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#PSYCHE: an interdisciplinary journal of research on consciousness#
#1039-723X/93#

ASCII conventions: #x# is boldface x; ^x^ is superscript x; ~x~ is subscript x; 
                   *x* is italicized x

#ARTICLE#

WHY CLASSICAL MECHANICS CANNOT NATURALLY ACCOMMODATE CONSCIOUSNESS BUT QUANTUM 
MECHANICS CAN

Henry P. Stapp

Theoretical Physics Group
Lawrence Berkeley Laboratory
University of California
Berkeley, California 94720
U.S.A.

hpstapp@lbl.gov

*Copyright (c) Henry P. Stapp 1995*
*Received 01/95; Accepted: 03/95*

URL: ftp://ftp.cs.monash.edu.au/psyche/psyche-95-2-1-QM_stapp-1-stapp.txt
   http://psyche.cs.monash.edu.au/psyche/public/volume2-1/
        psyche-95-2-1-QM_stapp-1-stapp.html

KEYWORDS: mind/brain, quantum theory, consciousness and physics

ABSTRACT: It is argued on the basis of certain mathematical characteristics 
that classical mechanics is not constitutionally suited to accommodate 
consciousness, whereas quantum mechanics is. These mathematical 
characteristics pertain to the nature of the information represented in the 
state of the brain, and the way this information enters into the dynamics.


1. INTRODUCTION

1.1 Classical mechanics arose from the banishment of consciousness from our 
conception of the physical universe. Hence it should not be surprising to find 
that the readmission of consciousness requires going beyond that theory.

1.2 The exclusion of consciousness from the material universe was a hallmark 
of science for over two centuries. However, the shift, in the 1920's, from 
classical mechanics to quantum mechanics marked a break with that long 
tradition: it appeared that the only coherent way to incorporate quantum 
phenomena into the existing science was to admit also the human observer 
(Stapp, 1972). Although the orthodox approach of Bohr and the Copenhagen 
school was epistemological rather than ontological, focusing upon "our 
knowledge" rather than on any effort to introduce consciousness directly into 
the dynamics, other thinkers such as John von Neumann (1955), Norbert Weiner 
(1932), and J.B.S. Haldane (1934) were quick to point out that the quantum 
mechanical aspects of nature seemed tailor-made for bringing consciousness 
back into our conception of matter.

1.3 This suggestion lay fallow for half a century. But the recent resurgence 
of interest in the foundations of quantum theory has led increasingly to a 
focus on the crux of the problem, namely the need to understand the role of 
consciousness in the unfolding of physical reality. It has become clear that 
the revolution in our conception of matter wrought by quantum theory has 
completely altered the complexion of problem of the relationship between mind 
and matter. Some aspects of this change were discussed already in my recent 
book (Stapp, 1993). Here I intend to describe in more detail the basic 
differences between classical mechanics and quantum mechanics in the context 
of the problem of integrating consciousness into our scientific conception of 
matter, and to argue that certain logical deficiencies in classical mechanics, 
as a foundation for a coherent theory of the mind/brain, are overcome in a 
natural and satisfactory way by replacing the classical conception of matter 
by a quantum conception. Instead of reconciling the disparities between mind 
and matter by replacing contemporary (folk) psychology by some yet-to-be-
discovered future psychology, as has been suggested by the Churchlands, it 
seems enough to replace classical (folk) mechanics, which is known to be 
unable to account for the basic physical and chemical process that underlie 
brain processes, by quantum mechanics, which does adequately describe these 
processes.


2. THOUGHTS WITHIN THE CLASSICAL FRAMEWORK

2.1 Thoughts are fleeting things, and our introspections concerning them are 
certainly fallible. Yet each one seems to have several components bound 
together by certain relationships. These components appear, on the basis of 
psycho-neurological data (Kosslyn, 1994), to be associated with neurological 
activities occurring in different locations in the brain. Hence the question 
arises: How can neural activities in different locations in the brain be 
components of a single psychological entity?

2.2 The fundamental principle in classical mechanics is that any physical 
system can be decomposed into a collection of simple independent local 
elements each of which interacts only with its immediate neighbors. To 
formalize this idea let us consider a computer model of the brain. According 
to the ideas of classical physics it should be possible to simulate brain 
processes by a massive system of parallel computers, one for each point in a 
fine grid of spacetime points that cover the brain over some period of time. 
Each individual computer would compute and record the values of the components 
of the electromagnetic and matter fields at the associated grid point. Each of 
these computers receives information only from the computers associated with 
neighboring grid points in its nearly immediate past, and forms the linear 
combinations of values that are the digital analogs of, say, the first and 
second derivatives of various field values in its neighborhood, and hence is 
able to calculate the values corresponding to its own grid point. The complete 
computation starts at an early time and moves progressively forward in time.

2.3 On the basis of this computer model of the evolving brain I shall 
distinguish the intrinsic description of this computer/brain from an extrinsic 
description of it.

2.4 The intrinsic description consists of the collection of facts represented 
by the aggregate of the numbers in the various registers of this massive 
system of parallel computers: each individual fact represented within the 
intrinsic description is specified by the numbers in the registers in *one* of 
these computers, and the full description is simply the conglomeration of 
these individual facts. This intrinsic description corresponds to the fact 
that in classical mechanics a complete description of any physical system is 
supposed to be specified by giving the values of the various fields (e.g., the 
electric field, the magnetic field, etc.) at each of the relevant spacetime 
points. Similarly, an intrinsic description of the contents of a television 
screen might be specified by giving the color and intensity values for each of 
the individual points (pixels)on the screen, without any interpretive 
information (Its a picture of Winston Churchill!), or any *explicit* 
representation of any relationship that might exist among elements of the 
intrinsic description (Pixel 1000 has the same values as pixel 1256!). The 
analogous basic classical-physics description of a steam engine would, 
similarly, give just the values of the basic fields at each of these relevant 
spacetime points, with no notice, or explicit representation, of the fact that 
the system can *also* be conceived of as composed of various *functional 
entities*, such as pistons and drive shafts etc.: the basic or intrinsic 
description is the description of what the system *is*, in terms of its 
logically independent (according to classical mechanics) local components, not 
the description of how it might be conceive of by an interpreter, or how it 
might be described in terms of large functional entities constructed out of 
the ontologically basic local components

2.5 I distinguish this intrinsic description from an extrinsic description.

2.6 An extrinsic description is a description that could be formed in the mind 
of an external observer that is free to survey in unison, and act upon 
together, all of the numbers that constitute the intrinsic description, 
unfettered by the local rules of operation and storage that limit the 
activities of the computer/brain. This external observer is given not only the 
capacity to "know", separately, each of the individual numbers in the 
intrinsic description; he is given also the ability to know this collection of 
numbers as a whole, in the sense that he can have a *single register* that 
specifies the entire collection of numbers that constitutes the intrinsic 
description. The entire collection of logically and ontologically independent 
elements that constitutes the intrinsic description can be represented by a 
single basic entity in the extrinsic description, and be part of the body of 
information that this external observer can access directly, without the need 
for some compositional process in the computer/brain to bring the information 
together from far-apart locations. In general, *collections of independent 
entities* at the level of the intrinsic description can become single entities 
at the level of an extrinsic description.

