what von Neumann calls his ‘abstract ego’.

what von Neumann calls his ‘abstract ego’.

http://www-physics.lbl.gov/~stapp/PTRS.pdf

Review

Quantum physics in neuroscience and psychology:

a neurophysical model of mind–brain interaction

Jeffrey M. Schwartz

1, Henry P. Stapp2 and Mario Beauregard3,4,5,*

1

UCLA Neuropsychiatric Institute, 760 Westwood Plaza, NPI Los Angeles, CA 90024-1759, USA

2

Theoretical Physics Mailstop 5104/50A Lawrence Berkeley National Laboratory, University of California,

Berkeley, CA 94720-8162, USA

3

De´partement de Psychologie, Centre de Recherche en Neuropsychologie Expe´rimentale et Cognition

(CERNEC),

4De´partement de Radiologie, and 5Centre de Recherche en Sciences Neurologiques (CRSN),

Universite´ de Montre´al, C.P. 6128, succursale Centre-ille, Montre´al, Que´bec H3C 3J7, Canada

Neuropsychological research on the neural basis of behaviour generally posits that brain mechanisms

will ultimately suffice to explain all psychologically described phenomena. This assumption stems

from the idea that the brain is made up entirely of material particles and fields, and that all causal

mechanisms relevant to neuroscience can therefore be formulated solely in terms of properties of

these elements. Thus, terms having intrinsic mentalistic and/or experiential content (e.g. ‘feeling’,

‘knowing’ and ‘effort’) are not included as primary causal factors. This theoretical restriction is

motivated primarily by ideas about the natural world that have been known to be fundamentally

incorrect for more than three-quarters of a century. Contemporary basic physical theory differs

profoundly from classic physics on the important matter of how the consciousness of human agents

enters into the structure of empirical phenomena. The new principles contradict the older idea that

local mechanical processes alone can account for the structure of all observed empirical data.

Contemporary physical theory brings directly and irreducibly into the overall causal structure certain

psychologically described choices made by human agents about how they will act. This key

development in basic physical theory is applicable to neuroscience, and it provides neuroscientists

and psychologists with an alternative conceptual framework for describing neural processes. Indeed,

owing to certain structural features of ion channels critical to synaptic function, contemporary

physical theory must in principle be used when analysing human brain dynamics. The new

framework, unlike its classic-physics-based predecessor, is erected directly upon, and is compatible

with, the prevailing principles of physics. It is able to represent more adequately than classic concepts

the neuroplastic mechanisms relevant to the growing number of empirical studies of the capacity of

directed attention and mental effort to systematically alter brain function.

Keywords:

mind; consciousness; brain; neuroscience; neuropsychology; quantum mechanics

The only acceptable point of view appears to be the one

that recognizes

both sides of reality—the quantitative

and the qualitative, the physical and the psychical—as

compatible with each other, and can embrace them

simultaneously.

(

Pauli 1955, p. 208)

1. INTRODUCTION

The introduction into neuroscience and neuropsychology

of the extensive use of functional brain

imaging technology has revealed, at the empirical

level, an important causal role of directed attention in

cerebral functioning. The identification of brain areas

involved in a wide variety of information processing

functions concerning learning, memory and various

kinds of symbol manipulation has been the subject of

extensive and intensive investigation (see

Toga &

Mazziotta 2000

). Neuroscientists consequently now

have a reasonably good working knowledge of the role

of a variety of brain areas in the processing of

complex information. But, valuable as these empirical

studies are, they provide only the data for, not the

answer to, the critical question of the causal

relationship between the aspects of empirical studies

that are described in psychological terms and those

that are described in neurophysiological terms. In

most of the cases, investigators simply assume that

measurable-in-principle properties of the brain are

the only factors needed to explain eventually the

processing of the psychologically described information

that occurs in neuropsychological experiments.

This privileging of physically describable

brain mechanisms as the core, and indeed final,

explanatory vehicle for the processing of every kind of

psychologically described data, is the foundational

assumption of almost all contemporary biologically

based cognitive neuroscience.

Phil. Trans. R. Soc. B

doi:10.1098/rstb.2004.1598

Published online

*

Author for correspondence (mario.beauregard@umontreal.ca).

