Science of Consciousness and the Hard Problem

                        Henry P. Stapp
                 Lawrence Berkeley Laboratory
                   University of California
                  Berkeley, California 94720

                          Abstract

Quantum theory is essentially a  rationally coherent theory of the  interaction
of mind and  matter, and it allows our  conscious thoughts  to  play a causally
efficacious  and  necessary role  in brain  dynamics.  It  therefore provides a
natural basis, created by  scientists, for the  science of consciousness. As an
illustration it is explained how the interaction of brain and consciousness can
speed up  brain  processing,  and  thereby  enhance the  survival  prospects of
conscious organisms, as compared to  similar organisms that lack consciousness.
As a second illustration it is explained how, within the quantum framework, the
consciously   experienced ``I''  directs the  actions  of a human  being. It is
concluded  that  contemporary  science  already has an  adequate  framework for
incorporating   causally  efficacious   experiential  events into  the physical
universe in a manner that: 1) puts the  neural correlates of consciousness into
the theory in a well  defined way, 2) explains in  principle how the effects of
consciousness,  per se, can  enhance the  survival prospects  of organisms that
possess  it,  3)  allows  this   survival  effect  to feed  into   phylogenetic
development, and 4)  explains how the consciously  experienced ``I'' can direct
human behaviour. 

             Based on a Plenary Talk at the Conference  
              Toward a Science of Consciousness  1996
                    University of Arizona 
                   Tucson, April 8-13, 1996.

                        Introduction

``The Hard Problem'' was the subject of the opening session of this conference.
More that any other single topic it has dominated our discussions here. Defined
by David Chalmers, the problem is this: Why do our conscious experiences, which
seem so  totally different  from the matter of  which our  brains are made, and
which, according to the  principles of classical  mechanics, can have no effect
upon processes in our  brain and bodies, exist at  all. In this final session I
address this  problem within the  context of the major  overall problem of this
conference,  the need  to create  an  adequate  theoretical  foundation for the
science of consciousness. Such a  foundation must accommodate in a rational and
useful way  our  knowledge of 1)  our  conscious  experiences, 2)  the physical
processes in  our brains,  and 3) the  tight  relationship that  exists between
these seemingly disparate parts of nature.

Daniel Dennett, in a  comment from the floor,  suggested that Chalmers may have
got it upside  down: he suggested that  the problems  identified by Chalmers as
the "easy"  problems were the hard  ones, and his "hard  problem" the easy one.
The intimation was, I think, that  there simply is no hard problem, essentially
because there is no consciousness, in any sense that could cause a problem.

I  shall argue  that   Dennett's   conclusion---though  not  his  argument---is
essentially correct. The  thesis to be expounded  here is that there is, today,
no ``hard problem'' within science, at least in the sense  posed by the rise of
modern  science. The reason is  that  scientists have already  solved it, or at
least provided  the foundation  for a  solution. But before  they solved it the
problem was certainly very hard: it took nearly 300 years to solve.

The problem arose at the  dawn of modern science  when Descartes suggested that
the world be  conceived to consist of  two different kinds  of things, mind and
matter, which interacted in human  brains. The difficulty was this: how can one
rationally   comprehend an   interaction between  two such   different kinds of
things. The problem was  compounded by the  development of classical mechanics,
which  entailed  that the  matter part  of  nature, by  itself, is  dynamically
complete: classical  mechanics asserted that the  dynamical evolution of matter
is completely  controlled by matter  alone. Thus mind,  contrary to the idea of
Descartes, was reduced to  an impotent witness to  the flow of material events:
mind became epiphenomenal.

This problem  was solved  around 1930 by  scientists led by  Niels Bohr, Werner
Heisenberg, and  Wolfgang Pauli, and  the mathematician  John von Neumann. They
went  beyond  classical   mechanics, and  created  the  practically  useful and
empirically successful  quantum theory. This theory  (in the von Neumann/Wigner
elaboration of  the  Bohr/Heisenberg  formulation) is  essentially a rationally
coherent framework for the interaction  of mind and matter and, as such, is the
natural foundation for the science of consciousness.

Patricia   Churchland   characterized as a  ``real   humdinger'' the  idea that
scientists  should use, as the  foundation of  their science  of consciousness,
science's own answer to  the basic question of how  to bring consciousness into
science in a  rationally  coherent way. She  meant to deride  as crazy the idea
that scientists should  employ their own hard-won  solution to this fundamental
problem. But the  men who created  quantum theory were  rational scientists who
were driven by the scientific need to accommodate, within a rationally coherent
and   practically  useful  theoretical   framework,  the fact  that  nature was
profoundly different from the classical-physics conceptualization of it. 

The failure of classical concepts first became manifest at the atomic level, in
a breakdown of the  normal reality  status of the atomic  particles. But due to
the tightknit  character of  the physical  world this  `reality-status' disease
infected  everything made out of  atoms: it automatically  spread to the entire
physical world, right up to our conscious experiences.

The  problem of the   relationship of mind  and matter  is  basically a physics
problem: it is the  problem of how two different  aspects of nature are related
to each other. Many of the problems about consciousness debated by philosophers
fade away once the tacit physics assumptions are made manifest. 

Take, for  example,  the zombie  question  that is  being hotly  debated at the
moment  (Sutherland,  1996). In  those  discussions a  ``zombie''  is typically
defined to be a creature that is just like a normal human being in every detail
of   behavior,  down to  the    submicroscopic   level, but  has  no  conscious
experiences. Can such a  thing exist? 

To avoid  working in a  theoretical  vacuum one  should specify  the underlying
physics   assumption. If one  is  referring to  real human  beings  then one is
speaking about  quantum systems, and  in a  quantum-mechanical description of a
human being  the interaction  between mind and  brain is a  crucial part of the
dynamics. Hence mind cannot be left  out. But if one is tacitly assuming that a
classical-mechanics conceptualization of the brain is adequate then, since mind
is epiphenomenal  within classical  mechanics,  consciousness can be eliminated
without affecting  behaviour at any  level. The natural  conclusion to be drawn
from this is simply that the counterfactual physics assumption is incorrect.

My aim  here is  first  to  describe the    quantum-mechanical  solution of the
mind/matter problem, and  then show how this  solution can resolve in principle
some basic problems that  arise from trying to  employ counterfactual classical
mechanics instead of empirically  adequate quantum mechanics as the theoretical
foundation of the  science of  consciousness. These  problems are to understand
how  consciousness can  aid   survival---epiphenomenal  consciousness certainly
cannot do so!---and can  evolve during phylogenetic  and individual development,
and to see how a satisfactory theory of "free will" pops out.

                Experience within  Science

Classical   Mechanics   purports to  describe  the  physical  world  and how it
functions,  and  claims to  achieve  this goal  without  bringing in  thoughts,
feelings,  or any  other  experiential  aspect  of nature.  For  centuries this
restriction  to the  purely  physical was  regarded as  an  important virtue of
science: science had  succeeded in taking us beyond  the primitive superstition
that spirits were  lurking everywhere,  and causing things  to happen. Instead,
the physical  world was  asserted to be built  out of nothing  but quantifiable
properties that  could be localized in  a spacetime, and  whose functioning was
completely determined by  rigid mathematical laws  that referred to nothing but
these physical properties themselves.  Thus when the creators of quantum theory
introduced ``our  experience'' and ``our  knowledge'' into the theory of atomic
phenomena their move was  initially opposed by the  scientific community. Soon,
however,  this  important  enlargement of  the  scientific  conception of basic
physical theory came to be accepted, at least nominally, by most workers in the
field. 

