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General Articles 2General Articles: 2 - Further general articles relative to quantum consciousness theories 1.) Unconscious perception - Merikle 2.) Putting the puzzle together - James Newman 3.) Emergence & the Mind/Body Proble 4.) Rhythms of the Brain - Gyorgy Buzsaki 5.) A quantum theory of the origin of life on Earth 6.) Inflationary theory and the origins of the universe - Roger Penrose - Road to Reality 7.) Now you see it, now you don't - Cell Doctrine 8.) Quantum mechanics in the brain - Koch & Hepp Psychological Investigations of Unconscious Perception Philip Merikle Dept. of Psychology, University of Waterloo Meredyth Daneman, Dept of Psychology, University of Toronto Journal of Consciousness Studies, 5, No 1, 1998, pp. 5-18 This paper discusses how it is possible to distinguish conscious and unconscious perception. These are shown to have qualitatively different effects. In a word experiment, subjects were shown words for 50 ms, which were not consciously perceived, and other words for 150 msecs, which were consciously perceived. After being shown these words, the subjects performed a memory test that demonstrated they were less successful with the words shown for 50 ms. A similar result was demonstrated with an experiment that involved naming a colour after, seeing a different colour either consciously or unconsciously. In the context of the debate about consciousness and in particular the ultra-reductionist ideas popularised by Daniel Dennett, the demonstration of the different effects of conscious and unconscious perception seems to undermine the argument that consciousness is simply brain processing, and has nothing of itself to add to unconscious brain processing. References:- Merikle, P. (1984) Towards a definition of awareness Bulletin of the Psychonomic Society, 22, pp. 449-50 Merikle, P. (1992) Perception without awareness American Psychologist, 47, pp. 792-5 Merikle, P. & Cheesman, J. (1987) Subliminal perception in Ed. Wallendorf, P. & Anderson, P. Advances in Consumer Research, Vol. XIV Association of Consumer Research Merikle, P. & Daneman, M. (1996) Memory for unconsciously perceived events Consciousness and Cognition, 5, pp. 525-41 Merikle, P. & Joordens, S. (1997) Measuring unconscious influences In Ed. Cohen, J. & Schooler, J. Scientific Approaches to Consciousness Erlbaum Merikle, P. et al (1995) Relative magnitude of unconscious influences Consciousness and Cognition, 4, pp. 422-39 Murphy, S. & Zajonc, R (1993) Affect, cognition and awareness Journal of Personality and Social Psychology, 64, pp. 723-39 Reingold, E. & Merikle, P. (1988) Perception without awareness Perception & Psychophysics, 44, pp. 563-75 Reingold, E. & Merikle, P. (1990) Study of unconscious processes Mind & Language, 5, pp. 9-28 Putting the Puzzle Together, towards a general theory of the neural correlates of consciousness James Newman Colorado Neurological Institute Journal of Consciousness Studies, 4, No. 2, 1997, pp. 100-21 Newmann suggests that orientation relative to the outer world, motor-sensory representation, and REM sleep converge on a core-conscious system called the extended reticular-thalamic activating system (ERTAS). The ERTAS has many projections with the cerebral cortex, and late 20th century research had increased knowledge of the connections between ERTAS and the major cognitive systems of the brain. It was noted as early as the mid 20th century that electrodes implanted into the thalamic system could alter the cortical EEG, either synchronising it, or desynchronising it. This area was associated with compulsion of attention and shifts in the reactivity of the nervous system. The thalamus appears to be the region of the brain that drives alpha rhythms in the cortex. Stimulation of the diffuse thalamic nuclei at the 8-12Hz alpha frequency drives cortical waves, whereas higher frequency stimulation could abolish cortical waves. alpha frequency stimulation of the diffuse thalamic nuclei on one side produced the same frequency waves in the same nuclei of the opposite hemisphere. Later research suggests that the reticular nucleus is the main pacemaker for the alpha spindles, although the intralaminar cortex is also important for their distribution in the cortex. Other studies suggest that the intralaminar complex controls the so-called 40Hz oscillation found in both alert states and dreaming. Newman stresses that EEG rhythms have been unfashionable in neuroscience during much of the late 20th century. However, studies back to the 1940s demonstrate correlations between alpha and cognitive activities. Alpha is most