Received

2 June 2004

Accepted

19 October 2004

1

q 2005 The Royal Society

It is becoming increasingly clear, however, that there

is at least one type of information processing and

manipulation that does not readily lend itself to

explanations that assume that all final causes are

subsumed within brain, or more generally, central

nervous system mechanisms. The cases in question are

those in which the conscious act of wilfully altering the

mode by which experiential information is processed

itself changes, in systematic ways, the cerebral mechanisms

used. There is a growing recognition of the

theoretical importance of applying experimental paradigms

that use directed mental effort to produce

systematic and predictable changes in brain function

(e.g.

Beauregard et al. 2001; Ochsner et al. 2002).

These wilfully induced brain changes are generally

accomplished through training in, and the applied use

of, cognitive reattribution and the attentional recontextualization

of conscious experience. Furthermore,

an accelerating number of studies in the

neuroimaging literature significantly support the thesis

that, again, with appropriate training and effort, people

can systematically alter neural circuitry associated with

a variety of mental and physical states that are frankly

pathological (

Schwartz et al. 1996; Schwartz 1998;

Musso

et al. 1999; Paquette et al. 2003). A recent

review of this and the related neurological literature has

coined the term ‘self-directed neuroplasticity’ to serve

as a general description of the principle that focused

training and effort can systematically alter cerebral

function in a predictable and potentially therapeutic

manner (

Schwartz & Begley 2002).

From a theoretical perspective, perhaps the most

important aspect of this line of research is the empirical

support it provides for a new science-based way of

conceptualizing the interface between mind/consciousness

and brain. Until recently, virtually all attempts to

understand the functional activity of the brain have

been based, at least implicitly, on some principles of

classic physics that have been known to be fundamentally

false for three-quarters of a century. According to

the classic conception of the world, all causal connections

between observables are explainable in terms of

mechanical interactions between material realities. But

this restriction on modes of causation is not fully

maintained by the currently applied principles of

physics, which consequently offer an alternative conceptual

foundation for the scientific description and

modelling of the causal structure of self-directed

neuroplasticity.

The advantages for neuroscience and neuropsychology

of using the conceptual framework of

contemporary

physics, as opposed to that of classic

physics, stem from five basic facts. First, terms such

as ‘feeling’, ‘knowing’ and ‘effort’, because they are

intrinsically mentalistic and experiential, cannot be

described exclusively in terms of material structure.

Second, to explain the observable properties of large

physical systems that depend sensitively upon the

behaviours of their atomic constituents, the founders

of contemporary physical theory were led to introduce

explicitly into

the basic causal structure of physics certain

important choices made by human beings about how

they will act. Third, within this altered conceptual

framework these choices are described in mentalistic

(i.e. psychological) language. Fourth, terminology of

precisely this kind is critically necessary for the design

and execution of the experiments in which the data

demonstrating the core phenomena of self-directed

neuroplasticity are acquired and described. Fifth, the

injection of psychologically described choices on the

part of human agents into the causal theoretical

structure can be achieved for experiments in neuroscience

by applying the same mathematical rules that

were developed to account for the structure of

phenomena in the realm of atomic science.

The consequence of these facts is that twentieth

century physics, in contrast to classic physics, provides a

rationally coherent pragmatic framework in which the

psychologically and neurophysiologically described

aspects of the neuroscience experiments mentioned

above are causally related to each other in mathematically

specified ways. Thus, contemporary physics

allows the data from the rapidly emerging field of selfdirected

neuroplasticity to be described and understood

in a way that is more rationally coherent, scientific and

useful than what is permitted by theories in which all

causation is required to be fundamentally mechanical.

To explicate the physics of the interface between

mind/consciousness and the physical brain, we shall in

this article describe in detail how the quantum

mechanically based causal mechanisms work, and

show why it is necessary in principle to advance to

the quantum level to achieve an adequate theory of the

neurophysiology of volitionally directed activity. The

reason, essentially, is that classic physics is an approximation

to the more accurate quantum theory, and that

this classic approximation

eliminates the causal efficacy of

our conscious efforts

that these experiments empirically

manifest.

We shall also explain how certain structural features

of ion conductance channels critical to synaptic

function

entail that the classic approximation fails in

principle to cover the dynamics of a human brain.

Quantum dynamics

must be used in principle. Furthermore,

once the transition to the quantum description is

made, the principles of quantum theory must, in order

to maintain rational consistency and coherency, be

used to link the quantum physical description of the

subject’s brain to their stream of conscious experiences.

The conscious choices by human agents thereby

become injected non-trivially into the causal interpretation

of neuroscience and neuropsychology experiments.

This caveat particularly applies to those

experimental paradigms in which human subjects are

required to perform decision-making or attentionfocusing

tasks that require conscious effort.