2.7 The information that is stored in any *one* of the simple logically 
independent computers, of which the computer/brain is the simple aggregate, is 
supposed to be minimal: it is no more than what is needed to compute the local 
evolution. This is the analog of the condition that holds in classical 
physics. As the size of the regions into which one divides a physical system 
tends to zero the dynamically effective information stored in each individual 
region tends to something small, namely the values of a few fields and their 
first few derivatives. And these few values are treated in a very simple way. 
Thus if we take the regions of the computer simulation of the brain that are 
represented by the individual local computers to be sufficiently small then 
the information that resides in any *one* of these local computers appears to 
be much less than information needed to specify a complex thought, such as the 
perception of a visual scene: entries from many logically independent 
(according to classical physics) computers must be combined together to give 
the information contained in an individual thought, which, however, is a 
single experiential entity. Thus the thought, considered as a single whole 
entity, rather than as a collection of independent entities, belongs to the 
extrinsic level of description, not to the intrinsic level of description. 

2.8 According to classical mechanics, the description of both the state of a 
physical system and its dynamics can be expressed at the intrinsic level. But 
then how does one understand the occurrence of experientially whole thoughts? 
How do extrinsic-level actual entities arise from a dynamics that is 
completely reducible to an intrinsic-level description? 

2.9 One possibility is that the intrinsic-level components of a thought are 
bound together by some integrative process in the mind of a spirit being, 
i.e., in the mind of a "ghost behind the machine", of an homunculus. This 
approach shifts the question to an entirely new realm: in place of the 
physical brain, about which we know a great deal, and our thoughts, about 
which we have some direct information, one has a new "spirit realm" about 
which science has little to say. This approach takes us immediately outside 
the realm of science, as we know it today. 

2.10 Alternatively, there is the functional approach. The brain can probably 
be conceived of, in some approximation, in terms of large-scale *functional 
entities* that, from a certain global perspective, might seem to be 
controlling the activity of this brain. However, in the framework of classical 
mechanics such "entities" play no actual role in determining of the course of 
action taken by the computer/brain: this course of action is completely 
controlled by local entities and local effects. The apparent efficacy of the 
large-scale "functional entities" is basically an illusion, according to the 
precepts of classical mechanics, or the dynamics of the computer/brain that 
simulates it: the dynamical evolution is completely fixed by local 
considerations without any reference to such global entities. 

2.11 As an example take a *belief*. Beliefs certainly influence, in some 
sense, the activities of the human mind/brain. Hilary Putnam characterized the 
approach of modern functionalism as the idea that, for example, a belief can 
be regarded as an entry in a "belief register", or a "belief box", that feeds 
control information into the computer program that represents the brain 
process. Such a belief would presumably correspond, physically, to 
correlations in brain activities that extend over a large part of the brain. 
Thus it would be an example of a functional entity that a human being might, 
as a short-hand, imagine to exist as a single whole entity, but that, 
according to the precepts of classical mechanics, is completely analyzable, 
fundamentally, into a simple aggregate of elementary and ontologically 
independent local elements. The notion that such an extrinsic-level functional 
entity actually *is*, fundamentally, anything more than a simple aggregate of 
logically independent local elements is contrary to the precepts of classical 
mechanics. The grafting of such an actual entity onto classical mechanics 
amounts to importing into the theory an appendage that is unnecessary, non-
efficacious, and fundamentally illusory from the perspective of the dynamical 
workings of that theory itself.

2.12 Since this appendage is causally non-efficacious it has no signature, or 
sign of existence, within classical physics. The sole reason for adding it to 
the theory is to account for our direct subjective awareness of it. Logically 
and rationally it does not fit into the classical theory both because it has 
no dynamical effects, beyond those due to its local components alone, and 
because its existence and character contravenes the locality principle that 
constitutes the foundation of the theory, namely the principle that any 
physical system is to be conceived of as fundamentally a conglomerate of 
simple microscopic elements each of which interacts only with its immediate 
neighbors. Neither the character of the basic description of the brain, within 
classical mechanics, nor the character of the classical dynamical laws that 
supposedly govern the brain, provides any basis for considering the brain 
correlate of a thought to be, at the fundamental as distinguished from 
functional level, a single whole entity. One may, of course, *postulate* some 
extra notion of "emergence". But nature must be able to confer some kind of 
beingness beyond what is entailed by the precepts of classical mechanics in 
order to elevate the brain correlate of a belief to the status of an 
ontological whole.

2.13 This problem with 'beliefs', and other thoughts, arises from the attempt 
to understand the connection of thoughts to brains within the framework of 
classical physics. This problem becomes radically transformed, however, once 
one accepts that the brain is a physical system. For then, according to the 
precepts of modern physics, the brain must in principle be treated as a 
quantum system. The classical concepts are known to be grossly inadequate at 
the fundamental level, and this fundamental inadequacy of the classical 
concepts is not confined to the molecular level: it certainly extends to large 
(e.g., brain-sized) systems. Moreover, quantum theory cannot be coherently 
understood without dealing in some detail with the problem of the relationship 
between thoughtlike things and brainlike things: some sort of non-trivial 
considerations involving our thoughts seems essential to a coherent 
understanding of quantum theory. 

2.14 In this respect quantum theory is wholly unlike classical physics, in 
which a human consciousness is necessarily idealized as a non-participatory 
observer --- as an entity that can know aspects of the brain without 
influencing it in any way. This restriction arises because classical physics 
is dynamically complete in itself: it has no capacity to accommodate any 
efficacious entities not already completely fixed and specified within its own 
structure. In quantum theory the situation is more subtle because our 
perceptions of physical systems are described in a classical language that is 
unable to express, even in a gross or approximate way, the structural 
complexity of physical systems, as they are represented within the theory: 
there is a fundamental structural mismatch between the quantum mechanical 
description of a physical system and our description of our perceptions of 
that system. The existence of this structural mismatch is a basic feature of 
quantum theory, and it opens up the interesting possibility of representing 
the mind/brain, within *contemporary* physical theory, as a combination of the 
thoughtlike and matterlike aspects of a neutral reality.

2.15 One could imagine modifying classical mechanics by appending to it the 
concept of another kind of reality; a reality that would be thought like, in 
the sense of being an eventlike grasping of functional entities as wholes. In 
order to preserve the laws of classical mechanics this added reality could 
have no effect on the evolution of any physical system, and hence would not be 
(publicly) observable. Because this new kind of reality could have no physical 
consequences it could confer no evolutionary advantage, and hence would have, 
within the scientific framework, no reason to exist. This sort of addition to 
classical mechanics would convert it from a mechanics with a monistic ontology 
to a mechanics with a dualistic ontology. Yet this profound shift would have 
no roots at all in the classical mechanics onto which it is grafted: it would 
be a completely *ad hoc* move from a monistic mechanics to a dualistic one. 