Recently some quantum  theorists have been trying  to exorcise ``the observer''
from quantum theory. These attempts encounter difficulties that I shall mention
later.  But in any  case the   important point  in our  quest for a  science of
consciousness  is not that our  basic physical  theory {\it  might conceivably}
some day be able to be  formulated without  introducing observers. It is rather
that our  basic theory of  matter, in  its  contemporary  orthodox form, has an
explicit and dynamically efficacious place for conscious experiencings. Science
already has in  place the basis of  rationally coherent  and practically useful
theory  of the  interaction  of mind  and  matter: there  is no need  to invent
another one.

The focus of orthodox quantum theory  on the experiential aspects of nature was
emphasized in the opening words of  Niels Bohr's principal book on the subject,
Atomic Theory and the Description of Nature (Bohr, 1934):

\begin{quote}
The task of science is both to extend the range of our experience and reduce
it to order. (p.1)
\end{quote}
Later he says:
\begin{quote}
In physics... our problem consists in the co-ordination of our experience
of the external world ...  (p.1)
\end{quote}
and
\begin{quote}
In our description of nature the purpose is not to disclose the real essence
of phenomena but only to track down as far as possible relations between the
multifold aspects of our experiences. (p.18)
\end{quote}
An analogous statement by Heisenberg (1958a) is:
\begin{quote}
The  conception of  the  objective  reality of the  elementary  particles has
evaporated  in a curious  way, not  into the fog of  some new,  obscure reality
concept, but into the transparent  clarity of a mathematics that represents no
longer the  behaviour of the  elementary particles but  rather our knowledge of
this behavior. (p.99)
\end{quote}

As these  quotations indicate, the  original formulation  of quantum theory was
essentially was about ``our experienced knowledge'' of the physical world. This
original formulation was  subsequently extended by  von Neumann, and it is this
formulation, as  elaborated by his close colleague  Eugene Wigner, that I shall
use  here. Wigner  called it  the  orthodox   interpretation, and I  think this
terminology is  justified by the fact  that all other  proposed interpretations
are compared to it, or to the  Copenhagen interpretation that it elaborates, to
determine whether the predictions of the proposed new interpretation agree with
the usual predictions.

But how can a physical  theory rationally encompass  two things so different as
matter and our experiencings, and accommodate an interaction between them?

To see how  this works  let it first  be recalled  how it is  done in classical
mechanics. All statements in science  must be transcribed into statements about
``our possible experiences'' before they can be tested by human beings, or used
make predictions about what our future experiences will be. All such prediction
are based  upon some  prior  knowledge of  the world  about us.  But this prior
knowledge  never   determines the  state  of the  world  exactly. In  classical
statistical  mechanics  this prior  knowledge, call  it K, is  represented by a
`probability  density function',  D(x,p;K). Here the  argument x represents the
positions  of  all  of the   particles of  the  system  being   examined, and p
represents  the  momenta  (or  velocities)  of  these  particles. The  function
D(x,p;K) defines the probability  density in phase space (i.e., in (x,p)-space)
corresponding to the prior knowledge K. 

For example, one might know only that  some set of particles of interest lie in
a  certain  box, and  have a  certain   temperature.  This  knowledge  K can be
represented  by  a  particular   probability  density  function  D(x,p;K): this
function  will vanish  when any  coordinate x_i  lies outside  the box, and the
momentum   dependence  will be  specified  in a  well-known  way  (i.e., by the
Boltzmann factor). 

Suppose I now  ask the  following question:  Given the  statistical information
represented  by the  probability  function  D(x,p;K),  what is the  probability
P(m,e;K) that if I observe the system in manner m I will have experience e.

Let E(m,e;x,p) be the probability  (density) that if the system is in the state
specified by the point (x,p) in phase space, and I observe it in manner m, then
I will have experience e. Folding  together these two probabilities one obtains
a basic formula of classical statistical mechanics: 

P(m,e;K)= Integral dx dp E(m,e;x,p) D(x,p;K).                (1) 

This same  formula holds  in quantum  mechanics.  But in quantum  mechanics the
quantities   D(x,p;K) and  E(m,e;x,p)  are not  positive  numbers,  and hence a
classical probability interpretation is ruled out. Also, the equation of motion
in quantum  theory is  such that  the  different  members of what  in classical
mechanics  would be a  `statistical  ensemble' of  independently  moving points
(x,p) in  phase space  do not  evolve  independently:  in quantum  theory these
`independent components'  are influenced by their  neighbors. Hence they cannot
be  conceived of  as members  of a  classical  statistical   ensemble. Thus the
physical significance of  the variables x and p  becomes obscure: our intuitive
conception of the physical part of nature fails. But the phenomenal variables e
and m are just  the same as  before: these are  the realities  that we can hang
onto. The commitment in quantum theory  is to hang onto this basic formula, and
to the {\it  experiential}  quantities, even  though this  means abandoning our
classical notion of what the physical part of nature is like. 

In the  original Copenhagen  interpretation of  Bohr and  Heisenberg, and their
colleagues, the variables x and p referred to an external system that was being
examined  by the   scientists.  Thus in  the  function  E(m,e;x,p)  the pair of
variables  (x,p)  referred to  one system  (some small  `observed'  part of the
universe) and the pair of variables  (m,e) referred to things associated with a
different part of the universe, namely the brain of the observer plus his body,
extended to include his measuring devices. 

Thus in the  original interpretation  the mapping function  E(m,e;x,p) connects
two different parts of the universe.  It therefore depends upon a separation of
the physical  universe into  parts. But this  separation of  the physical world
into  parts  was not  well  defined  within  the  theory. Thus  the  theory, as
originally formulated, was not fully satisfactory. 
  
John  von  Neumann  (1932) and  Eugene  Wigner  (1967)   extended the  original
Copenhagen  form of  the theory  by  identifying `the  system'  with the entire
universe.   Then  no    mysterious---and  probably   impossible  to  coherently
implement---separation of  the universe into two  completely different kinds of
matter  was  needed: the   variables x and  p  become the  variables  needed to
describe  the entire  universe,  including,  in  particular, the  brains of the
observers.  The function  E(m,e;x,p)  then relates  an  ``experiential space'',
whose elements are labelled by the  variables m and e, to a physical space that
includes,  in  particular,  the brain  of the  relevant  observer.  The mapping
E(e,m;x,p) from  experiences to  physical variables  defines in this theory the
neural    correlates of    consciousness,  which  thus  enter  the  theory in a
fundamental and well-defined way. 

This  injection  of the  neural   correlates of   consciousness into  the basic
equations of physics was troubling to  some physicists, who wished to return to
a more  classical type of  physics in  which  consciousness was  kept out. They
endeavoured (not  successfully I  think) to reformulate  quantum theory in some
way that gets consciousness out of physics. But, regardless of whether they can
succeed or not, for the deeper issues before us at this conference the orthodox
formulation is ideal.

A key difference between the classical and quantum theories concerns the nature
of the interaction between mind and matter.

When the  new experience  labelled by  (m,e)  occurs, the prior  knowledge K is
augmented:   K--->(K,(m,e)).  If the   observation can  yield only  the answers
YES=(m,e)  and  NO=(m, -e)  then the   transformations to  the new  probability
functions are, classically:

D(x,p;K)--->D(x,p; K, (m, e))= E(m,e;x,p)D(x,p; K),     (2a)

and

D(x,p;K)--->D(x,p; K, (m, -e))= E(m,-e;x,p)D(x,p; K),   (2b) 

where,

E(m,e;x,p) + E(m,-e; x,p) =1.                           (2c)

Here I  have  included  in the   probability  function    D(x,p;K,(m,e)) [resp.
D(x,p;K,(m,-e))] the probability that outcome e [resp. -e] appears.