2. PRACTICAL RAMIFICATIONS OF THE

ALTERED CONCEPT OF THE CAUSAL

STRUCTURE OF SELF-DIRECTED

NEUROPLASTICITY

Clarity is required about the sorts of neuroscientific

reasoning that remain coherent, given the structure of

modern physics and, contrastingly, the types of assertion

that can now be viewed as the residue of a

materialistic bias stemming from superseded physics.

Entirely acceptable are

correlational analyses about the

2 J.M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

relationship between mentalistic data and neurophysiological

mechanisms. Examining the qualitative and

quantitative aspects of brain function, and doing

detailed analyses of how they relate to the data of experience,

obtained through increasingly sophisticated

means of psychological investigation and subject selfreport

analysis (e.g. the entire September–October

2003 issue of

Journal of Consciousness Studies, volume

10, number 9–10, is dedicated to these questions), are

completely in line with fundamental physics. These

activities are the core of neuropsychological science.

What is not justified is the presumption, either tacit or

explicit, that

all aspects of experience examined and

reported are necessarily causal consequences solely of

brain mechanisms. The structure of contemporary

physics entails no such conclusion. This is particularly

relevant to data from first-person reports about active,

wilfully directed attentional focus, and especially to data

pertaining to which aspects of the stream of conscious

awareness a subject chooses to focus on when making

self-directed efforts to modify and/or modulate the

quality and beam of attention. In such cases, the

structure of orthodox quantum physics implies that

the investigator is not justified in assuming that the focus

of attention is determined wholly by brain mechanisms

that are in principle completely well-defined and

mechanically determined. Conscious effort itself can,

justifiably within science, be taken to be a primary

variable whose complete causal origins may be

untraceable

in principle

, but whose causal efficacy in the physical

world can be explained on the basis of the laws of

physics.

As already emphasized, the cognitive frame in which

neuroscience research, including research on cerebral

aspects of behaviour, is generally conducted contains

within it the assumption that brain mechanisms are in

principle fully sufficient to explain all of the observed

phenomena. In the fields of functional neuroimaging,

this has led to experimental paradigms that focus

primarily on changes in brain activation as primary

variables used to explain whatever behavioural changes

are observed—including ones understood as involving

essentially cognitive and emotional responses. As long

as one is investigating phenomena that are mostly

passive in nature this may be fully justified. A person is

shown a picture depicting an emotionally or perhaps a

sexually arousing scene. The relevant limbic and/or

diencephalic structures are activated. The investigator

generally concludes that the observed brain activation

has some intrinsic causal role in the emotional changes

reported (or, perhaps, the hormonal correlates of those

changes).

This method is all well and good, as far as it goes. In

addition, from the experimental subject’s perspective, it

is all quite passive—all that is really required on his or her

part is to remain reasonably awake and alert or, more

precisely, at least somewhat responsive to sensory

inputs. But when, as happens in a growing number of

studies, the subject makes an active response aimed at

systematically

altering the nature of the emotional

reaction—for example, by actively performing a cognitive

reattribution—then the demand that the data be

understood solely from the perspective of brain-based

causal mechanism is a severe and counter-intuitive

constraint. It is noteworthy that this demand for an

entirely brain-based causal mechanism is nullified, in

the quantum model developed here, by a specified

quantum effect, which will be described in detail below.

Surmounting the limitations imposed by restricting

one’s ideas to the failed concepts of classic physics

can be especially important when one is investigating

how to develop improved methods for altering the

emotional and cerebral responses to significantly

stressful external or internally generated stimuli. An

incorrect assignment of the causal roles of neurophysiologically

and mentalistically described variables can

impact negatively on a therapist’s selection of a course

of treatment, on a patient’s capacity to recover, and on

a neuroscientist’s design of clinically relevant research

programmes.

In the analysis and development of clinical practices

involving psychological treatments and their biological

effects, the possession and use of a rationally coherent

and physically allowable conception of the causal

relationship between mind and brain (or, if one prefers,

mentalistic and neurophysiological variables) is critical.

If one simply accepts the standard presumption that all

aspects of emotional response are passively determined

by neurobiological mechanisms, then the theoretical

development of genuinely effective self-directed

psychological strategies that produce real neurobiological

changes can be impeded by the fact that one is

using a theory that excludes from the dynamics what

logically can be, and in our model actually are, key

causal elements, namely our wilful choices.

