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Sir Roger Penrose: Cosmic Inflation Is ‘Fantasy'
April 4, 2014 1:59 PM   Subscribe

(NPR Science Friday) Sir Roger Penrose calls string theory a "fashion," quantum mechanics "faith," and cosmic inflation a "fantasy." ... What's wrong with modern physics—and could alternative theories explain our observations of the universe? Full lectures: Fashion, Faith, and Fantasy in the New Physics of the Universe (Lecture 1: FASHION)(Lecture 2: FAITH.)(Lecture 3: FANTASY.)

Discover Interview: Roger Penrose Says Physics Is Wrong, From String Theory to Quantum Mechanics
"Twistor" Theory Reignites the Latest Superstring Revolution
Roger Penrose on Twistors and Quantum Non-Locality
Upcomming USF Department of Mathematics: Sir Roger Penrose lecture (Monday, April 7 | 6pm | Presentation Theater )
posted by Golden Eternity (48 comments total) 30 users marked this as a favorite

 
Penrose may know his tiling but he did some grout work for me and it was terrible.
posted by GuyZero at 2:13 PM on April 4 [22 favorites]


Lecture on youtube: Roger Penrose: Fashion, Faith, and Fantasy Part 1 2 3 4 5 6 7 8 9 10
posted by Golden Eternity at 2:15 PM on April 4 [1 favorite]


I did not realize that the chess master Jonathan Penrose was his brother.

Just read the Discover interview, which is real chummy and doesn't press him too much on anything he is saying. But, what he is saying seems to be more restrained than the title of his book suggests. A lot of physicists distrust string theory and many-worlds, no?
posted by thelonius at 2:23 PM on April 4


Eh. String theory may end up being a dead end, but both quantum mechanics and cosmic inflation have performed the basic test of science: making a prediction that can be validated in observation or experiment, and has been. It may turn out that that they are only partial theories in the same way that Euclidean geometry or Newtonian mechanics are, but that doesn't make them "faith" or "fantasy". "Not right" or "not entirely right" is not the same thing as being not science.
posted by tavella at 2:24 PM on April 4 [18 favorites]


From the Discover interview:

"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."

In QM, he seems to be disputing the Copenhagen interpretation (Schrödinger's cat and all that) rather than the fundamentals of QM, while he's basically dismissing all of string theory. Which I have less trouble with – string theory could explain things or it could be epicycles.
posted by graymouser at 2:29 PM on April 4 [3 favorites]


The way he described it on Science Friday (as I remember and understand it) is that Schroedinger's equation is essentially half of quantum physics and is great and useful. The other half of is how 'observation' occurs (or probability wave function collapse.) The two halves of the theory are not consistent. If observation is part of the stuff of the universe, then Schroedinger's equation must apply to it as well, and then we get Schroedinger's cat.
posted by Golden Eternity at 2:37 PM on April 4


It may turn out that that they are only partial theories in the same way that Euclidean geometry or Newtonian mechanics are

That seems to be exactly what he's saying. The 'faith' part of QM is where people look at Schrödinger's cat and decide that the weird results of the application of QM to macroscopic phenomena must be true, even though they run counter to all our perceptions. He doesn't think quantum theory is garbage, just that the weird results are evidence that it's not completely correct. Some people go the other way and insist that the superposition of the dead/living cat has to be actually true.
posted by echo target at 2:40 PM on April 4 [1 favorite]


Penrose is hardly alone in saying this sort of thing: there's Lee Smolin's The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next from 2006. Here's an interesting review at a blog by Peter Woit that discusses these sorts of "physics in crisis" issues.
posted by mondo dentro at 2:45 PM on April 4 [5 favorites]


He doesn't think quantum theory is garbage, just that the weird results are evidence that it's not completely correct. Some people go the other way and insist that the superposition of the dead/living cat has to be actually true.

People have been saying this since Einstein, and yet the weird results predicted by it are always experimentally confirmed. At some point, you just have to admit that it's true.
posted by empath at 2:52 PM on April 4 [5 favorites]


Penrose has been suffering from engineer's disease (in this case the rarer Fred Hoyle variant) for a long time now though, where he is the only physicist clever enough to see the truth.
posted by MartinWisse at 2:54 PM on April 4 [10 favorites]


In QM, he seems to be disputing the Copenhagen interpretation (Schrödinger's cat and all that) rather than the fundamentals of QM

If this is the case, he's thoroughly in the mainstream of physics. The Copenhagen interpretation hasn't been taken seriously for decades.
posted by mr_roboto at 2:55 PM on April 4 [2 favorites]