These equations entail the equality

D(x,p;K,(m,e))+ D(x,p;K,(m,-e))= D(x, p; K).             (3)

This  identity means  that in  classical  mechanics the   observation itself is
`passive':  if  one  adds  together  the   probabilities   corresponding to the
alternative possible  outcomes, YES and NO, then  the result is the same as the
original probability function: nothing  is changed if one makes the observation
but does not discriminate between the results. 

In quantum mechanics the  functions D(x,p;K) and  E(m,e;x,p) can be regarded as
the matrix  elements  <x|D(K)|p> and  <p|E(m,e)|x> of {\it  operators} D(K) and
E(m,e).  (This change of  notation  also  accommodates the  generalization from
ordinary quantum mechanics to quantum field theory, which is what actually must
be  used.) Then a  huge  difference  between  quantum  mechanics and  classical
mechanics is that the occurrence of  the experience (m,e) is an event that acts
dynamically back on the  physical world. The  physical world before this event,
which is represented by D(K), is  transformed as follows:  

     D(K)--->D(K,(m,e)) = E(m,e)D(K)E(m,e),       (4a)  
or 

     D(K)--->D(K,(m,-e)) = E(m,-e)D(K)E(m,-e),    (4b)   
where  
     E(m,-e) + E(m,e) =1.                         (4c) 

The analogue of (3) does not hold here, in general, because (4), unlike (2), is
not linear in the  quantities E: the  observation changes  the physical system,
even if no discrimination is made between the two possible results. 

The transformation (4a)  represents a `reduction of  the state': the state D(K)
prior to  the  actual  experiential  event that  is  represented by  E(m,e)  is
transformed  to a new  state  D(K,(m,e)) that  incorporates the  new conditions
labeled by (m,e). In  keeping with this meaning,  the operator E(m,e) satisfies
the (idempot) condition  E(m,e)E(m,e)=E(m,e): a  single experience acting twice
has the same effect as its acting once.

This description  shows how our  experiencings become  woven into the fabric of
the  quantum  mechanical  description of  nature: they  are the  identifiers of
events that are  the comings into  being of these  experiencings, and that also
act efficaciously upon the  mathematical structure that represents the physical
aspect of nature. In this new picture of nature the physical aspect constitutes
the more  subtle  aspect of  reality:  it acts  merely as  a  substrate of {\it
propensities} for  experiential events to occur.  These experiential events are
the more robust basic realities.

Human  experiences are  presumed to be  very  high-level forms  of experiential
events.  They are  the  foundation of  the human   scientific  enterprise: they
constitute the data upon which our science is based.

Quantum    mechanics, as   formulated by  Niels  Bohr  and his   colleagues, is
predicated  on  the fact  that our   experiences of  the  physical  world---our
immediate  phenomenal  knowledge of  it---can be  described in  the language of
classical mechanics, considered as an extension of ordinary every-day language.
Quantum dynamics itself,  in the von Neumann/Wigner  form, entails that in many
situations classical mechanics can  provide a very accurate approximation. Thus
quantum theory is a  unified and seamless theory  that accurately describes the
quantum features of nature, but also justifies the use of classical concepts in
situations where those concepts are applicable.

       Problems with the Classical-Mechanical Description of the Brain

Classical mechanics  cannot account for the  empirically observed properties of
matter in  general, or of the  matter of which  brains are  made in particular.
However, because  consciousness is evidently  associated with large-scale brain
activities,  and with  chemical  processes that  seemingly can  be simulated by
quasi-classical processes that mock-up  the net effects of the quantum process,
it is widely  assumed  that the  crucial role of  quantum theory  in adequately
accounting for  brain dynamics is  merely a technical  complication that has no
basic ontological or physical  significance in the context of understanding the
dynamical effects of  consciousness, per se, on  brain activity. That is, it is
assumed that, as far as the effects of mind on brain dynamics is concerned,  is
legitimate  to   imagine the  brain to  be the  sort  of thing  that  classical
mechanics imagines it to  be rather than the  radically different sort of thing
that quantum  mechanics  claims it to  be. This  assumption that  the classical
conception  of the  brain is  adequate  in this  context  encounters  immediate
problems    associated  with  the    epiphenomenal   character of  mind  in the
classical-mechanical conception of nature.
 
The     classical-mechanical   description  of the   physical  world  (although
empirically false) is, logically speaking, dynamically complete, even though it
never  mentions  the  experiential  (i.e.,  phenomenal)  aspects of  nature. To
account,   within  this    framework, for  the   factual   occurrence  of these
experiential aspects some scientists  and philosophers have been led to suppose
that certain brain activities simply `elicit' corresponding experiences without
the latter reacting back on the brain. According to this idea, the experiential
world is  merely  an  epiphenomenal  add-on to a  physical  world  that, in the
context  of  the  mind-brain   question, can  be  imagined to  be  described by
classical mechanics.
 
This  scenario might  be  logically  possible, but it  seems  preposterous that
nature should  create a whole extra  world that is totally  unlike the physical
world, and in no way  entailed by the laws that  govern the physical world, and
then give this add-on world no dynamical role to play. 

The unnaturalness and non-parsimoniousness of this (classical dualistic) notion
has  led to  an  opposing   (classical      identity/functionalist)  claim that
experiencings simply ARE certain functional activities of the brain, described
in a phenomenal rather  that physical/functional  language: i.e., that all that
there is in  nature (at a  level that is  adequate to cope  with the mind-brain
problem) are the classically described physical/functional activities, but that
certain of these activities can be {\it identified} as {\it also} our conscious
experiences. I say ``also'' because if classical mechanics is accepted then one
has, in  principle, the  physical description  that it  entails: any other
description is then something beyond what classical mechanics itself entails. 

To examine the identity/functionalist  claim, suppose brain science has finally
evolved to the point where it can give a complete description of brain process:
suppose it can provide a detailed understanding of how `memory tracks' are laid
down in the  brain, and  how these  memory tracks  are accessed  by later brain
activities. And suppose that the brain scientist could even wire up a brain and
map out its  various patterns  of activity in  sufficient  detail to be able to
follow through  what happens in the  brain when the person  is asked ``What did
you eat for  breakast this  morning?'' Suppose  the brain  scientist is able to
follow  through the  progression  of  patterns of  excitations and  see how the
physical memory tracks  laid down during breakfast  come to be accessed, and to
see how the content of those memory  tracks feeds into the process that finally
produces  the  spoken  reply  ``Ham  and  Eggs!'', and  even  the  reply to the
follow-up question ``What color were the eggs?'': ``They were a chalky-whiteish
kind of yellow,  rather than an  orange-ish shade of  yellow!'' And suppose the
brain scientist's description is detailed enough to see even the laying down of
certain memory  tracks that will allow  the person to  respond to later queries
about  his  sequence of  thoughts  as he  was  formulating  his  answers to the
questions.  Suppose  further that the  brain  scientist is able  to construct a
mapping from the physical space of certain kinds of patterns of neural activity
to corresponding  `phenomenal events'  described in a  phenomenal language, and
that this mapping  is such that it  fits perfectly with  all the responses that
that person makes to  questions about his  ``experiencings'' of pain, of color,
and of every other kind of experience that he says he has. 