2.16 In view of this apparent logical need to move from monistic classical 
mechanics to a dualistic generalization, in order to accommodate mind, it is a 
striking fact that physicists have already established that classical 
mechanics cannot adequately describe the physical and chemical processes that 
underlie brain action: quantum mechanics is needed, and this newer theory, 
interpreted realistically, in line with the ideas of Heisenberg, *already is 
dualistic*. Moreover, the two aspects of this quantum mechanical reality 
accord in a perfectly natural way with the matterlike and thoughtlike aspects 
of the mind/brain. This realistic interpretation of quantum mechanics was 
introduced by Heisenberg not to accommodate mind, but rather to *to keep mind 
out of physics*; i.e., to provide a thoroughly objective account of what is 
happening in nature, outside human beings, without referring to human 
observers and their thoughts. Yet when this dualistic mechanics is applied to 
a human brain it can account naturally for the thoughtlike and matterlike 
aspects of the mind/brain system. The quantum mechanical description of the 
state of the brain is automatically (see below) an extrinsic-level 
description, which is the appropriate level for describing brain correlates of 
thoughts. Moreover, thoughts can be identified with events that constitute 
*efficacious choices*. They are integral parts of the quantum mechanical 
process, rather than appendages introduced *ad hoc* to accommodate the 
empirical fact that thoughts exist. These features are discussed in the 
following sections. 


3. THOUGHTS WITHIN THE QUANTUM FRAMEWORK

3.1 Let us consider now how the brain would be simulated by a set of parallel 
computers when the brain is treated as a quantum system. To make this 
description clear to every reader, particularly those with no familiarity with 
quantum theory, I shall start again from the classical description, but spell 
it out in more detail by using some symbols and numbers.

3.2 We introduced a grid of points in the brain. Let these points be 
represented by a set of vectors:

     x~i~, 

where i ranges over the integers from 1 to N. At each point x~i~ there was a 
set of fields:

     F~j~ (x~i~), 

where j ranges from 1 to M, and M is relatively small, say ten. For each of 
the allowed values of the pair (i,j) the quantity F~j~ (x~i~) will have (at 
each fixed time) some value taken from the set of integers that range from -L 
to +L, where L is a very large number. There is also a grid of temporal values 
t~n~, with n ranging from 1 to T.

3.3 The description of the classical system at any time t~n~ is given, 
therefore, by specifying for each pair of value (i,j) with i in the set 
{1,2,...,N} and j in the set {1,2,..., M} some value of F~j~ (x~i~) in the 
set {-L, ..., +L}. We would consequently need, in order to specify this 
classical system at one time t~n~, N x M "registers", each of which 
is able to hold an integer in the range {-L, ..., +L}.

3.4 We now go over to the quantum mechanical description of this same system. 
It is helpful to make the transition in two steps. First we pass to the 
classical *statistical* description of the classical system. This is done by 
assigning a probability to each of the possible states of the classical 
system. The number of possible states of the classical system (at one time) is 
(2L+1)^(M x N)^. If the probability assigned to each of the possible classical 
systems is one of K possible values then the statistical description of the 
classical system at one time requires (2L+1)^(M x N)^ registers, each with the 
capacity to distinguish K different values. This can be compared to the number 
of registers that was needed to describe the classical system at one time, 
which was M x N registers, each with a capacity to distinguish (2L +1) 
different values.

3.5 If the index m runs over the (2L+1)^(M x N)^ possible classical systems 
then a probability P~m~ is assigned to each value of m, where P~m~ > or = 0, 
and the sum over m of P~m~ equals 1.

3.6 The quantum-mechanical description is now obtained by replacing each P~m~ 
by a complex number:

     P~m~ --> r~m~ (cos (a~m~) + i sin (a~m~)),

where r~m~ is the square root of P~m~, a~m~ is an angle, cos (a) and sin (a) 
are the cosine and sine functions, and i is the square root of -1.

3.7 This replacement might seem an odd thing to do, but one sees that this 
description does somehow combine the particle-like aspect of things with a 
wavelike aspect: the probability associated with any specific classical state 
m is r^2^~m~ = P~m~, and an increase of a~m~ gives a wave-like oscillation.

3.8 I am not trying to explain here how quantum theory works: I am merely 
describing the way in which the *description* of the computer/brain system 
changes when one passes from the classical description of it to the quantum 
description.

3.9 For the classical description we needed just M x N registers, but for the 
quantum description we need 2 x (2L +1)^(M x N)^ registers. Thus the 
information contained in the quantum mechanical description is enormously 
larger: we need, simultaneously, a value of r~m~ and of a~m~ for *each possible
state* m of the classical system. That is, each of the possible states of the 
classical system is specified by giving, simultaneously, some value of 
F~j~ (x~i~) in the range (-L,..., L) for each of the MxN allowed pairs of 
indices (i,j), but to describe the quantum state on needs, *simultaneously for 
each of the possible classical states m of the entire system*, a pair of 
numbers (r~m,a~m~). 

3.10 Consider again a belief. As before, a belief would correspond physically 
to some *combination* of values of the fields at many well-separated field 
points x~i~. In the classical computer model of the brain there was no 
register that represented, *or could represent*, such a combination of values, 
and hence we were led to bring in an "external knower" to provide an adequate 
ontological substrate for the existence of the belief. But in the quantum-
mechanical description there *is* such a register. Indeed, each of the 2 x 
(2L+1)^(M x N)^ registers in the quantum mechanical description of the 
computer/brain corresponds to a possible correlated state of activity of the 
*entire* classically-conceived computer/brain. Consequently, there is no 
longer any need to bring in an "external observer": the quantum system itself 
has the requisite structural complexity. Moreover, if we accept von Neumann's 
(and Wigner's (1962)) suggestion that the Heisenberg quantum jumps occur 
precisely at the high level of brain activity that corresponds to conscious 
events then there is an "actual happening" (in a particular register, m) that 
corresponds to the occurrence of the conscious experience of having an 
awareness of this belief. This "happening" is the quantum jump that shifts the 
value of r~m~ associated with this register m from some value less than unity 
to the value unity. This jump constitutes the Heisenberg "actualization" of 
the particular brain state that corresponds to this belief. Jumps of this 
general kind are not introduced merely to accommodate the empirical fact that 
thoughts exist. Instead, they are already an essential feature of the 
Heisenberg description of nature, which is the most orthodox of the existing 
quantum mechanical descriptions of the physical world. Thus in the quantum 
mechanical description of the brain no reference is needed to any "ghost 
behind the machine": the quantum description already has within itself a 
register that corresponds to the particular state of the entire brain that 
corresponds to the belief. Moreover, it already has a dynamical process for 
representing the "occurrence" of this belief. This dynamical process, namely 
the occurrence of the quantum jump (reduction of wave packet), associates the 
thought with a *choice* between alternative classically describable 
possibilities, any one of which is allowed to occur, according to the laws of 
quantum dynamics. Thus the dynamical correlates of thoughts are natural parts 
of the quantum-mechanical description of the brain, and they play a 
dynamically efficacious role in the evolution of that physical system.