The clinician’s attention is thus directed away from

what can be in many cases, at the level of actual

practice, a powerful determinant of action, namely the

subject’s psychologically (i.e. mentalistically) framed

commitment to act or think in specific ways. The

therapist tends to becomes locked into the view that the

psychological

treatment of ailments caused by neurobiological

impairments

is not a realistic goal.

There is already a wealth of data arguing against this

view. For instance, work in the 1990s on patients with

obsessive compulsive disorder demonstrated significant

changes in caudate nucleus metabolism and the

functional relationships of the orbitofrontal cortex–

striatum–thalamus circuitry in patients who responded

to a psychological treatment using cognitive reframing

and attentional refocusing as key aspects of the

therapeutic intervention (for review, see

Schwartz &

Begley 2002

). More recently, work by Beauregard and

colleagues (

Paquette et al. 2003) has demonstrated

systematic changes in the dorsolateral prefrontal cortex

and parahippocampal gyrus after cognitive-behavioural

therapy for phobia of spiders, with brain changes significantly

related to both objective measurements and

subjective reports of fear and aversion. There are now

numerous reports on the effects of self-directed

regulation of emotional response, via cognitive reframing

and attentional re-contextualization mechanisms,

on cerebral function (e.g.

Schwartz et al. 1996;

Beauregard

et al. 2001; Ochsner et al. 2002; Le´vesque

et al

. 2003; Paquette et al. 2003;).

The brain area generally activated in all the studies

done so far on the self-directed regulation of emotional

response is the prefrontal cortex, a cortical region also

Model of mind–brain interaction

J. M. Schwartz and others 3

Phil. Trans. R. Soc. B

activated in studies of cerebral correlates of wilful

mental activity, particularly those investigating selfinitiated

action and the act of attending to one’s own

actions (

Spence & Frith 1999; Schwartz & Begley

2002

). There is, however, one aspect of wilful mental

activity that seems particularly critical to emotional

self-regulation, and that seems to be the critical factor

in its effective application—the factor of focused

dispassionate self-observation that, in a rapidly growing

number of clinical psychology studies, has come to be

called ‘mindfulness’ or ‘mindful awareness’ (

Segal et al.

2002

).

The mental act of clear-minded introspection and

observation, variously known as mindfulness, mindful

awareness, bare attention, the impartial spectator, etc.,

is a well-described psychological phenomenon with a

long and distinguished history in the description of

human mental states (

Nyanaponika 2000). The most

systematic and extensive exposition is in the canonical

texts of classic Buddhism preserved in the Pali language,

a dialect of Sanskrit. Because of the critical importance

of this type of close attentiveness in the practice of

Buddhist meditation, some of its most refined descriptions

in English are in texts concerned with meditative

practice (although it is of critical importance to realize

that the mindful mental state does not require any

specific meditative practice to acquire, and is

certainly

not

in any sense a ‘trance-like’ state).

One particularly well-established description, using

the name ‘bare attention’, is as follows:

Bare Attention is the clear and single-minded awareness

of what actually happens

to us and in us at the

successive moments of perception. It is called ‘Bare’

because it attends just to the bare facts of a perception

as presented either through the five physical senses or

through the mind

.without reacting to them.

(

Nyanaponika 1973, p. 30)

Perhaps the essential characteristic of mindful

observation is that you are just watching, observing

all facts, both inner and outer, very calmly, clearly and

closely. To sustain this attentional perspective over

time, especially during stressful events, invariably

requires the conscious application of effort.

A working hypothesis for ongoing investigation in

human neurophysiology, based on a significant body of

preliminary data, is that the mental action of mindful

awareness specifically modulates the activity of the

prefrontal cortex. Because of the well-established role

of this cortical area in the planning and wilful selection

of self-initiated responses (

Spence & Frith 1999;

Schwartz & Begley 2002

), the capacity of mindful

awareness, and by implication all emotional selfregulating

strategies, to specifically modulate activity

in this critical brain region has tremendous implications

for the fields of mental health and related areas.

It might be claimed that the designs and executions

of successful clinical practices (and of informative

neuropsychological experiments) that depend on the

idea of the causal efficacy of conscious effort, and which

fit so well into the quantum conceptualization that

actually explains the causal efficacy of these efforts,

could just as well be carried out within the conceptual

framework in which the causal efficacy of wilful effort is

an illusion, or is something very different from what it

intuitively seems to be. But such a claim is not easy to

defend. Simple models that are consistent with basic

intuition and lead directly to experimentally demonstrable

conclusions are better than philosophically

intricate ones that lead to the same conclusions. Of

course, if it could be argued that the simple model

could not be true because it violates the basic principles

of physics whereas the more intricate one obeys them,

then there might be reasonable grounds for question or

dispute. But in the present case the reverse is true: it is

the simple model that is built on the basic laws of

physics and it is the arcane and philosophically difficult

model, in which our basic human intuition concerning

the efficacy of mental effort is denied as not being what

it seems to be, which contradicts the laws of physics.