Within this context we may consider, in the framework of a classical-mechanical
conceptualization of the brain, the two alternative claims:

1. The phenomenal activity IS ELICITED BY a neural/functional activity.

2. The phenomenal activity IS the corresponding neural/functional activity.

The  advocate of claim  2, which I  call  (classical)  functionalism, can claim
parsimony, and  can point to  the  unnaturalness of the  existence, asserted by
claim 1, of a  whole world  that is  fundamentally different  from the physical
world, and has no effect upon the physical world. The existence of such a world
would seem to require a  whole new machinery in  nature, a machinery that would
somehow `cause'  the phenomenal events  to occur, or  `elicit' them, even though
nothing in the classical physical laws requires the existence of any such extra
machinery.

On the other hand, the  advocate of claim 1, which  I call (classical) dualism,
can insist that any claim  that two different  descriptions describe one single
thing must be supported by some explanation of how the one thing acquires these
two descriptions. For example, the  claim that temperature in thermodynamics IS
the same as mean  kinetic energy in  statistical mechanics  is supported by the
fact one can  {\it deduce}  this  correspondence from the laws  of physics. The
claim that The Morning Star IS The Planet Venus, is also explained on the basis
of the laws of physics,  by noting that the phrase  ``The Morning Star'' has an
original   meaning  that   refers to a   certain  kind of    `experiencing' (an
experiencing of a  certain brightness  in the morning sky  not too far from the
horizon), and by the fact  that this experiencing  can be deduced, on the basis
of the laws of  physics, to be caused  by sunlight  reflected off of the planet
called Venus, provided such `experiencings' of an observer can be assumed to be
evoked by  corresponding activities in  the brain of this  observer. But in the
case of the claim that ``The Pain P IS  The Functional Brain Activity F'' there
is no possibility of  deducing this connection from  the orthodox principles of
classical mechanics.

The functionalist can reply that he has in fact, on the basis of the principles
of classical mechanics, provided a detailed causal account of the very activity
in the  brain  that {\it   constitutes}   experiencing. He  can claim  that his
phenomenal knowings ARE,  precisely, his brain's  accessings and monitorings of
certain aspects of itself. He can  claim that his experiencings ARE his brain's
functional  activities of  laying down and  retrieving certain  kinds of memory
tracks  that: 1)  contain  all of  the  information  that he  feels  that he is
becoming  aware  of; and 2)  initiate  all of  the things  that he  feels he is
initiating.

The dualist can reply  that if one takes the  principles of classical mechanics
as   the   basic      principles   then   one  can   {\it    prove}   that  the
identity/functionalist hypothesis is false, provided one does not simply assume
it to be  true. The point  is that  from the  classical  principles and initial
boundary    conditions one  can  {\it  deduce}  the  presence  of the  physical
activities but cannot  deduce the presence of the  phenomenal activities. Hence
the  two   things are     distinguishable  within  that    framework.  Thus the
functionalist hypothesis,  though perhaps logically  possible, contradicts what
the classical principles by themselves entail.

This  looseness in  the logical  situation  arises  precisely  because there is
something that is  known first-hand to  be ontologically  real and present, but
whose  presence is not  implied by the  physical  theory that is  being used to
describe the system. 

This egregious omission arises, it  appears, from a faulty conceptualization of
the situation, namely from the use, in  the conceptualization of the mind/brain
system, of a physical  theory that has already been  found by science, on other
grounds,  to  be   inadequate  precisely  at the  point  at  issue,  namely the
relationship  between our  physical  description of  nature and  our phenomenal
knowledge  of it. If  one is  going to go  beyond the  principles  of classical
mechanics,  and add some  extra  hypothesis  regarding mind,  then the the most
reasonable  procedure, within science,  is to try first to  use the theory that
science itself has already discovered in this connection.

Within the Bohr/von-Neuman/Wigner  formulation of quantum theory the phenomenal
facts are introduced from the very  beginning as the basic actualities that the
theory is about. And  these actualities are  causally efficacious. Hence within
this  quantum  description of  nature there  is no need  to  introduce into the
theory any element  not clearly  entailed by the original  basic principles, or
any element that is  dynamically inert: we are not  forced by science to accept
an unreasonable stance on either  point, provided we accept what science itself
has been telling us for seventy years.

      Quantum Mechanics as the Solution to the Scientific Aspect 
                    of the Hard Problem

The ``Hard Problem'' has  several aspects. From the  perspective of science the
question  ``Why does  consciousness  exist?'' can  be compared  to the question
``Why does  the  electromagnetic  field  exist?'' A  physicist can  answer this
question   by   giving  an   account  of  the   important   function   that the
electromagnetic field  plays in workings of nature,  as they are represented in
his  physical theory.  Of  course,  consciousness plays  no role  at all in the
classical   mechanics  account of  nature, and  hence no  functional  answer is
possible within the  classical-mechanics  conceptualization of nature. Since it
is  unreasonable  for  nature to  have  such a   nonefficacious  component, the
question of `why  consciousness  exists' becomes  essentially a plea for a more
adequate conceptual  understanding of nature, one  in which consciousness plays
an essential role.

Two essential roles of consciousness in the quantum formulation are:

1. Our conscious  experiencings are  what both science in  general and  quantum
   theory in particular  are about. One cannot  eliminate our experiences from
   the theory without eliminating both  the connection of the theory to science
   and also the basic realities upon which the theory itself rests: experiences
   are the basic  realities that the  more subtle  `physical' aspects of nature
   are propensities for.

2. Technically,  experiences are used  to solve the  so-called basis problem in
   quantum  theory.  Within  the  physical domain  itself  there is  no natural
   foundation for  deciding  which special  states are the  ones into which the
   quantum state can ``collapse''. The  core idea of Bohr is that these special
   states correspond to our  experiences, and this  core idea is carried by the
   von Neumann/Wigner formulation into equations (1) and (4). Intuitively, this
   amounts to the  idea that the  body/brain  processes  generate possibilities
   that are presented to  the quantum selection  process, which interprets them
   in terms of possible  experiences, and then  selects, in accordance with the
   basic  quantum  statistical  rule, one of  these  possible  experiences, and
   actualizes it, and  its body/brain  counterpart. (Of  course, this intuitive
   interpretation  of  the  formulas (1) and  (4) is not  actually  needed: the
   formulas themselves define the  theory.) But this means that our experiences
   are not only the basic realities of  the theory, and the link to science, as
   noted  in 1,  but  also  play a  key in   specifying  the  ``set of  allowed
   possibilities'' that enter into the causal chain of mind/brain events. These
   allowed possibilities must be just  the ones that correspond to our possible
   experiences, at least for practical  purposes, or the whole theory loses its
   tight  connection  to  science: the  events in  the  theory would  no longer
   correspond to the experiential realities.

Of  course, one  could still  ask why  all this  could not  happen  without the
occurrence of any actual experiencings. 

Perhaps the dynamical  effects mentioned in point 2  could occur without actual
experiencings   ever   happening, but  the  connection  to  science  would then
dissolve, as  mentioned in  point 1. And as  regards the  dynamics mentioned in
point 2, the point is that the  physical aspects of nature alone do not seem to
define the preferred  states, and hence something  that is either consciousness
itself,  or a   stand-in  for   consciousness  that  plays a  role  essentially
indistinguishable  from it, is needed.  Since  consciousness is known to exist,
and something essentially  indistinguishable from  it seems needed to solve the
basis  problem in a   satisfactory way, it  would be  both  nonparsimonious and
perverse to  introduce something as  yet unknown to  simulate something that is
both known to exist, and in need of a role to play.

