6 ms·

Roger Penrose Says Physics Is Wrong, From String Theory to Quantum Mechanics

66 points by gnosis 17y ago

carpdiem 17y ago
I think this post title is misleading. Roger Penrose is not merely saying that quantum mechanics is wrong. Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. It's like Newtonian mechanics. Newtonian mechanics is correct, within its domain (for velocities much less than the speed of light). No one argues with the predictions of Newtonian mechanics within their domain. Einstein's achievement with special relativity, then, wasn't showing that Newtonian mechanics was wrong; instead, he just showed the world the true extent of its domain, and developed a theory (special relativity) that generalized Newtonian mechanics to a larger domain (velocities less than the speed of light). It's terribly unfair to Newtonian mechanics to call it 'wrong' in the same way that the statement 2+2=5 is 'wrong'. Similarly, the fantastic experimental success of quantum mechanics ensures that it would be unfair to call quantum mechanics 'wrong'. Incomplete? Certainly. Worthy of being challenged? Absolutely. Is it taken as gospel by too many physicists? Probably. But is quantum mechanics wrong? No, decades of successful experiments, and practically the entire modern electronics industry, would disagree with that sentiment. The problem is that we just don't know where the domain of quantum mechanics ends, nor the more general theory that will take its place.
- tamas 17y ago
  Roger Penrose is not merely saying that quantum mechanics is wrong. Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. That's how every scientific theory should be approached, as that's what sets them apart from dogmas.
- jacobolus 17y ago
  Even more importantly.... this is a lovely interview, that hits on many topics, of which the biographical details are much more interesting than the bit about quantum mechanics. Hopefully the fake-controversy of the title won't scare anyone away from reading it.
- teeja 17y ago
  Fully agreed. QM is like ... our knowledge of the Moon before the 1960s. Until we got 'out there' we couldn't see the whole thing. Lots of people like to look at the very complex stuff. But the year Einstein published several papers, it was all about very basic observations. We don't puzzle enough about the 'simple'. Heisenberg: "We have to remember that what we observe is not nature herself, but nature exposed to our method of questioning."
- Confusion 17y ago
  Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. Which is not an unusual view. Nobel prize winner 't Hooft has expressed the same sentiment.
- mjtokelly 17y ago
  What you say is well-put, but to nitpick the last paragraph: the limits of quantum mechanics are well-established. QM is a special case of quantum electrodynamics, which is a low-energy special case of the Grand Unified Theory. http://en.wikipedia.org/wiki/Quantum_electrodynamics http://en.wikipedia.org/wiki/Quantum_electrodynamics http://en.wikipedia.org/wiki/Unified_Field_Theory http://en.wikipedia.org/wiki/Unified_Field_Theory While the latter is not fully fleshed out, its uncertainty only begins in circumstances far weirder than what gives Roger Penrose pause. Penrose says that "The [QM] equation should describe the world in a completely deterministic way, but it doesn’t." But work such as Bell's theorem shows that no deterministic equation could ever be consistent with quantum mechanics: http://en.wikipedia.org/wiki/Bells_theorem http://en.wikipedia.org/wiki/Bells_theorem
  - Luc 17y ago
    > But work such as Bell's theorem shows that no deterministic equation could ever be consistent with quantum mechanics: This isn't quite right, because you left out the word 'local' - see http://en.wikipedia.org/wiki/Bohm_interpretation http://en.wikipedia.org/wiki/Bohm_interpretation Bell's theorem applies only to _local_ hidden variables.
    - mjtokelly 17y ago
      Right, but non-local determinism is difficult to square with general relativity.
      - Luc 17y ago
        Indeterministic laws and the non-existence of particle positions and trajectories are difficult to square with general relativity too - and Bohm's interpretation doesn't 'suffer' those problems, while it predicts the exact same observations. (Though I should say this is way out of my amateur-physicist league - I'm taking my cue from 'Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony' http://www.amazon.com/Quantum-Mechanics-Historical-Contingency-Foundations/dp/0226132048 http://www.amazon.com/Quantum-Mechanics-Historical-Contingen... ).
  - 17y ago
- moron4hire 17y ago
  2+2=5 for sufficiently large values of 2
- dstorrs 17y ago