prominent in the visual cortex. Alpha waves sweep periodically across the cortex and their speed depends on levels of arousal. It is suggested that alpha activity impacts on 40Hz gamma activity. Newman suggests that the ERTAS is central to the interplay of alpha and 40Hz. This oscillation is shown to travel from the front of the brain to the occipital lobe. Other studies suggest that this wave is involved in binding together the representations produced by different areas of the cortex. Thus spatially distributed neural actvities are bound in time. The succession of these bound moments could produce the stream of perceptions found in consciousness. Newman admits that the 40Hz synchrony idea does not deal with the problem of selectivity. We are only conscious of a tiny selection of the information in the brain, and somehow the rest has to be filtered out of consciousness. Newman thinks that the reticular nucleus is important in this respect. The nucleus is comprised of thin sheets of neurons on the left and right side of the thalamus. It projects mainly to the rest of the thalamus rather than the cortex. Nearly all the thalamocortical pathways pass through this area, which is in a good position for central control and representation of the information flow. The structure is seen as an array of tiny gates controlling the flow of neural information. Further experiments confirmed the role of the prefrontal in suppressing irrelevant stimuli and planning and monitoring goal orientated behaviour. At the same time, the posterior cortex is seen to stimulate selective attention. The thalamocortical circuit is thought to modulate which streams of information get attention. However, Newman does not think the modular approach to the brain is enough to deal with the problem of selecting information flows and also with the well-known binding problem of how unified consciousness is created. An article by J. Gray argues that the contents of consciousness are related to the limbic system, which surrounds the thalamus, and instantiates emotional processes. The prefrontal and the basal ganglia also have strong links to the limbic system. Parts of the frontal lobe, such as the cingulate, are seen as a kind of executive over the limbic, for working memory, inhibition of conditioned responses and goal directed attention. Gray points to the importance of understanding why there are differences between the conscious and unconscious and between the conscious present and the experience of memories. Things are more likely to be conscious if they vary to a significant degree from expectations. However, destruction of the limbic area does not oblate consciousness. The areas where this can happen are the reticular formation in the brain stem, the intralaminar complex in the thalamus and the parts of the cortex most strongly connected with this. References:- Crick, F. (1984) Function of the thalamic rreticular complex Proceedings of the National Academy of Sciences, USA, 81, pp. 4586-90 Freiburg, E. & Ross, D. (1993) Degeneration of thalamic reticular neurons Neuroscience Letters, 151, pp. 115-19 Funke, K. & Eyse, U. (1992) Corticogeniculate feedback Brain Research, 573, 217-27 Fuster, J. (1980) The Prefrontal Cortex Raven Press Goldman-Rakic, P. (1988a) Changing concepts of cortical connectivity John Wiley & Sons Goldman-Rakic, P. (1988b) The prefrontal contribution to working memory and conscious experience in Ed. Rakic, P. & Singer, W. Neurobiology of the Cortex John Wiley & Sons Ltd Gray, C. (1994) Synchronous oscillations Journal of Computational Neuroscience, 1, pp. 11-38 Gray, J. (1995) A neuropsychological conjecture Behavioural and Brain Sciences, 18 (4), pp. 659-722 Groenewegen, H & Berendse, H. (1994) Non-specific midline and intralaminar thalamic nuclei Trends in Neuroscience, 4 (2), pp. 52-8 Herkenham, M. (1986) Non-specific thalamocortical projections in Ed. Jones, E. & Peters A. Cerebral Cortex Plenum Press Hunter, J. & Jasper, H. (1949) Thalamic stimulation Electroencephalography and Clinical Neurophysiology, 1, pp. 305-21 Jasper, H. (1960) Unspecific thalamocortical relations in Ed. Field, J. et al Handbook of Neurophysiology American Physiological Society Laberge, D. (1995) Attentional Procesing Harvard University Press Llinas, R. & Paré, D. (1991) Dreaming and wakefulness Neuroscience, 44 (3), pp. 512-35 Llinas, R. & Ribary, U. (1992) The 40Hz response during sensory input In Ed. Basar, E. & Bullock, T. Induced Rhythms of the Brain Birkhauser Llinas, R. & Ribary, U. (1993) 40Hz oscillations characterise dream states Proceedings of the National Academy of Sciences USA, 90, pp.2078 Llinas, R. et al (1994) Temporal thalamocortical binding In Ed. Busaki, G. et al Temporal Coding in the Brain Springer Verlag Macchi, G. & Bentivoglio, M. (1986) Thalamic intralamina nuclei and the cerebral cortex In Ed. Jones, E & Peters, A. Cerebral Cortex, Vol. 5 Plenum Press McCormick, D. & Krosigk, M. (1992) Corticothalamic activation Proceedings of the National Academy of Sciences USA, 89, 2774-8 Mitrofanis, J. & Guillery, R. (1993) Thalamic reticular nucleus Trends in Neuroscience, 16 (6), pp. 240-5 Moruzzi, G. (1964) Reticular influences on the EEG Electroencephalography and Clinical Neurophysiology, 16, pp. 2-17 Moruzzi, G. & Magoun, H. (1949) Reticular formation and activation of the EEG Electroencephalography and Clinical Neurophysiology, 1, pp. 455-73 Newman, J. (1994) Consciousness requires global activation Psyche, 1, (1), pp. 73-6 Newman, J. (1995a) Thalamic contributions to attention and consciousness Consciousness and Cognition, 4, (2), pp. 172-93 Newman, J. (1995b) Reticular thalamic activation generates conscious contents Behavioural and Brain Sciences, 18 (4), pp. 691-2 Newman, J. (1996a) Reticular thalamic activation In Synchronous oscillations and the Emperor’s New Clothes Newman, J..(1997) Putting the puzzle together: Part I Journal of Consciousness Studies, 4 (1), pp. 47-66 Newman, J. & Baars, B. (1993) Access to consciousness Concepts in Neuroscience, 4 (2), pp. 255-90 Newman, J. & Baars, B. (1997) A model for attention and consciousness In Ed. O’ Nuallain, S. et al Two Sciences of Mind John Benjamins Papez, J. (1937) A proposed mechanism of emotion Archives of Neurology Psychiatry, 38, pp. 725-43 Parent, A. & Hazrati, L. (1995) Functional anatomy of the basal ganglia Brain Research Reviews, 20, pp. 91-127 Posner, M. (1994) The mechanisms of consciousness Proceedings of the National Academy of Sciences USA, 91, pp. 7398-403 Posner, M. et al (1987) Isolating attentional systems Psychobiology, 15 (2), pp. 107-21 Scheibel, A. (1980) Substrates of arousal In Ed. Hobson, J. & Brazier, M. The Reticular Formation Revisited Raven Press Scheibel, M. & Scheibel, A. (1966) The organisation of the nucleus reticularis Brain Research, 1, pp. 43-62 Shosaku, A. et al (1989) Inhibitory circuit in thalamus Progress in Neurobiology, 32, pp. 77-102 Sillito, A. et al (1994) Synchronisation of thalamic firing Nature, 369, pp. 479-82 Skinner, J. & Yingling, C. (1977) Central gating mechanisms In Ed. Desmedt, J. Event-related cerebral potentials, Vol. I Karger Steriade, M. et al (1991) Fast oscillation in the thalamocortical systems Proceedings of the National Academy of Sciences USA, 88, pp. 4396-400 Steriade, M. et al (1990) Thalamic Oscillations and Signalling John Wiley and Sons Steriade, M. et al (1993) Thalamocortical oscillations Science, 262, pp. 649-742 von der Malsburg, C. & Singer, W. (1988) Cortical network organisation In Ed. Rakic, P. & Singer, W. Neurobiology of the Cortex John Wiley Yingling, C. & Skinner, J. (1975) Unit activity in nucleus reticularis thalami Electroencephalography and Clinical Neurophysiology, 39, pp. 635-42 Emergence & the Mind-Body Problem Michael Silberstein Dept. of Philosophy, Elizabeth Town College, PA, USA Journal of Consciousness Studies, 5, No. 4, 1998, pp. 464 82 Silberstein considers that none of the popular explanations of consciousness are of much value, and he is particularly dismissive of philosophical approaches to consciousness. Physicalism seeks to reduce consciousness to the purely physical, but stands accused of not explaining why this is so or how consciousness can arise from non conscious matter. Silberstein distinguishes between reductive and non reductive forms of physicalism. The non-reductive type provides no explanation of how consciousness arises from the non-conscious. What he describes as reductive physicalism is otherwise known as identity theory, which seeks to say that certain brain systems are identical to consciousness in the way the H20 is identical to water. The author does not see this as a sufficient explanation for the observable phenomena of consciousness, presumably because we know enough about the components of water and their relationships to explain their behaviour, while what we know about biological matter does not provided a micro-explanation of the behaviour of consciousness. At the same time, Silberstein attacks fundamentalist theories that suggest that consciousness is some form of fundamental property. His view is that consciousness cannot be reduced to or identified with non-consciousness, and presumably assuming that we reject dualism, then consciousness can only be explained as a fundamental given of the