Thursday, March 16, 2006

Quantum Physics and Reality (Again)

I want to address this essay in Tuesday’s New York Times by science writer Dennis Overbye entitled, “Far Out Man. But Is It Quantum Physics?” (available with free registration). The essay correctly criticizes the misuse of physics by fuzzy-minded New Age people. But Overbye also errs in buying into an all-too-common misconception about the implications of Quantum Mechanics (QM).

Overbye begins with a discussion of the recent film “What the Bleep Do We Know!?” (which I have not seen). According to his account, the movie's premise is that QM implies the human mind essentially creates reality, so we should be able to alter and improve it as we like. Overbye traces the inspiration of this idea to Eugene Wigner’s suggestion (which followed on John von Neumann’s formulation of QM) that consciousness is the factor responsible for implementing measurements which collapse the superpositions of quantum states into a particular outcome. This idea has been enthusiastically picked up by the filmmakers and other New Ager’s, who inappropriately extrapolate it into the notion that the mind is somehow in control of reality. This opens the door to idealism, paranormal phenomena, and Deepak Chopra.

So far so good. But then we start running into problems when Overbye contrasts this improper use of physics with what he sees as the sober reality of the situation.

He starts by quoting Columbia’s David Albert as saying “It has been decades since anybody took Wigner’s idea seriously.” First, this is incorrect. There are people who have tried to build on the proposal; first and foremost I would cite Henry Stapp (see post here). Second, I believe the reason the mainstream hasn’t worked on the idea is because they lacked good research programs which had traction on the proposed intersection between consciousness and quantum systems; it is not because the idea has been shown to be wrong, which is the impression Overbye’s quick account leaves the reader. I’m personally skeptical that full-blown consciousness is the trigger for wave function collapse, but this remains an open question.

Next, Overbye misinterprets decoherence theory in this passage: “Many physicists today say the waves that symbolize quantum possibilities are so fragile they collapse with the slightest encounter with their environment. Conscious observers are not needed.” I’m sympathetic here since I made the same mistake for years. While I think we can legitimately infer from modern quantum theory and experimental results that natural systems ubiquitously implement measurements all around us, that is not what decoherence theory has shown. Decoherence describes how the interaction of a quantum system with the environment leads to a suppression of interference effects; rather than provide for an objective collapse, it still leaves a ‘mixture’ of states which prevails until we conduct a measurement (see this post for further discussion). The measurement problem remains. (Physicists also continue to explore explicit collapse models, but I think it's fair to say these remain problematic.)

Here’s Overbye’s bottom line:
“In other words, reality is out of our control. It’s all atoms and the void, as Democritus said so long ago. Indeed, some physicists say the most essential and independent characteristic of reality, whatever that is, is randomness. It’s a casino universe.”

This is a very common perspective, among scientists, philosophers and laypeople alike. They take the lesson of QM as being that the strictly deterministic clockwork metaphysics implied by classical physics should be simply overlaid with randomness. But regardless of the details, they assume that a worldview of materialism/physicalism which safely ignores the quantum measurement problem remains the correct stance.

I believe this is wrong. One cannot ignore that the reality implied by QM consists of both deterministically evolving quantum waves and the measurement events which give rise to the concrete phenomena of the macroscopic world. Measurement events remain unexplained within present-day physics. But I conclude the metaphysics necessary for a solution must be richer than physicalism. A property dualism where the ability to measure is an additional aspect of reality is needed (perhaps this could be incorporated into a version of neutral monism, too). And the proposal that this (likely ubiquitous) property and the emergent phenomena of life and consciousness are essentially linked is alive and well. It’s a shame the New Age antics seem to have raised a credibility hurdle for serious consideration of this view.

8 comments:

gugon said...

This is a fascinating post. I happen to know of a person that took this concept to an unbelievable extreme.

I am definitely a layman when it comes to this, but I'm interested. Isn't part of the problem that, simply by being human, we can never be truly objective? No matter how rigorous we believe our scientific method to be, simply by asking the questions, we are imposing a subjective preconception? And because of that, it might be impossible for us to ever REALLY understand what's going on. (As soon as you open the box and look inside, the experiment is contaminated.) As you said, it's far too fragile - and when the New Ager's talk about influencing reality, they have already contaminated the waters and influenced it in countless microscopically subtle ways that they could never understand.

I guess I'm asking - would this be an accurate assessment?

gugon said...

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Thanks - fascinating stuff here!

Steve said...

Hi gugon. Thanks for stopping by and commenting (certainly you can link here if you want).

