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Sir Roger Penrose

  1. Apr 10, 2014 #1

    wolram

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    http://www.sciencefriday.com/segment/04/04/2014/sir-roger-penrose-cosmic-inflation-is-fantasy.html

    What does Sir Roger know that others do not.

    Sir Roger Penrose calls string theory a "fashion," quantum mechanics "faith," and cosmic inflation a "fantasy." Coming from an armchair theorist, these declarations might be dismissed. But Penrose is a well-respected physicist who co-authored a seminal paper on black holes with Stephen Hawking. What's wrong with modern physics—and could alternative theories explain our observations of the universe?
     
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  3. Apr 10, 2014 #2

    Chronos

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    Sir Roger does not fear stepping outside the box. Did you see his paper on consciousness? He espoused the neuron is a quantum computer capable of holding enormous information - enough to create a mind.
     
  4. Apr 10, 2014 #3

    Ken G

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    Apparently, if quantum mechanics is faith, then it is his own faith!
     
  5. Apr 10, 2014 #4

    Chronos

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    Here is a paper discussing the concept http://www.quantumconsciousness.org/penrose-hameroff/consciousevents.html [Broken], it is interesting.
     
    Last edited by a moderator: May 6, 2017
  6. Apr 11, 2014 #5

    Ken G

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    Max Tegmark calculated that the physical scales of a microtubule doesn't even approach the quantum domain, but unfortunately I don't have the reference. Still, Penrose is an amazing intellect, I would never take any of his ideas lightly.
     
  7. Apr 11, 2014 #6

    Chalnoth

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    He was well-respected. He did a lot of important work in decades past. Essentially anybody who studies General Relativity these days knows his name.

    But sadly, I think he's spent that respect. It's really unfortunate, but he seems to have become rather divorced from reality. It's really too bad.
     
  8. Apr 11, 2014 #7
    Why do I feel I just listened to a political babble after reading that article lol.
     
    Last edited by a moderator: May 6, 2017
  9. Apr 11, 2014 #8

    strangerep

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    Amazing intellect? Yes, I'm sure.

    But unfortunately, if an idea doesn't yield edible fruit (i.e., experimentally testable predictions) within a reasonable time, it doesn't matter how smart its creator might be.

    About the "quantum consciousness" stuff...
    $$\text{MD} + \text{mathematician} ~\ne~ \text{physicist} ~. $$
     
  10. Apr 11, 2014 #9

    wolram

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    Does he have some new theory, Twistors are new to me?

    "Twistor" Theory Reignites the Latest Superstring Revolution
    USF Department of Mathematics: Sir Roger Penrose lecture
    Discover Interview: Roger Penrose Says Physics Is Wrong, From String Theory to Quantum Mechanics
    (video) Roger Penrose on Twistors and Quantum Non-Locality
     
  11. Apr 11, 2014 #10
    Whether or not Penrose criticisms of string theory, Qm and inflation are good criticisms have nothing to do with his own ideas of consciousness. Even if the latter ideas are total nonsense it does not make his criticisms any less valid.
    I think the phrases "fashion/faith/fantasy" are obvious hyperbole but we have to admit there are difficult foundational issues with all of these paradigms. Of course any alternatives need to fit within the existing framework of evidence. For QM that's over whelming , for inflation its growing (lets see if BICEP2 holds up or not, we should know by the end of the year) and string theory seems yet to achieve anything on this front.
    I was interested to hear Penrose claim about b modes. if I remember correctly he said primordial magnetic fields could produce such a signal. I have never heard that before, maybe Im remembering the interview wrong.
     
  12. Apr 11, 2014 #11

    Chalnoth

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    Yes, well, reality isn't easy to understand. Why should it be?
     
  13. Apr 11, 2014 #12
    Im not saying it should be.
     
  14. Apr 12, 2014 #13
    .... If you sum up QM. It is best fit with faith somehow.
     
  15. May 11, 2014 #14
    For those who wish to criticize Sir Roger Penrose:
    ( Sir Roger Penrose OM FRS, is an English mathematical physicist, recreational mathematician and philosopher. He is the Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute of the University of Oxford, as well as an Emeritus Fellow of Wadham College )
    Below is one person who has some contra-views :

    http://c2.com/cgi/wiki?MistakesOfRogerPenrose

    If one reviews the above, it can be seen that , apart from a substantial academic career, he is also a philosopher. This is a person engaged or learned in philosophy, especially as an academic discipline.