universe. He stresses that this is also a reductionist position, in the sense that all physical properties can ultimately be reduced to an explanation at the fundamental level. This is a useful reminder given the furious attacks on fundamentalist ideas by the mainstream reductionists. Silberstein feels that fundamentalism does not answer any questions either, and in particular he does not think it explains the connection between the brain and consciousness. He attacks fundamentalism as being just more materialism, just another way of seeing the world as an aggregation of particles. This might be considered rather too sweeping a criticism for all types of fundamental or quantum consciousness. Stapp for instance appears to suggest that consciousness is actually a separate property collapsing the wave function in the brain, while Penrose posits the idea of the geometry or possibly measurement of space time itself providing the essential element of consciousness, which goes somewhat beyond a mere aggregation of material particles. Silberstein’s own explanation looks close to that suggested by Burns and Hagelin, that consciousness is related to unified physics. He sees spontaneous symmetry breaking as a form of emergence, with the four forces of nature emerging by means of symmetry breaking from the original unified force. The weakness of the article is mainly that Silberstein seems too taken up with establishing the actual principle of emergence, and does not discuss the mechanism by which we get from unified force and symmetry breaking near the beginning of time and to consciousness in the modern brain. References:- Anderson, P. (1994) A Career in Theoretical Physics World Scientific Publishing Aspect, A. et al (1982) Experimental realisation of EPR Physical Review Letters, 49, pp. 91-4 Ghiradi, G., Rimini, A., & Weber, T. (1986) Unified dynamics for micro and macro systems Physical Review, D34, pp. 470-91 Hawthorne, J. & Silberstein, M. (1995) For whom the Bell arguments toll Synthese, 102, pp. 99-138 Kim, J. (1978) Supervenience and incommensurables American Philosophical Quarterly, 15, pp. 149-156 Kim, J. (1993 Supervenience and mind Cambridge University Press Lycan, W. (1996) Consciousness and experience MIT Press Primas, H. (1981) The Philosophical Issues of Theoretical Chemistry Springer Verlag Teller, P (1986) Relational holism and quantum mechanics British Journal for the Philosophy of Science, 37, pp. 71-81 Wigner, E (1983) Remarks on the mind-body question in Ed. Wheeler and Zurek Quantum Theory and Measurement Princeton University Press Rhythms of the Brain Gyorgy Buzsaki Buzsaki's book is disappointing in so much that it barely touches on the issue of consciousness, nor the possible involvement of the gamma synchrony. However, it is useful to the extent that few books discuss the existence of brain waves or oscillations in such detail. Much of the book concentrates on the oscillatory relationship between the pyramidal cells producing the excitatory neurotransmitter, glutamate, and the interneurons producing the inhibitory GABA neurotransmitter. These oscillations are related to the concept of self-organisation, which is itself fairly new in science. Biological systems are here viewed as complex, meaning not just complicated, but also involving non-linear relationships, and the amplifying or dampening of feed back loops. Neural systems that produce self-sustaining patterns of behaviour are called central pattern generators. Buszaki stresses that we are dealing with open complex systems far from equilibrium, sometimes called dissipative structures, which can progress themselves from disorganised to more organised. In this way, complicated protein structures can be built up by simple algorithmic steps in the variation of the four nucleic acids. Such systems can exchange energy, matter or entropy with the environment. This relates to non-linear dynamics and chaos theory. Buszaki stresses that brains should be understood in terms of interactions of the whole brain. Isolated bits of cortex in the laboratory fail to act spontaneously in the way that the brain does, and same problem is found in computer simulations of the brain. This appears to be a problem for Libet's idea of the 'mental field', which he suggests might be detected in experiments on isolated bits of cortex. Unexpected solutions emerge from non-linear equations, because the behaviour of a complex system cannot be predicted from its individual parts. Certain constituents of the whole gain dominance. This is described as an attractor or attractor property, and it decreases the degrees of freedom of the system. These systems