The major theoretical issue we address in this article

is the failure of classic models of neurobiological action

to provide a scientifically adequate account for all of the

mechanisms that are operating when human beings use

self-directed strategies for the purpose of modulating

emotional responses and their cerebral correlates.

Specifically, the assumption that all aspects of mental

activity and emotional life are ultimately explicable

solely in terms of micro-local deterministic brain

activity, with no superposed effects of mental effort,

produces a theoretical structure that both fails to meet

practical scientific needs, and also fails to accord with

the causal structure of modern physics.

In the alternative approach the role played by the

mind, when one is observing and modulating one’s own

emotional states, is an intrinsically active and physically

efficacious process in which mental action is affecting

brain activity in a way concordant with the laws of

physics. A culturally relevant way of framing this

change is to say that contemporary physics imbues

the venerable and therapeutically useful term

‘psychodynamic’ with rigorous neurophysical efficacy.

This new theory of the mind–brain connection is

supportive of clinical practice. Belief in the efficacy of

mental effort in emotional self-regulation is needed

to subjectively access the phenomena (e.g. belief in the

efficacy of effort is required to sustain mindfulness

during stressful events). Moreover, a conceptual

framework in which psychologically described efforts

have effects is needed to explain to patients what they

are supposed to do when directing their inner resources

to the challenging task of modifying emotional and

cerebral responses. Clinical success is jeopardized by a

belief on the part of either therapists or patients that

their mental effort is an illusion or a misconception.

It takes effort for people to achieve therapeutic

results. That is because it requires a redirection of the

brain’s resources away from lower level limbic

responses and toward higher level prefrontal functions—

and this does not happen passively. Rather, it

requires, in actual practice, both wilful training and

directed mental effort. It is semantically inconsistent

and clinically counterproductive to insist that these

kinds of brain changes be viewed as being solely an

intra-cerebral ‘the physical brain changing itself ’ type

of action. That is because practical aspects of the

activity of mind essential to the identification, activation,

application and use of directed mental effort are

4 J.M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

not describable solely in terms of material brain

mechanisms. The core phenomena necessary for the

scientific description of self-directed neuroplasticity are

processes that cannot be elaborated solely in terms of

classic models of physics.

Furthermore, as we will see in detail in the following

sections of this article, orthodox concepts of contemporary

physics are ideally suited to a rational and

practically useful understanding of the action of mindful

self-observation on brain function. Classic models of

physics, which view all action in the physical world as

being ultimately the result of the movements of material

particles, are now seriously out of date, and no longer

need be seen as providing the unique, or the best,

scientifically well-grounded paradigm for investigating

the interface between mind/consciousness and brain.

When people practice self-directed activities for the

purpose of systematically altering patterns of cerebral

activation they are attending to their mental and

emotional

experiences, not merely their limbic or

hypothalamic brain mechanisms. And although no

scientifically oriented person denies that those brain

mechanisms play a critical role in generating those

experiences, precisely what the person is training himor

herself to do is to wilfully

change how those brain

mechanisms operate—and to do that requires attending

to mental experience

per se. It is, in fact, the basic

thesis of self-directed neuroplasticity research that the

way in which a person directs their attention

(e.g. mindfully

or unmindfully) will affect both the experiential

state of the person and the state of his/her brain. The

existence of this close connection between mental effort

and brain activity flows naturally out of the dynamic

principles of contemporary physics, but is, within the

framework of classic physics, a difficult problem that

philosophers of the mind have been intensively engaged

with, particularly for the past 50 years. The core

question is whether the solution to this problem lies

wholly in the eventual development of a more sophisticated

philosophy that is closely aligned with the

classic known-to-be-fundamentally-false conception of

nature, or whether the profound twentieth century

development in physics, that assigns a subtle but

essential causal role to human consciousness, can

usefully inform our understanding of the effects

of human consciousness in neuropsychological experiments

that appear to exhibit the causally efficacious

presence of such effects.

