From stapp@thsrv.lbl.gov Thu Oct 23 10:54:08 2003 Date: Thu, 23 Oct 2003 09:51:03 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: "Balaguer, Mark" Subject: RE: your work On Wed, 22 Oct 2003, Balaguer, Mark wrote: > Dear Henry, > > Thanks for the paper, and yes, I would like a copy of the other one, if it's > not too much trouble. My address is: > > Mark Balaguer > Department of Philosophy > California State University, Los Angeles > 5151 State University Dr. > Los Angeles, CA 90032 > I've just sent it off. > What I'm interested in is your response to Tegmark. I haven't yet looked at > the paper you sent me in your email, but one response that I thought of is > this: Tegmark's argument, if cogent, suggests that there can't be neural > indeterminacies based on macro-level superpositions that collapse due to > neural processes. But your view doesn't involve macro-level superpositions; > it involves micro-level superpositions (of presynaptic calcium ions). So > even if Tegmark's argument is sound, it's irrelevant to your view. Does > this sound right to you? > Yes, the effect certainly does not involve macro superpositions. But is it correct to say that it involves microsuperpositions? Even if decoherence effects did extend down to the individual ion level, that would mean that the density matrix [S(t)] would be reduced to close to diagonal, but not exactly diagonal, in the coordinate-space basis. The Schr. Eqn. of motion would, however, move these diagonal elements around roughly in accord with the classical equations of motion: i.e., any "bump" in the probability distribution on the diagonal would move arould in accordance with the classical equations of motion, at least to first order. Thus classical physics would emerge, in the absence of "observations." But the von Neumann eqns show that even in this "classical" case the QZE would inhibit motions in the degree of freedom corresponding to P: the system would be constrained to stay in the subspace defined by P=1, or in any case to be inhibited from moving out of that subspace. So the mechanism that I exploit does not really involve even micro-superpositions, even though it is definitely a quantum effect. Superposition has to do with interference effects; with delicate effects of cancellation or reinforcement associated with phases. The QZE associated with observation can, within a many-worlds framework, be seen as an effect of the elimination of transition matrix elements between two parts of a system described by S(t) due to the differing effects of these parts on an "observing" system. One might therefore construe this elimination of the transition matrix elements as a "superposition" effect, in a many-worlds approach. But the von Neumann equations present this effect on S(t) as the postulated effect of an actual collapse. In any case, the decoherence effect considered by Tegmark are not supposed to disrupt the classical equations of motion. Quite the contrary, those decoherence effects are supposed to bring out the classical behavior. But the QZE "blocks" or "inhibits" the classical motion by setting to zero some transition matrix elements that Tegmark leaves intact in order to produce the classical results. Thus QZE operates at a finer level than Tegmark decoherence. It operates even if the later is carried to the extreme where free particle (ionic) motions are reduced to classical motions. Even in that extreme the QZE blocks the classical motion that Tegmark decoherence preseves. Of course, the "observation" is a very "macro" effect: it acts on a combination of microvariables, so that its effect on any individual microvariable is almost nill. We are talking about the effect of such a macro observation on what can be a "mixture of essentially classically describable particle (ionic) trajectories." > Best, > Mark Balaguer > P.S. I have a paper on libertarian free will that's coming out in NOUS and > that, I think, you would find interesting. In it, I turn the traditional > wisdom regarding randomness and non-randomness on its head. As you know, > enemies of libertarian free will have long argued that libertarianism is > incoherent because indeterminacy entails randomness. A few libertarians > (e.g., Kane) have tried to undermine this by arguing that indeterminacy is > compatible with non-randomness, so that if our decisions are undetermined, > they still COULD BE non-random. I argue for a much stronger claim, namely, > that the relevant kind of indeterminacy actually ENTAILS the relevant kind > of non-randomness, so that if our decisions are undetermined, then they ARE > non-random. Thus, if my argument succeeds, then the question of whether > libertarianism is true reduces to the question of whether our decisions (or > actually, decisions of a certain kind, which I define in the paper) are > undetermined. And this is a straightforward empirical question. If this > sounds interesting to you, I could send you a copy. > Yes, please send your paper. Henry > -----Original Message----- > From: stapp@thsrv.lbl.gov > To: Balaguer, Mark > Sent: 10/22/2003 7:32 PM > Subject: Re: your work > > On Mon, 20 Oct 2003, Balaguer, Mark wrote: > > > Dear Henry (if I may), > > > > I'm trying to get a hold of a paper of yours entitled "Decoherence and > > Quantum Theory of Mind: Closing the Gap between Being and Knowing". I > saw > > it referenced and the reference sent me to your website, but I > couldn't find > > the paper