could incorporate external influences into their future behaviour, and thus come to possess patterns for learning and growth. Excitatory & Inhibitory Influences Thermodynamics as applied to closed systems and inanimate matter only possesses an excitatory interaction and uni-directional change, as a result of collisions with other particles or objects. Brains differ from such purely excitatory systems in containing both excitatory and inhibitory forces. This represents the difference between thermodynamic equilibrium systems destined to move towards greater and greater disorder, and the structure of the brain and biological tissue, which trends towards order. The latter derives its order from the balancing effect between the excitatory and inhibitory forces. Excitation by itself generates further excitation, moving the system involved only in the forward direction. But a ring of excitatory neurons can have inhibitory neurons in the same circuit. Such networks can self-organise complex properties. The presence of inhibition introduces hard to predict non-linear effects. In the brain, the relationship between pyramidal cells and interneurons governs cortical activity. All the main excitatory pathways have a matching group of interneurons. In physics, the balance of opposing forces, such as the forces of excitation and inhibition seen in the brain, often gives rise to rhythmic behaviour. Rhythms arise when positive and negative forces balance one another. The positive force drives the system away from a state, and the negative drives it back towards the original state. In the brain, the frequency of the oscillation depends on the duration of inhibition. Interneurons utilise GABA wherever they are located in the brain, and GABA is connected to the gamma synchrony, which arises in most brain structures. The gamma synchrony constrains axon potentials, so indirectly interneurons are seen as co-ordinating the timing of action potentials. Short oscillations in the gamma synchrony have been detected between distant sites processing different but related inputs. Resonance & Oscillation Buzsacki sees resonance as a condition in which energy is fed into a system at the natural frequency of a system. The build up of energy in an object forces it to resonate. A sudden energy pulse can start the oscillation. An external force is supplied periodically at a frequency that matches the natural frequency of an object. Buzsaki views the neuron as a resonator-oscillator. The default state of cortical networks using glutamate and GABA is synchrony. Single neurons oscillate, because voltage-gated ion channels with opposite properties depolarise and hyperpolarise the membrane. Interneurons are the building blocks for network oscillators. Assemblies in the waking brain usually synchronise in the gamma range. The structure of the brain suggests an evolutionary preference for oscillation, which is the cheapest way of sustaining synchrony. The hypothalamus controls the daily or circadian fluctuations in body temperature, hormone secretion, heart rate, blood pressure and sleep/wake periods. Molecular mechanisms supporting the 24 hour cycle are present in every cell. The circadian cycle can be delayed or advanced by light. Certain neurons in the retina target the suprachiasmatic nucleus. This synchronises all cells in the body. Within the circadian are two other rhythms, one of 3-8 hours and within that one of 90-100 minutes. Sleep isolates the brain from the body and the environment. There are five stages of sleep. Stage I is the transfer between waking and sleeping, with mainly alpha and theta wave activity. Stage 2 witnesses the emergence of sleep spindles. Stage 3 is a mixture of sleep spindles and delta waves, while Stage 4 is dominated by delta waves. Approximately half of sleep consists of Stages 2 & 3. Stage 4 comprises 10-15%, and may be missing after age 40. Stage 3 & 4 are often grouped together as slow wave or delta sleep. REM comprises 20-25% of sleep time and occurs mainly towards the end of the sleep cycle. There are typically four or five sleep cycles of 70-90 minutes each night. The brain oscillations comprose delta waves from 0.5-4Hz, theta from 4-8Hz, alpha from 8-12Hz, beta from 12-30Hz, gamma from about 30-90Hz and the fast oscillation from 140-200Hz. Sleep spindles reflect interaction between GABA reticular neurons and excitatory thalamocortical cells. Alpha waves are released above the visual cortex, simply by closing the eyes, and this is taken to indicate a degree of cortical disengagement. The forebrain patterns of REM sleep are similar to waking. The metabolic cost of brain activity is