           Macroscopic Quantum Effects In Brain Dynamics

Brain Dynamics is  controlled by chemical  processes. Eventually, we will  want
to have a  coherent account in  which these  chemical  processes fit seamlessly
into the whole process. Hence ultimately, for these basically chemical reasons,
a quantum description will be needed

But I wish  to focus  here on more  macroscopic  quantum  effects: effects that
would  distinguish the quantum  treatment from  a classical  model in which the
currents flowing along neurons are described in classical terms.

Brain  process is   essentially a  search  process: the  brain,  conditioned by
earlier experience,  searches for a satisfactory  response to the new situation
that the  organism  faces.  It is  reasonable to  suppose  that a  satisfactory
response will be progammed by a template for action that will be implemented by
a  carefully tuned  pattern  of  firings of some   collection of  neurons. This
executive  pattern  would be a  quasi-stable  vibration  that  would commandeer
certain energy resources, and then  dissipate its energy into the initiation of
the  action  that  it   represents.  [See  Stapp  (1993)  for a  more  detailed
description of this process.] 

If the programmed action  is complex  and refined  then this executive pattern
must contain a great deal of information, and must, accordingly, be confined to
a small region of phase space. Stated  differently, the relative timings of the
pulses moving  along the  various neurons, or  groups of  neurons, will have to
conform to certain ideals to within  very fine levels of tolerance. The problem
is: How does the hot wet brain, which  is being buffeted around by all sorts of
thermal  and chaotic   disturbances, find  its way to  such a tiny  region in a
timely manner?

The   problem,   reduced to  it  basic   dynamical  form,  is  this:  How, in a
3n-dimensional space (where n represents some huge number of degrees of freedom
of the brain), does a point that is moving in a potential well that effectively
blocks out those brain states that are not good solutions to the problem (i.e.,
that do not represent templates for  satisfactory actions, under the conditions
at hand), but that does  not block the way to the  good solutions, find its way
in a  short  time to  a  good  solution,  under  chaotic   initial  conditions.
Classically,   the point  in the   3n-dimensional  space  must just  follow the
deterministic equation of motion until it eventually wiggles its way out of the
potential  well. But  the  quantum system  has the  advantage of  being able to
explore   simultaneously all  possible  ways to  get out.  This is  because the
quantum state  corresponds, essentially, to a  superposition of all the allowed
possibilites. Moreover,  this 3n-dimensional cloud  of virtual possibilities in
3n-dimensional space satisfies an  essentially hydrodynamic equation of motion:
it  acts like  a  single  glob of  water,  rather  than  like a   collection of
independently  moving  droplets. (Feynman,  1965). That is,  the motion of each
point in the cloud is  influenced by its neighbors,  as was emphasized earlier.
But then when some parts of the glob  find their way out of the potential well,
and thus flow  out of the  confined region  leaving a partial  void, the nearby
parts of the glob will flow in to take  their place, and will then in turn flow
out. Thus all of the glob will tend to flow out quickly, like water flowing out
of a leaky bucket.

The brain is a quantum  system, and will  automatically use this hydrodynamical
property,  and  hence  will  presumably  operate  faster in   searching for an
acceptable  template for  action than its  classical  counterpart can. Thus the
need to use quantum theory is not just a philosophical matter: it will probably
be needed to account for the speed of the (analog) search processes.

                     Decoherence

It has often been observed that the coupling of a system to its environment has
a tendency to make interference  phenomena that are present in principle within
quantum systems  difficult to observe  in practice. Phase  relationships, which
are essential to interference phenomena, get diffused into the environment, and
are difficult to  retrieve. The net  effect of this is to  make a large part of
the  observable   phenomena in a  quantum  universe  similar  to what  would be
observed in a world in  which certain collective  (i.e., macroscopic) variables
are  governed by  classical  mechanics. This  greatly  diminishes  the realm of
phenomena  that require  for their  understanding  the explicit  use of quantum
theory. 

These decoherence  effects will have a tendency to  reduce, in a system such as
the brain, the distances over which  the idea of a simple single quantum system
holds. This  will reduce  the  distances over which  the simple  hydrodynamical
considerations described above will hold. However, the following points must be
considered.

a) A calcium ion  entering a bouton through a  microchannel of diameter x must,
by Heisenberg's indeterminacy  principle, have a momentum spread of hbar/x, and
hence a velocity spread of (hbar/x)/m, and hence a spatial spread in time t, if
the   particle  were  freely   moving, of    t(hbar/x)/m.  Taking  t to  be 200
microseconds,  the typical  time for the ion  to diffuse from  the microchannel
opening to a triggering site for the  release of a vesicle of neurotransmitter,
and  taking x to  be one   nanometer, and   including a  factor of  10^{-5} for
diffusion slowing, one  finds the diameter of the  wave function to be about 40
times 10^{-8}  centimeters, which is comparable to  the size of the calcium ion
itself. Of course, this free-particle  spreading will be greatly reduced by the
multiple  scatterings of the  ion as it moves  through the  aqueous medium. But
this  quantum   speading of  wave  packets   constitutes    counterforce to the
mechanisms  that  tend to   diminish  quantum  coherence  effects. If  the wave
functions of  the centers  of mass of  these  calcium ions are  not confined to
regions  that are  small  compared to  the size  of the  ion itself  then if no
collapse occurs the brain must evolve into an amorphous superposition of states
corresponding to a continuum of different possible macroscopic behaviours.

b) The  normal process  that induces  decoherence  arises from  the fact that a
collision  of  a state   represented  by a  broad wave   function with  a state
represented by a narrow wave packet effectively reduces the coherence length in
the first state to  a distance  proportional to the width  of the second state.
But in an aqueous medium in which all the states of the individual systems have
broad  packets this  mechanism is no  longer  effective:  coherence lengths can
remain long.

c) Even if the coherence length were only a factor of ten times the diameter of
the atom or ion involved in some process, the cross section involved would be a
hundred times  larger. The search  processes under  consideration here involves
huge numbers of atoms and  ions acting together,  and the cross-section factors
multiply. Thus  even a small  effect at the  level of the  individual atoms and
ions  could  give, by  virtue  of the hydrodynamical  effect,  a large  quantum
enhancement  of the  efficiency of an  essentially  aqueous  macroscopic search
process.

                 Everett  and Consciousness

Einstein (1952) illustrated the central logical problem in contemporary quantum
theory with a simple  example. It involves a  radioactive source, a detector of
some product of the  decay, a pen that draws a line  on a moving strip of paper
and makes a blip when the decay is  detected, and a human observer of the blip.
If one uses the  Schroedinger equation  then one finds  that the system evolves
into a   continuous  superposition  of  states   corresponding to all  possible
positions of the blip on the strip of paper. But when the human observer looks,
he sees the blip in one  well defined place. Thus  the Schroedinger equation is
not  telling the  whole  story. If  one  wants to  have an  account  of what is
actually happening, then something  else needs to be added, namely Heisenberg's
`transition from  possible to actual'  (or some substitute  for it) that allows
the many possibilities generated by  the Schroedinger dynamics to be reduced to
the single actually experienced reality. The von Neumann/Wigner form of quantum
theory  accepts the  Heisenberg  transitions  from  possible to  actual as real
events.