The Electric Sun theory, part of the larger Electric Universe Theory. Also, Electric nature of comets, rather than being a dirty snowball.
posted by Pirate-Bartender-Zombie-Monkey at 3:00 PM on April 4


On the topic of macroscale quantum superposition and why we don't observe it much, this came out recently (more accessible commentary). The gist seems to be that Schrödinger’s equation is NP-hard, so past a certain scale the universe can't resolve multiple states for a quantum object and they just don't exist (assuming P≠NP, implying there are no efficient solutions for NP-hard problems). I'm not even remotely qualified to evaluate the idea, but it talks a good game.
posted by figurant at 3:04 PM on April 4 [6 favorites]


and yet the weird results predicted by it are always experimentally confirmed

The subatomic predictions, yes. The macroscopic predictions that come from extending the theory beyond the subatomic scale are the ones I was calling "weird". Infinite universes and cats that are simultaneously dead and alive are still a long ways from experimental confirmation.
posted by echo target at 3:05 PM on April 4


@roboto: That is surprising but welcome news re: the rejection of Copenhagen. Are there layman-accessible papers available to that effect?
posted by grumpybear69 at 3:15 PM on April 4


Infinite universes and cats that are simultaneously dead and alive are still a long ways from experimental confirmation.

a) The cat is a metaphor.
b) They've been working on superposition on a macro scale and they're actually getting somewhere.
posted by Talez at 3:45 PM on April 4 [4 favorites]


echo target: "The subatomic predictions, yes. The macroscopic predictions that come from extending the theory beyond the subatomic scale are the ones I was calling "weird". Infinite universes and cats that are simultaneously dead and alive are still a long ways from experimental confirmation."

Is this still true? From a 2010 article on physicsworld.com: Quantum effect spotted in a visible object

"Physicists in California have observed true quantum behaviour in a macroscopic object big enough to be seen with the naked eye. This is the first time this feat has been achieved and it could shed light on the mysterious boundaries between the classical and quantum worlds.
[...]
In this way the researchers created a superposition state of the resonator where they simultaneously had an excitation in the resonator and no excitation in the resonator, such that when they measured it, the resonator has to "choose" which state it is in. "This is analogous to Schrödinger's cat being dead and alive at the same time," says Cleland."

posted by Hairy Lobster at 3:46 PM on April 4 [2 favorites]


Poking around, apparently his favored vision of cosmology is a cyclical one, down to claims of being able to see patterns of a past universe in the CMB (which no one else has been able to reproduce with any statistical significance) So basically, he's criticizing a version of cosmology that is founded in observation when his own is much more a product of fantasy. Most cosmic expansion theorists are pretty clear it's a work in progress; we have a pretty solid idea that the universe expanded from a very hot dense state, because so far prediction and observation have matched, but we aren't sure about the final fate or the origin. Which is why people are trying to do, y'know, science to both test what we think we know and learn more.
posted by tavella at 4:08 PM on April 4 [1 favorite]


mr_roboto: "The Copenhagen interpretation hasn't been taken seriously for decades."

Sadly, this hasn't been my experience in talking with other physicists. Copenhagen is certainly not at the level of near-universal acceptance it had from about 1935 up through about 1985, but it's still the interpretation that a plurality of physicists seem to subscribe to, if not an outright majority. Have a look at this survey from a year or so ago — even at a conference about interpretations of QM, where you'd expect to find a wider diversity of views, Copenhagen still has a near-majority of the votes. And the most common reaction I get from fellow physicists when I tell them that I think Copenhagen is junk is some level of incredulity.

Now, if you're talking about philosophers of physics, that's another matter entirely, and I think you're entirely right — very few of them have taken Copenhagen seriously since the fall of logical positivism and the rise of scientific realism somewhere in the 1960s, if not before.
posted by freelanceastro at 4:09 PM on April 4 [7 favorites]


Quantum physicists are split between various interpretations of the measurement problem, but as soon as you ask their opinion they will give you a definitive answer and will stick to it.
posted by surrendering monkey at 4:10 PM on April 4 [28 favorites]


Just realized that my comment above may read like *I* am a cosmologist, which I am not, just an interested observer.
posted by tavella at 4:16 PM on April 4


Quantum physicists are split between various interpretations of the measurement problem, but as soon as you ask their opinion they will give you a definitive answer and will stick to it.
posted by surrendering monkey

Isn't this just Schrodinger's Cat all over again?
posted by carping demon at 4:30 PM on April 4 [2 favorites]


"And this whole hubbub about the higgs-boson is just so much collecting marbles in the play-yard," Penrose continued, twisting his tie in his fingers in a manner which strongly suggested it was manifesting epiphenomena.

