Chris,
Well at least we seem to have goaded you into debating an issue properly! Please continue, it is much appreciated!
For me at least, the fact that QM represents a world with multiple realities - all present in the wave function - is extremely suggestive that it is involved in some deep way (i.e. not just in defining the chemistry) in the action of the brain/mind. Before QM, whatever theory came along, it seemed that a chunk of matter, such as the brain, would simply follow the relevant equations essentially like clockwork, which seemed to leave no place for mind - at least as many of us conceive of it.
As I understand it, QM has been tested to very high accuracy (actually QFT) in terms of the time independent solutions of the wave equation which give rise to such things as energy levels, but that the collapse of the wave function might be more complex than imagined. Roger Penrose also seems to think this way.
Ultimately, if mind is distinct from brain (which I know you don't support) there has to be some level at which they couple together, and QM seems the most likely candidate.
Although quantum entanglement seems at first unlikely in a warm wet brain, there are at least two locations where this has been seriously proposed - the microtubules, present in all cells including neurons, and the tiny vesicles that store and release neurotransmitters across synapses.
It is true that there is no experimental evidence that QM is involved in consciousness, but how seriously should we take this, since the mechanism of consciousness is very little understood. At one time consciousness was thought of as being a computation - inspiring the Artificial Intelligence fad of the 1980's and early 1990's. This was an embarrassing and expensive flop. Consciousness was then associated with the concept of neural networks. It was argued that neurones operate as a relatively simple threshold switch with positive and negative inputs from other neurones, learning by the Hebb rule or similar. These were easily simulated on a computer, but my impression is that subject seems to have fizzled despite huge initial hopes.
Nobody knows what consciousness is, which is why we are having this debate.
David  |