  Were we reading the same article? "But when you accept the weirdness of quantum mechanics [in the macro world], you have to give up the idea of space-time as we know it from Einstein. The greatest weirdness here is that it doesn’t make sense. If you follow the rules, you come up with something that just isn’t right." "You’re led to a completely crazy point of view." "My own view is that quantum mechanics is not exactly right, and I think there’s a lot of evidence for that." "INTERVIEWER: In general, the ideas in theoretical physics seem increasingly fantastical. Take string theory. All that talk about 11 dimensions or our universe’s existing on a giant membrane seems surreal. PENROSE: You’re absolutely right. And in a certain sense, I blame quantum mechanics, because people say, “Well, quantum mechanics is so nonintuitive; if you believe that, you can believe anything that’s nonintuitive.” But, you see, quantum mechanics has a lot of experimental support, so you’ve got to go along with a lot of it. Whereas string theory has no experimental support." "[My new book] is called Fashion, Faith and Fantasy in the New Physics of the Universe. Each of those words stands for a major theoretical physics idea. ['Fantasy'] is quantum mechanics at all levels...." All of those quotes sound to me like pretty clear rejection of string theory and quantum mechanics and an implied rejection of much of modern higher physics. Yes, he accepts experimental proofs where available, but he seems to be saying that these theories are wrong because they don't make sense to him, or because they don't match the way we perceive the world. But when I look at the Hacker New logo, I don't perceive photons of wavelength 590 nanometers bouncing off my retina--I pereceive the color orange. Personally, as I read this, I kept hearing Clarke's 1st law (http://en.wikipedia.org/wiki/Clarke%27s_three_laws http://en.wikipedia.org/wiki/Clarke%27s_three_laws) looping in my head: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong."
  - camccann 17y ago
    But when I look at the Hacker New logo, I don't perceive photons of wavelength 590 nanometers bouncing off my retina--I pereceive the color orange. If you did perceive photons at 590nm that would be rather remarkable! More likely, you would perceive a mixture of photons at different wavelengths, mainly a combination of 615nm and 550nm or thereabouts. In actuality, you perceive this "orange" concept; in fact, you would perceive the same orange whether exposed to 590nm photons or the mixture, which emphasizes the point that what we experience in the real world doesn't necessarily relate to reality in an obvious way.
- thinksketch 17y ago
  I agree that the title is misleading. But I think his view is really important. Or maybe better said, it's really important that a great man like Penrose comes out and unequivocally makes this statement to generations who have too often been told to "shut up and just learn the theories". In college it drove me mad that I could not find any resources to question the "absolute validity" of paradoxes that arose in modern physics. To me, a paradox could not represent a universal truth - it must be seen as an opportunity to understand why our tools are insufficient to fully understand the universe. But the response to my questioning was always "who are you to question 100 years of experts?" Finally I found one physics professor who confided in me that he too had been trying to start a fertile dialogue about these things, but other professors would just scoff. He felt it was futile at best or career damaging at worst. So I learned that, truly the 'old experts' took modern theories with a grain of salt - it was only today that we took them so literally. But none of my classmates believed it and they thought I was brash and stupid for bothering to think about it. For a while, I met with that professor once a month or so to try to steer my knowledge in a direction that wasn't jaded by a blind acceptance of theories that were inconsistent with one another. I hated the feeling that it had to be some half-valid historical truth. It made me feel half-way delusional. It made me lose trust that the academic system would prepare me to really truly think. I wanted to learn about the paradoxes, the holes in our thinking, how we were wrong, because those are the exciting areas that need development. If you spend your whole education learning fundamentals while detached from the burden of these kinds of questions, how can you be prepared to tackle them once you raise your nose up out of the textbooks? So yes, it's misleading to make the title, "String Theory and Quantum Mechanics are wrong." But I hope his important point doesn't get lost, that it is also wrong to say that String Theory and Quantum Mechanics are completely right - end of story - no questions." Thank you Roger Penrose for taking this stance loud and clear.
