Roger Penrose Says Physics Is Wrong, From String Theory to Quantum Mechanics • Hacker News Board

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

#91

Post by Jach » Sat, May 05, 2012, 3:06 AM UTC

calibraxis wrote: post #56

Whodi wrote: post #20

"Is it true that you were bad at math as a kid?" "I was unbelievably slow... I always got lost... I was at least twice as slow as anybody else. Eventually I would do very well. You see, if I could do it that way, I would get very high marks." Speaking as someone who still struggles with math, and was generally the dumbest kid in the most advanced classes, it's a huge relief to hear that someone as brilliant as Penros…

Grothendieck is one of the towering figures of 20th century math. He said: "Since then I’ve had the chance in the world of mathematics that bid me welcome, to meet quite a number of people, both among my “elders” and among young people in my general age group who were more brilliant, much more ‘gifted’ than I was. I admired the facility with which they picked up, as if at play, new ideas, juggling them as if familiar…

Of course, there is a top, though it's hard to tell who's furthest ahead when all options are above your own level. It's healthier for my mental sanity to recognize that great things can still be done by those not at the top than to try and suppose the top is nearer to me than I would like or suppose that the top doesn't exist. If you asked me who I thought was at the top of humans thus far, I'd respond with von Neumann. An excerpt from an interview linked at http://infoproc.blogspot.com/2012/03/differences-are-enormou...

Fermi and von Neumann overlapped. They collaborated on problems of Taylor instabilities and they wrote a report. When Fermi went back to Chicago after that work he called in his very close collaborator, namely Herbert Anderson, a young Ph.D. student at Columbia, a collaboration that began from Fermi's very first days at Columbia and lasted up until the very last moment. Herb was an experimental physicist. (If you want to know about Fermi in great detail, you would do well to interview Herbert Anderson.) But, at any rate, when Fermi got back he called in Herb Anderson to his office and he said, "You know, Herb, how much faster I am in thinking than you are. That is how much faster von Neumann is compared to me."

And there was this piercing comment made here a while back: http://news.ycombinator.com/item?id=1054201 An excerpt:

Look, I'm sorry to be the one to break this to you, but if you have difficulty with any programming concept, you must not be a supergenius. You're just an ordinary genius at best.

The sad truth is that there are some people for whom programming comes as naturally as thinking, with code formed as easily as thoughts; and if it takes an effort to understand any aspect of programming, you have just learned that you are not one of those people. Alas.

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

#92

Post by vbtemp » Sat, May 05, 2012, 4:13 AM UTC

snowwrestler wrote: post #17

Of course it's wrong; all scientific theories are provisional approximations, and the conflicts between quantum mechanics and general relativity are well known. The hard part is proposing an alternative theory that fits all the known evidence. Quantum mechanics and general relativity both match a ton of observations; anything that is going to replace them will need to at least match the same set of evidence at least…

> Of course it's wrong; all scientific theories are provisional approximations

There's always a margin for experimental error, but I think scientific theories are much broader than just "provisional approximations". I think the key here is that they are conceptual models that we use to explain the phenomenon around us, which we then affirm by demonstrating their accuracy to within a certain margin. It's very much a reflection on us - the perceivers - as much as it is the phenomena themselves.

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

#93

Post by tomp » Sat, May 05, 2012, 4:55 AM UTC

pharrington wrote: post #85

drostie wrote: post #71

Earlier quoted context omitted.

Okay, so, let me try to enumerate these. (1) The hardest part of quantum mechanics to understand is intimately tied to our nature as subjects. Quantum mechanics is an entirely deterministic theory about waves in superpositions which even explains how, why, and when it disappears and averages out into classical probabilities. Except it doesn't tell you why we don't see your television as 50% in your bedroom and 50% in…

Just in case you are serious, or people believe you're serious: 1) Quantum mechanics operates on the quantum level. Macro objects, while composed of countless quantum systems, and thus are the result of the quantum systems of probabilistic particles and waves collapsing and such, are just that: the result of the quantum systems. This isn't subjective experience; it's an underlying behavior baring forth a different le…

1) The problem that quantum mechanics has with consciousness is that you can connect macro objects (a cat) with the quantum effects on the quantum level (detector), so that we should actually observe quantum effects on macro objects. That's why Schrödinger's Cat is a paradox.