Or whatever, I cast Kaku's Floating Disk of Summon PhysicsMatt with my Greene Wand of Brian +3 (vorpal).
posted by Panjandrum at 4:31 PM on April 4 [1 favorite]


I was listening to this today, and almost made an AskMe out of it. I am wondering, when he spoke of a need for a "new physics," what did he mean? Is it that we have gotten to a point where technology has enabled us to disprove old theories, such that there is now a void that needs to be filled?
posted by 4ster at 4:32 PM on April 4


Pirate-Bartender-Zombie-Monkey: "The Electric Sun theory, part of the larger Electric Universe Theory."

Personally, when it comes to Electric Universe, this is more my thing.
posted by symbioid at 4:44 PM on April 4


Sir Roger visited our department earlier this week to give a colloquium on the topic (I was supposed to have lunch with him, in fact, but due to a misdirected email ended up at the wrong restaurant). It's the second time I've seen him talk on the subject, and was equally unconvincing. Basically, based upon a set of assumptions about the far future (which may or may not hold) he argues that eventually there will be no relevant physics that has a physical scale associated with it, which he uses to justify asserting (and it's really no more developed than that) that for some reason physics then all rescaled itself so that the extremely diffuse, low density, low temperature state at the end of one cycle now looks like an extremely dense, high temperature state which marks the beginning of the next cycle of the universe.

The CMB evidence he cites is not at all convincing to those of us who have seen the long history of claims of funny behavior in the CMB (basically, certain properties of the CMB are expected to be perfectly Gaussian-distributed, and there have been many papers asserting that is violated) that have just not held up, either due to contamination by foreground signals (galaxies, gas in the Milky Way, etc.) or because of poor treatment of statistics (e.g., there are many cases where people were effectively doing dozens of statistical tests and found one significant signal out of them which they then touted as evidence of non-Gaussianity, not taking into account the fact that they performed so many tests of versions of non-Gaussianity that there would be a large probability of a false positive by chance).

It's always fun to think about the beginning of the Universe, regardless. One piece of good news is that Sir Roger agrees that his theory would be falsified if the recent claims from BICEP2 of evidence for strong gravitational waves from inflation are backed up in upcoming tests over the next few years, so this is at least testable (unlike much of string theory).
posted by janewman at 5:19 PM on April 4 [24 favorites]


Yeah guys, I'm flying to China tomorrow and don't have time to really go into this. The good Dr. Newman speaks wisdom, listen to him.
posted by physicsmatt at 5:28 PM on April 4 [3 favorites]


The subatomic predictions, yes. The macroscopic predictions that come from extending the theory beyond the subatomic scale are the ones I was calling "weird". Infinite universes and cats that are simultaneously dead and alive are still a long ways from experimental confirmation.

Quantum mechanics does not predict quantum effects at the macro scale, because of decoherence.
posted by empath at 5:56 PM on April 4 [1 favorite]


empath: Quantum mechanics does not predict quantum effects at the macro scale, because of decoherence.

This is not quite right. I can follow up with more later, when I'm not on my phone, but this is a great explanation of why decoherence doesn't solve the measurement problem at all.
posted by freelanceastro at 6:53 PM on April 4 [1 favorite]


This video Sir Roger Penrose, Aeons before the Big Bang (Copernicus Center Lecture 2010) is a full version of the whole 'rescaling' thing.
posted by zengargoyle at 7:00 PM on April 4


janewman,

Did you go to the Quantum Time Conference at the Center for Philosophy of Science? Some of my friends organized it, but I didn't get to go.
:[
posted by Jonathan Livengood at 7:51 PM on April 4


The timing is kinda wonky - like janewman mentioned, the recent (last week?) disclosure that the BICEP2 equipment was able to image polarized swirling of the cosmic background radiation - like, the vortices left behind a boat - that really really support the Cosmic Inflation theory.

Which Penrose isn't a fan of.

Quite a few (highly influential) theorists who started/vaunted alternate theories have publicly thrown in the the towel of their own theories immediately after announcement/publication of the BICEP2 results.
posted by porpoise at 8:43 PM on April 4 [1 favorite]


Jonathan: I didn't go to the conference -- I wasn't aware it was going on ( though even if I had noticed, it's a topic I don't know much about, and given my crazy travel schedule this month just staying caught up is a higher priority than going to a conference out of my field). Unfortunately I haven't had much opportunity thus far to take advantage of the History and Philosophy of Science department here at Pitt; I understand it's one of the best in the country, but don't know any of the members personally.
posted by janewman at 9:24 PM on April 4


what did he mean? Is it that we have gotten to a point where technology has enabled us to disprove old theories, such that there is now a void that needs to be filled?