I agree that it’s strictly true that we cannot have an objective view of the universe from our position within the universe. We are thoroughly entangled with the rest of nature. When we observe something, we act on it as well. Science is a method for simulating objectivity through careful inter-subjective agreement. So, you’re right that we won’t REALLY understand things in the sense of having a “God’s eye” objective view.

On the other hand, science and our other collective efforts to gain knowledge are still pretty good. Since we humans are a pretty homogeneous bunch, there’s no reason for extreme relativism (“I have my truth, you have your truth and no one is right”). Together, I think we can progressively improve our knowledge about the world.

metaphysics5 said...

The question is the measurement.



For me the question is the measurement, or more specifically what do we measure. Somehow I see that consciousness effects the probablity found in quantum physics.

I've read a lot on the subject but my knowledge is limited.

Thanks for your post.

Steve said...

Thanks for your comment. I think the measuring entity can influence the probability as well, perhaps through the way it repeats certain measurements (the quantum zeno effect).

Geoff Haselhurst said...

Would you please read on the spherical standing wave structure of matter in space. You are correct about monism (space), connection of subject and object (interconnection of spherical in and out waves, which is local as Einstein thought), yet also non local (when two wpherical standing waves move relative to one another you get de broglie phases wave with very high velocity c^2 / v).
There is much more, it is simple and obvious once known (given your knowledge of QT).
Sincerely,
Geoff Haselhurst
http://www.spaceandmotion.com/Physics-Quantum-Theory-Mechanics.htm

Steve said...

Thanks Geoff. I will check it out.

Michael said...

I didn't read the Overbye essay but I'm familiar with the popular myth that quantum mechanics is more or less equal to classical mechanics plus randomness. If we need counterexamples, we can consider superconductivity, regular ferromagnetism, transistors, lasers. Not to mention you can't make a stable atom out of a proton and an electron in a classical world. So you won't have anything like chemical bonds or solid tables. But, one can still take an attitude that, after we grant the basic properties of macroscopic objects, we can ignore quantum mechanics when talking about "big" or "warm" things. I tend to think we miss out on some interesting possibilities (and actualities) because the "mainstream scientific community" thinks of quantum mechanics this way.

As your post suggests, another factor that may influence the mainstream attitude towards quantum speculation is from a reaction against some enthusiasts "going too far." Of course no one knows where the line is between warranted speculation and going too far, so it seems that many scientifically-minded people want to bolster their street cred by dismissing every quantum speculation reflexively.

That said, my impression was that What the Bleep did go too far into enthusiasm and vague sensationalism. I saw it quite a while ago so I don't remember much detail, but I thought it made vague claims that seemed to equate "the power of positive thinking" with the interaction between a quantum system and a measurement apparatus. And I think there was a suggestion that we can magically change the world with our thoughts. Anyway, it's not that these ideas are intrinsically so insane that I refuse to entertain them, but I don't think that movie presented a serious case.

I lean towards blaming the reactionary "experts" more than people who get excited by the possibilities.

I'm with you on the debate about the existence or non-existence of the quantum measurement dynamic. It's real. I'm amazed that brilliant people like Gell-Mann and the string theorist popularizer Brian Greene will argue publicly that the wave function collapse is an illusion and there is no arrow of time in fundamental reality (except for that little exception in the electroweak theory). My knowledge of decoherence theory is fairly superficial, but it has always struck me as an attempt to deny the reality of the measurement dynamic, just like the many-worlds theory. They seem to try to convince themselves that if the wave-function amplitude becomes concentrated at at particular state, then it is "as if" that state had been actually been chosen by a collapse process.

Bergson made a lovely argument about how in a deterministic world there is no arrow of time, no "duration" in the sense of experienced duration, and nothing new ever actually happens! Quantum mechanics has rescued us from that scenario and for some reason the experts want to reject the solution? (Well, maybe they never accepted there was a problem--Bergson is not exactly respected by scientists, as far as I can tell. "He's a [lower voice] vitalist.") Maybe it's because of an implicit realization that conscious experience is our ONLY evidence of the arrow of time (second law arguments don't hold water). So if they don't deny the measurement process they'll have to deal with more freaks (like me, and you I think) trying to relate consciousness and quantum mechanics (--i.e. "trying to explain one mystery with another").

The denial of the wave function collapse (or state vector reduction if you prefer) reminds me of the denial of consciousness by Dennett and others. Of course we don't observe wave-function collapse directly like we do consciousness, but denying the reality of the arrow of time (which is also "proven" by our conscious experience) and that probabilities in our theories describe the distribution of actual events, seems similarly pathological.