Hal, Isn't it possible that decision processes of the brain, hence consciousness, DOES depend critically on quantum states? My understanding of the workings of the brain is that my action, whether thought or deed, is determined by whether or not certain neurons fire. This depends on many other neurons. So the brain can be in a state of delicate balance, where it could be impossible to predict whether or not the neuron fires. We all have to make decisions where the pluses apparently equal the minuses. It would take very little to tip the balance one way or the other. Perhaps, at the deepest level, the route we take depends on whether an electron has left or right polarization, or some other quantum property - which we agree can't be measured. If this is true, then perhaps Free Will (or at least behavior that is, in principle, unpredictable) does exist. Norman ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ----- Original Message ----- From: ""Hal Finney"" <[EMAIL PROTECTED]> To: <firstname.lastname@example.org> Sent: Saturday, June 18, 2005 2:02 PM Subject: Re: copy method important?
> I'm no physicist, but doesn't Heisenberg's Uncertainty Principle forbid > making exact quantum-level measurements, hence exact copies? If so, then > all this talk of making exact copies is fantasy. > Norman Samish You can't *specifically* copy a quantum state, but you can create systems in *every possible* quantum state (of a finite size), hence you can make an ensemble which contains a copy of a given quantum system. You can't say which specific item in the ensemble is the copy, but you can make a copy. That may or may not be sufficient for a particular thought experiment to go forward. In practice most people believe that consciousness does not depend critically on quantum states, so making a copy of a person's mind would not be affected by these considerations. Hal Finney