My understanding is he feels physics is currently incomplete and/or inconsistent and/or incoherent. The only way to fix the inconsistencies and continue building off of current theory is with mathematical Rube Goldberg contraptions like adding fourteen dimensions and with absurd explanations like multiverses and Schrodinger cats. Penrose wants a more elegant theory. Perhaps he is the one acting on faith in that respect. However, it is interesting how in this thread the faith is reversed. If a CMB pattern is found that supports some modified version of the Big Bang theory it is legit, but if a pattern is found that supports an alternate theory it is a statistical anomaly. I guess in enough time confidence in the CMB observations should improve and the data will be irrefutable. It seems to me the present day academic culture in the sciences is insufficiently supportive of contrarian ideas, as Paul Steinhart points out well:

Theories of Anything - Paul J. Steinhardt
“I think a priority for theorists today is to determine if inflation and string theory can be saved from devolving into a Theory of Anything and, if not, seek new ideas to replace them. Because an unfalsifiable Theory of Anything creates unfair competition for real scientific theories, leaders in the field can play an important role by speaking out—making it clear that Anything is not acceptable—to encourage talented young scientists to rise up and meet the challenge.”
The Inflation Debate - Is the theory at the heart of modern cosmology deeply flawed? - Paul J. Steinhardt

Why I Still Doubt Inflation, in Spite of Gravitational Wave Findings - (Science Journalist) John Horgan
I hope that turns out to be the case, because cosmology and physics desperately need a jolt of energy (which the anti-climactic discovery of the Higgs boson did not provide). But here is what I’d like to see: First, corroboration of the BICEP2 findings by other groups and observatories. Second, experiments from high-energy physics that provide some sort of corroborating evidence of the driving mechanism of inflation. Third, an explanation of why the Alice’s Restaurant Problem isn’t still a problem. Fourth, an explanation of why only inflation, and not other more conventional physical phenomena, can account for the gravity-wave findings.
It seems to me 'wavefunction collapse' is a more fundamental problem in quantum physics. Schrodinger's equation tells us all of the possible next states of a photon or the universe or whatever and the probabilities for each of those states, but it doesn't tell us exactly which of these states will happen, and there is weirdness where things only seem to exist and interact as probabilities until they are observed ('collapse'). But there is no explanation for the mechanism for how the one observed or collapsed state is picked out of all the possible states (or possible universes within the multi-verse or whatever) other than probability distributions. It is as if you still need a god in the form of a pseudo-random number generator or something that picks the outcome of each collapse in conformance with the theoretical probability distribution. What is the exact mechanism of these random collapses? Absolute randomness is incoherent it seems to me. Probability theory is an instrument for measuring our lack of knowledge rather than an explanation in itself.
posted by Golden Eternity at 10:50 PM on April 4 [1 favorite]


Penrose's theory of consciousness relies on QM, as I understand it; but a new and as yet undiscovered kind of QM.
posted by Segundus at 11:50 PM on April 4


My understanding is he feels physics is currently incomplete and/or inconsistent and/or incoherent. The only way to fix the inconsistencies and continue building off of current theory is with mathematical Rube Goldberg contraptions like adding fourteen dimensions and with absurd explanations like multiverses and Schrodinger cats. Penrose wants a more elegant theory.

To be honest, while a lot of physics is driven by the search towards a more elegant theory of how the universe works, the fixation on elegance as a predictor for truthfulness and the harping on how inelegant, incomplete or inconsistent the current state of play is, often is the sign of the kook.

And from everything I've read about Penrose and his theories, he does seem to be in danger of slipping into kookdom.
posted by MartinWisse at 1:16 AM on April 5


"Kookdom" is exactly where he needs to play.

Everything we know thus far has been "elegant". The chances are, everything that we learn in the future will continue to be so.

In this context, "elegance" means but understanding.
posted by Zenabi at 3:03 AM on April 5


Penrose has claimed that "the Chinese Room argument refutes Strong AI", so although I'm interested in what he has to say and will watch the videos, IMO he's quite capable of being very wrong about the more philosophical aspects of physics.
posted by sfenders at 4:09 AM on April 5 [2 favorites]


Did he shake his cane at the bohr model, too?
posted by clvrmnky at 5:21 AM on April 5 [1 favorite]


But there is no explanation for the mechanism for how the one observed or collapsed state is picked out of all the possible states (or possible universes within the multi-verse or whatever) other than probability distributions.

