The Full Wiki

Roger Penrose: Wikis

Advertisements
  
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

From Wikipedia, the free encyclopedia

Sir Roger Penrose

Roger Penrose at Brookhaven Lab, 6 February 2007.
Born 8 August 1931 (1931-08-08) (age 78)
Colchester, Essex, England
Residence United Kingdom
Canada (During WWII)
Nationality British
Fields Mathematical physics
Mathematics
Institutions Bedford College, London
St John's College, Cambridge
Princeton University
Syracuse University
King’s College, London
Birkbeck, University of London
University of Oxford
Alma mater University of Cambridge
University College London
University College School
Doctoral advisor John A. Todd
Other academic advisors William Hodge
Doctoral students Tristan Needham
Richard Jozsa
Richard Ward
Andrew Hodges
George Burnett-Stuart
Matthew Ginsberg
Adam Helfer
Lane P. Hughston
Peter Law
Claude LeBrun
Ross Moore
Duncan Stone
Tim Poston
George Sparling
K. Paul Tod
Asghar Qadir
Known for Penrose tiling
Twistor Theory
Geometry of spacetime

Cosmic censorship
Weyl curvature hypothesis

Moore-Penrose pseudoinverse
Newman-Penrose formalism
Penrose stairs
Penrose inequalities
Orch-OR
Influences Dennis W. Sciama
Influenced Michael Atiyah
Stuart Hameroff
Notable awards Wolf Prize (1988)
Dirac Medal (1989)
Copley Medal (2008)
Signature
Notes
He is the brother of Jonathan Penrose and Oliver Penrose, and son of Lionel Penrose. He is the nephew of Roland Penrose.

Sir Roger Penrose, OM, FRS (born 8 August 1931) is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College. He has received a number of prizes and awards, including the 1988 Wolf Prize for physics which he shared with Stephen Hawking for their contribution to our understanding of the universe.[1] He is renowned for his work in mathematical physics, in particular his contributions to general relativity and cosmology. He is also a recreational mathematician and philosopher.

Contents

Career

Born in Colchester, Essex, England, Roger Penrose is a son of Lionel S. Penrose and Margaret Leathes.[2] Penrose is the brother of mathematician Oliver Penrose and of chess Grandmaster Jonathan Penrose. Penrose was precocious as a child.[3] He attended University College School. Penrose graduated with a first class degree in mathematics from University College London. In 1955, while still a student, Penrose reinvented the generalized matrix inverse (also known as Moore-Penrose inverse).[4] Penrose earned his Ph.D. at Cambridge (St John's College) in 1958, writing a thesis on "tensor methods in algebraic geometry" under algebraist and geometer John A. Todd. He devised and popularised the Penrose triangle in the 1950s, describing it as "impossibility in its purest form" and exchanged material with the artist M. C. Escher, whose earlier depictions of impossible objects partly inspired it. In 1965 at Cambridge, Penrose proved that singularities (such as black holes) could be formed from the gravitational collapse of immense, dying stars.[5]

Oil painting by Urs Schmid (1995) of a Penrose tiling using fat and thin rhombus.

In 1967, Penrose invented the twistor theory which maps geometric objects in Minkowski space into the 4-dimensional complex space with the metric signature (2,2). In 1969 he conjectured the cosmic censorship hypothesis. This proposes (rather informally) that the universe protects us from the inherent unpredictability of singularities (such as the one in the centre of a black hole) by hiding them from our view behind an event horizon. This form is now known as the "weak censorship hypothesis"; in 1979, Penrose formulated a stronger version called the "strong censorship hypothesis". Together with the BKL conjecture and issues of nonlinear stability, settling the censorship conjectures is one of the most important outstanding problems in general relativity. Also from 1979 dates Penrose's influential Weyl curvature hypothesis on the initial conditions of the observable part of the Universe and the origin of the second law of thermodynamics.[6] Penrose and James Terrell independently realized that objects travelling near the speed of light will appear to undergo a peculiar skewing or rotation. This effect has come to be called the Terrell rotation or Penrose-Terrell rotation.[7][8]