    From Roget's Thesaurus:
    synonyms: thinker, theorist, theorizer, theoretician, philosophizer, metaphysicist, metaphysician, epidemiologist, dialectician, logician; speculator, hypothesizer, seeker after truth, dreamer; scholar, intellect, intellectual, learned person, sage, wise man, Solomon, guru, pundit.
    So could we give the revered gentleman some credit?
    After all, he is not young enough to know everything....!
     
    Last edited: May 11, 2014
  16. May 11, 2014 #15
    Most physicists have faith in a particular interpretation of QM and little or no faith in another or others despite the fact that they can't be distinguised by experiment. Penrose isn't doubting the formalism as tested thus far. His main objection to QM is that we have an incomplete understanding of measurement in QM, since the unitary evolution of the wavefunction must also include the measuring apparatus. He has postulated a mechanism for how quantum gravity plays the role wavefunction collapse and made testable predictions based upon it, which could be tested within a realistic time horizon. What he's talking about isn't as controversial as it first might look.

    This isn't the full story. There's a sequence of papers starting with Tegmark's paper which you refer to, that I posted in the following thread:

    https://www.physicsforums.com/showthread.php?t=748536

    Briefly, since Tegmark's paper, we have mounting evidence that biology has indeed mastered coherent quantum states, including experimental measurements of them in microtubules. It's perhaps a little early so say that Penrose was right, but his argument is in a much stronger position than ever.
     
    Last edited: May 11, 2014
  17. May 11, 2014 #16

    Chalnoth

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    Yes, he has had a great career, at least in his younger life. But the way that he dealt with this conformal cyclic cosmology idea has been, well, pretty horrible. I wouldn't expect a decent Bachelor's physics student to make the mistakes he made.
     
  18. May 11, 2014 #17
    Just because someone is highly intelligent, well-informed, and even knows considerable advanced mathematics doesn't preclude human comfort zones and their influence on confidence. Although Einstein finally came around, Fred Hoyle, a highly accomplished scientist responsible for seminal physics in nucleosynthesis, coined the (derogatory) phrase "Big Bang" and fought it essentially till the day he died (2001), even after MWB and Quasar distribution, etc. gathered extreme momentum in the foundations of what we now call The Standard Model.

    As Lee Smolin has pointed out we are about to see a lot of "shipwrecks" very soon and continuing for a decade at least because of new technologies. Who would have guessed that a monumental Gamma Ray Burst would have provided a "drag race" for photons that would so thoroughly send so many "foamers" back to the drawing board? and this is just the beginning. We certainly live in trying but exhilarating times.
     
  19. May 13, 2014 #18
    Twistors are from about 30 years ago and didn't catch on, but now Witten endorses them so there is a fad.
     
  20. May 13, 2014 #19
    GOTO:

    http://link.springer.com/article/10.1007/BF00668831

    Or:
    Abstract:
    "The formalism of twistors [the ‘spinors’ for the group O(2,4)] is employed to give a concise expression for the solution of the zero rest-mass field equations, for each spin (s=0, 1/2, 1, ...), in terms of an arbitrary complex analytic functionf(Z α) (homogeneous of degree −2s −2). The four complex variablesZ α are the components of a twistor. In terms of twistor space (C-picture) it is analytic structure which takes the place of field equations in ordinary Minkowski space-time (M-picture). By requiring that the singularities off(Z α) form a disconnected pair of regions in the upper half of twistor space, fields of positive frequency are generated.

    The twistor formalism is adapted so as to be applicable in curved space-times. The effect of conformai curvature in theM-picture is studied by consideration of plane (-fronted) gravitational ‘sandwich’ waves. TheC-picture still exists, but its complex structure ‘shifts’ as it is ‘viewed’ from different regions of the space-time. A weaker symplectic structure remains. The shifting of complex structure is naturally described in terms of Hamiltonian equations and Poisson brackets, in the twistor variablesZ α, Z¯α . This suggests the correspondence Z¯α=∂/∂Zα as a basis for quantization. The correspondence is then shown to be, in fact, valid for the Hubert space of functionsf(Z α), which give the above twistor description of zero rest-mass fields. For this purpose, the Hubert space scalar product is described in (conformally invariant) twistor terms. The twistor expressions for the charge and the mass, momentum and angular momentum (both in ‘inertial’ and ‘active’ versions, in linearised theory) are also given.