Why do we need to posit any mechanism at all? If QM is a good description of how stuff actually behaves, as we have good evidence to say that it is, why not simply take it at face value, and work with the idea that this is just how nature is?

If we have these initial conditions and we allow some time to elapse and then make this kind of measurement, what good reason do we actually have for believing that the outcomes should be more tightly predictable than QM's probability distributions allow for?

The fundamental understanding underneath any such expectation of repeatability, it seems to me, is mechanism: the idea that what we're investigating is some kind of machine-analogue with controls and behaviours, where if you set the controls a certain way you will always see the same behaviours.

The fact that QM is successful clearly says to me, at least, that on the fine scale this is simply not how nature is. On the fine scale, nature just does whatever the hell it likes. It never came with guarantees about repeatable performance; that's just something we've noticed it does at the coarse scales we're able to perceive directly, so we assume more or less intuitively that it's going to do that at all scales. Personally I have never encountered any rigorous theoretical underpinning for any such assumption.

It is as if you still need a god in the form of a pseudo-random number generator or something that picks the outcome of each collapse in conformance with the theoretical probability distribution.

Or it's as if the theoretical probability distribution has been carefully worked out by really smart people in order to match reality well enough to be able to make accurate predictions about its observed and observable behaviours.

In other words: you have it backwards. Observations constrain probability distributions, not the other way around. Nature just does what it does, and all we can do is describe that as best we can.

What is the exact mechanism of these random collapses? Absolute randomness is incoherent it seems to me.

If you like, you can think of a random result as one whose causal inputs are simply too numerous and/or uncontrollable and/or unmeasurable to allow it to be predicted even if it were in fact possible to model it somehow. You don't need to give up causal determinism to allow for such results, merely acknowledge that in the real world it is often not possible even to identify all relevant causes, much less measure them accurately enough to be useful.

It's tempting to look at a physical theory that makes probabilistic predictions and conclude that it's in some way parallel to a simplistic theory of flipped coins or dice, and that a more detailed or comprehensive or correct physical theory would allow one to do the equivalent of measuring the exact starting position of a coin and the exact forces on it so as to make an accurate prediction about which way up it's going to land. But again, that's an intuitive expectation, not some necessary and fundamental truth about the way the world "must" work.

Probability theory is an instrument for measuring our lack of knowledge rather than an explanation in itself.

What kind of explanation are you after? Something that says that e.g. a photon is sufficiently like some more-familiar non-photon that knowledge about the latter has some useful applicability to making predictions about the former?

Why not cut out the middle-man, and go straight to being able to make correct predictions about real-world systems involving interactions that employ the concept of photons as described by the mathematics that models them? They're not little billiard balls; they're their own kind of thing.

Personally I'm happy that we have some really good and detailed explanations that say look, here are these little bundles of behaviour we call photons, and here is some mathematics that models them. And if that mathematics happens to be probabilistic, so what? Photons might not even exist except as a convenient conceptual way to bundle observed correlations between photon-emission events and photon-absorption events.

I seem to recall that it was Heisenberg who said we should just take the mathematics at face value, and avoid making up too many just-so stories about what's "actually" going on "between" observable events.
posted by flabdablet at 8:35 AM on April 5


Perhaps he is the one acting on faith in that respect. However, it is interesting how in this thread the faith is reversed. If a CMB pattern is found that supports some modified version of the Big Bang theory it is legit, but if a pattern is found that supports an alternate theory it is a statistical anomaly.

Golden Eternity, you'll find pretty of skepticism out there about the BICEP2 results; based on the fact that the team only published when they had confirmation from a new instrument, even the team itself was concerned, but that test has allayed many worries. In general the theorists are waiting to see if other experiments will find consistent polarization patterns, and the experimentalists are lamenting that their projects were less optimized for this measurement than BICEP2 and trying to figure out what they can do in the short term.

In contrast, at least three different teams have failed to confirm the CMB anomalies claimed by Gurzadyan et al. as being statistically significant. In his previous talk at Pitt, Penrose described Gurzadyan as a member of the WMAP team (and hence a real expert on the satellite's data), but that's not the case; I kind of wondered at the time if Gurzadyan's credentials had been misrepresented to him.