Roger Penrose is well known for his 1974 discovery of Penrose tilings, which are formed from two tiles that can only tile the plane nonperiodically, and are the first tilings to exhibit fivefold rotational symmetry. Penrose developed these ideas based on the article Deux types fondamentaux de distribution statistique[9] (1938; an English translation Two Basic Types of Statistical Distribution) by Czech geographer, demographer and statistician Jaromír Korčák. In 1984, such patterns were observed in the arrangement of atoms in quasicrystals.[10] Another noteworthy contribution is his 1971 invention of spin networks, which later came to form the geometry of spacetime in loop quantum gravity. He was influential in popularizing what are commonly known as Penrose diagrams (causal diagrams). In 2004 Penrose released The Road to Reality: A Complete Guide to the Laws of the Universe, a 1,099-page book aimed at giving a comprehensive guide to the laws of physics. He has proposed a novel interpretation of quantum mechanics.[11] Penrose is the Francis and Helen Pentz Distinguished (visiting) Professor of Physics and Mathematics at Pennsylvania State University.[12]

Penrose is married to Vanessa Thomas, with whom he has one child. He has three sons from a previous marriage to American Joan Isabel Wedge (1959).

Physics and consciousness

Penrose has written controversial books on the connection between fundamental physics and human (or animal) consciousness. In The Emperor's New Mind (1989), he argues that known laws of physics are inadequate to explain the phenomenon of consciousness. Penrose hints at the characteristics this new physics may have and specifies the requirements for a bridge between classical and quantum mechanics (what he terms correct quantum gravity, CQG). He claims that the present computer is unable to have intelligence because it is an algorithmically deterministic system. He argues against the viewpoint that the rational processes of the mind are completely algorithmic and can thus be duplicated by a sufficiently complex computer—this is in contrast to views, e.g., artificial intelligence, that thought can be simulated. Penrose notes that a process can conceivably be deterministic without being algorithmic. This is based on claims that consciousness transcends formal logic systems because things such as the insolubility of the halting problem and Gödel's incompleteness theorem restrict an algorithmically based logic from traits such as mathematical insight. Penrose believes that such deterministic non-algorithmic processes may come in play in the quantum mechanical wave function reduction, and may be harnessed by the brain. These claims were originally made by the philosopher John Lucas of Merton College, Oxford.

In 1994, Penrose followed up The Emperor's New Mind with Shadows of the Mind and in 1997 with The Large, the Small and the Human Mind, further updating and expanding his theories. Marvin Minsky, responded by noting that Penrose "tries to show, in chapter after chapter, that human thought cannot be based on any known scientific principle." In contrast, Minsky proposes that men are, in fact, machines, whose functioning, although complex, is fully explainable on the basis of current physics, without invoking any new or unknown scientific principles. Accordingly, Minsky maintains that "one can carry that quest [the quest for scientific explanation] too far by only seeking new basic principles instead of attacking the real detail. This is what I see in Penrose's quest for a new basic principle of physics that will account for consciousness."[13]

Penrose and Stuart Hameroff have speculated that consciousness is the result of quantum gravity effects in microtubules, which they dubbed Orch-OR (orchestrated objective reduction). But Max Tegmark, in a paper in Physical Review E, calculated that the time scale of neuron firing and excitations in microtubules is slower than the decoherence time by a factor of at least 10,000,000,000. The reception of the paper is summed up by this statement in his support: "Physicists outside the fray, such as IBM's John A. 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." The Tegmark paper has been widely cited by critics of the Penrose-Hameroff proposal. It has been claimed by Hameroff to be based on a number of incorrect assumptions (see linked paper below from Hameroff, Scott Hagan and Jack Tuszyński), but Tegmark in turn has argued that the critique is invalid (see rejoinder link below). In particular, Hameroff points out the peculiarity that Tegmark's formula for the decoherence time includes a factor of T2 in the numerator, meaning that higher temperatures would lead to longer decoherence times. Tegmark's rejoinder keeps the factor of T2 for the decoherence time.

