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

http://discovermagazine.com/2009/sep/06-discover-interview-roger-penrose-says-physics-is-wrong-string-theory-quantum-mechanics

by ColinWright • 14 years ago

129 109 14 years ago

discovermagazine.com

drallison• 14 years ago

Not much content in this article. Read his books to get a feeling for the breadth and depth of his thought.

Flow• 14 years ago

Are any of his book suitable as casual on-the-tram reading? Could you recommend one of his books? Thanks.

ktizo2• 14 years ago

All books are suitable for casually reading on trams, apart from really old and delicate or oversized ones.

I loved 'The Emperors's New Mind' and 'Shadows of the Mind', and did read some of those two while on train journeys, if that helps at all.

arethuza• 14 years ago

Depends how strong you are - I have a copy of "The Road to Reality" on my desk at work, but not sure I'd want to carry it about!

te_platt• 14 years ago

I wouldn't say any of his books are exactly casual reading. The Large the Small and the Human Mind is probably the most casual in that it merely requires thinking and even then some of that is done for you the responses from Abner Shimony, Nancy Cartwright, and Stephen Hawking (contributing authors). The others require active engagement to work through. Especially Road to Reality - there is nothing casual about that one.

ilitirit• 14 years ago

This quite an old article.

> From the September 2009 issue; published online October 6, 2009

gwern2• 14 years ago

> And yet the 78-year-old Penrose—now an emeritus professor at the Mathematical Institute, University of Oxford—seems to live the humble life of a researcher just getting started in his career. His small office is cramped with the belongings of the six other professors with whom he shares it, and at the end of the day you might find him rushing off to pick up his 9-year-old son from school.

Wonder if that's his kid? If I were feeling particularly sour today, I'd look up how much extra risk of birth defects etc using 69 year old sperm (rather than a more normal 30-40s) entails.

mike_ivanov2• 14 years ago

I guess that's none of your business.

stefantalpalaru• 14 years ago

You might want to start by looking up the way sperm is being produced. It will help you clear the confusion with the link between the mother's age and birth defects.

ceejayoz• 14 years ago

Age of the father does have an effect, actually. http://www.webmd.com/infertility-and-reproduction/news/20030...

edit: Also, as someone who's had to use sperm donation to conceive...

> Wonder if that's his kid?

is pretty offensive. It's his kid, whether he's the genetic father or not.

zmj• 14 years ago

It's so sad to see old age claim a great mind.

maxharris3• 14 years ago

I don't understand what you mean. His intellect certainly shines through in the interview, especially in the latter part where he talks about physics.

Symmetry3• 14 years ago

Really? I thought that the parts about physics were really disappointingly fuzzy. Especially: "physicists have to say, well, somehow your consciousness takes one route or the other route without your knowing it." I think that its sort of shocking that he could fail to understand the arguments of his opponents so badly as to end up saying something so ridiculous.

adharmad• 14 years ago

Care to elaborate?

jasonwatkinspdx3• 14 years ago

It's sad to see judgmental certainty claim a young mind.

mike_ivanov2• 14 years ago

Note this: "I was unbelievably slow ... we had to do this mental arithmetic ... I was struggling away to do these tests ... I was at least twice as slow as anybody else."

aidenn0• 14 years ago

Of course by this definition of wrong, Newtonian mechanics is wrong, which didn't stop me from taking a 400 level course on it.

diminish• 14 years ago

Roger Penrose has fundamental thoughts about the physics and AI, not simply callling them wrong wrong in the sense of falsifibility..Read his books.

nollidge• 14 years ago

I don't think the aidenn0 is talking about falsifiability, but accuracy. As in, Newtonian mechanics is not 100% accurate, but it works well enough for macro-level calculations.

Like Asimov said, "when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together." - http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm

snowwrestler3• 14 years ago

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 as well.

Put another way--when one theory replaces another, it must be fully contain the previous theory. General relativity, when applied to everyday human experience (i.e. not super fast, super big, super heavy), produces Newton's law of gravity.

Personally I think the next step in scientific understanding is in information theory. It has the possibility of unifying chaos theory, computer science, physics, and biology. I think this is how we'll develop an description of consciousness for example. We've already seen some preliminary reports that information theory can reproduce gravitation theory for instance.

http://www.technologyreview.com/blog/arxiv/24975/

jessriedel5• 14 years ago

Roger Penrose believes quantum mechanics will fail long before it conflicts with general relativity, which is a bold claim. In addition, the conflict between general relativity and quantum mechanics is popularly overstated. My understanding is that no one knows yet whether the non-renormalizability of gravity in QFT near the Planck scale is necessarily a sign that the theory breaks, rather than just a problem with perturbation theory. It's conceivable that non-perturbative effects will save the day.

planetguy8• 14 years ago

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 smacks a bit of the old argument:

1. I don't understand baseball

2. I don't understand women

3. Therefore, women and baseball must be related somehow

but he has slightly better reasons than that for believing what he does.

