I.  INTRODUCTION

It has been claimed by a number of physicists\[1-9\] that quantum
theory, as contrasted to classical physics, is the theory appropriated
to the study of the connection between the aspects of our scientific
description of nature that are described in the mathematical language of
physics and those that are described in terms of the experiences of
observers. It is well-known \[10\] that quantum theory was born after
the failure of an intensive twenty-year effort to find some space-time
conception of the atom that was compatible with the empirical data
pertaining to spectral lines and the dispersion of light by atoms.
Confronted by the mounting complexities and contradictions, Heisenberg,
stimulated by Pauli's arguments, and by the 1905 success of Einstein's
program of basing physics of observables, focused on the arrays of
observables such as the transition amplitudes of dispersion theory, and
came up with matrix mechanics. Although Schroedinger did come up with
his wave picture, Bohr and his colleagues successfully argued that this
space-time structure could not represent a space-time reality in any
normal sense, and that the manipulations that could be done with it to
give empirical predictions had to be viewed as "a purely symbolic
procedure" (Bohr 1963, p5)

> In fact, wave mechanics, just as the matrix theory, represents on this
> view a symbolic transcription of the problem of motion of classical
> mechanics adapted to the requirements of quantum theory and only to be
> interpreted by an explicit use of the quantum postulate. (Bohr 1934,
> p.75)

But if the space-time aspects of the description of atoms are "purely
symbolic" this raises the logical issue of where the ordinary space-time
description of the measuring device comes from. Orthodox (Copenhagen)
quantum theory evades the need to specify some physical process of
nature that somehow gives "macroscopic" devices a real classical
space-time structure. That would require specifying when something is
"macroscopic", and what the mechanism is that endows macroscopic objects
with real space-time structure, when all space-time aspects of its
component atoms are purely symbolic.

How does orthodox quantum theory evade this problem, and claim itself to
be complete without addressing it?

It evades this problem by first specifying that

> 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 experience. (Bohr 1934,
> p. 18)

What makes a mathematical formalism into a scientific theory is a
specification of how to relate the mathematical symbols to
empirical/experiential data. Recognition that essential aspects of
science are our perceptual experiences, and the communication of the
content of these experiences to our colleagues, makes our conscious
experiences, and our descriptions of them, a basic component of the
scientific theory. This understanding provides the means by which
orthodox quantum mechanics evades the need to specify a physical
mechanism to endow the measuring devices with a classical space-time
description. It is our experiences themselves that supply the space-time
structure that is pertinent to our descriptions of the devices both to
ourselves and our colleagues:

> The decisive point is to recognize that the description of the
> experimental arrangement and the recording of the observations must be
> given in plain language, suitably defined by the usual terminology.
> This is a simple logical demand, since by the word "experiment" we can
> only mean a procedure regarding which w are able to communicate to
> others what we have done and what we have learnt. (Bohr 1963, p.3)
>
> .Strictly speaking, the mathematical formalism of quantum mechanics
> and electromagnetism merely offers rules of calculation for the
> deduction of expectations about observations obtained under
> well-defined experimental conditions specified by classical physical
> concepts. (Bohr 1963, p.60)

Thus orthodox quantum mechanics avoids the need to introduce a physical
mechanism for endowing the measuring device with a space-time form by
exploiting the fact that what the scientific endeavor is really about,
in the final analysis, are relationships between the experiences of
observers.

John von Neumann (1955/1932), in his rigorization of orthodox quantum
theory, recognizes this key role of experience:

> First, it is entirely correct that the measurement or the related
> process of the subjective perception is a new entity relative to the
> physical environment and is not reducible to the latter. Indeed,
> subjective perception leads us into the intellectual inner life of the
> individual....(p. 418)
>
> the boundary (between the observer and the system he is observing)
> must be put somewhere, if the method is not to proceed vacuously,
> i.e., if a comparison with experiment is to be possible. Indeed,
> experience only makes statements of this type: an observer has made a
> certain (subjective) observation; and never any like this: a physical
> quantity has a certain value"(p. 420).

Von Neumann formalizes this assertion by considering a number of
different placements, where the part III is "the observer". In the final
placement, the part of the world *not* in III is the entire physically
described world including, in particular, the entire brain of the
observer. In this case, von Neumann calls part III the observer's
"abstract ego". This is what is left of the observer after all of his
physical parts have been taken away. What is left is the part that is
the essential element of both science in general and quantum mechanics
in particular, namely the subjective experiences of the scientists who
set up the experiments and witness and record and communicate to others
what they have done and what they have learned.

Orthodox quantum mechanics is forthrightly about our conscious
experiences, whereas classical mechanics purports to be about some
mechanical space-time reality that orthodox quantum theory claims does
not really exist in the sense that classical mechanics presumes that it
exists.

At this point the theory might appear too abstract to be of much use.
But that is not the case. Let us accept the idea, developed by von
Neumann, of representing the quantum state by what is called *the
density matrix.* Heisenberg (1958 Ch. 3) proposed that the functional
meaning of the quantum state be understood in terms of the Aristotelian
idea of "potentia", which is an "objective tendency". In the quantum
case this tendency becomes a tendency for the occurrence of a "collapse
event". In orthodox quantum theory a collapse event occurs in
conjunction with an "experience", and it reduces the quantum state of
the observed system to the part of itself that is compatible with the
increase in knowledge associated with the experience. Using the final
location (described above) of von Neumann's boundary gives a relatively
simple conceptual connection between the quantum mechanically described
brain of an observer and his (subjective) experience. This will be
illustrated below.

The description given above is essentially a précis of the rationale, as
developed in (6), behind the idea of using orthodox quantum mechanics as
the foundation of a physics-based approach to the connection between
mind and brain.

REFERENCES

6.  \+ (2007a) *Mindful Universe: Quantum Mechanics and the
    Participating Observer*, Springer, Berlin, Heidelberg, New York

> +(2007b) Whitehead, James, and Quantum Theory, *Mind and Matter*

Volume 5(1) 83-109..

10\. Mehra, J & Rechenberg, H: The Historical Development of Quantum
Mechanics, Volume 2. Chapters III, IV, & V.

Bohr, N. (1934) Atomic Theory and the Description of Nature, Cambridge
UP

Bohr, N. (1963) Essays 1958-1962 on Atomic Physics and Human Knowledge

Wiley, New York

Heisenberg, W. (1958) Physics and Philosophy, Harper, New York