In his book, The Web's Awake, Phillip Tetlow states that Penrose's ideas about the human thought process are not widely accepted in scientific circles, citing Minsky's criticisms, and quoting science journalist Charles Seife, who notes that Penrose is one of a handful of scientists for whom the nature of consciousness suggests a quantum process. [14]

Religious views

Penrose has stated that he does not hold to any religious doctrine.[15] In the film A Brief History of Time he stated: "There is a certain sense in which I would say the universe has a purpose. It's not there just somehow by chance. Some people take the view that the universe is simply there and it runs along–it's a bit as though it just sort of computes, and we happen by accident to find ourselves in this thing. I don't think that's a very fruitful or helpful way of looking at the universe, I think that there is something much deeper about it, about its existence, which we have very little inkling of at the moment."[16]

Awards and honours

Roger Penrose during a lecture, explaining the tessellation in the MC Escher lithograph Circle Limit IV

Penrose has been awarded many prizes for his contributions to science. He was elected a Fellow of the Royal Society of London in 1972. In 1975, Stephen Hawking and Penrose were jointly awarded the Eddington Medal of the Royal Astronomical Society. In 1985, he was awarded the Royal Society Royal Medal. Along with Stephen Hawking, he was awarded the prestigious Wolf Foundation Prize for Physics in 1988. In 1989 he was awarded the Dirac Medal and Prize of the British Institute of Physics. In 1990 Penrose was awarded the Albert Einstein Medal for outstanding work related to the work of Albert Einstein by the Albert Einstein Society. In 1991, he was awarded the Naylor Prize of the London Mathematical Society. From 1992 to 1995 he served as President of the International Society on General Relativity and Gravitation. In 1994, Penrose was knighted for services to science.[17] In 1998, he was elected Foreign Associate of the United States National Academy of Sciences. In 2000 he was appointed to the Order of Merit. In 2004 he was awarded the De Morgan Medal for his wide and original contributions to mathematical physics. To quote the citation from the London Mathematical Society:

His deep work on General Relativity has been a major factor in our understanding of black holes. His development of Twistor Theory has produced a beautiful and productive approach to the classical equations of mathematical physics. His tilings of the plane underlie the newly discovered quasi-crystals.

In 2005 Penrose was awarded an honorary doctorate (Honoris Causa) by Warsaw University and Katholieke Universiteit Leuven (Belgium), and in 2006 by the University of York. In 2008 Penrose was awarded the Copley Medal. He is also a Distinguished Supporter of the British Humanist Association and one of the patrons of the Oxford University Scientific Society.

Works

  • Techniques of Differential Topology in Relativity (1972, ISBN 0-89871-005-7)
  • Spinors and Space-Time: Volume 1, Two-Spinor Calculus and Relativistic Fields (with Wolfgang Rindler, 1987) ISBN 0-521-33707-0 (paperback)
  • Spinors and Space-Time: Volume 2, Spinor and Twistor Methods in Space-Time Geometry (with Wolfgang Rindler, 1988) (reprint), ISBN 0-521-34786-6 (paperback)
  • The Emperor's New Mind: Concerning Computers, Minds, and The Laws of Physics (1989, ISBN 0-14-014534-6 (paperback); it received the Rhone-Poulenc science book prize in 1990)
  • Shadows of the Mind: A Search for the Missing Science of Consciousness (1994, ISBN 0-19-853978-9 (hardback))
  • The Nature of Space and Time (with Stephen Hawking, 1996, ISBN 0-691-03791-4 (hardback), ISBN 0-691-05084-8 (paperback))
  • The Large, the Small, and the Human Mind (with Abner Shimony, Nancy Cartwright, and Stephen Hawking, 1997, ISBN 0-521-56330-5 (hardback), ISBN 0-521-65538-2 (paperback), Canto edition: ISBN 0-521-78572-3)
  • White Mars or, The Mind Set Free (with Brian W. Aldiss, 1999, ISBN 978-0-316-85243-2 (hardback))
  • The Road to Reality: A Complete Guide to the Laws of the Universe (2004, ISBN 0-224-04447-8 (hardcover), ISBN 0-09-944068-7 (paperback))

Penrose also wrote forewords to Quantum Aspects of Life and Zee's book Fearful Symmetry.