The strangeness of Heisenberg's idea  (1958b) of transitions from `possible' to
`actual',  naturally has led  scientists to explore  diligently the possibility
that these   transitions never  happen: that  the  Schroedinger  equation never
fails. This  possibility  was examined  in some  detail by  Everett (1957). The
consequence of that work, and of many  later efforts to clarify it, is to focus
attention   even more   strongly than  ever on  the  problem  of our  conscious
experience. For if the  Schroedinger equation never  fails then there is a huge
disparity  between the  objective world, which  is represented  by the evolving
state of the universe, and our subjective experiences of it. 

The basic problem  with this  interpretation is that the  needed psychological,
i.e.,  experiential, properties of  brains do not follow  from the Schroedinger
equation. The latter can perhaps  generate independently evolving `branches' of
the wave  function  of the  brain,  with  different  branches  corresponding to
different streams of consciousness,  but these branches are {\it conjunctively}
present.  However, in order to  obtain the  statistical  predictions of quantum
theory,  which  pertain  to our   experiences, the   experiential  streams that
correspond to these different physical branches must be {\it disjunctive}. That
is, the  objective  physical state  will contains  branch A {\it  and} B, etc.,
whereas to  get  statistical  statements about our  subjective  experiences one
needs the logical  structure of experience A {\it  or} experience B, etc.. This
means that `mind' needs an ontology and dynamics that does not logically follow
from the   Schroedinger equation  that  controls the  `brain'.  This need for a
second  level  of  reality,   controlled by a   dynamics that  does  not follow
logically from  the first,  appears to nullify  the advantage  that the Everett
interpretation  seemed at  first to provide.  In any case, a  spotlight becomes
focused  more  strongly than  ever on  the  problem of the   connection between
objective  aspects of a  mind/brain  represented in  the  conjunctively present
branches  of  the  wave  function  and the disjunctive  subjective   aspects.

Looking  at the   evaluations by   physicists who  are  pursuing  environmental
decoherence  effects, and other  essentially `Everett'  ways of approaching the
problem of  quantum  measurement we  find Zurek  (1986, p.96)  saying, of these
approaches, that they do  not allow us to  understand how we as `observers' fit
in, and hence  they appear to  him to be  merely ``a hint  about how to proceed
rather than the means to settle the  issue quickly.'' Joos (1986, p.12) says ``
Of  course  the   central  problem   remains   unsolved:  Why are   there local
observers?'' Gell-mann  and Hartle[14] emphasize  that: ``If history dependence
can be properly  introduced into the  explicit treatment  of quantum mechanics,
then we may be able to  handle individuality [of  observers] with the care that
it deserves''. Omnes  (1994, p.348), who gives  perhaps the most comprehensive
description of  these Everett-type  theories says, about  the Everett proposal,
that he feels ``it impossible to accept as a satisfactory answer to the problem
of actuality.'' So  almost forty years  after the Everett  paper appeared it is
acknowledged by these workers, and I  think by all others who have examined the
matter with  sufficient care, that the  problem of `the  observer' has not been
banished by that approach. This issue, namely the problem of how our individual
experiences fit into nature, becomes  reinstated in the Everett approach as the
central unsolved problem:  this approach makes that  problem even more pressing
than before. The Everett approach  tries to resolve the problem of the observer
without  going  beyond the   Schroedinger  equation, but  it  certainly has not
succeeded in doing so.

There are also  some proposed  interpretations that try to  leave consciousness
out  altogether. One is  the  pilot-wave model of  David Bohm  (1952). Einstein
rejected  this  model as the  real  solution on  the basis  of its  being ``too
cheap'', and Bohm agreed with this  assessment. In the last chapter of his book
with Basil Hiley (Bohm and Hiley, 1993) on the subject he tried to go beyond it,
and to bring in consciousness. But the effort was not carried very far.

The other most highly  developed theory is that of  Ghirardi, Rimini, and Weber
(1986) and Pearle  (1989, 1996). In  this model the free  parameters have to be
very finely adjusted (Pearle, 1994; Collett, 1995) in order for the predictions
to be compatible with experiment, and it may be ruled out altogether in the not
too distant  future. It seems  that nature  would have to be  very malicious to
have finely tuned the parameters so  that we could not distinguish between this
state of affairs and the orthodox theory, which fits all known data without any
fine tuning.

In view of these  considerations it is, I think,  completely reasonable to take
the orthodox  (Bohr/Heisenberg/von-Neumann/Wigner)  interpretation as the
`best' one, as far as the science of consciousness is concerned.

                   Causality and Chance

One can  ask what  causes a   particular  phenomenal event  to  occur. Orthodox
quantum  theory  says   `statistical  cause': the  quantum  state of  the brain
specifies the `propensities' for the various phenomenal possibilities. Thus the
cause of the phenomenal events is not the local deterministic (mechanical) sort
of cause that occurs in  classical mechanics. If  one insists on naming what it
is that  picks out the  one particular  possibility  that  actually occurs in a
given situation, orthodox quantum theory can only answer: pure chance!

As regards the role of chance Bohr (1958, p.73) says this:

\begin{quote}
The circumstance that, in general, one and the same experimental arrangement
may yield different recordings is sometimes picturequely described as a `choice
of nature' between such possibilities. Needless to say, such a phrase implies
no allusion to a personification of nature, but simply points to the
impossibility of ascertaining on accustomed lines directives for the course
of a closed indivisible phenomenon. Here, logical approach cannot go beyond
the deduction of the relative probabilities for the appearance of the individual
phenomena under given conditions.
\end{quote}

Bohr carefully  avoids  affirming that there  actually is in  nature herself an
irreducible element of chance. He says, rather, that the entry of chance is due
to       difficulties   that   arise   from    trying  to    apply    customary
(local-reductionistic) thinking to  closed indivisible phenomena. This suggests
that nature herself must have some  [necessarily nonlocal (Mermin, 1994: Stapp,
1993. p. 5) ] way of determining which event will actually occur: i.e., that we
do not  have to  accept the  absurdity  of  something  definite  arising out of
absolutely nothing at all. 

Be that as  it may,  quantum theory,  in its  contemporary form,  separates the
dynamics into  two parts: the   Schroedinger-directed  evolution of the quantum
state, and the quantum selection process, which appears to operate according to
some specified rules of  chance. This second  process surveys the quantum state
in terms of  the possible  experiences  that it  (the selection  process) could
extract from that state, and  actualizes one of the possibilities in accordance
with the quantum statistical rules.

Science may aspire to probe more  deeply into this selection process, but doing
so within the scientific paradigm  would appear to require data indicating some
deviations, under certain conditions,  from the quantum statistical rules. Here
I stay strictly within  the bounds of contemporary orthodox science in accepting
the quantum statistical rules as  primitive elements of our basic theory.

             General Description of Brain/Mind Dynamics

Before going further I give a general  overview of the conception of brain/mind
dynamics  that  seems best  to fit the  quantum process. This  is a very brief
synopsis of the description of mind/brain dynamics given in my book (Stapp,
1993, Ch. 6)

Body-World Schema 

It is  accepted  here  (or  postulated)  that there  is in a   person's brain a
high-level represention of his body  and its environment: i.e., that a person's
body  and  its   environment  are   represented in  his  brain  by  patterns of
neurological  and other  brain  activity. This  representation  in the person's
brain of his body and its environment  is called the `body-world schema'. It is
expanded to include  representations of beliefs,  and hence is sometimes called
the   body-world-belief schema,  but I shall  stick to  the  shorter name. Each
phenomenal quantum event  is assumed to actualize a  body-world schema. An {\it
attentional} event  up-dates the body-world schema;  an {\it intentional} event
actualizes a  body-world  schema that is an  image of an  intended state of the
body-world.  This projected  (into the future)  image serves  as a template for
action: the automatic unfolding, in  accordance with the Schroedinger equation,
of the  pattern of  neural  activity that constitutes  the B-W  schema tends to
evolve into the intended action.