3.11 The essential point, here, is that the quantum description is 
automatically holistic, in the sense that its individual registers refer to 
states of the *entire brain*, whereas the individual registers in the 
classically conceived computer/brain represent only local entities. Moreover, 
the quantum jump associated with the thought is also a holistic entity : it 
actualizes as a unit *the state of the entire brain* that is associated with 
the thought.

3.12 The fundamentally holistic character of the quantum mechanical 
description nature is perhaps its most basic and pervasive feature. It has 
been demonstrated to extend to the macroscopic (hundred centimeter) scale in, 
for example, the experiments of Aspect, Grangier, and Roger (1982). In view of 
the fact that the holistic character of our thoughts is so antithetical to the 
principles of classical physics, it would seem imprudent to ignore the 
holistic aspect of matter that lies at the heart of contemporary physics when 
trying to grapple with the problem of the connection of matter to 
consciousness.


4. ON THE THESIS THAT 'MIND IS MATTER'

4.1 Faced with the centuries-old problem of reconciling the thoughtlike and 
matterlike aspects of nature many scientists and philosophers are turning to 
the formula: 'mind is matter' (Churchland, 1992). However, this solution has 
no content until one specifies what matter is. This need to define 'matter' is 
highlighted by the extreme disparity in the conceptions of matter in classical 
mechanics and quantum mechanics. 

4.2 One might try to interpret the 'matter' occurring in this formula as the 
'matter' that occurs in classical physics. But this kind of matter does not 
exist in nature. Hence the thesis 'mind is matter', with matter defined in 
this way, would seem to entail that thoughts do not exist.

4.3 The thesis that 'mind is matter' has been attacked on the ground that 
matter is conceptually unsuited to be identified with mind. The main rebuttal 
to this criticism given in ref. 9 is that one does not know what the 
psychological theory of the future will be like. Hence it is conceivable that 
the future theory of mind may not involve the things such as 'belief', 
'desire' and 'awareness' that we now associate with mind. Consequently, some 
*future* theory of mind could conceivably allow us to understand how two such 
apparently disparate things as mind and matter could be the same. 

4.4 An alternative way to reconcile a theory of mind with the theory of matter 
is not through some future conception of our mental life that differs so 
profoundly from the present-day one, but rather through the introduction the 
already existing modern theory of matter. Let me elaborate.

4.5 The main objection to the thesis that mind is matter --- as contrasted to 
the view that mind and matter are different aspects of a single neutral 
reality --- is based on the fact that each mind is known to only one brain, 
whereas each brain is knowable to many minds. These two aspects of the 
mind/brain are different in kind: a mind consists of a sequence of private 
happenings, whereas a brain consists of a persisting public structure. A 
mind/brain has both a private inner aspect, mind, and a public outer aspect, 
brain, and these two aspects have distinctive characteristics. 

4.6 In the quantum description of nature proposed by Heisenberg reality has, 
similarly, two different aspects. The first consists of a set of 'actual 
events': these events form a sequence of 'happenings', each of which 
actualizes one of the possibilities offered by the quantum dynamics. The 
second consists of a set of 'objective tendencies' for these events to occur: 
these tendencies are represented as persisting structures in space and time. 
If we correlate thoughts with high-level quantum events in brains, as 
suggested by von Neumann, Wigner, and others, then we can construct a theory 
that is a dual-aspect theory of the mind/brain, in the sense that it 
correlates the inner, or mental, aspects of the mind/brain system with 'actual 
events' in Heisenberg's picture of nature, and it identifies the outer, or 
material, aspects of the mind/brain with the 'objective tendencies' of 
Heisenberg's picture of nature.

4.7 This theory might, on the other hand, equally well be construed as a 
theory in which 'mind is matter', if we accept the criteria for inter-
theoretic reduction  proposed in Churchland (1992). For this quantum theory of 
the brain is built directly upon the concepts of the contemporary theory of 
matter, and it appears (Stapp, 1993) to be able to explain in terms of the 
laws of physics the causal connections underlying human behavior that are 
usually explained in psychological terms. Yet in this theory there is no 
abandonment of the normal psychological conception of our mental life. It is 
rather the classical theory of matter that is abandoned. In the terminology 
used by Churchland folk psychology is retained, but folk physics is replaced 
by contemporary physics. 
 

5. FINAL REMARKS

5.1 It will be objected that the argument given above is too philosophical; 
that the simple empirical fact of the matter is that brains are made out of 
neurons and other cells that are well described by classical physics, and 
hence that there is simply no need to bring in quantum mechanics. 

5.2 The same argument could be made for electrical devices by an electrical 
engineer, who could argue that wires and generators and antennae etc. can be 
well described by classical physics. But this would strip him of an adequate 
*theoretical* understanding of the properties of the materials that he is 
dealing with: e.g., with a coherent and adequate theory of the properties of 
transistors and conducting media, etc. Of course, one can do a vast amount of 
electrical engineering without paying any attention to its quantum theoretical 
underpinnings. Yet the frontier developments in engineering today lean heavily 
on our quantum theoretical understanding of the way electrons behave in 
different sorts of environments.

5.3 In an even much more important way the processes that make brains work the 
way they do depend upon the intricate physical and chemical properties of the 
materials out of which they are made: brain processes depend in an exquisite 
way on atomic and molecular processes that can be adequately understood only 
through quantum theory. Of course, it would seem easy to assert that small-
scale processes will be described quantum mechanically, and large-scale 
processes will be described classically. But large-scale processes are built 
up in some sense from small-scale processes, so there is a problem in showing 
how to reconcile the large-scale classical behaviour with the small-scale 
quantum behaviour. There's the rub! For quantum mechanics at the small scale 
simply does not lead to classical mechanics at the large scale. That is 
exactly the problem that has perplexed quantum physicists from the very 
beginning. One can introduce, by hand, some arbitrary dividing line between 
small scale and large scale, and decree that, in our preferred theory, the 
quantum laws will hold for small things and the classical laws will hold for 
large things. But this partition is completely ad hoc: there is no natural 
way to make this division between small and large in the brain, which is a 
tight-knit physical system of interacting levels, and there is no empirical 
evidence that supports the notion that any such separation exists at any level 
below that at which consciousness appears: all phenomena so far investigated 
can be understood by assuming that quantum theory (and in particular the
Schroedinger equation) holds universally below the level where consciousness 
enters.