See also

Notes

  1. ^ Penrose, R (2005), The Road to Reality: A Complete guide to the Laws of the Universe, Vintage Books, ISBN 0-099-44068-7 
  2. ^ Penrose and his father shared mathematical concepts with Dutch graphic artist M. C. Escher which were incorporated into a number of pieces, including Waterfall, which is based on the 'Penrose triangle', and Up and Down.
  3. ^ J. C. Raven's 1936 MSc thesis features introspections from Penrose, aged four and two thirds, as he solved what are now known as Raven's Progressive Matrices, c.f. note 52 of Watt, D. C. (1998). Lionel Penrose, F.R.S. (1898-1972) and Eugenics: Part One. Notes and Records of the Royal Society of London, 52, 137-151
  4. ^ Penrose, R. "A Generalized Inverse for Matrices" Proc. Cambridge Phil. Soc. 51, 406-413, 1955)
  5. ^ Ferguson, 1991: 66
  6. ^ R. Penrose (1979). "Singularities and Time-Asymmetry". in S. W. Hawking and W. Israel. General Relativity: An Einstein Centenary Survey. Cambridge University Press. pp. 581–638. 
  7. ^ Terrell, James (1959), "Invisibility of the Lorentz Contraction", 116: 1041–1045, doi:10.1103/PhysRev.116.1041 .
  8. ^ Penrose, Roger (1959), "The Apparent Shape of a Relativistically Moving Sphere", Proceedings of the Cambridge Philosophical Society 55: 137–139 .
  9. ^ Jaromír Korčák (1938): Deux types fondamentaux de distribution statistique. Prague, Comité d’organisation, Bull. de l'Institute Int'l de Statistique, vol. 3, pp. 295–299.
  10. ^ Steinhardt, Paul (1996), [http://www.pnas.org/content/93/25/14267.full "New perspectives on forbidden symmetries, quasicrystals, and Penrose tilings"], PNAS 93: 14267–14270, http://www.pnas.org/content/93/25/14267.full .
  11. ^ "If an Electron Can Be in Two Places at once, Why Can't You?". http://discovermagazine.com/2005/jun/cover/article_view?b_start:int=0&-C=. Retrieved 2008-10-27. 
  12. ^ "Dr. Roger Penrose at Penn State University". http://www.phys.psu.edu/people/display/index.html?person_id=233&mode=contact.. Retrieved 2007-07-09. 
  13. ^ Marvin Minsky. "Conscious Machines." Machinery of Consciousness, Proceedings, National Research Council of Canada, 75th Anniversary Symposium on Science in Society, June 1991.
  14. ^ Tetlow, Phillip, The Web's Awake Wiley-IEEE, 2007 ISBN 0470137940, 9780470137949 p. 166
  15. ^ http://www.samharris.org/site/book_letter_to_christian_nation/
  16. ^ http://www.godresources.org/intelligent_design5.shtml
  17. ^ Official announcement knighthood. The London Gazette. 11 June 1994.

References

  • Ferguson, Kitty (1991). Stephen Hawking: Quest For A Theory of Everything. Franklin Watts. ISBN 0-553-29895-X.
  • Misner, Charles; Thorne, Kip S. & Wheeler, John Archibald (1973). Gravitation. San Francisco: W. H. Freeman. ISBN 0-7167-0344-0. ; see Box 34.2.

External links

Advertisements

Quotes

Up to date as of January 14, 2010

From Wikiquote

Science is a great deal more than mindless computation.

Sir Roger Penrose (born 8 August 1931) is an English mathematical physicist and Professor of Mathematics at the Mathematical Institute, University of Oxford, famous for his work in mathematical physics, cosmology, general relativity, and his musings on the nature of consciousness.

Contents

Sourced

Children are not afraid to pose basic questions that may embarrass us, as adults, to ask.
Although I'm regarded as a dangerous radical by particle physicists for proposing that there may be loss of quantum coherence, I'm definitely a conservative compared to Roger. Stephen Hawking.
  • Some years ago, I wrote a book called The Emperor's New Mind and that book was describing a point of view I had about consciousness and why it was not something that comes about from complicated calculations. So we are not exactly computers. There's something else going on and the question of what this something else was would depend on some detailed physics and so I needed chapters in that book, which describes the physics as it is understood today. Well anyway, this book was written and various people commented to me and they said perhaps I could use this book for a course Physics for Poets or whatever it is if it didn't have all that contentious stuff about the mind in that. So I thought, well, that doesn't sound too hard, all I'll do is get out the scissor out and snip out all the bits, which have something to do with the mind. The trouble is that if I did that — and I actually didn't do it — the whole book fell to pieces really because the whole driving force behind the book was this quest to find out what could it be that constitutes consciousness in the physical world as we know it or as we hope to know it in future
  • Understanding is, after all, what science is all about — and science is a great deal more than mindless computation.
    • As quoted in The Golden Ratio : The Story of Phi, the World's Most Astonishing Number (2002) by Mario Livio, p. 201
  • Does life in some way make use of the potentiality for vast quantum superpositions, as would be required for serious quantum computation? How important are the quantum aspects of DNA molecules? Are cellular microtubules performing some essential quantum roles? Are the subtleties of quantum field theory important to biology? Shall we gain needed insights from the study of quantum toy models? Do we really need to move forward to radical new theories of physical reality, as I myself believe, before the more subtle issues of biology — most importantly conscious mentality — can be understood in physical terms? How relevant, indeed, is our present lack of understanding of physics at the quantum/classical boundary? Or is consciousness really “no big deal,” as has sometimes been expressed?
    It would be too optimistic to expect to find definitive answers to all these questions, at our present state of knowledge, but there is much scope for healthy debate...
    • Foreword (March 2007) to Quantum Aspects of Life (2008), by Derek Abbott.

