From stapp@thsrv.lbl.gov Thu Oct 9 14:58:53 2003 Date: Thu, 9 Oct 2003 11:12:53 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: Mszlazak@aol.com Subject: Re: Dr. Stapp. A Request for help in QT discussion. On Thu, 9 Oct 2003 Mszlazak@aol.com wrote: > Hi Dr. Stapp. > > I've referenced your work on many-worlds versus orthodox QM in this thread, > but we're not up to the task of really talking about it. Would you take a look > and please consider joining in? We've done this before and I will rely and > post the email messages. > > http://www.iscid.org/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=6&t=000397&p=9#0001 > 25 > > Thanks and cheers. Mark Szlazak. > Dear Mark, I have looked over the thread you sent, which started with Langan's posting of 08 October 13:10, and ended with that of "gedanken" on 09 October 10:17. I do not know what CTMU is, and hence do not really understand the context well enough to make comments that are exactly on target. Also, I do not have the time now to research the origins of quotes. But I am willing to make a few quick comments, for what they are worth in view of my lack of knowledge of some of the relevant background. The comment about the CI "falling out of favor with physicists" sounds like David Deutsch (or maybe W. Zurek) and reflects, I believe, the views of a small coterie who are out of line with the huge bulk of practicing physicists. The majority, I believe, go along with the CI view that science in general, a quantum theory in particular, is about what we scientists know or can know: it is about doing experiments that reveal apparent regularities in the structure of human experiments, and the mathematical codification of these regularities that allow useful predictions to be made about what our experience are likely to be under various alternative possible empirical conditions that we (humans) might choose to create. "Science", from this perspective that is inculcated into the minds of physicists during their training to do quantum theory, is fundamentally epistemological, not ontological. Questions about how the world can possibly be, in order to yield relations among experiences that are in accord with the predictions of QM, need not be resolved in order to do good science. That is the Copenhagen view, and the many-worlds attempt to provide an ontology so extravagant is surely not "accepted" as the real truth by most practicing physicists. But beyond this issue of what constitutes good science there is the question of the technical adequacy of MW. The reason that the founders of quantum theory found it expedient to abandon the 200-year-old policy of keeping our experiences out of the physical theory was that that policy seemed difficult to reconcile with the discrete (Yes-No) character of our observation when experiments probing quantum properties were performed. In order to make the formulas work some paricular way of probing the quantum system had to be specified. But if one followed the Schroedinger equation for the entire unviverse, including ourselves, one gets continuous features, not discrete ones: no sufficiently definite way of probing is singled out. This is known as "the basis problem," and the way it was resolve in CI was to accept the practical fact that we ourselves do in fact choose which experiment we will perform. This crucial-to-the-theory choice, attributed to "us," was formalized by von Neumann as "Process 1." It does not come out of the Schroedinger evolution. This difficulty is not solved by MW! I have elaborated upon this flaw in MW in my paper in Canadian Journal of Physics (80, 1043-1052 2002) (Also in http://www-physics.lbl.gov/~stapp/stappfiles.html) I myself believe that trying to go beyond the epistemological level, and striving to achieve an ontological understanding, though not feasible during the twentieth century, may bear fruit during the twenty-first. Bohr, Heisenberg, and Pauli, the three principal founders of CIQT, all made some strivings for, or indicated the need for, eventual progress in this direction. In this connection, it is I think important that the status of mathematics, and mathematics-based physical theories, is already somewhat cloudy: to what extent is mathematics, and the concepts of probability and knowledge, something belonging to a mental realm? The separation between mental and physical, between subjective and objective, is, I think, in need of careful scrutiny. I suspect that nature has a unity that has "objective physical" aspects that can be represented by the mathematical descriptions provided by quantum theory, and has "subjective experiential" aspects that can be described as elements of "streams of consciousness," but that the "objective physical" descriptions are features of an imbedding reality that is basically both objective and experiential, and that our "subjective experiences" are aspects of this objective-experiential-physical world. But I shall not attempt here to describe the reconciliation of what Descartes and classical physics has set asunder, but quantum theory mends. Let me say only that the experiential aspect is the definite settling or fixing of physical features that are not fixed by the physical aspects determined by the Schroedinger equation. From stapp@thsrv.lbl.gov Thu Oct 9 14:59:55 2003 Date: Thu, 9 Oct 2003 14:56:20 -0700 (PDT) From: stapp@thsrv.lbl.gov Reply-To: hpstapp@lbl.gov To: Mszlazak@aol.com Subject: Re: Dr. Stapp. A Request for help in QT discussion. On Thu, 9 Oct 2003 Mszlazak@aol.com wrote: > Hi Dr. Stapp. > > Thank you for responding. > > I was being provocative but I think accurate in the this thread by saying > that MW with decoherence doesn't make any predictions that are actually observed. > What I meant by this is that you don't observe everything being "smeared-out" > like you would if you had permanent double/multiple-vision or blurred-vision, > but that's all that MW with decoherence gives you! So it's really not an > alternative interpretation to orthodox QM. This is the way that I read your > articles. Is this correct or close? > > Can I post your responses in that thread? > > Mark Szlazak. > I think a many-worlder would say that the smearing out would not be observed because it would be too small. My point was different: it is that the discrete set of orthogonal subspaces needed for the application of the probability rules of QM is not fixed by the Schroedinger evolution. Think of a spinning Stern-Gerlach device that is stopped at a time specified by the detection of a radioactive decay. According to the Schr. Eqn the device is in a superposition of overlapping states. So how does one get a favored basis of orthogonal states from the Schr. Eqn alone? The Human Observers would themselves be in superpositions of overlapping states. Copenhagen breaks the impasse by asserting that observers can in fact make choices about which experiments they will perform: *they* inject the extra information needed to make the theory work *in practice* (for all practical purposes.) By adopting an epistemological stance about science the CI evades the need to explain what is "really going on": that problem is handed off to speculative philosophers. You can post these responses if in your judgement they will be useful. But I am not interested in being diverted from my research. A second edition of my book Mind, Matter, and Quantum Mechanics is due out this month, and my views are explained in detail therein. Best regards, Henry