BRadmin 17y ago
"In my view the conscious brain does not act according to classical physics. It doesn’t even act according to conventional quantum mechanics. It acts according to a theory we don’t yet have." Do most modern AI researchers disagree with this?
- daeken 17y ago
  I don't think we have enough information to say one way or another. We've gained a lot of knowledge about the brain, but it's still very much a black box. I think it's worth holding off on making any assumptions until we understand a whole lot more about it.
- rw 17y ago
  The sensible response is: "show me ". Quantum effects are not known to be significant. I believe that our mind is an emergent property: lots of neurons and chemicals interacting. Sure, there are a lot of variables, we need the dynamical systems perspective to even begin to understand the whole process... but a new kind of physics? Don't be so anthropic! AFAICT cognition happens at the multicellular level--huge, from a QM perspective. This reminds me of that old anti-strong-AI bugaboo, "intelligence in the gaps": http://en.wikipedia.org/wiki/God_of_the_gaps http://en.wikipedia.org/wiki/God_of_the_gaps
- lkozma 17y ago
  Yes, most modern AI researchers believe that the functioning of the brain can be explained by electromagnetic and chemical phenomena, accurately described by 1900s theories. The fact that we don't fully understand its workings is due to its organizational complexity. Penrose's arguments are discussed for example here: http://www.scottaaronson.com/democritus/lec10.5.html http://www.scottaaronson.com/democritus/lec10.5.html
  - 10ren 17y ago
    It's funny, but to be certain that consciousness can be explained by known laws - we just don't know exactly how - itself requires faith and is quite unscientific. Although I too believe it.
btilly 17y ago
Penrose contributed a lot and I don't want to minimize that. However when he stepped outside of his own domain he makes some serious basic mistakes that make him ignorable. As an example in The Emperor's New Mind he makes a number of claims about consequences of Gödel's theorem for human thought that were flat out wrong. I remember reading criticism of it from a logician in the mid-90s, and Penrose's response. While I'm no logician, I know enough about it to know that the logician was right and Penrose was wrong. Human thinking is known to accept inconsistencies and so you can't apply Gödel's theorem to derive any interesting conclusions. When he moves from logic to physics he is even more out of his depth. Given his verifiable mistakes in logic, I am comfortable in concluding that his startling assertions about physics are far more likely to arise from further mistakes of his than from his having found serious reasons to question the foundations of modern physics.
- deleted 17y ago
  [deleted]
- anatoly 17y ago
  I agree with your description of Penrose's Goedelian claims (the logician was Solomon Feferman), but I'm not sure why you say he'd be even more out of his depth in physics. Penrose is primarily a mathematical physicist, not a mathematican.
  - btilly 17y ago
    You are right. I had known his mathematical work, but didn't know his biography. That said, his physics work seems to have been in general relativity, not quantum mechanics. Given what I know about how he messed up when he stepped out of his area in math, I find it more likely that he has made similar types of mistakes in quantum mechanics than that he has truly demonstrated that mainstream physics is wrong.
    - slackenerny 17y ago
      not quantum mechanics Except the twistor formalism he created (following ideas of no one else but Dirac) is important branch of research in quantum mathematical physics and string theory, not only classical gravity. Just like Hawking or Freeman Dyson had, Penrose too earned his right to odd, and even braggart opinions on everything. Especially since opinions are by definition not meant to advance knowledge, or demonstrate results, but to provoke and inspire discussion.
teeja 17y ago
http://mindbody.blogspot.com/2009/10/penrose-kind-o-gets-it.html http://mindbody.blogspot.com/2009/10/penrose-kind-o-gets-it.... "Schrödinger, Einstein, and Paul Dirac. They were all quantum skeptics in a sense. Dirac is the one whom people find most surprising, because he set up the whole foundation, the general framework of quantum mechanics. People think of him as this hard-liner, but he was very cautious in what he said. When he was asked, 'What’s the answer to the measurement problem?' his response was, 'Quantum mechanics is a provisional theory. Why should I look for an answer in quantum mechanics?'" http://www.afterourtime.com/wiki/index.php?title=Quantum_Gravity http://www.afterourtime.com/wiki/index.php?title=Quantum_Gra...
