of academic papers showing that cortical interneurons linked to gap junctions are correlated to the so-called 40Hz (actually a range of 30-70Hz) gamma synchronous oscillations, which is one of best known neural correlates of consciousness. The microtubule/condensate hypothesis is tied together with Penrose's ideas in the ORCH OR. Bose-Einstein condensates extending over large areas of the brain are suggested to collapse under their own gravitational self energy, rather than interaction with the environment. This form of collapse connects them to the non-computational decision taking available at the level of the fundamental space time geometry, at the same time as connecting them to, and allowing them to influence cognitive activity in the brain. The ORCH of the ORCH OR stands for orchestrated and refers to the the hypothetical process by which the mictotubule associated proteins (MAPs) influence or 'orchestrate' the quantum processing of the microtubules. The theory could also can be taken to regard non-computational activity at the fundamental universe as also being equivalent to the raw experience/awareness or qualia associated with consciousness. Quantum Computing, Brains & Robots The theory also proposes that the microtubules act as quantum computers. Quantum computing, which currently exists only in prototypes, and involves formidable technical problems, is based on the non-local entanglement of quantum particles or qbits, with the amount of computing power doubling with each new particle that the computer entangles. It is important to stress, however, that normal quantum computing does not involve consciousness, because the computation would be terminated by a measurement rather than the kind of objective reduction suggested by Penrose. However, quantum computing, could solve some of the other problems of brain function and the related area of artificial intelligence/robotics. Many commentators on the subject take the view that there is no adequate algorithm for perception in the brain, or for decision, for instance which route, out of a potentially infinite number of routes, an animal might take in evading a predator. This problem looks similar to the problems that have dogged artificial intelligence, where despite a huge rise in available computing power, we have not developed autonmous robots to tackle any wide range of everyday tasks. Objections to Quantum Consciousness The most cogent objection to any form of quantum consciousness is that the environment of the brain would lead to rapid decoherence of quantum states. Hameroff's main reply to this has been to argue that the microtubules and other parts of the cytoskeleton are capable of being sufficiently screened from conditions in the rest of the brain. The main form of screening suggested involves a cyclical process by which actin filaments, themselves part of the cytoskeleton turn the interior of the cell from a watery solution into a type of gel or quasi-solid. While the cell is in this state, water near to the microtubules would be in an ordered state. It is argued that the electric dipoles of the water molecules could becomes aligned with those of protein molecules forming the microtubules. It is proposed that the combination of the gel state and the ordering of water could screen the microtubules sufficiently to allow them to carry quantum coherent processing. Further to the actual screening of the microtubules, it is argued that the condensates could be akin to high temperature superconductivity. The normal model is for condensates to only occur at temperatures close to absolute zero, but there are examples of superconductivity at temperatures as high as -23 degrees centigrade as a result of energy pumping. It is suggested that the brain condensates could be supported by energy pumping, as a result of the thermal disequilibrium maintained in biological tissues. In respect of this, it is argued that critics of the theory assume thermal equilibrium when calculating time to decoherence, but biological systems are far from thermal equilibrium. Evidence for Quantum Coherence in the Brain There is, moreover, a limited amount of evidence for the existence of quantum coherence in the brain. This does not refer to condensates, but it does undermine the basic argument that quantum coherence of any kind could not exist in the brain for a useful length of time. In 2000 coherence was detected in an experimemt aimed at finding improves MRI methods. The experiemt was conducted at Princeton by W. Warren, W. Richter et al. In another experiment, also in 2000, Zizzi et al detected quantum coherence in the frontal, pre-motor, parietal and visual areas of the cortex. The most interesting factor here was that the duration of the coherence was around 25ms, which could be viewed as related to the 40Hz gamma oscillation between the cortex and the thalamus. Finally in 2006, V. Prokhorenka at the University of Toronto showed that a process of isomerisation was steered by quantum wave effects. The conclusion in this experiment was that the wave properties of matter can be observed and even manipulated in systems as large and complex as the brain. Possibly the most interesting experimental work in this area is the study of photosynthesis by Engel et al of the University of California, Berkeley published in Nature in April 2007. This paper points out that photosynthetic complexes are adapted to capture light, and to put its energy into long-term storage. This process has normally been described in classical terms, and quantum coherence has been to a good extent ignored in the traditional analysis. However, the possibility of quantum coherence has been predicted, and in this paper the authors describe evidence for long-lived quantum coherence being involved in energy transfer within photosynthetic systems. The wavelike process is thought to account for the efficiency of the sytem, because it allows the sampling of large areas of phase space, in order to find the most efficient path, or to transfering energy to the area in the lowest energy state. The Engel et al experiment involved electronic spectroscopy to observe the evolution of electronic coherence. Quantum beating was found to last for 660 fs, which was much more than the 250 fs estimated for conventional models. Conventional models had assumed that quantum coherence would be rapidly destroyed, and had therfore not factored it into their models of photosynthetic systems. By contrast, the authors conclude that long-lived quantum coherence must play an active role in photosynthetic systems. A quantum coherent system allows sampling in order to direct energy to the lowest energy state. The system is viewed as performing a quantum computation, in which it senses many states simultaneously and from these selects the correct answer. This is seen as analogous to Grover's algorithm, allowing both the discovery of the lowest energy state and the transfer of coherence. This is more efficent than any classical search engine. Protein is seen as providing the structure in which coherence can be preserved and at the same time modulating the coherence as a result of the local dielectric environment. Plants are clearly structurally very different from brains, but the significant point here is that quantum coherence is sustained in a biological tissue, with a temperature and complexity of environment that would conventionally be expected to result in rapid decoherence. |
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