The Emperor's New Mind (1989)

Except as otherwise noted, page numbers refer to the 1989 Penguin edition, ISBN 0140145346
  • It seems to me that we must make a distinction between what is "objective" and what is "measurable" in discussing the question of physical reality, according to quantum mechanics. The state-vector of a system is, indeed, not measurable, in the sense that one cannot ascertain, by experiments performed on the system, precisely (up to proportionality) what the state is; but the state-vector does seem to be (again up to proportionality) a completely objective property of the system, being completely characterized by the results it must give to experiments that one might perform.
    • Ch. 6, Quantum Magic and Quantum Mastery, p. 269
  • What right do we have to claim, as some might, that human beings are the only inhabitants of our planet blessed with an actual ability to be "aware"? [...] The impression of a "conscious presence" is indeed very strong with me when I look at a dog or a cat or, especially, when an ape or monkey at the zoo looks at me. I do not ask that they are "self-aware" in any strong sense (though I would guess that an element of self-awareness can be present). All I ask is that they sometimes simply feel!
    • Ch. 9, Real Brains and Model Brains, p. 383
  • It is hard to see how one could begin to develop a quantum-theoretical description of brain action when one might well have to regard the brain as "observing itself" all the time!
    • Ch. 10, Where Lies the Physics of the Mind?, p. 447
  • Beneath all this technicality is the feeling that it is indeed "obvious" that the conscious mind cannot work like a computer, even though much of what is involved in mental activity might do so.

    This is the kind of obviousness that a child can see—though the child may, later in life, become browbeaten into believing that the obvious problems are "non-problems", to be argued into nonexistence by careful reasoning and clever choices of definition. Children sometimes see things clearly that are obscured in later life. We often forget the wonder that we felt as children when the cares of the "real world" have begun to settle on our shoulders. Children are not afraid to pose basic questions that may embarrass us, as adults, to ask. What happens to each of our streams of consciousness after we die; where was it before we were born; might we become, or have been, someone else; why do we perceive at all; why are we here; why is there a universe here at all in which we can actually be? These are puzzles that tend to come with the awakenings of awareness in any one of us—and, no doubt, with the awakening of self-awareness, within whichever creature or other entity it first came.

    • Ch. 10, Where Lies the Physics of the Mind?, p. 448–9 (p. 580 in 1999 edition)

Quotes about Penrose

  • Although I'm regarded as a dangerous radical by particle physicists for proposing that there may be loss of quantum coherence, I'm definitely a conservative compared to Roger. I take the positivist viewpoint that a physical theory is just a mathematical model and that it is meaningless to ask whether it corresponds to reality. All that one can ask is that its predictions should be in agreement with observation. I think Roger is a Platonist at heart but he must answer for himself.
    • Stephen Hawking, in The Nature of Space and Time (2000) by Stephen W. Hawking and Roger Penrose, Ch. 1 : Classical Theory, p. 3

External links

Wikipedia
Wikipedia has an article about:

Simple English

Sir Roger Penrose, OM, FRS (born 8 August 1931) is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College. He is renowned for his work in mathematical physics, in particular his contributions to general relativity and cosmology. He is also a recreational mathematician and philosopher. Roger Penrose is the son of scientist Lionel S. Penrose and Margaret Leathes, and the brother of mathematician Oliver Penrose and correspondence chess grandmaster Jonathan Penrose. He was born in Colchester, Essex, England.


Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message