- nopinsight 17y ago
  In a way, a wise creator of a theory should be the one least fixated by it, as he knows all its potential weaknesses inside-out and the messy way it came into being. From your description, Dirac seems to be one of those wise geniuses.
  - teeja 17y ago
    I'm sure you're right. Plus, in the sciences, he knows how his colleagues minds work (and all the politics). Dirac probably kept mostly quiet about his doubts because Bohr, the Godfather of QM, thought QM was the Cat's Meow, which Schrodinger didn't. And Schrodinger knew that he pulled his famous equation out of a hat (not derived). Likewise with Feynman, who always repeated "nobody understands quantum mechanics." Too, because of the very competitive culture in the hard sciences, you don't talk about things that are poorly understood. Because if you make a mistake, you'll catch a lot of (friendly or unfriendly) ribbing later.
thisrod 17y ago
I'd love to hear why Penrose really thinks the Everett interpretation is crazy. He gives a very weak reason in the interview. No doubt he accepts the atomic theory of matter, despite his inability to see atoms, so his inability to see superpositions should not prevent him from accepting quantum mechanics. It would be interesting to hear him address that.
- hegemonicon 17y ago
  Probably the same reason everyone else seems to - it runs completely counter to our intuitions about how the world works. As far as I know (and my knowledge of QM can charitably be described as 'nonexistant') if you ignore intuitions and simply resolve the math, the Everett interpretation is what pops out of the equations.
- Daniel_Newby 17y ago
  But you can measure atoms indirectly. I have not heard of a many-worlds theory that is measurable even in principle.
  - thisrod 17y ago
    In principle, you could demonstrate superposition states of cats the same way you'd demonstrate them for atoms or photons: return the live and dead cats to the same state, and look for interference fringes. There are two difficult parts. First, you have to kill the cat, rescusitate it, and restore every molecule of its body to the original orbital, without leaving even one photon of evidence. Once you've done that, it's a simple matter of getting the cat to sit still while you measure its position within a tiny fraction of the diameter of an atomic nucleus. I found a fascinating history of the atomic theory at http://www.aare.edu.au/02pap/har02049.htm http://www.aare.edu.au/02pap/har02049.htm, in the section titled "The History of the Particle Theory". Atoms were once as fantastic as superposition states are today, then they gradually became real. The same page points out that the plausibility of atoms is largely a fluke. People imagine that solid gold has the color of a gold atom, and gas pressure comes from squeezing the atoms together. Quantum theory doesn't lend itself to such simple but wrong explanations.
Estragon 17y ago
To be specific, he's saying that the Copenhagen interpretation of QM is wrong. I'm inclined to agree.
Ixiaus 17y ago
Modern day science is built upon a mosh pit of physical theories that don't all fit together well. The number one premise failing physical theory today, is the concept of a stationary container (the Universe) within which "matter" interacts. Traditional physical theory states that the Universe is one of matter, which is oh so limiting. Another hallmark of popular physical theory is much of it's theories are based on empirical findings rather than a set of purely theoretical postulates... Physical theory today is a posteriori rather than a priori and using scientific experimentation to verify the theoretical deductions. Consider, for a moment, that the primary component of the Universe is not matter, but motion. Discard the idea that there is a static natural reference system (or stage) upon which things can be measured (you can tell actors are moving on the stage because the stage doesn't move). Instead of there being three dimensions with a fourth dimension added for time; there are three dimensions of both space and time (time being a reciprocal of space). Also consider, in this system, that there can be motion without anything moving. If the primary component of the Universe is motion, then material objects are a compound aggregate of motion; motion is, therefore, the antecedent to matter. For more, look here: http://www.reciprocalsystem.com/nbm/nbm02.htm http://www.reciprocalsystem.com/nbm/nbm02.htm

