Does Quantum Theory Explain Consciousness? 729
astroengine writes "Quantum theory is often seen as the root cause of unrelated, mysterious phenomena. Take consciousness for example. British physicist Roger Penrose recently argued 'that we will need to invoke 'new physics and exotic biological structures': rewriting quantum theory to make sense of consciousness.' But why do this, especially as there is no apparent causal link between quantum mechanics and the conscious mind? There appears to be a very basic logical fallacy here that even the most prominent physicists seem to be making."
What fallacy? (Score:4, Insightful)
Care to state it?
As the saying goes... (Score:4, Insightful)
Penrose is a mystic (Score:5, Insightful)
He wants the brain to be non-computable, non-simulatable. In short, he wants it to be magic. He has no real justification for his position.
Huh? (Score:2, Insightful)
This is the most vague, hand-wavy summary I have ever read (didn't read the article...maybe just as vague?). I am a physicist, but even for the non-physicist, this is vague.
It's all about free will (Score:4, Insightful)
People want to be an uncaused cause. That's what the concept of free will boils down to. The will can cause things, but itself is not caused by anything. If it were caused, it wouldn't be free. Of course, this would make any learning impossible. Either the will is a part of the chain of cause and effect, and therefore not free, or the soul (or whatever you believe to be the seat of consciousness) can never learn.
Re:Consciousness is mysterious not weird. (Score:2, Insightful)
You're playing pointless, autofellating wordgames.
So, uh, keep up the good job with your philosophy courses!
The SMBC rule applies (Score:4, Insightful)
Re:What fallacy? (Score:5, Insightful)
Is randomness really more satisfying than determinism? Is there really more "free will", by any useful definition?
No, I think the appeal is that it appears random, and that we don't (yet) understand a mechanism by which the waveform collapses into one state or another, other than that it collapses with more frequency in some places than others. It's essentially a god-of-the-gaps argument, only this time for "consciousness" or "free will"...
It is, of course, pure speculation. Worse, we are learning more and more about how the brain actually works, and I suspect at some point we will come to terms with the fact that what we call "consciousness" is an emergent phenomenon of the brain, and that it is no more free than a glider in Conway's Game of Life.
Now, is it actually a fallacy? I suspect there's an informal one in there somewhere -- it certainly feels ad-hoc.
Re:Consciousness is weird (Score:5, Insightful)
>>Consciousness is weird. Quantum theory is weird. Therefore quantum theory must explain consciousness.
Quantum Theory is the new "magic" for all sorts of New Age thinkers.
Penrose at least proposes a mechanism of action (quantum tube thingies), which has the benefit of at least giving his theory something more than hand-waving to base his theory on, but has the downside of having absolutely no evidence to support it from studies of the structure of the brain.
Penrose is a smart guy (black holes and tiling and all that) but he does like to propose some rather outlandish things in his free time. Might be a correlation between the two, who knows.
Re:Consciousness is weird (Score:5, Insightful)
Consciousness is weird. Quantum theory is weird. Therefore quantum theory must explain consciousness.
That's essentially the argument here, and it's pretty easily seen as fallacious.
Well, the slashdot link, and the New Statesman story linked to from it, don't really do justice to Penrose's idea, so it's not surprising that you've gotten the impression that there's absolutely nothing there. Actually there's something to it, and although as a physicist I don't buy it, it's not completely stupid.
The basic idea is that there are various ways to interpret quantum mechanics. The most popular interpretations are the Copenhagen interpretation [wikipedia.org] and the many-worlds interpretation (MWI) [wikipedia.org].
My own take on it is that Copenhagen and MWI are just different words for talking about the theory, so the distinction isn't empirically testable. Copenhagen does a good job of depicting the psychological experience of doing experiments with quantum-mechanical systems, but Copenhagen is illogical because it gives a special role to measurement, which is actually a physical process like any other.
Penrose's idiosyncratic idea is that he takes Copenhagen seriously, so he says that measurement is somehow *different* from other physical processes. That suggests that consciousness is somehow different from other physical processes. He also claims that his idea is at least in principle empirically testable, that we should be able to see this process happen by studying neurons. He thinks there is something special going on in microtubules.
Slashdot's readers would have been a lot better off just reading the WP article [wikipedia.org] on Penrose's theory.
Re:This Place Is Full Of Quantum (Score:5, Insightful)
This place is full of Quantum; it's everywhere you look
It's in the halls of Physicists, and pages of a book.
"There has to be a fallacy!" the comment summarised,
And if we care to challenge that, we aren't very wise?
But 'consciousness is quantum' is facile, don't you think?
One hell of a non sequitur; he's right to raise a stink.
Without supporting data, the statement is absurd,
I'm with OP, this is dopey - at best the logic's blurred!
Re:This Place Is Full Of Quantum (Score:4, Insightful)
"Blurred" is just the kind of logic that the quantum minds require.
Like Hellen's scientists, with their Earth, Wind, Water, Fire.
You see, a lot of the mystery becomes quite easy to explain
By introducing "aether" - why that's what's in the brain!
Re:What fallacy? (Score:5, Insightful)
I suspect at some point we will come to terms with the fact that what we call "consciousness" is an emergent phenomenon of the brain, and that it is no more free than a glider in Conway's Game of Life.
Bingo.
Re:Quantum Theory is not relevant (Score:2, Insightful)
Molecules behave classically is a statement of probable, not certain, behavior.
"Random" is just a place-holder word for "we don't know, or aren't specifying, what the causal factors are".
If I wanted to install an undetectable back-door to allow manipulation physical reality, along the lines of what I might do as a software developer to an operating system, QM is exactly what I'd do, incidentally.
Big topics, little time.
Re:Recently? (Score:3, Insightful)
"Human are capable of recognizing when an algorithm will halt (or not); computers are not; therefore thought cannot be reduced to computation"
This isn't really right. humans are capable of recognizing when SOME algorithms will halt. That isn't very spectacular, computers can do the same. Solving the halting problem would mean being able to recognize whether ANY algorithm will halt without resorting to dumb brute force methods. Humans are limited just as much as computers in this respect.
Re:Recently? (Score:3, Insightful)
Beyond this, Penrose is refuted by physics. The holographic principle and its near-corollary, the Bekensten bound, guarantees that one cannot build a physical artifact more powerful than a Turin machine (finite number of distinguishable quantum states in a region of finite surface area => there are no arbitrary-precision real numbers in physics in a finite space => no super-Turing machines possible). Indeed, restricting ourselves to artifacts with finite spatial extent, any physical object can at best have the power of a mere linarly bounded automata (though non-deterministic one, due to QM, which is more powerful than its deterministic counterpart, but still less powerful than a Turing machine). Unfortunately, our brain happens to be a physical artifact. The mind is a collection of thought patterns and these directly map to physics by their neural correlates. Penrose's case is just a sad example of wishful thinking, the inability to admit that our minds are too subject to (likely unknowable) limitations, our own analogues of the halting problem.