only slightly reduced during sleep. There is a strong neuronal synchrony in sleep brought about by various oscillations. A Quantum theory of the origin of life on Earth Zeeya Merali New Scientist: 8th December 2007 This recent article in the New Scientist revives a long-established idea that the origin of life on Earth could derive from a quantum process. The first to suggest this appears to have been Schrodinger in his 1944 book, 'What is Life? The idea has been relaunched by Jonjoe McFadden of the University of Surrey UK, who has also proposed the idea of an electromagnetic field as a quantum substrata of consciousness. The proposal is in many ways the mirror image of the proposals for quantum consciousness. The quantum process is suggested to provide an explanation for something that macroscopic science has failed to explain, and the main argument against the quantum is the same as in the case of consciousness, that is that decoherence in the conditions of the primordial Earth would be far too quick for quantum coherence to be relevant. As with the quantum consciousness idea, proponents of the quantum view have argued for possible shielding of the quantum process. The origin of life is not as hard a problem as consciousness, but it has certainly proved difficult. The idea that life arose from some primordial soup of molecules is inherently plausible. The difficulty arises in getting the molecules to combine in the right order. The simplest self-replicating structure is estimated to require 165 base-pair molecules placed in the right order and the odds against getting the right structure is 4^165, a number said to be greater than the number of electrons in the universe. Of course, if Nature made enough tries for long enough it should get there eventually. However, life on Earth appeared quite soon after the planet became at all suitable for life, making the 4^165 chance a bit improbable. McFadden proposes that a form of quantum computing arose in the primordial conditions allowing a 'search' of all the possible ordering of the molecules, and leading to the discovery of the sequence that self-replicated. Some support is given to his idea by the suggestion that the speed at which nucleotide bases are matched up when cells split also requires quantum processes. As with quantum consciousness, the main problem for the proposal is the speed at which quantum decoherence would be expected to occur in the type of conditions that would permit the origin of life. However, two other researchers, Asoke Mitra and Garge Mitra-Delmotte have suggested how quantum processes could have been shielded, in a manner rather akin to Hameroff's idea of quantum processes being shielded within the microtubule. The Mitras focus on sub-sea vents that have been seen as a favourite location for the origin of life in recent years. Another scientist, Michael Russell at the University of Glasgow had already shown that the necessary molecules could react with iron sulphide found close to the vents. The Mitras argue that chambers found near sub-sea vents could shield quantum processes. Magnetic fields generated by the iron sulphide are suggested to protect the quantum states of the necessary molecules. The Mitras point out that magnetic fields are used in an analogous manner in proto-type quantum computers in order to maintain the entanglement of particles used as qubits. The idea is claimed to be testable by means of existing technology. Substantiation of the idea would not in itself appear to prove that consciousness is explained at the quantum level. However, if quantum processes were seen to have been involved in the origin of life, that would seem to be an inherent plausibility that the adaptive advantages of the speed of quantum search processes would have been incoroporated into living organisms. Inflationary theory and the early universe Based on 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. Now you see it, now you don’t Cell doctrine Neil Theise Beth Israel Medical Centre, New York Nature, vol. 435, June 2005 Complexity theory describes the emergent self-organisation of complex adaptive systems, and has an important place in modern scientific thinking. One principle of complexity is that things look different at different scales. Something that can be recognised as a dynamic organisation at the level of the interacting agents may look like a single entity at a higher scale. An ant hill can be recognised as an emergent self-organisation of the individual ants, when viewed at close quarters, but at a higher scale, say a distance of some metres, it may appear as a single dark mass. Biological cells