Facilitation, Associative  Recall, and Control 

The  persistence of a  pattern of neural excitation  `etches' this pattern into
the  physical   structure of  the  brain, in  the  sense that  this  pattern is
`facilitated' (made easier to activate), and that a later activation of part of
the  pattern tends to  spread to  the whole.  This  facilitation  and spreading
effect provides the basic  mechanism for an  explanation of associative recall,
and of the control aspect of the body-world schema.

The Effect of Quantum Theory

The effect of quantum theory is  essentially the same as it was in the Einstein
example   described  earlier: the   evolution  controlled by  the  Schroedinger
equation  will  produce,  instead of  one single   body-world  scheme, rather a
continuum, consisting of a  superposition of all the possibilities, with no one
possibility  singled out  as the one  that is  actually  experienced. Thus, for
example, for every possibility in  which a `synaptic event' ---the release of a
vesicle  of     neuro-transmitter---  occurs  there will  be  other  superposed
possibilities in  which this event  does not occur; and  for every situation in
which an action potential spike exists at one place along an axon there will be
other  superposed  possibilities in which the  spike is a  little earlier, or a
little later, and  still others in  which it is much  earlier or much later. To
extract the  actually experienced  reality from this  amorphous conglomerate of
superposed   possibilities  one needs,   according to the   Heisenberg ontology
accepted here,  a transition  from `possible'  to `actual'.  This transition is
called an actualization event: it selects and actualizes one of the alternative
possibilities generated by the Schroedinger-equation-controlled evolution.

Many people, even many  scientists, suppose that  the quantum events (i.e., the
collapse events) occur at a  microscopic level. However, there is no reason for
this to be so, and no empirical evidence that is is so. Indeed any evidence for
microscopic quantum  events would be evidence {\it  against} the correctness or
completeness of contemporary quantum theory, and no such evidence has ever been
found. 

A core idea  of the  quantum model is  that each  actual event  is a phenomenal
event  that is   essentially  an  integrated  picture  of the   body-world that
expresses the information contained in the body-world schema that is actualized
by the event.

    Survival Value of Consciousness, and Phylogenetic Development 

A major difficulty with the  classical-physics approach to consciousness is the
problem of the  connection of  consciousness to survival.  Consciousness is not
entailed by the principles of classical mechanics, and hence it cannot, per se,
have any  effect on the  dynamics: within that  framework it  is epiphenomenal.
Postulating that  the functional  activities ARE the  conscious activities does
not help, because  this postulate is,  logically, an  addition to the classical
principles, which already  give a dynamically  complete framework: the physical
evolution would be exactly the same even if the extra postulate were not added,
and consciousness were not present. 

But then  within  the  classical  framework  consciousness  cannot  enhance the
survival prospects of creatures that possess it. Hence it is not understandable
in naturalistic terms why we should possess it. 

In the quantum  world consciousness  {\it can be} causally  efficacious, and in
the  orthodox  theory being  discussed  here   consciousness {\it  is} causally
efficacious. Thus  creatures  possessing consciousness  could in principle have
enhanced survival  prospects. In this section I  shall show how, in the quantum
model, the survival prospects of a creature could be enhanced by the possession
of consciousness.

It has already been  mentioned that high-level  brain process is essentially an
analog search process, and that the hydrodynamical character of the quantum law
of evolution  can speed  up this  process. This  speed-up does  not require any
brain-wide   quantum  coherence:   short-distance  coherence   suffices. If one
imagines a big potential well that is  being explored for a route into a little
pocket that represents the appropriate template for action, then we immediately
see an  additional speed-up  arising from the  physical action  associated with
conscious  experiences. In a  model with no  collapses, and  this includes both
classical models and Everett-type  quantum models, and also the Bohm pilot-wave
model,  once the  little  pocket gets  filled it  may tend  to stay  filled, in
equilibrium  with other  parts of the  system. But  in the  orthodox model this
little pocket can be repeatedly probed  by the selection process. If the result
is YES, then the experience occurs and the state is collapsed into this pocket,
and the resulting action  proceeds. But if the  answer is NO then no experience
occurs. But then, in accordance with  (4b) and (4c), the pocket is cleared out,
in accordance with  the new fact the  the system is now  ``known'' to be not in
this state. That  is, the probability  function will have  a ``hole'' where the
probability has dropped down to zero, to signify that the system is not in this
region. But then  the hydrodynamic  effect will tend to  shift more probability
into this hole, to fill it up. But  then the selection process can have another
crack at it. So at least in principle  the orthodox model would tend to be more
efficient at implementing effective  action. If a similar species, otherwise on
a par, but organized so that its templates for action do not mesh with possible
conscious    experiences, then  for  these  creatures  there  could be  no such
dynamical  effect and  they would tend  to act more  slowly, and  hence be less
likely to survive.

Bats and dogs and other animals are probably conscious. So we do not expect all
possible experiences in nature to be  just like our own. Indeed, the demands of
phylogenetic  development  would  entail that there  be a  continuum or closely
spaced spectrum of possible experiences extending back down to a very primitive
level. Then the  survival advantage  mentioned above could  enter at a very low
level and  work its  way by  natural  selection up the   phylogenetic ladder. A
similar  chain would  probably  be operative  in the  embryonic  and subsequent
development of the individual organism.

I stress that the enhancement of the  survival prospects of conscious creatures
in this quantum  theory of  consciousness arises simply  from following through
the logic of the orthodox  (Bohr/Heisenberg/von-Neumann/Wigner) quantum theory,
as  represented,  basically, by  equations  (1) and  (4), and the  Schroedinger
equation. It  does not depend  upon exotic  effects such as  brain-wide quantum
coherence, which would be  very difficult to  achieve, or upon the difficulties
involved with reconciling quantum theory and general relativity. 

At the  present stage of  empirical  technique it  is probably  not possible to
confirm  empirically the  existence or   nonexistence of the  dynamical effects
described  in this  section. But  they do  follow  rationally from  the quantum
principles,  and provide a  basis for  understanding in a  naturalistic way the
occurrence of consciousness in connection with human brain process. 

                   Free Will

In his plenary talk David Hodgson  noted that our justice and moral systems are
based on the normal  ``folk psychology'' notion of  personal responsibility for
one's acts.  Thus the  abandonment of  folk  psychology,  suggested by Patricia
Churchland  (1986) and  others, would  undermine  the foundation  of the social
fabric. Hodgson asks whether this change in our conception of the nature of man
is actually entailed by science. 

The quantum theoretical approach to the science of consciousness described here
leaves  folk   psychology  essentially   intact: it  abandons   instead, at the
foundational   level,  and on  good  grounds,  folk  physics  (i.e.,  classical
mechanics). 