66 points by gnosis 17y ago

I think this post title is misleading. Roger Penrose is not merely saying that quantum mechanics is wrong. Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. It's like Newtonian mechanics. Newtonian mechanics is correct, within its domain (for velocities much less than the speed of light). No one argues with the predictions of Newtonian mechanics within their domain. Einstein's achievement with special relativity, then, wasn't showing that Newtonian mechanics was wrong; instead, he just showed the world the true extent of its domain, and developed a theory (special relativity) that generalized Newtonian mechanics to a larger domain (velocities less than the speed of light). It's terribly unfair to Newtonian mechanics to call it 'wrong' in the same way that the statement 2+2=5 is 'wrong'. Similarly, the fantastic experimental success of quantum mechanics ensures that it would be unfair to call quantum mechanics 'wrong'. Incomplete? Certainly. Worthy of being challenged? Absolutely. Is it taken as gospel by too many physicists? Probably. But is quantum mechanics wrong? No, decades of successful experiments, and practically the entire modern electronics industry, would disagree with that sentiment. The problem is that we just don't know where the domain of quantum mechanics ends, nor the more general theory that will take its place.

tamas 17y ago
Roger Penrose is not merely saying that quantum mechanics is wrong. Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. That's how every scientific theory should be approached, as that's what sets them apart from dogmas.
jacobolus 17y ago
Even more importantly.... this is a lovely interview, that hits on many topics, of which the biographical details are much more interesting than the bit about quantum mechanics. Hopefully the fake-controversy of the title won't scare anyone away from reading it.
teeja 17y ago
Fully agreed. QM is like ... our knowledge of the Moon before the 1960s. Until we got 'out there' we couldn't see the whole thing. Lots of people like to look at the very complex stuff. But the year Einstein published several papers, it was all about very basic observations. We don't puzzle enough about the 'simple'. Heisenberg: "We have to remember that what we observe is not nature herself, but nature exposed to our method of questioning."
Confusion 17y ago
Instead it would be more fair to say that he views quantum mechanics as an incomplete theory, and one that should be continually challenged. Which is not an unusual view. Nobel prize winner 't Hooft has expressed the same sentiment.
mjtokelly 17y ago
What you say is well-put, but to nitpick the last paragraph: the limits of quantum mechanics are well-established. QM is a special case of quantum electrodynamics, which is a low-energy special case of the Grand Unified Theory. http://en.wikipedia.org/wiki/Quantum_electrodynamics http://en.wikipedia.org/wiki/Quantum_electrodynamics http://en.wikipedia.org/wiki/Unified_Field_Theory http://en.wikipedia.org/wiki/Unified_Field_Theory While the latter is not fully fleshed out, its uncertainty only begins in circumstances far weirder than what gives Roger Penrose pause. Penrose says that "The [QM] equation should describe the world in a completely deterministic way, but it doesn’t." But work such as Bell's theorem shows that no deterministic equation could ever be consistent with quantum mechanics: http://en.wikipedia.org/wiki/Bells_theorem http://en.wikipedia.org/wiki/Bells_theorem
- Luc 17y ago
  > But work such as Bell's theorem shows that no deterministic equation could ever be consistent with quantum mechanics: This isn't quite right, because you left out the word 'local' - see http://en.wikipedia.org/wiki/Bohm_interpretation http://en.wikipedia.org/wiki/Bohm_interpretation Bell's theorem applies only to _local_ hidden variables.
  - mjtokelly 17y ago
    Right, but non-local determinism is difficult to square with general relativity.
    - Luc 17y ago
      Indeterministic laws and the non-existence of particle positions and trajectories are difficult to square with general relativity too - and Bohm's interpretation doesn't 'suffer' those problems, while it predicts the exact same observations. (Though I should say this is way out of my amateur-physicist league - I'm taking my cue from 'Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony' http://www.amazon.com/Quantum-Mechanics-Historical-Contingency-Foundations/dp/0226132048 http://www.amazon.com/Quantum-Mechanics-Historical-Contingen... ).
- 17y ago
moron4hire 17y ago
2+2=5 for sufficiently large values of 2
dstorrs 17y ago