To appreciate the major conceptual changes made in

basic physical theory during the twentieth century, one

must know about certain key features of the older

theory.

3. CLASSIC PHYSICS

Classic physics is a theory of nature that originated with

the work of Isaac Newton in the seventeenth century

and was advanced by the contributions of James Clerk

Maxwell and Albert Einstein. Newton based his theory

on the work of Johannes Kepler, who found that the

planets appeared to move in accordance with a simple

mathematical law, and in ways wholly determined by

their spatial relationships to other objects. Those

motions were apparently

independent of our human

observations of them

.

Newton effectively assumed that all physical objects

were made of tiny miniaturized versions of the planets,

which, like the planets, moved in accordance with

simple mathematical laws, independently of whether

we observed them or not. He found that he could then

explain the motions of the planets and also the motions

of large terrestrial objects and systems, such as cannon

balls, falling apples and the tides, by assuming that

every tiny planet-like particle in the solar system

attracted every other one with a force inversely

proportional to the square of the distance between

them.

This force was an

instantaneous action at a distance: it

acted instantaneously, no matter how far the particles

were apart. This feature troubled Newton. He wrote to

a friend ‘That one body should act upon another

through the vacuum, without the mediation of anything

else, by and through which their action and force may

be conveyed from one to another, is to me so great an

absurdity that I believe no man, who has in philosophical

matters a competent faculty of thinking, can ever

fall into it’ (

Newton 1687, p. 634). Although Newton’s

philosophical persuasion on this point is clear, he

nevertheless formulated his universal law of gravity

without specifying how it was mediated.

Albert Einstein, building on the ideas of Maxwell,

discovered a suitable mediating agent, a distortion of

the structure of space–time itself. Einstein’s contributions

made classic physics into what is called a

local

theory

: there is no action at a distance. All influences are

transmitted essentially by contact interactions between

tiny neighbouring mathematically described ‘entities’,

and no influence propagates faster than the speed of

light.

Classic physics is, moreover,

deterministic: the

interactions are such that the state of the physical

world at any time is completely determined by the state

at any earlier time. Consequently, according to classic

theory, the complete history of the physical world

for all

time

is mechanically fixed by contact interactions

between tiny component parts, together with the initial

condition of the primordial universe.

This result means that, according to classic physics,

you are a mechanical automaton

: your every physical

action was predetermined before you were born solely

by mechanical interactions between tiny mindless

entities. Your mental aspects are

causally redundant:

everything you do is completely determined by

mechanical conditions alone, without any mention of

your thoughts, ideas, feelings or intentions. Your

intuitive feeling that your conscious intentions make a

difference in what you do is, according to the principles

of classic physics, a false and misleading illusion.

There are two possible ways within classic physics to

understand this total incapacity of your mental side

(i.e. your stream of conscious thoughts and feelings) to

make any difference in what you do. The first way is to

consider your thoughts, ideas and feelings to be

epiphenomenal by-products of the activity of your

brain. Your mental side is then a causally impotent

sideshow that

is produced, or caused, by your brain, but

that

produces no reciprocal action back upon your brain.

Model of mind–brain interaction

J. M. Schwartz and others 5

Phil. Trans. R. Soc. B

The second way is to contend that each of your

conscious experiences—each of your thoughts, ideas,

or feelings—is the

very same thing as some pattern of

motion of various tiny parts of your brain.

4. PROBLEMS WITH CLASSIC PHYSICS

William James (

1890, p. 138) argued against the first

possibility, epiphenomenal consciousness, by claiming

that ‘

The particulars of the distribution of consciousness, so

far as we know them,

points to its being efficacious.’ He

noted that consciousness seems to be ‘an organ,

superadded to the other organs which maintain the

animal in its struggle for existence; and the presumption

of course is that it helps him in some way in this

struggle, just as they do. But it cannot help him without

being in some way efficacious and influencing the

course of his bodily history.’ James said that the study

described in his book ‘will show us that consciousness is

at all times primarily a

selecting agency.’ It is present

when choices must be made between different possible

courses of action. He further mentioned that ‘It is to

my mind quite inconceivable that consciousness should

have

nothing to do with a business to which it so

faithfully attends’ (1890, p. 136).

If mental processes and consciousness have no effect

upon the physical world, then what keeps a person’s

mentalworld aligned with their physical situation?What

keeps their pleasures in general alignment with actions

that benefit them, and pains in general correspondence

with things that damage them, if felt pleasures and pains

have no effect at all upon their actions?