5.4 Bohr resolved this problem of reconciling the quantum and classical aspect 
of nature by exploiting the fact that the only thing that is known to be 
classical is *our description of our perceptions of physical objects*. Von 
Neumann and Wigner cast this key insight into dynamical form by proposing that 
the quantum/classical divide be made not on the basis of size, but rather on 
the basis of the qualitative differences in those aspects of nature that we 
call mind and matter. The main thrust of ref. 5 is to show, in greater detail, 
how this idea can lead, on the basis of a completely quantum mechanical 
treatment of our brains, to a satisfactory understanding of why our 
*perceptions* of brains, and of all other physical objects, can be described 
in classical terms, even though the brains with which these perceptions are 
associated are described in completely quantum mechanical terms. Any 
alternative theoretical description of the mind/brain system that is 
consistent and coherent must likewise provide a resolution to the basic 
theoretical problem of reconciling the underlying quantum-mechanical character 
of our brains with the classical character of our perceptions of them.


6. CONCLUSIONS

6.1 Classical mechanics and quantum mechanics, considered as conceivable 
descriptions of nature, are structurally very different. According to 
classical mechanics, the world is to be conceived of as a simple aggregate of 
logically independent local entities, each of which interacts only with its 
very close neighbors. By virtue of these interactions large objects and 
systems can be formed, and we can identify various 'functional entities' such 
as pistons and drive shafts, and vortices and waves. But the precepts of 
classical physics tell us that whereas these functional units can be 
identified by us, and can be helpful in our attempts to comprehend the 
behaviour of systems, these units do not thereby acquire any special or added 
ontological character: they continue to be simple aggregates of local 
entities. No extra quality of beingness is appended to them by virtue of the 
fact that they have some special functional quality in some context, or by 
virtue of the fact that they define a spacetime region in which certain 
quantities such as 'energy density' are greater than in surrounding regions. 
All such 'functional entities' are, according to the principles of classical 
physics, to be regarded as simply consequences of particular configurations of 
the local entities: their functional properties are just 'consequences' of the 
local dynamics; functional properties do not generate, or cause to come into 
existence, any extra quality or kind of beingness not inherent in the concept 
of a simple aggregate of logically independent local entities. There is no 
extra quality of 'beingness as a whole', or 'coming into beingness as a whole' 
within the framework of classical physics. There is, therefore, no place 
within the conceptual framework provided by classical physics for the idea 
that certain patterns of neuronal activity that cover large parts of the 
brain, and that have important functional properties, have any special or 
added quality of beingness that goes beyond their beingness as a simple 
aggregate of local entities. Yet an experienced thought is experienced as a 
whole thing. From the point of view of classical physics this requires either 
some 'knower' that is not part of what is described within classical physics, 
but that can 'know' as one thing that which is represented within classical 
physics as a simple aggregation of simple local entities; or it requires some 
addition to the theory that would confer upon certain functional entities some 
new quality not specified or represented within classical mechanics. This new 
quality would be a quality whereby an aggregate of simple independent local 
entities that *acts* as a whole (functional) entity, by virtue of the various 
local interactions described in the theory, *becomes* a whole (experiential) 
entity. There is nothing within classical physics that provides for two such 
levels or qualities of existence or beingness, one pertaining to persisting 
local entities that evolve according to local mathematical laws, and one 
pertaining to sudden comings-into-beingness, at a different level or quality 
of existence, of entities that are bonded wholes whose components are the 
local entities of the lower-level reality. Yet this is exactly what is 
provided by quantum mechanics, which thereby provides a logical framework that 
is perfectly suited to describe the two intertwined aspects of the mind/brain 
system.


APPENDIX A. SALIENT FEATURES OF THE QUANTUM THEORY OF THE MIND/BRAIN DESCRIBED 
IN REF. 5

A.1. _Facilitation._ The excitation of a pattern of neural firings produces 
changes in the neurons that have the effect of facilitating subsequent 
excitations of that pattern.

A.2. _Associative Recall._ The facilitations mentioned above have the feature 
that the excitation of a part of the pattern tends to spread to the whole 
pattern: the sight of Harry's ear brings Harry to mind.

A.3. _Body-World Schema._ The physical body of the person and the surrounding 
world are represented by patterns of neural firings in the brain: these 
patterns contain the information about the positioning of the body in its 
environment. They are represented in the context of neural templates for 
impending action.

A.4. _Body-World-Belief Schema._ The body-world schema has an extension that 
represents beliefs and other idea-like structures.

A.5. _Records._ The B-W-B Schema are representations that have the properties 
required for records: they endure, are copiable, and are combinable (Stapp, 
1991). These requirements entail that these representations are engraved in 
degrees of freedom that can be characterized as "classical". Superpositions of 
such classically describable states are generally not classical. This 
characterization of "classical" (in terms of durability, copiability, and 
combinability) does not take one outside quantum theory: it merely 
distinguishes certain functionally important kinds of quantum states.

A.6. _Evolution Via the Schroedinger Equation._ The alert brain evolves under 
the quantum dynamical laws from a state in which one B-W-B schema is excited 
to a state in which a quantum superposition of several such states are 
excited. That is, the brain evolves from a state in which one neural template 
for action is actualized into a quantum state that is a superposition of 
several alternative possible neural templates for the next action of the 
organism.

A.7. _The Quantum Jump._ The Heisenberg actual event occurs at the high-level 
of brain activity where different classically describable alternative possible 
neural templates have come into being: this event actualizes one template and 
eradicates the others. This process is in exact accord with Heisenberg's idea 
of what happens in a measuring device. The brain is, in effect, treated as a 
Heisenberg-type quantum measuring device.

A.8. _Thoughts._ The occurrence of the Heisenberg event at this high level, 
rather than at some lower level (e.g., when some individual neuron fires) is 
in line with Wigner's suggestion that the reduction of the wave packet occurs 
in the brain *only* at the highest level of processing, where conscious 
thoughts enter. The state of the brain collapses to a classically describable 
branch that records, in the form of a facilitated template for action, the 
template that was just actualized. It is postulated that this actualizing 
event at the level of the wave function is associated with a conscious event 
that is the experiential feel of the act of initiating the action initiated by 
the neural template: the experiential and physical events are concordant. The 
physical and mental events can be regarded as two aspects of the same event-
like reality. The physical event is the image in the physicist's 
representation of reality of some reality that has also an experiential 
'feel'. 

A.9. _Limitations._ The theory covers only those collapses that occur in the 
parts of the physical world associated with the organs that control the 
actions of organisms: e.g., in systems that act in some ways like human 
brains. Whether similar events occur in man-made devices is not specified, and 
need not be specified. There is no empirical evidence to support the notion 
that similar events occur in devices, and the connection to the evolutionary 
pressure for the survival of the organism that will be mentioned below would 
not carry over to such devices.