Were we reading the same article? "But when you accept the weirdness of quantum mechanics [in the macro world], you have to give up the idea of space-time as we know it from Einstein. The greatest weirdness here is that it doesn’t make sense. If you follow the rules, you come up with something that just isn’t right." "You’re led to a completely crazy point of view." "My own view is that quantum mechanics is not exactly right, and I think there’s a lot of evidence for that." "INTERVIEWER: In general, the ideas in theoretical physics seem increasingly fantastical. Take string theory. All that talk about 11 dimensions or our universe’s existing on a giant membrane seems surreal. PENROSE: You’re absolutely right. And in a certain sense, I blame quantum mechanics, because people say, “Well, quantum mechanics is so nonintuitive; if you believe that, you can believe anything that’s nonintuitive.” But, you see, quantum mechanics has a lot of experimental support, so you’ve got to go along with a lot of it. Whereas string theory has no experimental support." "[My new book] is called Fashion, Faith and Fantasy in the New Physics of the Universe. Each of those words stands for a major theoretical physics idea. ['Fantasy'] is quantum mechanics at all levels...." All of those quotes sound to me like pretty clear rejection of string theory and quantum mechanics and an implied rejection of much of modern higher physics. Yes, he accepts experimental proofs where available, but he seems to be saying that these theories are wrong because they don't make sense to him, or because they don't match the way we perceive the world. But when I look at the Hacker New logo, I don't perceive photons of wavelength 590 nanometers bouncing off my retina--I pereceive the color orange. Personally, as I read this, I kept hearing Clarke's 1st law (http://en.wikipedia.org/wiki/Clarke%27s_three_laws http://en.wikipedia.org/wiki/Clarke%27s_three_laws) looping in my head: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong."
- camccann 17y ago
  But when I look at the Hacker New logo, I don't perceive photons of wavelength 590 nanometers bouncing off my retina--I pereceive the color orange. If you did perceive photons at 590nm that would be rather remarkable! More likely, you would perceive a mixture of photons at different wavelengths, mainly a combination of 615nm and 550nm or thereabouts. In actuality, you perceive this "orange" concept; in fact, you would perceive the same orange whether exposed to 590nm photons or the mixture, which emphasizes the point that what we experience in the real world doesn't necessarily relate to reality in an obvious way.
thinksketch 17y ago
I agree that the title is misleading. But I think his view is really important. Or maybe better said, it's really important that a great man like Penrose comes out and unequivocally makes this statement to generations who have too often been told to "shut up and just learn the theories". In college it drove me mad that I could not find any resources to question the "absolute validity" of paradoxes that arose in modern physics. To me, a paradox could not represent a universal truth - it must be seen as an opportunity to understand why our tools are insufficient to fully understand the universe. But the response to my questioning was always "who are you to question 100 years of experts?" Finally I found one physics professor who confided in me that he too had been trying to start a fertile dialogue about these things, but other professors would just scoff. He felt it was futile at best or career damaging at worst. So I learned that, truly the 'old experts' took modern theories with a grain of salt - it was only today that we took them so literally. But none of my classmates believed it and they thought I was brash and stupid for bothering to think about it. For a while, I met with that professor once a month or so to try to steer my knowledge in a direction that wasn't jaded by a blind acceptance of theories that were inconsistent with one another. I hated the feeling that it had to be some half-valid historical truth. It made me feel half-way delusional. It made me lose trust that the academic system would prepare me to really truly think. I wanted to learn about the paradoxes, the holes in our thinking, how we were wrong, because those are the exciting areas that need development. If you spend your whole education learning fundamentals while detached from the burden of these kinds of questions, how can you be prepared to tackle them once you raise your nose up out of the textbooks? So yes, it's misleading to make the title, "String Theory and Quantum Mechanics are wrong." But I hope his important point doesn't get lost, that it is also wrong to say that String Theory and Quantum Mechanics are completely right - end of story - no questions." Thank you Roger Penrose for taking this stance loud and clear.