are also agents within a complex system. One criteria for a complex system is that it has a large number of agents self-organising to maintain stable conditions, often by means of negative feed back loops. Negative feedback means that a system contains the means by which its output is limited or controlled. A central heating system and a thermostat comprise a simple negative feed back loop, and in the body the hormone system is a negative feedback loop with signals from the cell back to the hypothalamus in the brain to limit the output of hormones. Such a system of so-called ‘quenched disorder’ is neither random nor exactly determined by some particular feature of its structure or input. This definition is similar to the definition of information, where a pattern can be detected in something that is neither random nor rigidly ordered. After the discovery of the biological cell, the cell came to be seen as the fundamental unit in the complexity of the body’s systems, creating the so-called cell doctrine. However, in recent decades research has revealed that the biological cell is itself a complex system. Despite this the cell has continued to be seen as the fundamental unit in conventional neuroscience. Theise suggests that the biomolecules of the cell fulfil the criteria for agents in a complex system at their level, just as much as cells do at theirs. Previously biomolecular processes were though to be a deterministic function of ATP binding and hydrolysis, but they are now viewed as a combination of this and random brownian motion in the watery cytoplasm of the cell interior. This represents constrained movement or ‘quenched disorder’ that is neither random nor rigidly determined. Actin/myosin binding involved in the movement of muscles and ligand binding to receptors are examples of such hybrid processes in the cell. The author concludes by saying that more recently acquired knowledge about the internal workings of the cell, suggests that alternative models of the body involving these should dethrone the cell doctrine from its present dominant position. Quantum mechanics in the brain Christof Koch and Klaus Hepp Nature, vol. 440, 30th March 2006 Koch and Hepp produced a surprisingly misleading essay on quantum consciousness in the March 2006 edition of Nature. Unfortunately this essay is all too typical of mainstream writers’ casual approach to quantum consciousness, the assumption presumably being that its not worthy of serious study. The essay is headed by a graphic of the infamous Schrödinger cat paradox, along with a caption claiming that a recently developed thought experiment ‘challenges the idea that a quantum framework is needed to explain consciousness.’ However, it is not until readers are getting towards the end of the two page essay that they discover that the quantum framework that is actually challenged by the experiment is the physicist Wigner’s proposal that it was the consciousness of the observer that collapsed the wave function. Wigner’s idea is not one of the main modern ideas for quantum consciousness, and in fact it is actually not a quantum consciousness theory at all. Wigner proposed that consciousness could collapse the wave function, but he did not advance any theories, either classical or quantum, as to how consciousness arose in the brain. The essay mentions the Penrose/Hameroff model as being the best known approach to quantum consciousness. The surprising thing here is that Penrose’s proposal is the precise opposite of Wigner’s. Whereas, Wigner proposed that consciousness collapses the wave function, Penrose proposed that the wave function collapse gives rise to consciousness. This might seem an easy mistake to make in dealing with esoteric theories, except that Koch has debated the Penrose proposal with Penrose’s collaborator, Stuart Hameroff, and should have been well aware of the nature of their model. This is not the only shortcoming in this essay. The authors repeat the old argument that action potentials along axons and signalling at synapses is on to macroscopic a scale to allow quantum coherence, somehow failing to mention that none of the main quantum theories suggest quantum coherence of this kind. This again, despite the debate with Hameroff on the details of his model. The paragraph arguing that the models for the necessary mathematical operations for perception in the brain are available looks doubtful given the continuing difficulties with artificial intelligence and counter claims that algorithms for perception that are capable of running on classical computers are so far lacking. |
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