These liabilities of the notion of epiphenomenal

mind and consciousness lead many thinkers to turn to

the alternative possibility that a person’s mind and

stream of consciousness is

the very same thing as some

activity in their brain: mind and consciousness are

‘emergent properties’ of brains.

A huge philosophical literature has developed

arguing for and against this idea. The primary

argument against this ‘emergent-identity theory’ position,

within a classic physics framework

, is that in classic

physics the full description of nature is in terms of

numbers assigned to tiny space–time regions, and there

appears to be no way to understand or explain how to

get from such a restricted conceptual structure, which

involves such a small part of the world of experience, to

the whole. How and why should that extremely limited

conceptual structure (which arose basically from

idealizing, by miniaturization, certain features of

observed planetary motions) suffice to explain the

totality of experience, with its pains, sorrows, hopes,

colours, smells and moral judgements? Why,

given the

known failure of classic physics at the fundamental level

,

should that richly endowed whole be explainable in

terms of such a narrowly restricted part?

The core ideas of the arguments in favour of an

identity-emergent theory of mind and consciousness

are illustrated by

Roger Sperry’s (1992) example of a

‘wheel’. A wheel obviously does something: it is

causally efficacious; it carries the cart. It is also an

emergent property

: there is no mention of ‘wheelness’ in

the formulation of the laws of physics and ‘wheelness’

did not exist in the early universe; ‘wheelness’

emerges

only under certain special conditions. And the macroscopic

wheel exercises ‘top-down’ control of its tiny

parts. All these properties are perfectly in line with

classic physics, and with the idea that ‘a wheel is,

precisely, a structure constructed out of its tiny atomic

parts’. So why not suppose mind and consciousness to

be, like ‘wheelness’, emergent properties of their

classically conceived tiny physical parts?

The reason that mind and consciousness are not

analogous to ‘wheelness’, within the context of classic

physics, is that the properties that characterize

‘wheelness’ are properties that are

entailed, within the

conceptual framework of classic physics, by properties

specified in classic physics, whereas the properties that

characterize conscious mental processes, namely the

various ways these processes feel, are not

entailed within

the conceptual structure provided by classic physics,

but by the properties specified by classic physics.

That is the huge difference-in-principle that distinguishes

mind and consciousness from things that,

according to classic physics, are constructible out of the

particles that are postulated to exist by classic physics.

Given the state of motion of each of the tiny physical

parts of a wheel, as it is conceived of in classic physics,

the properties that characterize the wheel (e.g. its

roundness, radius, centre point, rate of rotation, etc.)

are specified within the conceptual framework provided

by the principles of classic physics, which specify only

geometric-type properties such as changing locations

and shapes of conglomerations of particles and

numbers assigned to points in space. But given the

state of motion of each tiny part of the brain, as it is

conceived of in classic physics, the properties that

characterize the stream of consciousness (the painfulness

of the pain, the feeling of the anguish, or of the

sorrow, or of the joy) are not specified, within the

conceptual framework provided by the principles of

classic physics. Thus it is possible, within that classic

physics framework, to strip away those feelings without

disturbing the physical descriptions of the motions of

the tiny parts. One can, within the conceptual framework

of classic physics, take away the consciousness

while leaving intact the properties that enter into that

theoretical construct, namely the locations and

motions of the tiny physical parts of the brain and its

physical environment. But one cannot, within the

conceptual framework provided by classic physics,

take away the physical characteristics that define the

‘wheelness’ of a wheel without affecting the locations

and motions of the tiny physical parts of the wheel.

Because one can, within the conceptual framework

provided by classic physics, strip away mind and

consciousness without affecting the physical behaviour,

one cannot rationally claim,

within that framework, that

mind and consciousness are the

causes of the physical

behaviour, or are

causally efficacious in the physical

world. Thus the ‘identity theory’ or ‘emergent property’

strategy fails in its attempt to make mind and

consciousness efficacious, insofar as one remains

strictly within the conceptual framework provided by

classic physics.Moreover, the whole endeavour to base

brain theory on classic physics is undermined by the

fact that classic theory is unable to account for

behavioural properties (such as electrical and thermal

6 J.M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

conductivity, and elasticity, etc.) that depend sensitively

upon the behaviour of the atomic, molecular and

ionic constituents of a system, and brains are certainly

systems of this kind, as will be discussed in detail later.

