From stapp@thsrv.lbl.gov Tue Sep 12 15:04:46 2000 Date: Mon, 11 Sep 2000 15:33:29 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: Kathryn Blackmond Laskey Cc: Subject: Re: Kathy to Ted (Lumley) Dear Kathy, I think you stated my position accurately and well. Newton himself recognized that scientific theories were by nature "provisional". and subject to future development. The apparent completeness of Newtonian physics, and more generally, of classical physics, had caused some physicists and scientists to loose sight of this key feature of physical theory. Indeed, scientists who have failed to really comprehend the significance of the failure of classical physics may still be insufficiently sensitive to this provisional character of physical theory. But the profound failure of the classical precepts, and their replacement by quantum theory should make clear to every scientist the fact that our understanding of nature is in the process of growing, and that even the most basic idea are subject to revision. On the other hand, the continual checking against empirical reality on a very broad front probably ensures that the advances are moving generally closer to some underlying truths. I believe that this close connection to empirical reality does justify examining closely the most rational contemporary science-based approach to an understanding of ourselves and our connections to nature, and accepting, provisionally, its picture of both ourselves and nature, and its identification of where the remaining mysteries lie. Raising general public awareness of what contemporary science SEEMS to be saying could contribute to better dialog between person's coming the scientific and religious perspectives, by showing that the deepest scientific studies of basic issues leads to a view of man and nature that is not incompatible with the idea that man is, in a certain specified sense, created in the image of `god', and that the scientific description itself has three well defined specific aspects that, at our present level of scientific understanding of the theory, could quite reasonably be identified as `body',`mind', and `spirit'. I note two places where my thinking has undergone some shifting. At one time I identified religion as an approach based on dogma and ancient texts and miracles, and distanced my self from it. But you, Kathy, and Stan, strongly urged that there is another stream of religious thought that takes the texts as metaphorical rather than literal. I used that idea at the conference in New York, and found some resistance to it from the religious folk there. But any dialog between science and religion requires an approach to each that breaks away from old dogmas. The second shift has to do with words such as "god". My earlier opinion was that these words were so loaded with both ambiguity and emotional baggage that it was best never use them. That may indeed be best when talking to scientists about science. But if it is beneficial to man to increase, broadly, public understanding of science then it may be useful to, in effect, appropriate A MEANING of such a word that is descriptive of some well defined aspect of the scientific model, and make it clear that this specific meaning is being used to convey to a broader public a feature of this quantum understanding of man or nature. This defining might serve, eventually, to 1focus attention on some aspects of human self understanding where some broad agreement is possible across diverse parts of the world's population. A do not aspire to limit in this way, unduly, the conception of, say, God, but merely to aid communication among different kinds of people by identifiying some specific meanings that can be exemplified in a science-based model. Refinement of the meanings of key words is the first and necessary step to rational discourse, and examples from a comprehensive science-based model of nature could be very helpful in the process of making meanings less ambiguous. Best, Henry --------------------------------------------------------- From stapp@thsrv.lbl.gov Tue Sep 12 15:05:13 2000 Date: Tue, 12 Sep 2000 14:58:03 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: Kathryn Blackmond Laskey Cc: Subject: Re: a question on the vN/W/S interpretation On Mon, 11 Sep 2000, Kathryn Blackmond Laskey wrote: > Henry, > > You call your interpretation the von Neumann/Wigner/Stapp > interpretation of QT. > > I have read von Neumann's Mathematical Foundations of Quantum > Mechanics pretty carefully, with particular attention to the sections > on measurement. I have found no place where he ascribes any aspect > of measurement to free choice of a conscious observer. My reading of > von Neumann is much closer to what I recall of interpretations of him > that I've read in "lay person physics by physicists" writings, such > as Davies and Penrose. As I recall (I should probably go back and > re-read these) von Neumann is said to treat the statistical ensemble > as a statistical ensemble, and not to deal directly with individual > measurements. > That is correct. I build this into my formulation