From: SMTP%"PSYCHE-D@rfmh.org" 9-OCT-1996 05:25:13.17 To: STAPP CC: Subj: Physics and Philosophy Approved-By: PATRICKW@CS.MONASH.EDU.AU Approved-By: STAPP@THEORM.LBL.GOV Message-Id: <961009025454.222048b1@theorm.lbl.gov> Date: Wed, 9 Oct 1996 02:54:54 -0700 Reply-To: PSYCHE Discussion Forum Sender: PSYCHE Discussion Forum From: Henry Stapp Subject: Physics and Philosophy To: Multiple recipients of list PSYCHE-D Pat Hayes's latest posting (Oct 8) says that it all hangs on my term `boundary conditions'. Let us examine his point. In order to derive any conclusions from CM about a specific system one must, of course, specify what the system is, and do so within the language and conceptual framework of that theory. These specifications within the mathematical framework of CM are the `boundary conditions' that a physicist must introduce to make the problem mathematically well defined. Pat agrees, and even accepts as trivially true, that as long as one stays within the mathematical framework of the "CM model", and takes the boundary conditions to be boundary conditions formulated within that model, one will never be able to deduce the existence of consciousness from the principles of CM and these boundary conditions . But he points out (as I would phrase it) that any physical application must bring in boundary conditions construed more broadly as including also the `bridging laws' that tie the mathematical model to our perceptions. This unavoidably brings subjective aspects into the discussion. Let us look more closely at his point in the context of the "gas-laws" example raised by Pat. Within the formal CM framework one can introduce the idea of the "pressure" in a gas, and can introduce, within that theoretical framework, also the idea of a "pressure gauge", with a "spring" and a "pointer", that would measure the pressure in the gas, and display this pressure by the position of the pointer on a dial. All of this is formulated within a CM model. The fact that within this CM model the pointer points to a number 8.5 would indicate that within this model the pressure of the gas is 8.5, in some units. This position of the pointer, within the model, might be part of some possible boundary condition, in the narrow sense of the term. A possible bridging law might be that such `a pointer pointing to 8.5', within the CM model, is to be associated with what a human observers who is looking at a measuring device would perceive as `a pointer pointing to 8.5'. One might be able to follow, within the CM model, the passage of the light signal from the pointer to the eye, and scientists might someday even be able to follow the information about the position of the pointer into a classically conceived brain, or perhaps into a psuedo-classical brain in which all atomic and molecular processes are simulated by some suitable "psuedo-classical" process. And one might conceivably, through extensive empirical studies of the NCC (the neural correlates of consciousness), be able to associate certain patterns of "brain" activity, within the CM model of some actual person, with that person's perceiving `a pointer pointing to 8.5'. This leads to a second sort of possible bridging principle, one in which the subjective experience of seeing `a pointer pointing at 8.5' is associated with a complex neural activity. This brings one to the Einstein-Bohr debate. To arrive at a logically satisfactory and pragmatically useful theory that encompasses quantum phenomena, including classical mechanics as a limiting case, Bohr adopted a position that was simultaneously objective and subjective. He, and his colleagues, devised a theory that was fundamentally about `our experiences', but he construed the theory to be specifically about `our classically describable experiences', such as the experiencing of `a pointer pointing to 8.5' (to within certain limits of error). Phenomenal facts such as these are `objective' in the sense that the entire community of communicating observers who are observing the pointer should agree about them. Yet each experiencing of `a pointer pointing to 8.5' is a subjective perception. So what about `boundary conditions' and `bridging laws'? This linking of the CM model to reality does indeed require a bridging law, and this bridging law is, moreover, not entailed by the mathematical principles of CM themselves: it would not contradict the mathematical principles of CM if for some human-like biological structures there simply was no phenomenal reality. This is exactly what I was claiming. What is Pat's point? He says: " If, on the other hand, boundary conditions are thought of as descriptions in CM of the particular boundary circumstances of the finite system being described, then indeed Stapp is correct in noting that the no sentence about subjectivity is derivable from the conjunction of CM and these conditions. Again this is a simple logical point; it follows from the fact that these sentences are now entirely couched in the vocabulary of CM, which does not admit any assertions about subjectivy. It is an application of what is sometimes called the Beth definabliity theorem. However, this is true not just for sentences about subjectivity, but about any sentence about anything not expressly written in the vocabulary of CM. And in spite of Stapp's protests, this includes most of science, including the gas laws. Of course he is right that the gas laws can be derived from CM, *IF* the derivation is allowed to include the appropriate 'definitions' of pressures, etc.; but this involves the introduction of bridging laws which connect gas-law vocabulary to CM vocabulary, and so returns us to the first case. Maybe people will figure out appropriate definitions of 'experience' in terms of CM one day. Stapp may find this implausible, but he has given us no arguments against it." The consciousness case is essentially different from the gas-law case. A pressure gauge is definable within the CM model, and within that model it measures pressure. If the position of the pointer, relative to the dial, is fed into the gas-law theory, along with the readings of other measuring devices, similarly introduced, then the gas-law theory becomes entailed by the principles of CM. The position of the pointer becomes an indicator of certain properties of the gas by virtue of the laws of CM, not by virtue of a bridging principle that lies logically outside what is entailed by the mathematical principles of CM. The gas-law theory is therefore not some independent theory that cannot be encompassed by CM, and that therefore requires some extra bridging laws. Rather it can be deduced as a consequence of CM, to the extent that one introduces models of the appropriate gauges and meters into the CM model, and then considers the readings on these devices as the relevant variables of the gas-law theory. This step introduces into the CM model just the variables that both CM and QM take as the basis of the `bridge laws' to the phenomenal world, namely the readings on measuring devices. Thus the relationships of the gas-law theory to experience lies in the same bridging laws as the rest of physical theory, namely the bridging laws that associate, for example, `a pointer pointing to 8.5' in the theory to `a pointer pointing to 8.5' in the experience of an experiencing human being. The only needed bridging laws that stand outside the basic physical principles are those that relate the "pointer variables" of the mathematical model to the perceptions of these "pointer variables". One might think to introduce, similarly, a CM model of the brain as a "device" that reads the reading on the devices, much as the models of the usual measuring devices read the pressure and temperature of the gas. But this leads to the problem of what the observer of this brain-device would be. In a naturalistic approach one does not want the observer to be outside the physical system. So it does not seem feasible to just treat the brain as another classical system, since the CM model itself is a monal thing, not a dual one. On the other hand, the QM model of the brain is naturally dual, having both a matter-like aspect represented by naturally evolving the wave function, and another aspect represented by the collapsing of this wave function to a form compatible with an occurring thought, in accordance with the basic rule of pragmatic QM. Henry P. Stapp