Consciousness and quantum mechanics are both fascinating problems to understand; personally I don't think they're the same problem but I don't mind if some smart folks want to think carefully about the possibility that they are.

If consciousness is a property of quantum mechanics then this ought to be at least partially measurable. All you have to do is to construct an intelligent non-quantum computer and ask it "Hey, are you conscious?" Of course this doesn't really help you, because what if the computer just thinks it's conscious but doesn't have real consciousness the way we do? What would this even mean? What is it like to be an intelligent but non-conscious mind? In my own opinion the question is meaningless which is why I think consciousness is some kind of inevitable emergent property of intelligent systems; but of course there's thousands of philosophers out there tackling this very question so I won't pretend to have any original thoughts on it.

natep3• 14 years ago

I don't see that as an accurate description of how Penrose is thinking about the problem (disclaimer: I've only read this interview, and not any of his books). I think he's saying that

1. Everything about QM other than its extremely accurate predictions is wrong

2. We don't have a theory that explains consciousness

And since he is looking for a unified theory, he wants his theory to encompass all of general relativity, the current domain of QM, and consciousness. He certainly understand current QM theory better than most of its detractors (AFAICT from this interview)

baddox• 14 years ago

I don't understand why some researchers are so quick to blame our failure to understand consciousness on the fact that consciousness is a quantum phenomenon. I was under the impression that we're still nowhere near fully understanding the brain even from a classical perspective.

endtime• 14 years ago

>In my own opinion the question is meaningless which is why I think consciousness is some kind of inevitable emergent property of intelligent systems;

Uh-oh...I was mostly with you up until that sentence. See http://lesswrong.com/lw/iv/the_futility_of_emergence/ (or the underlying http://lesswrong.com/lw/iu/mysterious_answers_to_mysterious_...).

snowwrestler3• 14 years ago

Oh I definitely am just responding to this headline and article; I won't pretend to be any sort of expert on Penrose's views.

Personally I agree with you that consciousness is an emergent property of certain complex systems. I think some folks would like to rest free will on the probabilistic uncertainties we see in quantum equations. But IMO that is not necessary since we know through chaos theory that deterministic systems can still produce unpredictable results at high levels of complexity. And the brain is pretty damn complex.

dgregd• 14 years ago

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

jasonwatkinspdx3• 14 years ago

"Put another way--when one theory replaces another, it must be fully contain the previous theory."

This is certainly our hope and desire, but I think you're taking it too far. For example, if we took what you're saying as some sort of prescriptive rule that is improper to violate, we wouldn't have found quantum theory in the first place!

So I think it's important to allow proliferation of theories that explain portions of the evidence, because that explores the space in which we might hope to find a unifying theory.

rudiger• 14 years ago

Can you recommend a good introduction to the theory of conciousness, especially one that relates it to physics and the Universe? I've seen the term "consciousness" in relation to these topics used before, but have a hard time getting information beyond "human conciousness" and how the brain works. Definitionally.

anamax• 14 years ago

> The hard part is proposing an alternative theory that fits all the known evidence. ... Put another way--when one theory replaces another, it must be fully contain the previous theory.

Early astronomy didn't "fully contain" the astrology of the time. Same for chemistry vs alchemy.

I'm not saying that a replacement for quantum mechanics and general relativity will "contain less", just that it wouldn't be the first time if it did.

andrewcooke• 14 years ago

i agree on information. i see occasional references and try to keep track of them, but i have never found a good blog or similar to follow. do you know of anything?

various random links: http://www.scottaaronson.com/democritus/lec9.html http://perimeterinstitute.ca/personal/cfuchs/Oviedo.pdf http://carnap.umd.edu/philphysics/bub_courses.html

vbtemp• 14 years ago

> 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.

Whodi2• 14 years ago

"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 Penrose experienced the same difficulties.

planetguy8• 14 years ago

I don't know how old you are, but I'm pretty sure Penrose overtook you by the time he was your age.

