Friday, December 03, 2004

Do Quantum Effects Explain Consciousness?

There is a new posting on the Stanford Encyclopedia of Philosophy on “Quantum Approaches to Consciousness”. The summary is written by Harald Atmanspacher.

It seems natural that the intriguing features of quantum mechnanics (QM), such as the duality of observing and observed systems and the notion of a collapse of superposition states, would over time get pressed into service to try to shed light on the problem of consciousness. Atmanspacher gives a brief taxonomy of several such efforts.

The aspect of this I’m commenting on is the attempts by several philosophers and physicists to postulate that it is macroscopic-size components of the human brain which implement quantum effects thereby helping explain the mysterious nature of human consciousness as it relates to phenomenal experience and/or free will, etc. I think these efforts are looking in the wrong place to find the connection between QM and consciousness.

Guided by other critiques (like this one), I’m very skeptical that macroscopic quantum coherence can be maintained in the brain sufficient to, say, orchestrate collapses of quantum superposition states which affect whole neuronal assemblies. The evidence I’ve seen from experimental accounts suggests that coherence is very fragile, and that while progress is being made at preserving coherence for larger molecules in the laboratory, the likelihood of the warm, wet brain supporting macroscopic coherence seems the longest of long shots.

Nevertheless, I think quantum effects do provide evidence for the existence of a proto-experiential element within nature (see my previous post). But it seems it must be the case that this is instantiated at the microscopic level where decoherence typically occurs. Then, the question becomes whether and how macroscopic systems are able to leverage this part of nature into something robustly experiential. The answer to this must come from the systems’ functional organization and complexity.

Now, the brain is a compelling unique object in our world – it is the most complex system there is. Furthermore the living cells within our brain have an extremely intricate structure themselves. And therefore I think we can expect that this incredibly complex functional organization forms the basis for the remarkable features of our mind up to and including our reflective stream of self-consciousness.

So, going back to David Chalmer’s separation of consciousness studies into the “easy problems” (explaining the workings of various cognitive sub-systems like sensory perception, memory, etc.) and the “hard problem” (explaining the existence of subjective experience itself): I think QM provides evidence for the existence of a panexperientialist solution to the hard problem at a micro-level in nature. Therefore I think it follows that analyzing the functional organization of the brain and its cells will eventually provide explanations for the easy problems, including what I might call the “hardest easy problem”: the way the brain leverages the proto-experiential nature of its very small parts into the robust consciousness which we humans uniquely enjoy in the world.

I admit I have no idea at this point how this works, but I think the functional coordination of the quantum interactions we know to be occurring at the microscopic level is the place to look for consciousness.

1 comment:

Michael said...

Steve,

If you are persuaded that there can't be any macroscopic quantum states in the brain, I'm afraid you can't appeal to quantum states to solve the "unity" or "combination" problem any more. I tend to think that the arguments against macro quantum brain states are more dubious than the arguments that independent micro-consciousnesses can add up to a big macro-consciousness. William James killed the latter idea.

Was it Stapp that convinced you macro quantum brain states are implausible?