The quantum  framework leads naturally  to the normal  ``folk'' concept of free
will and  personal  responsibility. The key  point is the  concept of ``I''. In
classical  mechanics the  personally  experienced ``I'' is not  entailed by the
(dynamically  complete) physical  principles, and it thus  lies impotently, and
hence without  responsibility, outside the causal  chain of physical events. In
the quantum picture the  experienced quality of  ``I-ness'' is experienced, and
is therefore  {\it part}  of the  stream of  conscious events:  the experienced
``I-ness''   belongs to the   experience, not  vice versa.  It  belongs to what
William James calls the ``fringe'' of experience. Surrounding the central focus
of our experience  is a slowly  changing background part  that keeps us vaguely
aware of who we  are and what we are  doing, both in the  long and short terms.
The way  the  dynamics works  is that  the state  of the  brain (and  universe)
evolves under  the control of  the  Schroedinger equation, and  then a collapse
occurs. This  collapse  actualizes a template  for action that  is the physical
counterpart of the  corresponding  experienced thought.  Thus the effect of the
thought gets injected into the causal chain of events. 

The overall guidance part of the  thought comes from the slowly changing fringe
part that  is the  experienced  ``I''. This  part is  carried over  time by the
memory  structure in the  brain, and reflects  both genetic  input, educational
training,  and the  effects of all  earlier  conscious  experiences, which have
likewise had their effects injected  into the causal chain of brain/mind events
by means of collapses to  templates for action that  are the physical images of
these thoughts. In this way the experienced ``I'' feeds into one's behaviour in
essentially the way that we intuitively feel that it does, and is in turn being
created in its forward development by the combined effect of its own input into
the physical process and the action of the environment upon the body and brain.

There is, of course, some  ``static'' injected into  this process of personally
controlled  behaviour  by the  quantum  selection  process, but  this static is
limited to  selections between  options to  which our own  personal process has
assigned significant statistical  weight. Thus although the quantum selection
process  gets the  final say at  the level  of the  individual  selections, the
statistical  weights  are  controlled by the  personal  process  that is itself
controlled  basically by the  experienced  ``I''. For more  details see my book
(Stapp, 1993) 

I have adhered  throughout to the orthodox position  that the quantum selection
process is  bound by  the  quantum  statistical rules  of  contemporary quantum
mechanics.  Any  suggestion  that this  law  fails in  certain cases  should be
supported by powerful data or reasoning, for the failure of this law would open
a Pandora's box of theoretical difficulties and uncertainties.

                 Open Questions 

The  major   research  problem  is to   determine  the  neural   correlates of
consciousness. These correlates are represented in the theory by the quantities
  E(m,e;x,p).   Determining them is a  major part  of what  Chalmers called the
``easy'' problem. 

But there are  also deeper  questions. What  are the  principles and mechanisms
that determine the  set of possible  experiences? Since  this set must be large
and varied there must be some process that determines them. From a naturalistic
perspective   this  process  must be a   natural  process.  However,  the basic
equations of  quantum theory, namely  the Schroedinger  equation, and equations
  (1)    and    (4),  do not   immediately  shed  much light  on  this deeper
question. 

This   difficulty  emphasizes  the  fact that  quantum  theory  is  basically a
pragmatic  theory (Stapp,  1972): it  is a way of  making  progress toward some
practically  useful   understanding of  nature without  knowing  how everything
really works at the fundamental level. This is perhaps a humbling admission for
science. But the fact is  that we still have a long  way to go. The creators of
quantum theory did  provide us, however, with a  rational theoretical framework
that allows progress to made. 

                    Acknowledgements

I  thank  Pat  Hayes  and  Aaron   Sloman  for  helpful   email  dialogs  about
functionalism, and W. Swiatecki for useful comments.

                      References

Bohm, D. (1952). A suggested interprtation of quantum theory in terms of 
  ``hidden'' variables, I and II. {\it Physical Review 85}, 166-193.

Bohm, D. and Hiley, B. (1993). {\it The Undivided Universe}. London: Rutledge.

Bohr, N. (1934). {\it Atomic Theory and the Description of Nature}. Cambridge:
  Cambridge University Press.
 
Bohr, N. (1958). {\it Atomic Physics and Human Knowledge}. New York: Wiley.

Churchland, Patricia S. (1989). {\it Neurobiology: Toward a Unified Science of 
   the Mind-Brain}.  Cambridge MA: MIT Press.

Einstein, A. (1952). In  P.A. Schilpp (Ed.), {\it Albert Einstein: 
   Philosopher-Scientist} (pp.667-673). New York: Tudor.

Everett, Hugh, III. (1957). Relative state interpretation of quantum mechanics.
{\it Reviews of Modern Physics 29}, 463-62.

Feynman, R.P., Leighton, R.B., and Sands, M. (1965.) {\it The Feynman Lectures 
   in Physics.} ( Vol. III, Chapter 21). New York: Addison-Wesley.

Gell-Mann, M and Hartle, James B. (1991). {\it Classical Equations for Quantum 
   Systems} UCSBTH-91-15

Ghirardi, G.C., Rimini, A. and Weber, T. (1986). Unified dynamics for
   microscopic and macroscopic system. {\it Physical Review. D 34}, 470-491.

Heisenberg, W. (1958a). The representation of reality in contemporary physics.
   {\it Daedelus, 87(3)}, 95-108. 

Heisenberg, W. (1958b). {\it Physics and  Philosophy}. New York: Harper Row. 
    Chapter III.

Joos, E. (1986). Quantum theory and the appearance of a classical world. In
   Daniel M. Greenberger (Ed.), {\it New Techniques and Ideas 
   in  Quantum Measurement Theory, Annals of the New York Academy of 
   Science, 480}. ( p.12). New York: New York Academy of Science.

Mermin, N.D. (1994). Quantum mysteries refined. {\it American Journal of
   Physics, 62}, 880-887.  

Omnes, R. (1994). {\it The Interpretation of Quantum Theory}.  (p.348). 
   Princeton NJ: Princeton University Press.

Pearle, P. (1989). Combining stochastic dynamical state-vector reduction
with spontaneous localization. {\it Physical Review A 39,} 2277-2289

Pearle, P. (1996). Relativistic collapse model with tachyonic features.
   {\it Hamilton College Physics Preprint}

Pearle, P., and Squires, E. (1995). Bound state excitation, nucleon decay
experiments, and models for wave function collapse. {\it Physical Review
Letters 73,} 1-5

Collett, B., Pearle, P., Avignone, F., and Nussinov, S. (1995). 
  Constraint on collapse model by limit on spontaneous X-ray emmision in Ge.
  {\it Foundations of Physics 25,} 1399-1412

Stapp, H.P. (1972). The Copenhagen interpretation. {\it American Journal of
Physics 40,} 1098-1116.

Stapp, H.P. (1993). {\it Mind, Matter, and Quantum Mechanics}.
   Heidelberg, Berlin, New York, London, Paris and Tokyo:  Springer-Verlag.

Sutherland, K. (Ed.) (1995). Conversations with zombies. {\it Journal of 
Consciousness Studies 2(4),} 312-72.

von Neumann, N. (1932). {\it Mathematical Foundations of Quantum Mechanics.} 
    (Ch. VI).(English Transl. 1955) Princeton NJ: Princeton University Press.

Wigner, E. (1967). Remarks on the mind-body problem. {\it Symmetries and Reflections} 
   Indiana University Press, Bloomington. 171-184.

Zurek, W.H. (1986). Reduction of the wave packet and environment-induced 
   superselection. In  Daniel M. Greenberger (Ed.), {\it New Techniques and 
   Ideas in  Quantum Measurement Theory, Annals of the New York Academy of 
   Science, 480}, (p.96). New York: New York Academy of Science.

\footnote{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.}

\end{document}