by distinguishing the von Neumann Process 1 [S--> PSP + (1-P)S(1-P)] from the the Dirac Process (the choice on the part of Nature) that picks Yes [{PSP + (1-P)S(1-P)}--> PSP] or No [{PSP +(1-P)S(1-P)}-->(1-P)S(1-P)] > In fact, in his discussions on thermodynamics, von Neumann contrasts > unitary evolution, in which a state "goes over into a state," with > measurement, in which a state "goes over into a mixture." He uses > this to argue that measurement increases entropy. Thus, it seems to > me that von Neumann in these passages could be interpreted as being > consistent with a many worlds theory, in which it is the mixtures and > not the states that are ascribed "real existence." > Yes, the von Neumann theory, which applies quantum principles to the entire universe, is the basis of ALL the efforts to do better at the basic theoretical level than the practically useful Copenhagen rules. > Your theory would seem to go beyond a strict literalist reading of > von Neumann in assuming that (1) after the state "goes over into a > mixture," Nature selects one of the states in this mixture to become > actual, and does this according to the Dirac probabilities; and (2) > which measurement to take is a free choice of the observer. > > Am I missing something in von Neumann? Am I reading the wrong one of > his writings? > > Does Wigner directly relate measurements to free choices of > observers? Can you point me to a reference where he makes this clear? > > Thanks! > > Kathy Dear Kathy, Wigner was a close colleague of von Neumann from their childhood days together in Hungary, and put forth a view point that he ascribed to von Neumann but went beyond what can be found in von Neumann's book. In Wigner's paper "The Problem of Measurement" [Americal Journal of Physics, Vol 31, pages 6-15, reprinted in Eugene Wigner, Symetries and Reflections, Indiana University Press, Blomington, 1967] Wigner says that the view that he describes was an outgrowth of Heisenberg's uncertainty paper, whose far-reaching implications where first fully appreciated by von Neumann. Wigner calls this view the "orthodox" view, but it is fundamentally different from the Copenhagen view, which many physicists consider the "orthodox" view. Wigner emphasizes, as I always do, the provisional nature of scientific knowledge about matters pertaining to ultimate truth, but also believes, as do I, that it is interesting to understand "the ultimate implications of quantum theory's formulation of the laws of physics." Wigner discusses and defends a theory in which "the result of the measurement is not the state vector such as (2) [superposition of possibilities] but *** ONE of the state vectors (3) [the part corresponding to the mu-th possible outcome], and that this particular state will emerge with probability |alpha_mu| squared." This reduction would be of the kind referred to by Dirac as what results from "a choice on the part of nature". I call this choice a "Dirac Choice". Of course, if one considers quantum theory to be purely a statistical theory, as von Neumann does, not a theory about what actually happens, then one would represent WHAT THE THEORY SAYS by representing the transition from superposition to individual outcome by a von Neumann process I. Wigner appears to accomodate this by inserting the words "a so-called mixture" in the place indicated by the three asterisks *** in the above passage. This makes Wigner's words a little unclear on exactly the point under discussion, but I interprete him to be saying that although there is a real transition is to ONE of the possible outcomes, quantum theory, as it exists today, gives only statistical information about which of the possibilities actually occurs. This interpretation is in general agreement with Heisenberg's ideas of a transition from 'possible' to 'actual', and Dirac's idea of a choice on the part of nature. But the place of the transition from the possible to the actual occurs at the device, according to Heisenberg, even though both he and Dirac agree that the mathematical THEORY is a statistical theory about connections between increments in "our knowledge". von Neumann's analysis allows the brain to be the ultimate measuring device: a person's brain can be the place where the transition from actual to possible really occurs, in conjunction with an increment in that person's knowledge. Wigner's article "Remarks on the Mind-Body Question" [in 'The Scientist Speculates', I.J. Good ed. London: Wm. Heinemann 1961; and New York: Basic Books Inc. 1962, and in 'Symmetries and Reflections.] is an extended discussion about these matters that can be regarded as the general foundation of what I call von Neumann/Wigner quantum theory. It argues for a breakdown of the Schroedinger equation when consciouswness enters and the idea of an INTERACTION between mind and matter. Let me turn next to your question about the choice on the part of the observer. The von Neumann treatment of the measurement problem was in the context of examining a measurement process, and tracing the development stage by stage from the measured system up