From Wikipedia, the free encyclopedia/ Blogger Ref http://www.p2pfoundation.net/MultiDimensional_Science
Author  Roger Penrose 

Cover artist  Joel Nakamura 
Country  USA 
Language  English 
Subject  Artificial intelligence, mathematics, & quantum mechanics 
Publisher  Oxford University Press, 1st edition 
Publication date
 1994 (1st ed.) 
Media type  Hardback 
Pages  457 pages 
ISBN  ISBN 0198539789 (1st ed.) 
OCLC  30593111 
006.3 20  
LC Class  Q335 .P416 1994 
Preceded by  The Emperor's New Mind: Concerning Computers, Minds and The Laws of Physics 
Penrose hypothesizes that:
 Human consciousness is nonalgorithmic, and thus is not capable of being modelled by a conventional Turing machinetype of digital computer.
 Quantum mechanics plays an essential role in the understanding of human consciousness, specifically, he believes that microtubules within neurons support quantum superpositions.
 The objective collapse of the quantum wavefunction of the microtubules is critical for consciousness.
 The collapse in question is physical behaviour that is nonalgorithmic and transcends the limits of computability.
 The human mind has abilities that no Turing machine could possess because of this mechanism of noncomputable physics.
Contents
[hide]Argument[edit]
Mathematical thought[edit]
Main article: OrchOR § The Penrose–Lucas argument
In 1931, the mathematician and logician Kurt Gödel proved his incompleteness theorems, showing that any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. Further to that, for any consistent formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true, but not provable in the theory. The essence of Penrose's argument is that while a formal proof system cannot, because of the theorem, prove its own incompleteness, Gödeltype results are provable by human mathematicians. He takes this disparity to mean that human mathematicians are not describable as formal proof systems and are not running an algorithm, so that the computational theory of mind is false, and computational approaches to artificial general intelligence are unfounded. (The argument was first given by Penrose in The Emperor's New Mind (1989) and is developed further in Shadows of The Mind. An earlier version of the argument was given by J. R. Lucas in 1959.^{[1]} For this reason, the argument is sometimes called the PenroseLucas argument).Objective reduction[edit]
Main article: Penrose interpretation
Penrose's theory of Objective Reduction is a prediction of Sir Roger Penrose about the relationship between quantum mechanics and general relativity. Penrose proposes that a quantum state remains in superposition until the difference in spacetime curvature reaches a significant level.^{[2]} This idea is inspired by quantum gravity, because it uses both the physical constants and . It is an alternative to the Copenhagen interpretation, which posits that superposition fails under observation, and the manyworlds hypothesis, which states that each alternative outcome of a superposition becomes real in a separate world.^{[3]}Penrose's idea is a type of objective collapse theory. In these theories the wavefunction is a physical wave, which undergoes wave function collapse as a physical process, with observers playing no special role. Penrose theorises that the wave function cannot be sustained in superposition beyond a certain energy difference between the quantum states. He gives an approximate value for this difference: a Planck mass worth of matter, which he calls the "'onegraviton' level".^{[2]} He then hypothesizes that this energy difference causes the wave function to collapse to a single state, with a probability based on its amplitude in the original wave function, a procedure taken from standard quantum mechanics.
Orchestrated objective reduction[edit]
Main article: OrchOR
When he wrote his first consciousness book, The Emperor's New Mind in 1989, Penrose lacked a detailed proposal for how such quantum processes could be implemented in the brain. Subsequently, Hameroff read The Emperor's New Mind and suggested to Penrose that certain structures within brain cells (neurons) were suitable candidate sites for quantum processing and ultimately for consciousness.^{[4]}^{[5]} The OrchOR theory arose from the cooperation of these two scientists and was developed in Penrose's second consciousness book Shadows of the Mind (1994).^{[6]}Hameroff's contribution to the theory derived from studying brain cells (neurons). His interest centred on the cytoskeleton, which provides an internal supportive structure for neurons, and particularly on the microtubules,^{[5]} which are the important component of the cytoskeleton. As neuroscience has progressed, the role of the cytoskeleton and microtubules has assumed greater importance. In addition to providing a supportive structure for the cell, the known functions of the microtubules include transport of molecules, including neurotransmitter molecules bound for the synapses, and control of the cell's movement, growth and shape.^{[5]}
Criticism[edit]
Gödelian argument and nature of human thought[edit]
