How did consciousness get into QM?

I recently rediscover this article describing how and why it did.

Quantum Mysticism: Gone but Not Forgotten
June 8, 2009 By Lisa Zyga

Does mysticism have a place in quantum mechanics today, or is the idea that the mind plays a role in creating reality best left to philosophical meditations? Harvard historian Juan Miguel Marin argues the former - not because physicists today should account for consciousness in their research, but because knowing the early history of the philosophical ideas in quantum mechanics is essential for understanding the theory on a fundamental level.

In a recent paper published in the European Journal of Physics, Marin has written a short history, based on a longer analysis, of the mysticism controversy in the early quantum physics community. As Marin emphasizes, the controversy began in Germany in the 1920s among physicists in reaction to the new theory of quantum mechanics, but was much different than debates on similar issues today. At the turn of the last century, science and religion were not divided as they are today, and some scientists of the time were particularly inspired by Eastern mysticism. In his analysis, Marin lays out each player’s role and perspective in the controversy, and argues that studying the original interpretations of quantum mechanics can help scientists better understand the theory, and could also be important for the public in general.

“Becoming aware of this subject would help general audiences realize that there are many other alternatives besides the ones offered by the disjunction between science and religion,” Marin told “Science vs. religion is a very recent forced choice that the founders of quantum mechanics would have never recognized, much less accepted.”

Mind Matters

The controversy boils down to the age-old question of the nature of reality. As Einstein (a firm realist) once asked, does the moon exist only when looked at? Although such a viewpoint seems unlikely in our everyday lives, in quantum mechanics, physicists’ observations can sometimes affect what they’re observing on a quantum scale. As the famous Copenhagen interpretation of quantum mechanics argues, we cannot speak about an objective reality other than that which is revealed through measurement and observation.

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This links to the long version.
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Nice article, thanks.

This is something I've alredy posted a while ago. It is one way of putting why "mind matters" that I find particularly cogent:

Definite outcomes are not in the equations of quantum mechanics. That is quite well known, it's because the equations of quantum mechanics say that a closed system (like if we could put an experiment and everything involved with it inside a closed box) evolves unitarily. That means that if it starts out in a definite state, it remains always in a definite state.
However, that definite state only applies to the whole closed system-- it includes various probabilities of outcomes for the states of its subspaces when those substates "decohere" (meaning they acquire randomized phase relationships with each other when you project from the full state of the closed system onto the subspaces).

So a typical "subspace" would be the spin of a particle, say, and when you do a spin measurement you decohere the spin states from each other. But the closed system still has no way to pick out a particular spin state, they are all still there in the equations of quantum mechanics. The picking out of a particular spin state is, in practice, always done only one way: completely manually. That means the experimenter exits the theory of quantum mechanics and just asserts the outcome they perceive, manually throwing away the parts of the wavefunction of the whole system that don't show that outcome. No equation does that, because it is nonunitary.

The reason this is necessary is that the perception requires it, and for no other reason, so I merely point out the reason that we have this step at all-- because we are conscious of a need for it.

Now, many-worlds says we shouldn't throw away the parts of the wave function we don't perceive, they are still there but we just don't perceive them. Our perception is seen to be less than the reality. However, this does not make the question of why we perceive what we perceive go away, because a universe with no perception would never need to assert what outcome was perceived to occur. So many-worlds still requires that perception enter the picture, it is the process that picks out one of the many worlds. The need for it is not gone, but the unitary evolution of the unperceived universe is salvaged, pretty much at the cost of empiricism as science's epistemological lychpin.

Another approach is deBroglie-Bohm, which holds that the equations of quantum mechanics cannot be the fundamental dynamical equations, expressly because they have this unpleasant feature of not connecting wiell with single outcomes. In DeBB, the one outcome is completely deterministic, nothing is thrown away and the "manual" step in quantum mechanics is there because quantum mechanics is incomplete. But to complete quantum mechanics, one must simply assume that there is information that is hidden from our view. It is essential to the dynamics that this information be hidden-- if it isn't, the dynamics is different (as in which-way information in a two-slit experiment). So behavior of the system depends on what we can know about it, even though the system is still evolving from a definite state (that we cannot know without changing the evolution) to another definite state. But note this still has not banished a role for perception, because defining what we can know about a system, which affects its evolution, is caught up in how we know things about systems, which relates to perception.