through several layers of devices up to the "abstract ego", which I take to be the conscious experience itself. vN must get the same answer that Copenhagen gets. In the Copenhagen view the "observer" has choosen to probe some particular aspect of the measured system, and has both set up the apparatus in an appropriate way and is directing his attention in such a way as to be able to know, when the signal arrives whether or not Nature's answer conforms or not to some specifications that he has in mind. Thus he is interested in whether or not the observation lies in a certain finite range that is associated with some definite yes-no question, The two alternative answers to this question are represented at EACH device---in a chain of systems that extend from `measured' system to observer's brain---by a P and a (1-P) acting on the degrees of freedom of that device. The dynamical conditions of a "good measurement" put the pairs P and (1-P) at the various stages into correspondence (i.e., they are correlated so that a P associated with a high-level device will be dynamically tied to each lower level P, including the P that acts directly on the measured system.) Thus the actualization of the brain state associated with the brain-state projector P will mean that the measured system is also in the state associated with the measured state projector P. This is just a quick summary of what vN shows. But I am tying it into the choices made by the experimenter observer of what question he is asking. If he does not set his mind to recognize the appropriate things then no observation of the to-be-measured property will occur: for an observation to occur the observer must choose an appropriate mind set. In the bigger context of a Copenhagen measurement there is in fact a lot more to be decided by the observer than just his final mind set, but my emphasis is on THAT choice on the part of the observer. This choice was taken for granted in vN's treatment of a measurement, but in the more general context of the evolution of a brain under the action of the Schroedinger evolution, where a CONTINUUM of possibilities will certainly arise, the basic problem of measurement theory is how a particular P (or basis) is choosen when the state of the "brain" is a CONTINUUM of possibilities. Even if we put in some sort of `classicality' condition on the possibilities, there is still the basic problem of measurment theory to be faced: how does one get a discrete choice of P (or basis) out of a state that has a continuous range of possibilities to choose from. Bohm puts in his classical world, in order to make this choice. In general, something outside the physical world, as it is described by quantum theory, is needed. That is why the many-world approach fails in the end: it allow no other reality that can help to specify this critical choice. My answer is to appeal to a reality that is not part of "physical reality", as it is represented in quantum theory (e.g., by the quantum state S), but is nonetheless an integral part of the theory, and is also something that is known to exist, and that is in fact the basis of all our knowledge, namely the elements in the sequences that constitute our streams of conscious events: I bring in "mind" to do this critical job of choosing P, and thus link mind to matter using the vN formulas. I have suggested (in recent papers) a specific model, in order to have a definite theory. I assume that there is a set of possible experiences E, each associated with a projection operator P(E) that acts on the state of a person's brain [S_b =Tr_{-b} S] and that P(E) projects onto a substate that is "compatible" with experience E. This is the basis Copenhagen rule, which I accept. In particular, if E is an experience of an intended activity and there is a P such that P S-b P projects onto a brain state that, on the basis of past experience, is likely to produce a feed-back experience of that activity then this P is compatible with E. I spell out a detailed mathematical rule in recent papers. The way in which these correspondences, E-->P(E), come into being over the course of development of the organism needs to be worked out in detail, but at this point I am just positing the eventual existence of such connections as a provisional premise. In order to make these choices clearly efficacious I allow mental effort to control the rate at which projections P (with positive experiential correlates) occur. Then the quantum Zeno effect allows mental effort to hold an idea in place, or at least slow down the diffusive effects of the quantum uncertainties that are built into ANY brain dynamics that is CONSISTENT with the quantum principles. This leads to differences in principle between the behavior of a real (i.e., quantum) brain and any classical mockup of it that encompasses, in the noise, the uncertainties mandated by quantum theory. The question of the how the E-P connection is forged is basically an open one, and I am happy about your endeavor to work out the development of the E-P connection in a way that makes good sense to you. Best regards, Henry