APPENDIX B. SURVIVAL ADVANTAGE

B.1 Contemporary quantum theory does not have any definite rule that specifies 
where the collapses occur. The proposal adopted here is designed to produce a 
simultaneous resolution of the quantum measurement problem and the mind-matter 
problem. Thus the proposal is justified by the fact that it produces a 
coherent model of reality that accords with our actual experience. Yet the 
deeper question arises: *Why* should the world be this way, and not some other 
way? *Why* should the collapses be to single high-level classical branches, 
rather than to either lower-level states, such as firings of individual 
neurons, or to still higher-level states that might include, for example, many 
classical branches.

B.2 If we suppose that the determination of where the collapses occur is fixed 
not by some *a priori* principle but by *habits* that become ingrained into 
nature, or by some yet-to-be-discovered characteristic of matter that does not 
single out the classical branches *ab initio*, then the question arises: Is 
the placement of the collapses at high-level classical branches, as specified 
in our model, favorable to survival of the organism? If so, then there would 
be an evolutionary pressure for the collapse location to migrate, in our 
species, to this high-level placement. The fact that the collapses, and hence 
the accompanying  experiences, are classical and high-level would then be 
consequences of underlying causes, rather than being simply an unexplained 
fact of nature: it would be advantageous to its survival for the organism to 
be organized so that whatever fundamental property induces collapses 
occurs in conjunction with the top-level templates for action..

B.3 In fact, it is evident that placement of the collapses at a lower level 
would introduce a disruptive stochastic element into the dynamical development 
of the system. Any sort of dynamical process designed to allow the organism to 
respond in an optimal way to its environmental situation would have a tendency 
to be disrupted by the introduction of stochastically instituted low-level 
collapses, which will not always be to states that are strictly orthogonal. 
Thus there would be an evolutionary pressure that would tend to push the 
collapses to higher levels. On the other hand, this pressure would cease once 
the highest possible level of classically specified branches is reached. The 
reason is that in order for the organism to *learn* there must be records of 
what it has done, and these records must be able to control future actions. 
But these properties are essentially the properties by which we have defined 
"classical". *Superpositions* of such classical states have, because of the 
local character of the interaction terms in the quantum mechanical laws, no 
ability to reproduce themselves, or to control future actions of the organism 
(Stapp, 1991). Thus there should be no migration of the location of the 
collapse to levels higher than those specified in our model. 

B.4 This evolutionary advantage of the classically describable consciousness 
within the quantum framework is described in more detail in Stapp (1995b). It 
is of course widely believed that consciousness should confer a survival 
advantage. But within the deterministic framework of classical physics, where 
the course of events is the same whether or not consciousness is appended to 
the local variables specified in classical-physics description, consciousness 
is non-efficacious, and hence of no relevance to the survival of the species.


APPENDIX C. MANY-WORLDS THEORIES

C.1 I have accepted here Heisenberg's idea that there are real events, that 
each one represents a transition from "the possible" to "the actual", and that 
the quantum state can be regarded as a representation of "objective 
tendencies" for such events to occur. In fact, it is difficult to ascribe any 
coherent meaning to the quantum state in the absence of such events. For there 
is then nothing in the theory for the probabilities represented by the wave 
function to be probabilities *of*: What does it mean to say that something 
happens with probability P if nothing actually 'happens', or if everything 
happens together?

C.2 In our model, if we say that there is no collapse then all the branches 
continue to exist: there is no singling out and actualization of one single 
branch. Each of the several branches will evolve independently of the others, 
and hence it is certainly plausible to say that the different realms of 
experience that we would like to associate with the different branches should 
be independent and non-communicating: the records formed in one branch will 
control only that one branch, and have no effect upon the others. But if there 
is no collapse then, insofar as the world is represented by the wave function
alone, all of the various branches, though dynamically independent, occur in
unison, together, and with probability unity. Yet that does not give a match 
with experience. In order to get a match with experience we must be able to 
effectively discard in the limit of an infinite number of repetitions of an 
experiment those branches that have a quantum weight that tends to zero in 
this limit. That is, quantum states with tiny quantum weights should occur 
almost never: they should not occur with probability unity! Hence without some 
added ontological or theoretical structure a theory with no collapse of the
wave function cannot give a sensible account of the statistical predictions of 
quantum theory.

C.3 Of course, the key question is not whether a certain experience X 
*occurs*, but rather whether *my* experience will be experience X. However, 
the idea that many experiences occur, but that *my* experience will be only 
one of them involves some new sort of structure involving a "me" that 
separates into *alternative* "me's", even though the wave function is 
separating into branches that exist *conjunctively*, in unison. It involves
introducing or admitting some structure that takes one beyond the idea that 
the world is represented simply by a quantum state evolving in accordance with 
the Schroedinger equation. At that  level the various classically describable 
branches are components that are combined *conjunctively*: the universe 
consists of branch 1 *and* branch 2 *and* branch 3 *and* ...; not branch 
1 *or* branch 2 *or* branch 3 *or* ... . Yet the world must be decomposed in 
terms of *alternative* possibilities in order to assign 
different statistical weights to the different components: the *and* 
composition given by the basic quantum structure must be supplemented by
something that provides for the notion of an *or* composition. This 
restructuring requires the introduction of some new 
sort of beingness: it does not emerge simply from a  acceptance of the 
idea that the Schroedinger equation should not suddenly fail. The 
idea of a psychological being that splits into *alternative* branches while 
the associated physical body, evolving in accord with the Schroedinger 
equation, is splitting into a *conjunction* of corresponding branches in a 
highly non-trivial sort of notion. It is really much more complex and strange, 
logically, than the idea that the wave function represents an objective 
tendency (propensity) for something to happen, as Heisenberg suggests, and 
that this happening imposes on the universe a new condition that changes the 
propensities pertaining to the next happening. 


APPENDIX D. LOCALITY

D.1 A referee suggested that some further discussion of locality in classical 
and quantum theory would be helpful: I have stressed the nonlocal character of 
quantum theory and the local character of classical theory, yet orthodox 
quantum field theory is local in an important sense, and Newton's classical 
theory of gravity had instantaneous action at a distance, and hence was 
nonlocal. Some sorting out of the various meanings of "locality" is needed.

D.2 Orthodox modern classical field theory conforms to the requirements of the 
theory of relativity. It does not permit any faster-than-light transfer of 
information: a disturbance introduced in a spacetime region R will not produce 
any physical change at a point P that cannot be reached from R by a smooth 
spacetime path that is always directed into the closed forward lightcone. 
Moreover, in the (covariant) field-theoretic formulation the basic 
interactions are always among immediate neighbors. In these two sense 
classical theory is local.

D.3 Orthodox quantum field theory, in its covariant form, is local in an 
analogous sense: the basic interactions that govern the deterministic 
evolution of the (Heisenberg picture) operators are always between neighbors, 
and the theory specifies that certain 'commutation relations' must be such 
that a disturbance in a region R (e.g., the performing of a 'different' 
measurement in that region) will have no effect on the *predictions* made by 
the theory for any physical quantity located at a point P that cannot be 
reached from R by a smooth spacetime path that is always directed into the 
closed forward lightcone.