there. Is there some easy way to access it? > > > > Thanks. > > Best, > > Mark Balaguer > > > > I can send a hard copy, if you want it. > The attached paper is similar. > > Henry > <<>> > From stapp@thsrv.lbl.gov Fri Oct 24 10:38:36 2003 Date: Fri, 24 Oct 2003 10:34:50 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: "Balaguer, Mark" Subject: RE: your work On Thu, 23 Oct 2003, Balaguer, Mark wrote: > Hi, Henry. After reading your message earlier, I went back to your paper > "Pragmatic Approach to Consciousness," where you say that your view involves > a collapse of the wave function of presynaptic calcium ions. Now, you're > saying that this doesn't involve a superposition. This confuses me > (remember, I'm not a physicist) because I thought "collapse" just MEANT > collapsing out of a superposition state into a non-superposition state, > i.e., a state involving a unique value for the given observable. Am I > missing something? > --Mark The important distinction here is between the ideas of "superposition" and "mixture." In quantum theory there are two quite different way of combining two (or more) possibilities, "superposition" and "mixture." In a *superposition* the difference in the "phase" of the two parts are controlled by the experimental conditions. Then the two parts can "interfere": the two contributions can combine so as to (partially or totally) cancel if one observable is measured, but to yield "more that the sum of the individual contributions taken alone" if some other observable is measured, but such that the sum of the probabilities of any complete set of observables adds to unity. In a *mixture* the information about the phase difference (i.e., where the crests and troughs of the two parts are situated relative to each other) has become lost. Then there is no "interference": the two contribution add together "independently", namely independently of the existence of the other part. This phase information is lost if, for example, either part of the original system interacts strongly with some other *probing* system, which can be a "measuring device" which responds in two distinct ways depending on which part of "the system being probed" it "sees/finds". In this second case, there will be, by virtue of the automatic working of the quantum laws, no interference: the two possible outcomes of the (originally considered) measurement/observation on the (original) system will be exactly (if the first measurement/observation is "good") correlated with the distinctive tate of the probing measuring device, and even if that distinctive state of that probing/observing/measuring device is not known there will be no interference between the two parts of the probed (original) system: the probabilities for all observables "pertaining solely to that originally considered system alone" will be simply additive. So, superpositions and mixtures are very different. But in principle one must keep the (two) parts of a mixture, because if measurements can be done later on the "full system" consisting of the original system plus the probing device then the parts coresponding to the two parts of the mixture can interfere. All of these features follow automatically from the mathematical formulas, and have been experimentally verified. In the case of a brain, the interactions with "the environment" (which acts as a probe) can reduce the state of some pertinent subsystem of the brain (say the subsystem that holds/instantiates a template for action) to a mixture (so that parts corresponding to appreciably different coordinate values do not appreciable interfere). But the equation of motion for the state S(t) (the density matrix) will still be able to preserve to good approximation the essentially classical equation of motion for the diagonal elements . The state (density matrix) S(t) contains the pertinent information about the effects of the environment (the matrix elements get severely damped for x appreciably different from x'), but the equation of motion for the diagonal elements involve only the first and second derivative with respect to x, and hence can be left pretty much unaffected by the environmental decoherence. Indeed, this is exactly what tends to make the classical approximation very good: the environmental decoherence tends to destroy all interference effect involving appreciably nonzero values of x-x', while preserving to first order the classical equations for the diagonal elements . Thus the system is effectively reduced to a "mixture" by the interaction with the environment, but this does not mean that is set to zero for all values of x except for one. In the broader context of the state of the whole universe (as opposed to the state S(t) of some special part of the brain, defined by taking a trace over the remaining variables) all of the values of x are still "present": nothing has picked out some particular value of x as the really existing one. In the von Neumann framework no reduction takes place except via Process 1. And this Process 1 will not pick out some particular value of x. It will take S(t) to P(E)S(t)P(E) + (1-P(E))S(t)(!-P(E)), where P(E) projects onto the full part of the Hilbert space that corresponds to experience E. I hope this clarifies things. If my words above have failed to communicate, then any quantum physicist (who has thought much about quantum measurement) should be able to explain to you what I am saying, Best wishes, Henry