    It is suggested that twistors may supply a link between quantum theory and space-time curvature. On this view, curvature arises whenever a ‘shift’ occurs in the interpretation of the twistor variablesZ α, Z¯α as the twistor ‘position’ and ‘momentum’ operators, respectively.

    • This work was partly carried out during the author's five-month stay at Cornell University."
     
  21. May 14, 2014 #20

    I agree that we should maintain a level of skepticism on many advanced Physics theories until there is a large amount of independently verified reliable proof. Lets not forget that the cmbr is just a radio signal and the most incredible pantheon of theories have been built on its back. Penrose is right to shake and stir the pot imho.

    I also agree with Lee Smolin where he has pointed out we are about to see a lot of "shipwrecks" very soon and continuing for a decade at least because of new technologies.
     
    Last edited: May 14, 2014
  22. May 14, 2014 #21

    Chalnoth

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    The way in which the CMB was emitted makes it an exceptionally clear signal of many aspects of the physics of the early universe. In many ways it is vastly more accurate at distinguishing the behavior of our universe than observations of galaxies, for instance. I don't think there is any "just" about it: the CMB is an incredibly powerful window into the behavior of our universe.
     
  23. May 14, 2014 #22
    Did someone just use the word "proof" here? OMG! My beverage of choice has proof, my mathmatics has proofs, and that's it. Suggest anyone worshipping at the Alter of Proof should avoid fouling themselves with the heresy of the Scientific Method which requires all "knowledge" to be contingent.
    The current 'fashion' is to avoid asking the tough question about how these various theories lead to testable predictions. That is, they want to re-define the scientific method. (If this sounds like "It depends on what the definition of 'is' is" to you, you are correct). Perhaps we are in a post-scientific age, where we can pick our theories based not on how well they predict, but on their esthetics and what their explanatory power is. I don't think so. Getting your undies twisted by theories which have no reasonable possibility of ever being tested (strings, multiverses) isn't something any good scientist of yore would countenance. OTOH, perhaps this is just the eye of the storm and we are awaiting the next paradigm shift. In order to grow the new paradigm, a lot of fertilizer has to be spread...if you get my meaning.
     
  24. May 14, 2014 #23

    Chalnoth

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    I don't see how it's a 'fashion'. It's simply a recognition that Popperian falsifiability is a really poor test of whether or not a theory is good or even scientific.

    Ultimately, the test for whether or not an idea should be pursued is, "Can we ever check to see if this idea is accurate?"

    For many theories, that answer is clearly "yes" even if they aren't strictly falsifiable. How can this be? Well, it's because of the possibility that the theory has some free parameters which can take many different values. It is possible that some theory might be true, but have parameters such that we could never, ever test its validity. But if it were to have some different values for those parameters, we could easily see its impact in experiments.

    Such a theory isn't strictly falsifiable, but it is verifiable: there is the possibility that a future experiment will detect a deviation of a specific type predicted by this theory.

    A good recent example is the B-mode (primordial gravity wave) prediction of inflation. It turns out that there is a large amount of model space for inflation where the B-mode polarization would have been entirely too small to ever detect. In this sense, inflation isn't falsifiable through B-mode observations at all: if the B-mode signal were too low, that would say nothing about the truth of inflation. But, if it turns out that we're lucky and the B-mode signal is high enough, then we can detect that signal.

    In this instance, it turns out that we were very lucky indeed.
     
  25. May 14, 2014 #24
    This cmbr claim only lasted 8 weeks:

    Eight weeks ago, physicists announced that they'd discovered evidence of gravitational waves in the early universe, potential proof that our universe began with a bang and inflated from there. But the most significant cosmological discovery in years might just be an experimental artifact.

    http://io9.com/recently-discovered-big-bang-smoking-gun-could-be-a-b-1575597952


    I am not saying that anything is wrong with our Cosmology Theories, but I get just a little concerned when so many theories seem to rest one on top of the other and all on top of a radio signal. Lets also remember that we admit that 95% of the Universe is unknown to us in the form of dark matter and dark energy which also must surely add a tiny element of uncertainty.
     
  26. May 15, 2014 #25

    Chronos

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    I view it as not only difficult, but, rather pointless to test a theory not yet proposed. The holy trinity of the scientific method is theorize, predict and observe - and generally in that order, as I recall.
     
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