BRadmin 17y ago

"In my view the conscious brain does not act according to classical physics. It doesn’t even act according to conventional quantum mechanics. It acts according to a theory we don’t yet have." Do most modern AI researchers disagree with this?

daeken 17y ago
I don't think we have enough information to say one way or another. We've gained a lot of knowledge about the brain, but it's still very much a black box. I think it's worth holding off on making any assumptions until we understand a whole lot more about it.
rw 17y ago
The sensible response is: "show me ". Quantum effects are not known to be significant. I believe that our mind is an emergent property: lots of neurons and chemicals interacting. Sure, there are a lot of variables, we need the dynamical systems perspective to even begin to understand the whole process... but a new kind of physics? Don't be so anthropic! AFAICT cognition happens at the multicellular level--huge, from a QM perspective. This reminds me of that old anti-strong-AI bugaboo, "intelligence in the gaps": http://en.wikipedia.org/wiki/God_of_the_gaps http://en.wikipedia.org/wiki/God_of_the_gaps
lkozma 17y ago
Yes, most modern AI researchers believe that the functioning of the brain can be explained by electromagnetic and chemical phenomena, accurately described by 1900s theories. The fact that we don't fully understand its workings is due to its organizational complexity. Penrose's arguments are discussed for example here: http://www.scottaaronson.com/democritus/lec10.5.html http://www.scottaaronson.com/democritus/lec10.5.html
- 10ren 17y ago
  It's funny, but to be certain that consciousness can be explained by known laws - we just don't know exactly how - itself requires faith and is quite unscientific. Although I too believe it.

btilly 17y ago

Penrose contributed a lot and I don't want to minimize that. However when he stepped outside of his own domain he makes some serious basic mistakes that make him ignorable. As an example in The Emperor's New Mind he makes a number of claims about consequences of Gödel's theorem for human thought that were flat out wrong. I remember reading criticism of it from a logician in the mid-90s, and Penrose's response. While I'm no logician, I know enough about it to know that the logician was right and Penrose was wrong. Human thinking is known to accept inconsistencies and so you can't apply Gödel's theorem to derive any interesting conclusions. When he moves from logic to physics he is even more out of his depth. Given his verifiable mistakes in logic, I am comfortable in concluding that his startling assertions about physics are far more likely to arise from further mistakes of his than from his having found serious reasons to question the foundations of modern physics.

deleted 17y ago
[deleted]
anatoly 17y ago
I agree with your description of Penrose's Goedelian claims (the logician was Solomon Feferman), but I'm not sure why you say he'd be even more out of his depth in physics. Penrose is primarily a mathematical physicist, not a mathematican.
- btilly 17y ago
  You are right. I had known his mathematical work, but didn't know his biography. That said, his physics work seems to have been in general relativity, not quantum mechanics. Given what I know about how he messed up when he stepped out of his area in math, I find it more likely that he has made similar types of mistakes in quantum mechanics than that he has truly demonstrated that mainstream physics is wrong.
  - slackenerny 17y ago
    not quantum mechanics Except the twistor formalism he created (following ideas of no one else but Dirac) is important branch of research in quantum mathematical physics and string theory, not only classical gravity. Just like Hawking or Freeman Dyson had, Penrose too earned his right to odd, and even braggart opinions on everything. Especially since opinions are by definition not meant to advance knowledge, or demonstrate results, but to provoke and inspire discussion.

teeja 17y ago

http://mindbody.blogspot.com/2009/10/penrose-kind-o-gets-it.html http://mindbody.blogspot.com/2009/10/penrose-kind-o-gets-it.... "Schrödinger, Einstein, and Paul Dirac. They were all quantum skeptics in a sense. Dirac is the one whom people find most surprising, because he set up the whole foundation, the general framework of quantum mechanics. People think of him as this hard-liner, but he was very cautious in what he said. When he was asked, 'What’s the answer to the measurement problem?' his response was, 'Quantum mechanics is a provisional theory. Why should I look for an answer in quantum mechanics?'" http://www.afterourtime.com/wiki/index.php?title=Quantum_Gravity http://www.afterourtime.com/wiki/index.php?title=Quantum_Gra...

