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

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

#71
post #33

Earlier quoted context omitted.

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…

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.

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 your living room. For that we start to invent things like many universes, half of which have a TV in your bedroom and half of which have a TV in your living room -- or Penrose's idea that perhaps some magical interaction not yet observed forces something as large as a TV to "make up its mind" due to its gravitational warpings. It's just the fact that your subjective experience doesn't see this TV as half in one place, and half in another, where the wavefunction description fails. The rest is clean, deterministic, and precise.

(2) The second hardest part of consciousness to understand is something we basically take for granted in the hardest part of quantum mechanics. Compatibilist theories of free will make you feel warm and fuzzy but they don't really feel like they address the fundamental mystery: How can a deterministic system be said to "choose" something when that's a fuzzy airy-fairy notion and the actual outcome was written down in the book of history 13.7 billion years ago, full stop? Why do we feel like we've got a million options open when in fact this is false, false, utterly false, moronically-out-of-touch-with-reality crazy false? But in quantum mechanics, the idea that a quantum system has many options open, and can even "sniff around" over the whole space, and that it might make a difference if it does or not -- these things are very acceptable even if you take a deterministic approach to wavefunction collapse. You could maybe in principle go from "warm and fuzzy but I don't get it" to "weird and fuzzy but I think I get it," if the brain is intrinsically quantum.

(3) The hardest problem of consciousness -- how we reconcile our touchy-feely alive experience of red with a machine's cold unemotional ones and zeros -- is very easy to solve by saying "we aren't a machine; subjectivity is something more than a program." In fact, since programs can carry out programs, if consciousness is mechanical we might well ask, how do you know that your brain isn't a different conscious process which happens to be carrying out your own conscious process, and might someday soon get bored and kill you out of its own boredom and desire to live authentically? (This absurdity is also at the heart of Searle's Chinese Rooom argument.) The problem is that machines are such a good model that we have no idea what to replace them with. If quantum systems could really feel in a way that machines really can't, this would solve the problem neatly.

(4) One minor problem in consciousness is about how I'm able to hear things as I am seeing them -- multithreading would suggest that we have multiple consciousnesses doing the separate tasks separately; multitasking would suggest that we switch between these things so fast that it gives an illusion that they all come together, but I can't really do both at once. Quantum mechanics offers a tantalizing hint; for example, in a superconductor, two electrons of opposite momentum "get together" to form a larger particle called a Cooper pair. (You're advised not to think too hard about how they "stay together" with opposite momenta, because It's All Just An Excitation Anyways.) That larger particle can even do something which electrons never can -- it can form a Bose-Einstein condensate: it can conduct current without resistance.

(5) Everybody who watches Star Trek wonders what would happen if someone accidentally forgot to dematerialize you before re-materializing you down on the planet -- which one would be the right "you"? Quantum systems cannot be cloned in this way. The closest we can get is to identically prepare a system -- i.e. take another baby with the same genetic code and give it all of the same life experiences, and kill the ones who don't make the same choices in the same order. Without one of those, you can't clone an arbitrary unknown system into two copies without measuring it and thus forcing it into a classical state. If consciousness is quantum, then the classical state is dead. But if consciousness is just a program, then we're faced with a much scarier situation: in the transporter, you will actually die, but that's okay, because we'll create an impostor who will sleep with your wife for you -- in other words, it's okay because we'll never know the difference, and you'll be dead.

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

#72

Earlier quoted context omitted.

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

Please be charitable.

I thought I was. There's only a few dozen people on the planet who should be insulted by being told that they're not as good at mathematics as Roger Freaking Penrose.

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

#73

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…

> 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.

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

#74
post #62

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.

Telescopes show that Venus displays phases like the moon while Mars and Jupiter don't, which is important evidence for heliocentrism and the order of the planets relative to Earth. Telescopes also show that Jupiter's satellites experience eclipses, which isn't direct heliocentric evidence, but does tell you that Jupiter and its moons shine by reflected sunlight rather than intrinsic luminosity. Telescopes also show s…

Telescopes also show that Mars does loops as it pans across our sky

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

#75

Earlier quoted context omitted.

> 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).

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?

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

#76
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.

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

#77
post #30

Earlier quoted context omitted.

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, the…

That is what aidenn0 seems to be talking about, but that's not what Penrose is talking about. Penrose is very clear that the predictions of QM are extremely accurate. His contention is that the implications of QM cannot be true (that there must be parallel worlds or "it doesn't matter what's really happening in a superposition of states, just that the predictions are accurate"), therefore QM as it is today cannot be…

So basically equation helps you to make your measurement more accurate. (on some scales) what happens underneath is known but can't be accurately measured because it interferes with physical process. (wich comes to no suprise because the measurmenst are done from whitin the universe while it's "running", and that is why your measurment will have effect on future state of universe, )

Seems like Penrose is claiming that different interpretations of this measurement interference are not necessary. thats what i get from article. at least.

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

#78

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 favorit…

> 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).

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

#79

Earlier quoted context omitted.

A large slab of Penrose's book The Emperor's New Mind is, if I recall correctly, devoted to describing how certain structures of the brain just might have some quantum mechanics involved. I don't recall the details and I don't know whether it's all been disproven as we understand the brain better.

I really have to read this book, since I've heard this sort of thing before and it never made sense to me why this matters. I mean, of course quantum mechanics is involved in the operations of the brain; it's involved in the operations of literally every single aspect of physical reality except gravity. People say things like "the brain uses quantum mechanics" and I think "yes, but so does Coca Cola, erosion, and rus…

I think part of it is conflating a few different views:

1.) The brain is some sort of quantum computer (almost certainly false)

2.) The brain as a physical system is somehow sensitive to quantum uncertainty, for example, in the probability of a neuron firing when stimulated. We might hypothesize that this explains our subjective experience of free will: we might be able to chose our world in the sense of the many worlds interpretation, but the worlds we're limited to are just different patterns of deterministic activity within the brain. This is very speculative, but appealing, and I think it deserves more consideration.

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

#80
post #67
post #48

Earlier quoted context omitted.

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).

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
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