Dear Mark, Dec. 8, 1997 I am sorry that I have been so busy that I have not had time to look at the things you have been sending. But I just looked at the abstract of your note of 7 DEC, and realized that your proposal involves a seriously incorrect understanding of quantum theory. The recorded em activity from the brain associated with the collapse and from the other brain should be essentially the same! This is part of the difficulty that I have so often referred to, that there is FAPP (for all practical purposes) no empirical way of determining when or where the collapse occurs: the macroscopically recorded data will be the same FAPP. This is part of the consequence of von Neumann's analysis of the process of measurement. The easiest way to understand this, perhaps, is from the point of view of Feymann's sum over all paths formalism, in which one imagines the full wave function to be composed of contributions from all possible classical paths. The total set of paths contributing to a world compatible with a given set of classical specifications (e.g., the pointer is pointing to the number 10, to a very good approximation) will single out the same set of classical worlds independently of who observers this classically describable property: the set of possible worlds compatible with this classically describable condition will be essentially the same no matter whether it is effected by a collapse that occurs already at the device, or when that information is recognized by observer 1 or observer 2. That is why in quantum theory one can speak of ``our knowledge'': the knowledge reduces the wave function to the same collection of classical possibilities no matter when or where one imagines the collapse (to possiblities compatible with a classically describable condition) to be implemented. Reading on I find in your point 1 the idea that events contribute to uncertainty. At least in my terminology events reduce uncertainty. The uncertainty is inherent in the quantum description and it tends to increase due to the evolution in accord with the Schroedinger equation, but is decreased by an event, which eliminates all possible contributions that are incompatible with the new information/knowing. I find your point 8 unclear: what is this `one mind'? Universally or invividual? According to my model, there will be collapse events in the brains of both observers, because each observation is to some extent personal: it involves a lot of contextual structure coming from the individual's history and momentary state of attention, but the classically describable component (the pointer is very close to 10 on the dial) will represent a common bit of information about the state of the world. This latter part will be fixed by some earliest event that fixes it, but all later events will be constrained so as to confirm to this condition, and will look like they could have been responsible for imposing it. It is true that the collapse is supposed to occur all at once, across the whole brain. But this collapse effectively pulls out a collection a entire classically evolving spacetime trajectories: it is as if the other possible worlds incompatible with the classically describable condition simply never came into being. So one will not see any sudden signal from different parts of the brain. But there is, in connection with the Libet thing, a possible experiment. According to my model, at least, the collapse occurs after the full template for action has been formed, and it "might" have the property of pulling out brain states that are more temporally correlated over large distances than what a purely classical model would yield. This suggests that if one did controlled experiments of the Libet type, but sometime after the build-up began, yet before the conscious thought occurred, injected some disturbing influence that prevented the thought from occurring, then the build up BEFORE THE DISTURBANCE would be less coordinated across the brain than it would typically be if the disturbance were not injected. If this effect were to occur it would be an effective action of future on past: a clear indication of the failure of classical ideas. Presumeably one could do this experiment on momkeys. Best regards, Henry