From: SMTP%"PSYCHE-D@rfmh.org" 12-SEP-1996 21:15:43.73 To: STAPP CC: Subj: QM_vs_Classicism and The Observer. Approved-By: PATRICKW@CS.MONASH.EDU.AU Approved-By: STAPP@THEORM.LBL.GOV Message-Id: <960912084118.2220011e@theorm.lbl.gov> Date: Thu, 12 Sep 1996 08:41:18 -0700 Reply-To: PSYCHE Discussion Forum Sender: PSYCHE Discussion Forum From: Henry Stapp Subject: QM_vs_Classicism and The Observer. To: Multiple recipients of list PSYCHE-D Re: QM vs Classicism and The Observer. This is a constructive comment on some basic issues raised in the postings of Sept 10. I shall begin with a quotation of a passage from Heisenberg, which wraps up in one paragraph much of the essence of Heisenberg's view on the subjects under discussion here. It speaks of an ontology based on the concepts of `possible' and `actual', and of transitions from `possible' to `actual', and of the role in physical theory of the `probability function' of quantum mechanics: "Therefore, the transition from the `possible' to the `actual' takes place during the act of observation. If we want to describe what happens in an atomic event, we have to realize that the word `happens' can apply only to the observation, not to the state of affairs between two observations. It applies to the physical not the psychical act of observation, and we may say that the transition from `possible' to `actual' takes place as soon as the interaction of the object with the measuring device, and thereby with the rest of the world, has come into play; it is not connected with the act of registration of the result in the mind of the observer. The discontinuous change in the probability function, however, takes place with the act of registration, because it is the discontinuous change of our knowledge in the instant of registration that has its image in the discontinuous change of the probability function." The probability function is the central quantity in the quantum mechanical formalism. The above description preserves the basic idea of the Copenhagen interpretation, which is that the probability function is to be interpreted as a computational tool, which we scientists can use to calculate expectations pertaining to certain changes in `our knowledge'. Heisenberg is, however, adding here to the essentially epistemological content of the Copenhagen interpretation, the ontological idea that the world is constituted, at least in part, of transitions from the `possible' to the `actual', and that these actualizations are not intrinsicsally the same as quantum jumps in probability functions: the actual things in nature, or at least certain actual things in nature, have the character of transitions from `possible' to `actual', and our theoretical representation of nature is not a faithful image of the actual reality, but is rather a useful tool for certain specified tasks. Von Neumann brought the physical body and brain of the observer onto the picture. At the final stage of his analysis he separates nature into three parts: I is everything up to the retina of the observer; II is his retina, optic nerve, and brain; and III is his abstract `ego'. And he shows that Heisenberg's transition from `possible' to `actual' can be placed at either at the boundary between I and II, or at the boundary between II and III, without altering the predictive content of the theory. His assumption is that the sequence experiences that he calls the abstract ego is isomorphic, in a certain sense, to a corresponding sequence of actualized brain states, as represented within the quantum formalism. Within this general framework it is natural to regard the experiences of the observer to be *actual things* of Heisenberg's ontology that occur when the transition from possible to actual takes place at the boundary between II and III. The point is that the quantum framework provides a natural way for experiences to be actual realities, and the probability functions of the quantum formalism to be essentially just a tool that we have created that provides a way of making predictions about these realities, which are, of course, exactly the realities that science must in the end make predictions about, namely our experiences. To tie this quantum view of things into the postings of Sept 10, I note first Thomas Clarke's mention of Keith Sutherland's contention that we must simply accept the deliverances of consciousness as the place to start in consciousness studies. This contention is in accord with the quantum view in that our experiences are the basic realities. But in accepting this idea we do not have to start from scratch in order to tie our experiences into the vast pool of knowledge derived from the physical sciences: this connection is exactly what is provided by quantum theory. That was precisely the key move of Bohr and Heisenberg et. al., namely to recognize that science was actually about our knowledge, which is imbedded in our experience, and hence that the correct way to formulate physical theory was as a useful tool for making predictions about our experiences. This quantum viewpoint should satisfy the defender's of the idea that experiences are realities that must be dealt with up front as real `observables', for in this view experiences are the basic realities of the ontology, the epistomology, and the physical theory. There is no problem with the `observer' or any infinite regress: the quantum view is in line with the ideas of William James, "thought is itself the thinker" [Stapp, 1993]. This is the attitude expressed by Pat Hayes's "we *are* our consciousness", which was mentioned several times in the Sept 10 postings. There were several references to the idea of giving an operational definition of consciousness. This is impossible if one is trying to express the definition in terms of the elements of classical mechanics, because the logical structure of classical mechanics pertains exclusively to, and encompasses solely, things expressible in terms of certain objective concepts, the classical notions of particles and fields. These are concepts that correspond to idealized versions of what can be "seen" by an observer that is far away from and detached from, what is being observed, whereas experiences *are* the observer: the thought is the thinker. Within the quantum framework the concepts of classical mechanics are on the one hand concepts in terms of which we organize and communicate certain of our experiences, and on the other hand certain idealized limiting forms of the quantum mechanical description of nature. These limiting forms have no counterpart of the "collapses of the wave function" that are the images in the quantum formalism of the transitions from possible to actual that are our experiences. Thus although the classical idealization can be very accurate and useful in representing the external aspect of reality that are "far away from and detached from" the brain of the observer, they are of course completely inappropriate for representing the aspects of brain activity that are associated with consciousness, because they systematically exclude the very aspects that are the images of our experiences, namely the "collapses". Within the quantum framework the "operational definition" of consciousness must be expressed ultimately in terms of the basic realities, experiences. On the other hand, there is also the theoretical representation in terms of the quantum mechanical representation of nature: a human conscious experience is represented by a certain "collapse" of wave function associated with (the action of a projection operator that acts on the part of the wave function that is associated with) a human brain. Analogous "experiences" associated with other systems could presumeably be inferred from the theory, eventually, rather than simply being asserted to be present by some arbitrary operational definition. Henry P. Stapp http://www-physics.lbl.gov/~stapp/stappfiles.html W.Heisenberg in Physics and Philosophy (Harper & Rowe, New York, 1958) Ch III The Copenhagen Interpretation of Quantum Theory, p. 54-55 H.P. Stapp, Mind, Matter, and Quantum Mechanics (1 800 SPRINGER)p.22, 160.