2) You can't really predict the future of a non-trivial closed system from within the closed system itself - no matter how you would "calculate" the future, you would never be able to include the state of your calculator/computer into the prediction (perfect compression does not exist). I.e., if I make a machine that predicts the future, I know the future, I can act to change it, so the future is different... and the machine does not predict the future, really.

In a way, the universe is the computer that is calculating its own future all the time.

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

#94

Post by flom » Sat, May 05, 2012, 4:58 AM UTC

olalonde wrote: post #80

flom wrote: post #67

Earlier quoted context omitted.

You make a good point. In my earlier post, replace "universe" with "solar system." Then, I can represent the states of the solar system in some subset of the universe, and I'll place this computer sufficiently far from the solar system so it doesn't interfere. Now I should be able to predict what happens on earth, unless you think that variables outside of our solar system significantly affect activities on earth, ri…

1) Don't underestimate the butterfly effect. 2) We can already predict the future to a certain extent. 3) What you wish the universe was like is irrelevant. http://en.wikipedia.org/wiki/Wishful_thinking

Re 2: There should be an obvious qualitative difference between being able to predict where a ball will land if I throw it, and predicting who the passengers riding a particular train in 15 years will be.

Re 3: I was commenting on Roger Penrose's assumption that quantum must be "wrong" because it's "unintuitive" by expressing my opinion that I think quantum is more intuitive than deterministic theories. Indeed, Dr. Penrose and I are both using "wishful thinking," as did Einstein when he hypothesized that the speed of light is "constant in a vacuum." http://en.wikipedia.org/wiki/Speed_of_light#Special_relativi...

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

#95

Post by tomp » Sat, May 05, 2012, 5:09 AM UTC

waterlesscloud wrote: post #75

Symmetry wrote: post #47

Earlier quoted context omitted.

Telescopes don't show you that (contrary to what your inner ear is telling you) its the Earth that moves rather than the sun. At best they tell you that Jupiter has things orbiting it.

What did tell us that the Earth moves rather than the sun?

Nothing. Movement is relative, based on your chosen point of origin.

But, I guess your question was, how did we learn about the structure of the solar system, planets and orbits and all...

By observing the planets, you can map out their path, and you can see that they are not orbiting earth. The only sensible explanation is that all the planets, including Earth, must be orbiting the Sun.

Kepler then further observed that the orbits are elliptical, and then postulated Kepler's laws (that planets orbit the sun in an ellipse, with the sun in one of the focuses).

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

#96

Post by flom » Sat, May 05, 2012, 5:28 AM UTC

gibybo wrote: post #87

flom wrote: post #44

Due to the inconsistency between quantum and relativity, I'm more inclined to believe that the problem is with relativity. The idea that physics is fundamentally non-deterministic satisfies me philosophically. If physics were deterministic, than I should be able to theoretically build a computer, input the state of the universe, and then be able to know what will happen in your life (assuming I don't tell anyone the…

I don't think modern quantum theory holds that the universe is non-deterministic. I think it's still somewhat of an open question. However, I also don't think a deterministic universe would be sufficient to allow you to predict it, because getting the state of the universe is still impossible following the uncertainty principle.

I'm not a physicist, but my understanding is that the debate about whether or not "quantum is deterministic" centers around what your interpretation is of the wave function. I think most physicists, who Penrose would probably criticize, believe the "Copenhagen Interpretation," which says that the wave function of a system is literally the function that, when you take the inner product with its conjugate, gives you the probability distribution of the state of the system, and hence, the state is non-deterministic.

The uncertainty principle arises from quantum. Specifically, it's a statement about the commutativity of operators that act on the wave function, which, going by the Copenhagen interpretation of physics, means it's a consequence of the non-determinism of the universe. I think this is a philosophically satisfying explanation for why getting the state of the universe is impossible.