Given that what they're looking for is patterns in the noise, which varies over time and is correlated between nearby regions of the sky, to do this right almost certainly requires analyses of the WMAP 'time-stream data' (i.e., what temperature was measured at what position on the sky at what time) rather than using the maps built out of the time-stream data, which is what Gurzadyan did. That's a lot more difficult, though.
posted by janewman at 9:46 AM on April 5 [1 favorite]


The problem with the Copenhagen interpretation is that what constitutes "observation" is poorly defined and handwavey.

But if it's poorly defined and handwavey and works, physicists will use it anyway.

It pisses off mathematicians a lot.
posted by Zalzidrax at 2:07 PM on April 5 [2 favorites]


Honestly, I think most working physicists don't really care one way or the other about Copenhagen interpretation vs. many worlds vs. whatever other philosophical interpretation you care to choose.

Why? Because on some level, the only thing (most) physicists are going to care about is what you can actually measure. And Schroedinger's equation (well, relativistic versions of it, if needed) describes what we measure very well.

And I say this as a string theorist. (Who, like most working string theorists today, actually spends a lot more time working on dualities inspired by string theory than I do on actual strings).
posted by nat at 2:21 PM on April 5 [3 favorites]


Maybe I'm wrong and everybody involved is really keeping it in mind all the time, but sometimes it sure feels like the people who like to argue over the interpretations and "meaning" have forgotten that quantum mechanics is just a model. A damn fine model, but still just a model.

(Or, to misappropriate a quote: the best model of reality is reality)
posted by Dr.Enormous at 2:26 PM on April 5


The problem with the Copenhagen interpretation is that what constitutes "observation" is poorly defined and handwavey.

Isn't observation just synonymous with measurement? I've found these to be interesting discussions of the measurement problem (or lack thereof):

The Measurement Problem

Experimental motivation and empirical consistency in minimal no-collapse quantum mechanics - Maximilian Schlosshauer


I've just been listening to the lecture on 'Twisters and Non-Locality,' and have a question I'm hoping a mefi phyicist can help me with. What distinguishes 'non-locality' in quantum entanglement from the following situation?
I have two playing cards, lets say the queen of hearts and the king of spades. I put each card in an envelope, shuffle the envelopes, and send one of them to my friend in New york and one to my friend in Seattle. After they receive them, I call my friend in NY ask which card he received. I now know instantaneously what is in the envelope in Seattle.
If this situation is no different, I really don't see how there is any "spooky action at a distance" or "instantaneous communication" as Penrose talks about, or anything that mysterious or necessarily non-local about quantum entanglement. I'm guessing the difference is that a quantum property (like particle spin) actually must be in a superposition of all states until it is observed (it is not just that we don't know which state it is in) and this comes from the double slit and similar experiments?
posted by Golden Eternity at 5:26 PM on April 6


I have two playing cards, lets say the queen of hearts and the king of spades. I put each card in an envelope, shuffle the envelopes, and send one of them to my friend in New york and one to my friend in Seattle.

Not that I understand the maths at all, but having just seen Roger Penrose give a lecture about this stuff I think it would be something like this: When either recipient of the cards looks to see which card he's got, he's only allowed to look at one side. If New York happens to look at the back of their card, they don't find out what card it was, but they do know that whichever side Seattle happens to look at it will turn out to be the back of the card as well. Whichever result you get from the measurement of one card tells you something about what the people with the other card will see when they look at theirs. That something is random, so it doesn't do you any good in terms of communicating information faster than light.

I like Penrose's brand of "objective reduction". Not that there's evidence for it yet, but it seems like as good a guess as any I've seen in popular science.
posted by sfenders at 7:13 PM on April 6


I have two playing cards, lets say the queen of hearts and the king of spades. I put each card in an envelope, shuffle the envelopes, and send one of them to my friend in New york and one to my friend in Seattle. After they receive them, I call my friend in NY ask which card he received. I now know instantaneously what is in the envelope in Seattle.

It is kind of like that, except imagine that you have sent 2 cards out of a set of a possible four. An even black card, an odd black card, an even red card and an odd red card.

You can only measure the card for even-ness or color, but not both at the same time.

If you measure for evenness, and yours is even, you will find that your partners card is odd. But the color information is lost for both cards. If you measure for color, you'll find that your card is red and your partners is black, but the evenness information is lost for both cards.
posted by empath at 11:06 PM on April 6 [1 favorite]


What happens if I measure for evenness and my partner measures for color?
posted by flabdablet at 11:58 PM on April 6 [1 favorite]


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