D.4 On the other hand, there are three senses in which orthodox quantum theory 
is nonlocal: 

a. It is nonlocal in the sense that if Everett-type theories are excluded, say 
for the reasons mentioned in Appendix C, then for certain highly-correlated 
systems of two particles the *set of correlations predicted by quantum theory* 
between the results of certain possible measurements on these two particles is 
incompatible with the following 'locality' condition: the result of any 
possible measurement M must be independent of any free choice---say by a human 
experimenter---that is to be made (in some corresponding frame of reference)
 *later* than the mechanical recording of the result of the measurement M 
(Stapp, 1993b,1995a,1992,1994): one *cannot* assume that there is no faster-than-light influence 
of any kind.

b. It is nonlocal in the sense that any Heisenberg collapse of the wave 
function, F~i~ --> F~(i+1)~ = P~i~ F~i~, generally changes expectation values 
all over the universe. 

c. It is nonlocal in the sense that the projection operator P~i~ in the above 
equation is constructed from operators that act at some given time over an 
extended region in space, such as a human brain. The operator P~i~ places a 
restriction on the *entire state of the brain all at once*: it projects onto a 
state F~(i+1)~ in which certain classically describable conditions *pertaining
to an entire brain* are satisfied together: e.g., the electric field E(x,t) at 
t=t~0~ is confined to a domain:

     E~i~(x) - D~i~(x) <  E(x,t~0~) <  E~i~(x) + D~i~(x)  

for all x in the brain, where E~i~(x) and D~i~(x) are some functions defined 
over the whole brain. The effect of the action of P~i~ on F~i~ is to select 
*one* of the classically describable top-level patterns of neural activity;
i.e., *one* of the alternative possible neural templates for the impending 
action of the organism. This neural template is one of the host of superposed 
templates automatically generated by the local deterministic evolution 
specified by the Schroedinger (or Heisenberg) equation of motion. The contrast 
between the *local deterministic* matter-like evolution that generates of a set 
of possible neural templates for action, and the *nonlocal and brain-wide 
action* of the operator P~i~ that selects and actualizes one of these templates
is what this paper is about.

D.5 This *nonlocal and brain-wide* action of the projection operator P~i~ is
closely linked to the description given in section 3 of the computer model
of the brain. In the context of that description the action of the operator
P~i~ is to set all of the variables r~m~ to zero, except for one, which is set
to unity. Note that the effect of this action is to set the probability
associated with *one single one* of the (2L+1)^(N x M) registers to unity, and
the probability associated to all the rest of these registers to zero. This
``actualization'' of the quantum state associated with one single one of these 
registers is a brain-wide action: this single register specifies a state of the
whole brain, within the context of the computer model.

D.6 To carry the computer model over to the brain, one may consider that the
values specified in the registers of the model represent the values of the
quantities that occur in classical electromagnetism. These latter values are
related to physics by means of a coarse-grain averaging over small spacetime
regions. The size of these small spacetime regions correspond to the grid size
in the model. And the intervals associated with the (2L+1) alternative values 
that the register can take on can be associated with the intervals appearing in
paragraph D.4c. The macroscopic degrees of freedom represented in this way are,
of course, only a tiny fraction of the full set of degrees of freedom of the
brain: there is the chaotic ocean of microvariables upon which these sluggish
macrovariables ride. But the projection operator P~i~ acts on the
macrovariables alone, and probably on the macrovariables associated with only
some regions of the brain, rather than every part of it. But the key point is
that the action of P~i~ is brain-wide because the *single register* that
specifies the actualized quantum state corresponds to a set of simultaneous 
conditions on physical quantities located all over the brain.        

APPENDIX E. DECOHERENCE

E.1 A second referee indicated that the effect upon the arguments advanced 
here of the disruptive influences of thermal agitations, and the loss of phase 
coherence arising from the interactions with environment should be discussed.

E.2 It is important to recognize that although these thermal and environmental 
factors are important at the practical or pragmatic level, they have no 
significant impact on the matters of principle described in the present work. 
Physicists are accustomed to thinking in the pragmatic way recommended by 
Bohr. That was very useful, and had beneficial effects on science during the 
period before the mind-brain problem could be profitably attacked. On the 
other hand, it allowed delicate points to be obscured by the fact that our 
knowledge of the states of macroscopic systems was extremely limited. 

E.3 The present approach is ontological rather than pragmatic. The 
assumption is that there exists in nature a wave function, or state vector, 
that represents the matter-like aspect of reality, and that each experienced 
idea or thought corresponds, within this representation, to a quantum event, 
i.e., to a collapse of the wave function. In this ontological setting neither
a breakdown of the meaning of the wave function nor collapse of the wave 
function is entailed either by our lack of knowledge of what its actual value 
is, or by the absence of all effective means for us to determine what its 
actual value is. 

E.4 In both classical mechanics and quantum mechanics a change of variables is 
allowed, and is often useful. A prime example is the introduction of the 
center-of-mass of an object as one of the variables. More generally there will 
be many useful macrovariables: the system can be represented in terms of a 
collection of sluggish macrovariables, of coordinate type, riding on a chaotic 
ocean of microvariables. The first-order description is in terms of the 
macrovariables. A first main effect of the microvariables is to destroy 
observable interference effects between macrostates that are significantly 
different: this is a consequence of the local character of the underlying 
dynamics. 

E.5 In spite of the chaotic background of microvariables, the von Neumann 
analysis of the process of measurement proceeds essentially as usual: because 
the causal connections between various measuring devices is largely controlled 
by the macro-variables, the von-Neumann-type correlations between the macro-
states of the various devices in the von Neumann chain of devices will be 
maintained. But within the brain the underlying microscopic 
activity will cause additional branchings of the macrostates, as discussed in 
Stapp (1995b). The underlying chaotic microactivity is not ignored or 
disregarded: it is the microscopic foundation upon which the evolution of the 
macrovariables rests. 

E.6 The periodic collapses to states in which certain macrovariable components 
of the brain state conform to classically describable conditions, as a 
consequence of the evolutionary pressure for the survival of the organism, 
keeps the description in terms of classically describable conditions a good 
first-order description, even though this brain is connected in a complex way 
to the surrounding universe. For a more detailed discussion of these points 
the reader is referred to Stapp (1995b), which, however, is written for readers 
having some familiarity with Hilbert-space concepts. 


APPENDIX F. COMPARISON WITH SEARLE

F.1 John Searle (1992) has described his views on the mind-brain problem in a 
recent book "The Rediscovery of the Mind". He does not endorse there the thesis 
that classical mechanics must be replaced by quantum mechanics in order to 
reconcile mind and matter, but his arguments lend strong support to that 
conclusion. 