So I believe I have argued with simple logic that neither the equations of quantum mechanics, nor the popular interpretations of what those equations mean, has banished a role of conscious perception, they merely cause its role to crop up in different ways. The bottom line for me is, all of physics, all the language we use to talk about physics, requires that we insert a conscious perceiving agent somewhere in the story, even if that agent is inserted only hypothetically to give us a language we can use to talk about what is happening. So some role of a conscious perceiving agent is absolutely inescapable, even in systems that claim to have banished any need for it.

Reference and further discussion
The core of this issue (IMHO) is that practical QM has to be based on a fudge - we talk about a system being observed, and apparatus. However, no such separation can be made, because the apparatus is made up of the same fundamental particles as those under test.

Scientists before the time of QM thought of observing as obtaining information - not altering the system.

Using the above mentioned fudge, it is possible to assert that when a particle is detected - e.g. on the screen behind a 2-slit experiment - it's wave function is collapsed. However, it is equally valid to say that its wave function becomes entangled with the particles comprising the screen.

There is no rational place to make the distinction between what is being observed and what is doing the observing. So at least one way to solve this problem is to move to the point where a conscious observer becomes aware of the outcome of the experiment. One way of thinking about Schroedinger's gedanken cat experiment, is to ask if the cat is conscious enough to also collapse wave functions.

This situation is not like Newtonian mechanics - which doesn't need an observer in order to happen.

As Bucky has pointed out, if you do away with wave function collapse and opt for the Many Worlds Interpretation, the problem is that the equations say (roughly) 'Anything can happen, mate, all you can do is wait and see!' In a way this interpretation introduces the nature of consciousness even more intimately - how to 'we' (our consciousness) navigate this unimaginably vast space of possibilities?

To be clear my previous post is a quote from a discussion on that I was following, and that I found well put, but it's not mine.
That's the way it is, production of a result (observation) from *all* past correlations. Too complicated to analyse individually, and any other way than probabilistically. And that observation naturally feeds into future observations. As you say, there ain't anywhere to make the cut physically, the body is part of the same external world as the apparatus. I just don't think it's complicated at all, and I don't think QM is a fudge.

Nothing is lost no matter how long ago, or how far away. Systems interact and gain information from each other according to their past interactions. What is revealed to us when we interact is all that is allowed to be revealed to us, based on all our past interactions.

Where we've got summat interesting going on is around the apparent choice of the concious observer as to what to observe. And recently perhaps the discovery of error correction going on within the previously discarded bits of the QM calculations.

That this latter bit has got no traction on here is surprising, because of what it implies.


Two discussion showing possible connection between consciousness and quantum phenomena:

People May Sense Single Photons

People can detect flashes of light as feeble as a single photon, an experiment has demonstrated—a finding that seems to conclude a 70-year quest to test the limits of human vision.

The study, published in Nature Communications on July 19, “finally answers a long-standing question about whether humans can see single photons — they can!” says Paul Kwiat, a quantum optics researcher at the University of Illinois at Urbana–Champaign. The techniques used in the study also open up ways of testing how quantum properties—such as the ability of photons to be in two places at the same time—affect biology, he adds.

The most amazing thing is that it’s not like seeing light. It’s almost a feeling, at the threshold of imagination,” says Alipasha Vaziri, a physicist at the Rockefeller University in New York City, who led the work and tried out the experience himself.

Quantum physics is invading biology

"...The traditional theory is that different shaped molecules attach to receptors in the nose and produce different smells, but some molecules are very similar in shape, yet smell very different, whilst some molecules that are really different smell the same. Some scientists are saying this could be down to the quantum properties.

They say smelly molecules start a process called ‘quantum tunnelling’. Certain bonds in molecules provide a vibration that moves receptor electrons from one point to another via a quantum tunnel, meaning they don’t travel through the space in between. This would mean molecules have a tunnelling signature, as so to speak, for identification by the brain.

Annoyingly for biologists, there is some solid evidence for this, including the fact that sulphur and boranes have no molecular similarities, but they do have similar bond vibrations, and they smell the same. While, this is not proof, but physicists reckon soon they’ll have cracked the smell problem once and for all....."