18 March 2007

Clutching at the quantum straw

Quantum mechanics is mysterious, and consciousness is mysterious. Q.E.D.: Quantum mechanics and consciousness must be related.

Christof Koch

Ever since an awareness of quantum mechanics began to penetrate the mass public mind, individuals here and there have seized upon it as a pretext to try to legitimize various traditional mystical beliefs. Quantum mechanics, after all, embraces a number of unexpected and bizarre phenomena; it does not seem wholly bound by the deterministic quality of classical physics; and in some cases quantum reactions even seem to be influenced by whether or not they are being observed or recorded. Scientists, of course, are very cautious in assessing the implications of these phenomena. Unfortunately mystics and philosophers are rather less restrained. Claims have appeared in print to the effect that quantum mechanics vindicates such concepts as the soul, or ghosts, or various forms of eastern mysticism. As a result, we now have whole herds of people who have absorbed a vague sense that science is now moving toward, or supporting, a religious or mystical world-view (I have had a number of very frustrating conversations with people like this, who could barely articulate exactly what they were asserting -- such beliefs are usually rooted more in emotional comfort than in coherent logic -- but were firmly convinced of it nevertheless).

An example of this misuse of barely-understood science which has recently drawn attention on the internet involves the hypothesis proposed by physicist Roger Penrose and professor Stuart Hameroff on brain microtubules. To summarize, microtubules are tiny support structures within brain neurons. Penrose and Hameroff believe that they use quantum effects to perform computations which are an integral part of the brain's overall data-processing functionality, and that this fact (brain function is partly based on quantum mechanics) explains why consciousness exists. As far as I know, this hypothesis is not generally accepted and there is no actual evidence that microtubules perform quantum computation, or have anything to do with the brain's computational processes at all; however, Penrose and Hameroff are not mystics and are not asserting anything mystical or supernatural. They are merely proposing a solution to the rather baffling question of how the physical brain sustains consciousness.

In the popular mind, however, the hypothesis has been seized upon for two purposes: to legitimize concepts such as the soul and disembodied afterlife (Andrew Sullivan recently posted an e-mail containing such claims, and given his site's prominence, the meme is sure to proliferate widely), and to assert that brain uploading is impossible, on the grounds that quantum effects could not be simulated in a computer and therefore human consciousness could not be sustained that way.

The latter argument, contrary to what some apparently think, is not new. Ray Kurzweil was aware of it in 2005 and addressed it in The Singularity Is Near on pp. 450-452 (click here for a PDF version of the chapter in which this discussion appears -- you need to scroll down to the pages cited). As he points out, even if Penrose and Hameroff are right, there is no reason to think that a computer could not be built to perform the same kind of quantum computation; and in any case, everything we know of that the brain is capable of doing can be accounted for by the standard model of neuron functioning, without resort to quantum effects.

But facts have never stopped mystics from clutching at the quantum straw.



Blogger Ron Coleman said...

Infidel, have you someone demonstrated that the "mystics" are "clutching at straws" just because phenomena are amenable to mechanistic (if speculative) explanations? All you've shown is that the there are such speculative mechanistic explanations and that they're not new. So?

18 March, 2007 16:43  
Blogger Infidel753 said...

When an explanation based on well-established laws of physics is available, there is no point in seeking alternate explanations based on supernatural phenomena for whose existence there is not a scintilla of evidence. If we can explain thunder on the basis of ordinary natural events, there is no reason to invoke Thor's hammer -- unless of course one's agenda to start with was to justify a belief in Thor's hammer, and one is just casting around for any pretext that can be used to prop up that belief.

18 March, 2007 17:54  
Blogger Star Larvae said...

Part of the problem is that quantum physics is so unlike "normal" physics, that it can seem mystical. Some clarification is given at http://www.starlarvae.org/Star_Larvae_The_Physics_of_Subjectivity.html


02 April, 2007 07:25  

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