Whodi2• 14 years ago

Haha, that's an understatement, I'm sure he was light years ahead of me as early as 10. It's just inspiring to know that one can struggle with some of the basics and rebound to do great things.

pradocchia• 14 years ago

Please be charitable.

calibraxis2• 14 years ago

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 with them from the cradle–while for myself I felt clumsy, even oafish, wandering painfully up an arduous track, like a dumb ox faced with an amorphous mountain of things I had to learn (so I was assured) things I felt incapable of understanding the essentials or following through to the end. Indeed, there was little about me that identified the kind of bright student who wins at prestigious competitions or assimilates almost by sleight of hand, the most forbidding subjects."

There are many other such mathematicians who aren't flashy. (I recall that Hilbert is a famous example.) So I wouldn't be discouraged by this. Environmental factors are probably far more important.

Jach• 14 years ago

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.

guscost• 14 years ago

I agree!

lkrubner• 14 years ago

If anyone is interested in the earlier Hacker News discussion of this article, it is here:

http://news.ycombinator.com/item?id=925539

Symmetry3• 14 years ago

A rather depressing interview. I enjoyed a lot of the explanations of Physics in *The Emperor's New Mind", but even there I could see big holes in his arguments about consciousness. For example, he talks about how its impossible to make an algorithm tile a grid in a certain way, but I had a screensaver which in fact did what he was saying was impossible. Here I just feel sort of sad and lost.

I think my least favorite line was probably this: "The trouble is, what can you do with it? Nothing. You want a physical theory that describes the world that we see around us." If you're going to use that to reject theories about the reality of the wave function, astronomers in the Renaissance would have been equally justified in rejecting the heliocentric system on account of it being at odds with what they saw around them, or Greek astronomers rejecting the notion that the world was round.

maxharris3• 14 years ago

> astronomers in the Renaissance would have been equally justified in rejecting the heliocentric system on account of it being at odds with what they saw around them

False. Sights observed through a telescope were also part of "what they saw around them." A true theory accounts for all the evidence (and if it's not ultimately reducible to or based on something you can get from the five senses, it's not evidence).

Symmetry3• 14 years ago

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.

saraid216• 14 years ago

Uh. That's what evidence is for. If you have new evidence arguing for a different theory, then you present that evidence and have it tested. It gets added to the pool of "what we see around us".

That's why Penrose is unable to argue against QM the way he argues against string theory: there's experimental evidence and he can't gainsay that.

nu23• 14 years ago

> he talks about how its impossible to make an algorithm tile a grid in a certain way.

My guess, is that here he is talking about undecidability which appears quite often in mathematical problems, maybe something like this http://en.wikipedia.org/wiki/Wang_tile or http://www.nd.edu/~svandend/Tilings.pdf (pdf).

maxharris3• 14 years ago

By the way, if you're looking for a good book to read on philosophy and the history of science, give David Harriman's book a shot. It's called "The Logical Leap: Induction in Physics."

flom4• 14 years ago

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 computer output, because that would perturb the dynamics). I find that prospect far more unsettling than having to account for a superposition of states until I obtain more information in the future.

CrLf• 14 years ago

You would never be able to predict future states of the universe, simply because you cannot represent such states within the universe they represent. Without the ability to predict, the universe is effectively non-deterministic (literally, no one within it can determine its future states).

flom4• 14 years ago

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, right?

jakeonthemove• 14 years ago

But you can in fact build such a computer - you'll just have to solve the little problem of accounting for absolutely all the factors that directly and indirectly affect the result. Then predicting the future is easy peasy :-)...

gibybo• 14 years ago

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.

flom4• 14 years ago

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.

Peaker• 14 years ago

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.

tanvach• 14 years ago

Personally I like the article, and I agree with his concluding paragraph that there must be coherence preservation somewhere.

You need to look at one of the pillars of quantum mechanics he mentioned, where the observables of a system are only the probability, and this is due to 'decoherence' from a measurement. What he's trying to point out is that the coherence in the system must be preserved somehow, otherwise where could it go? It seems that this is very central to the difference between quantum mechanics and general relativity, and that the tiny connections to marry these two are yet to be found. His position is clearly 'it's in the details' not 'we must change everything' of string theory.

This argument reminds me very much of Thorne–Hawking–Preskill bet about information paradox.

PS: fascinating development in quantum weak measurement, where trading off measurement accuracy provides a window into coherence of a system.

rsofaer• 14 years ago

We have so much more to understand about brain functioning in our current paradigm, and no pressing reason to try to build a new physics to help neuroscience. The theory of mind/experience of consciousness is an output of the brain, not part of its architecture.

eevilspock• 14 years ago

Penrose's idea about the relationship between Consciousness and Quantum Mechanics was used by Neal Stephenson in his SciFi tome, Anathem. Very interesting concept, mediocre book.

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

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