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