F.2 Searle's theme can be divided into three parts. The first is encapsulated 
in a sentence appearing in the first paragraph of chapter one: "Mental 
phenomena are caused by neurological processes in the brain and are themselves 
features of the brain." The same point is repeated many times: "... the 
*mental* state of consciousness is just an ordinary biological, that is, 
*physical*, feature of the brain."(p. 13); "The brain causes certain 'mental' 
phenomena, such as conscious mental states, and these are simply higher-level 
features of the brain."(p.14);" Consciousness is a mental, and therefore 
physical, property of the brain in the sense in which liquidity is a property 
of a system of molecules"(p.14); "...these [mental] properties are ordinary 
higher-level biological properties of neurophysiological systems such as human 
brains."(p.28); "... consciousness is just an ordinary biological feature of 
the world." (p.85); " ...consciousness is a causally emergent property of 
systems. It is an emergent feature of certain systems of neurons in the same 
way that solidity and liquidity are emergent features of systems of 
molecules."(p. 112)

F.3 The second sub-theme is this: "Conscious mental states and processes have 
a special feature not possessed by other natural phenomena, namely, 
subjectivity."(p.93); "the phenomena itself, the actual pain itself, has a 
subjective mode of existence, and it is in that sense which I am saying that 
consciousness is subjective."(p.94); "What more can we say about this 
subjective mode of existence? Well, first it is essential to see that in 
consequence of its subjectivity, the pain is not equally accessible to any 
observer. Its existence, we might say, is a first-person existence." 
(p.94);"...the ontology of the mental is an irreducibly first-person 
ontology." (p.95); "No description of third-person, objective, physiological 
facts would convey the subjective, first-person character of the pain simply 
because the first-person features are different from the third-person 
features." (p. 116)

F.4 The third sub-theme is that the first two sub-themes are not 
contradictory: "The facts are that biological processes produce conscious 
mental phenomena, and these are irreducibly subjective." (p. 98); "What I want 
to insist upon, ceaselessly, is that one can accept the obvious facts of 
physics---for example that the world is made up entirely of physical particles 
in fields of force---without at the same time denying the obvious facts about 
our own existence---for example that we are all conscious and that our 
conscious states have quite specific *irreducible* phenomenological 
properties."(p.28); "According to atomic theory, the world is made up of 
particles. These particles are organized into systems. Some of these systems 
are living, and these types of living systems have evolved over long periods 
of times. Among these, some have evolved brains that are capable of causing 
and sustaining consciousness. Consciousness is, thus, a biological feature of 
certain organisms in exactly the same sense of 'biological' in which 
photosynthesis, mitosis, digestion, and reproduction are biological features 
of organisms."(p.93)

F.5 Searle's main and central point is precisely that there are in nature *two 
modes of existence: two ontological types of beingness*. Although he rejects 
labels, he is an "ontological dualist". He chides the various kinds of 
"materialists" for not accepting the obvious idea that consciousness is 
essentially what it seems to be: a physical feature of brains that is not 
ontologically reducible to third-person features. 

F.6 Of course, the reason why traditional "materialists" try to evade or deny 
what Searle sees as obvious is this: a dualistic ontology appears to them to 
be contrary to the scientific conception of the physical world. Indeed, 
Searle's ontologically dualistic conception of the brain is certainly contrary 
to the conception of the physical world that characterizes classical 
mechanics. That conception deals exclusively with third-person realities: it 
has no natural place for a first-person mode of existence, and no causal laws 
or logical requirements that would demand any type of beingness that goes 
beyond the third-person kind that it deals with exclusively. 

F.7 Searle's argument is based on the fact that consciousness obviously 
exists, and hence must be included in our account of nature. But the proper 
conclusion to be drawn from his arguments is that classical mechanics is 
fundamentally deficient: a better mechanics is needed to account for the known 
properties of the mind/brain. Of course, physicists have already reached this 
same conclusion, or at least a closely related one, on the basis of results 
stemming from empirical studies of the properties of atoms and materials.

F.8 Several conceivable quantum ontologies are being pursued by physicists, 
but all are fundamentally dualistic. The Bohm-type ontology has both an 
objectively existing quantum wave function and also a classical world whose 
essential property is that *it*, not the quantum wave function, determines 
what our experiences will be. The Everett-type interpretations, in which there 
is a wave function that evolves always in accordance with the Schroedinger 
equation, but in which there is no singled-out classical world, as there is in 
Bohm's model, also forces one to introduce some other entities for the 
probabilities to refer to. This was discussed in Appendix C. These other 
entities control what our thoughts and experiences will be. In the Heisenberg 
ontology there are the 'actual events' and also the 'objective tendencies' for 
these events to occur. The objective tendencies evolve in accordance with 
local deterministic laws (the Heisenberg equations of motion) that are direct 
analogs of corresponding laws of classical mechanics, whereas the actual 
events control what our thoughts and experiences will be. In the Wigner-von-
Neumann version of the Heisenberg ontology the actual events are either our 
thoughts and experiences themselves, or they are the images of these 
experiences in the physicist's mathematical representation of the physical 
world. In every case the ontology is dualistic, and one of the two parts of 
the quantum reality is subject to the local deterministic  quantum-mechanical 
law of motion, which is the quantum analog of the local  deterministic law 
that governs the material aspect of nature in classical mechanics , whereas 
the second part of the quantum reality controls what our thoughts and 
experiences will be. 

F.9 Searle insists that "consciousness is just an ordinary biological feature 
of the world"---"a biological feature of certain organisms in exactly the same 
sense of  'biological' in which  photosynthesis, mitosis,  digestion and 
reproduction are  biological features of organisms". This claim does not 
exactly  square with the fact that  digestion and  photosynthesis are, 
ontologically, third-person features, whereas consciousness is of a different 
ontological type: it is first-person feature. The generation---by a system of 
ontological type A---of something of the *same* type, A, is not exactly the 
same as the generation of something of a *different* ontological type, B. 
Indeed, there is no possibility within the ordinary framework of classical 
mechanics for causal relationships between neurons of the kinds that occur in 
classical mechanics, to generate anything that has a mode of being different 
from the third-person mode, for that is the only kind of beingness that occurs 
in classical mechanics. Some new kind of mechanics is needed to generate, from 
the third-person realities that classical mechanics deals with, anything with 
another mode of existence: classical mechanics is not conceptually constituted 
to create anything having a mode of existence other than the third-person mode 
that it deals with exclusively. 

F.10 Searle's ontological conclusions are, for the reasons given, not 
compatible with the ontological underpinnings of classical mechanics: they 
call for a new kind of mechanics. This new kind of mechanics is  ontologically 
similar to quantum mechanics, if not identical to it.


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This work was supported by the Director, Office of Energy Research, Office of 
High Energy and Nuclear Physics, Division of High Energy Physics of the U.S. 
Department of Energy under Contract DE-AC03-76SF00098.