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

#97

Post by dangrossman » Sat, May 05, 2012, 5:28 AM UTC

tomp wrote: post #93

pharrington wrote: post #85

Earlier quoted context omitted.

Just in case you are serious, or people believe you're serious: 1) Quantum mechanics operates on the quantum level. Macro objects, while composed of countless quantum systems, and thus are the result of the quantum systems of probabilistic particles and waves collapsing and such, are just that: the result of the quantum systems. This isn't subjective experience; it's an underlying behavior baring forth a different le…

1) The problem that quantum mechanics has with consciousness is that you can connect macro objects (a cat) with the quantum effects on the quantum level (detector), so that we should actually observe quantum effects on macro objects. That's why Schrödinger's Cat is a paradox. 2) You can't really predict the future of a non-trivial closed system from within the closed system itself - no matter how you would "calculate…

> In a way, the universe is the computer that is calculating its own future all the time.

Reminds me of this book:

http://www.amazon.com/Programming-Universe-Quantum-Computer-...

> Is the universe actually a giant quantum computer? According to Seth Lloyd—Professor of Quantum-Mechanical Engineering at MIT and originator of the first technologically feasible design for a working quantum computer—the answer is yes. This wonderfully accessible book illuminates the professional and personal paths that led him to this remarkable conclusion.

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

#98

Post by Peaker » Sat, May 05, 2012, 5:37 AM UTC

flom wrote: post #44

Due to the inconsistency between quantum and relativity, I'm more inclined to believe that the problem is with relativity. The idea that physics is fundamentally non-deterministic satisfies me philosophically. If physics were deterministic, than I should be able to theoretically build a computer, input the state of the universe, and then be able to know what will happen in your life (assuming I don't tell anyone the…

Software execution is an entirely deterministic process (at least in theory), and even then, we cannot actually compute the result of that process on a sufficiently large computer.

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

#99

Post by olalonde » Sat, May 05, 2012, 6:04 AM UTC

pharrington wrote: post #85

drostie wrote: post #71

Earlier quoted context omitted.

Okay, so, let me try to enumerate these. (1) The hardest part of quantum mechanics to understand is intimately tied to our nature as subjects. Quantum mechanics is an entirely deterministic theory about waves in superpositions which even explains how, why, and when it disappears and averages out into classical probabilities. Except it doesn't tell you why we don't see your television as 50% in your bedroom and 50% in…

Just in case you are serious, or people believe you're serious: 1) Quantum mechanics operates on the quantum level. Macro objects, while composed of countless quantum systems, and thus are the result of the quantum systems of probabilistic particles and waves collapsing and such, are just that: the result of the quantum systems. This isn't subjective experience; it's an underlying behavior baring forth a different le…

I agree with most of what you said except "Seven years from now your body will be made of entirely different cells than it is now". Some neurons in the brain are never replaced http://askanaturalist.com/do-we-replace-our-cells-every-7-or... (couldn't find a better reference)

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

#100

Post by dgregd » Sat, May 05, 2012, 7:57 AM UTC

planetguy wrote: post #28

snowwrestler wrote: post #17

Of course it's wrong; all scientific theories are provisional approximations, and the conflicts between quantum mechanics and general relativity are well known. The hard part is proposing an alternative theory that fits all the known evidence. Quantum mechanics and general relativity both match a ton of observations; anything that is going to replace them will need to at least match the same set of evidence at least…

You seem to be engaging more with the headline writer than with Penrose. They're both, perhaps, wrong, but Penrose is wrong in a far more interesting way. Penrose doesn't just think quantum mechanics is wrong in the sense that it can't quite be lined up with general relativity, he thinks that quantum mechanics and consciousness are the same problem and that we can't understand one without the other. Now, to me this s…

It seems that consciousness is overvalued. There are more and more fields where conscious human brain losses against dumb silicon. E.g. chess, search.