Penrose's views on the human thought process are not widely accepted in scientific circles (Drew McDermott,^{[7]} David Chalmers^{[8]} and others). According to Marvin Minsky, because people can construe false ideas to be factual, the process of thinking is not limited to formal logic. Further, AI programs can also conclude that false statements are true, so error is not unique to humans. Another dissenter, Charles Seife, has said: "Penrose, the Oxford mathematician famous for his work on tiling the plane with various shapes, is one of a handful of scientists who believe that the ephemeral nature of consciousness suggests a quantum process."In May 1995, Stanford mathematician Solomon Feferman attacked Penrose's approach on multiple grounds, including the mathematical validity of his Gödelian argument and theoretical background.^{[9]} In 1996, Penrose offered a consolidated reply to many of the criticisms of "Shadows".^{[10]}
John Searle criticises Penrose's appeal to Gödel as resting on the fallacy that all computational algorithms must be capable of mathematical description. As a counterexample, Searle cites the assignment of license plate numbers to specific vehicle identification numbers, to register a vehicle. According to Searle, no mathematical function can be used to connect a known VIN with its LPN, but the process of assignment is quite simple—namely, "first come, first served"—and can be performed entirely by a computer.^{[11]}
Microtubule hypothesis[edit]
Penrose and Stuart Hameroff have constructed the OrchOR theory in which human consciousness is the result of quantum gravity effects in microtubules. However, in 2000, Max Tegmark calculated in an article he published in Physical Review E^{[12]} that the time scale of neuron firing and excitations in microtubules is slower than the decoherence time by a factor of at least 10^{10}. Tegmark's article has been widely cited by critics of the PenroseHameroff hypothesis. The reception of the article is summed up by this statement in his support: "Physicists outside the fray, such as IBM's John Smolin, say the calculations confirm what they had suspected all along. 'We're not working with a brain that's near absolute zero. It's reasonably unlikely that the brain evolved quantum behavior', he says."^{[13]}However, in 2007, Gregory S. Engel claimed that all arguments concerning the brain being "too warm and wet" have been dispelled, as multiple "warm and wet" quantum processes have been discovered.^{[14]}^{[15]}
See also[edit]
 The Emperor's New Mind
 Computational theory of mind
 Quantum mind
 Alan Turing, creator of the Turing test
 OrchOR
Notes and references[edit]
 Jump up ^ Minds, Machines and Gödel
 ^ Jump up to: ^{a} ^{b} Penrose, Roger (1999) [1989], The Emperor's New Mind (New Preface (1999) ed.), Oxford, England: Oxford University Press, pp. 475–481, ISBN 0192861980
 Jump up ^ 'Folger, Tim. "If an Electron Can Be in 2 Places at Once, Why Can't You?" Discover. Vol. 25 No. 6 (June 2005). pp3335.
 Jump up ^ Hameroff, S.R., and Watt, R.C. (1982). "Information processing in microtubules". Journal of Theoretical Biology 98 (4): 549–561. doi:10.1016/00225193(82)901370. PMID 6185798.
 ^ Jump up to: ^{a} ^{b} ^{c} Hameroff, S.R. (1987). Ultimate Computing. Elsevier. ISBN 0444702830.
 Jump up ^ Penrose, Roger (1989). Shadows of the Mind: A Search for the Missing Science of Consciousness. Oxford University Press. p. 457. ISBN 0198539789.
 Jump up ^ Penrose is Wrong Drew McDermott, PSYCHE, 2(17), October 1995
 Jump up ^ Minds, Machines, And Mathematics – A Review of Shadows of the Mind by Roger Penrose David J. Chalmers, PSYCHE 2(9) June 1995
 Jump up ^ Penrose's Gödelian argument (PDF) Feferman, PSYCHE 2(7) May 1995
 Jump up ^ Beyond the Doubting of a Shadow – A Reply to Commentaries on Shadows of the Mind Roger Penrose, PSYCHE, 2(23), January 1996
 Jump up ^ Searle, John R. The Mystery of Consciousness. 1997. ISBN 0940322064. pp 85–86.
 Jump up ^ Tegmark, M. (2000). "Importance of quantum decoherence in brain processes". Phys. Rev. E 61 (4): 4194–4206. arXiv:quantph/9907009. Bibcode:2000PhRvE..61.4194T. doi:10.1103/PhysRevE.61.4194.
 Jump up ^ Tetlow, Philip (2007). The Web's Awake: An Introduction to the Field of Web Science and the Concept of Web Life. Hoboken, NJ: John Wiley & Sons. p. 166. ISBN 9780470137949.
 Jump up ^ Engel, Gregory S.; Calhoun, Tessa R., Read, Elizabeth L., Ahn, TaeKyu, Mančal, Tomáš, Cheng, YuanChung, Blankenship, Robert E., Fleming, Graham R. (12 April 2007). "Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems". Nature 446 (7137): 782–786. Bibcode:2007Natur.446..782E. doi:10.1038/nature05678. PMID 17429397. Retrieved 7 December 2011.
 Jump up ^ Panitchayangkoon, Gitt; Dugan Hayes; Kelly A. Fransted; Justin R. Caram; Elad Harel; Jianzhong Wen; Robert E. Blankenship; Gregory S. Engel (6 July 2010). "Longlived quantum coherence in photosynthetic complexes at physiological temperature.". Proceedings of the National Academy of Sciences 107 (28). doi:10.1073/pnas.1005484107. PMC 2919932. PMID 20615985.
 This article includes text originally by Philip Dorrell which is licensed under the GFDL

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