nopinsight 17y ago
In a way, a wise creator of a theory should be the one least fixated by it, as he knows all its potential weaknesses inside-out and the messy way it came into being. From your description, Dirac seems to be one of those wise geniuses.
- teeja 17y ago
  I'm sure you're right. Plus, in the sciences, he knows how his colleagues minds work (and all the politics). Dirac probably kept mostly quiet about his doubts because Bohr, the Godfather of QM, thought QM was the Cat's Meow, which Schrodinger didn't. And Schrodinger knew that he pulled his famous equation out of a hat (not derived). Likewise with Feynman, who always repeated "nobody understands quantum mechanics." Too, because of the very competitive culture in the hard sciences, you don't talk about things that are poorly understood. Because if you make a mistake, you'll catch a lot of (friendly or unfriendly) ribbing later.

thisrod 17y ago

I'd love to hear why Penrose really thinks the Everett interpretation is crazy. He gives a very weak reason in the interview. No doubt he accepts the atomic theory of matter, despite his inability to see atoms, so his inability to see superpositions should not prevent him from accepting quantum mechanics. It would be interesting to hear him address that.

hegemonicon 17y ago
Probably the same reason everyone else seems to - it runs completely counter to our intuitions about how the world works. As far as I know (and my knowledge of QM can charitably be described as 'nonexistant') if you ignore intuitions and simply resolve the math, the Everett interpretation is what pops out of the equations.
Daniel_Newby 17y ago
But you can measure atoms indirectly. I have not heard of a many-worlds theory that is measurable even in principle.
- thisrod 17y ago
  In principle, you could demonstrate superposition states of cats the same way you'd demonstrate them for atoms or photons: return the live and dead cats to the same state, and look for interference fringes. There are two difficult parts. First, you have to kill the cat, rescusitate it, and restore every molecule of its body to the original orbital, without leaving even one photon of evidence. Once you've done that, it's a simple matter of getting the cat to sit still while you measure its position within a tiny fraction of the diameter of an atomic nucleus. I found a fascinating history of the atomic theory at http://www.aare.edu.au/02pap/har02049.htm http://www.aare.edu.au/02pap/har02049.htm, in the section titled "The History of the Particle Theory". Atoms were once as fantastic as superposition states are today, then they gradually became real. The same page points out that the plausibility of atoms is largely a fluke. People imagine that solid gold has the color of a gold atom, and gas pressure comes from squeezing the atoms together. Quantum theory doesn't lend itself to such simple but wrong explanations.

Estragon 17y ago

To be specific, he's saying that the Copenhagen interpretation of QM is wrong. I'm inclined to agree.

Ixiaus 17y ago

Modern day science is built upon a mosh pit of physical theories that don't all fit together well. The number one premise failing physical theory today, is the concept of a stationary container (the Universe) within which "matter" interacts. Traditional physical theory states that the Universe is one of matter, which is oh so limiting. Another hallmark of popular physical theory is much of it's theories are based on empirical findings rather than a set of purely theoretical postulates... Physical theory today is a posteriori rather than a priori and using scientific experimentation to verify the theoretical deductions. Consider, for a moment, that the primary component of the Universe is not matter, but motion. Discard the idea that there is a static natural reference system (or stage) upon which things can be measured (you can tell actors are moving on the stage because the stage doesn't move). Instead of there being three dimensions with a fourth dimension added for time; there are three dimensions of both space and time (time being a reciprocal of space). Also consider, in this system, that there can be motion without anything moving. If the primary component of the Universe is motion, then material objects are a compound aggregate of motion; motion is, therefore, the antecedent to matter. For more, look here: http://www.reciprocalsystem.com/nbm/nbm02.htm http://www.reciprocalsystem.com/nbm/nbm02.htm