[David Bailey]

Chris,

As you must obviously know, the issue as to where the wave function is collapsed (or even if it is) is hard to pin down. Let us say that a photon hits one of two photomultipliers. Conventionally it is said that the photon wave function collapses at this point, but because the photomultiplier itself is made up of particles that obey QM, it is equally valid to consider that the wave function for the two photomultipliers (horrendous as that mathematical object would be) itself becomes a superposition of the two possibilities. This process can go all the way back to the brain, and in the Everett interpretation is never resolved, in other interpretations the buck stops with consciousness.

Schrodinger introduced his cat to discuss precisely these issues, and I assume most of us debating here are aware of those background facts.

As I joked to Paul, the word "Quantum" is used by some people in a completely meaningless way, but I would not have thought that any of the discussions here would have given you the impression that we were following this style!

As I understand him, Stapp is considering quantum processes in the brain that may be controlled by the 'quantum zeno effect' that we all discussed earlier.

Roger Penrose has written several books on the subject of the possible involvement of QM in consciousness - but he takes a somewhat different approach to Stapp - I recommend you read "Shadows of the Mind".

BTW, I am not personally wedded to Stapp's approach.

David