Although classic physics is unable to account for

observable properties that depend sensitively on the

behaviours of atoms, molecules and ions, the classic

theory is an approximation to a more accurate theory,

called quantum theory, which

is able to account for

these observable macroscopic properties. But if classic

physics is unable to account for the moderately

complex behavioural properties of most other large

systems, then how can it be expected to account for the

exquisitely complex behavioural properties of thinking

brains?

5. THE QUANTUM APPROACH

Early in the twentieth century scientists discovered

empirically that the principles of classic physics could

not be correct. Moreover, those principles were wrong

in ways that no minor tinkering could ever fix. The

basic

principles

of classic physics were thus replaced by new

basic principles

that account uniformly for all the

successes of the older classic theory and for all the

data that are incompatible with the classic principles.

The key philosophical and scientific achievement of

the founders of quantum theory was to forge a

rationally coherent and practicable linkage between

the two kinds of description that jointly comprise the

foundation of science. Descriptions of the first kind are

accounts of psychologically experienced empirical

findings, expressed in a language that allows us to

communicate to our colleagues what we have done and

what we have learned. Descriptions of the second kind

are specifications of physical properties, which are

expressed by assigning mathematical properties to

space–time points and formulating laws that determine

how these properties evolve over the course of time.

Bohr, Heisenberg, Pauli and the other inventors of

quantum theory discovered a useful way to connect

these two kinds of description by causal laws. Their

seminal discovery was extended by John von Neumann

from the domain of atomic science to the realm of

neuroscience and, in particular, to the problem of

understanding and describing the causal connections

between the minds and the brains of human beings.

In order to achieve this result, the whole

concept of

what science is

was turned inside out. The core idea of

classic physics was to describe the ‘world out there’,

with no reference to ‘our thoughts in here’. But the core

idea of quantum mechanics is to describe both

our

activities as knowledge-seeking and knowledge-acquiring

agents

, and the knowledge that we thereby acquire. Thus,

quantum theory involves, essentially, what is ‘in here’,

not just what is ‘out there’.

This philosophical shift arises from the

explicit

recognition by quantum physicists that science is

about

what we can know. It is fine to have a beautiful

and elegant mathematical theory about a

really existing

physical world out there

that meets various intellectually

satisfying criteria. But the essential demand of

science is

that the theoretical constructs be tied to the experiences

of the human scientists who devise ways of testing

the theory and of the human engineers and technicians

who both participate in these tests and eventually put

the theory to work. Thus, the structure of a proper

physical theory must involve not only the part describing

the behaviour of the not-directly experienced

theoretically postulated entities, expressed in some

appropriate symbolic language, but also a part describing

the human experiences that are pertinent to these

tests and applications, expressed in the language that

we actually use to describe such experiences to

ourselves and to each other. And the theory must

specify the connection between these two differently

described and differently conceived parts of scientific

practice.

Classic physics meets this final requirement in a

trivial way. The relevant experiences of the human

participants are taken to be direct apprehensions of the

gross properties of large objects composed of huge

numbers of their tiny atomic-scale parts. These

apprehensions (of, for example, the perceived location

and motion of a falling apple or the position of a

pointer on ameasuring device) were taken to be

passive:

they had no effect on the behaviours of the systems

being studied. But the physicists who were examining

the behaviours of systems that depend sensitively upon

the behaviours of their tiny atomic-scale components

found themselves forced to introduce a less trivial

theoretical arrangement. In the new scheme the human

agents are no longer passive observers. They are

considered to be

active agents or participants.

The participation of the agent continues to be

important

even when the only features of the physically

described world being observed are large-scale properties of

measuring devices

. The sensitivity of the behaviour of the

devices to the behaviour of some tiny atomic-scale

particles propagates first to the devices and then to

the observers in such a way that the choice made by an

observer about what sort of knowledge to seek can

profoundly affect the knowledge that can ever be

received either by that observer himself or by any other

observer with whom he can communicate. Thus the

choice

made by the observer about how he or she will act

at a macroscopic level has, at the practical level, a

profound effect on the physical systembeing acted upon.

That conclusion is not surprising. How one acts on a

system would, in general, be

expected to affect it. Nor is

it shocking that the effect of the agent’s actions upon

the system being probed is specified by the quantum

mechanical rules. But the essential point not to be

overlooked is that the logical structure of the basic

physical theory has become fundamentally transformed.

The agent’s choice about how to act has

been introduced into the scientific description at a basic

level and in a way that specifies, mathematically, how

his or her choice about how to act affects the physical

system being acted upon.

The structure of quantum mechanics is such that,

although the effect upon the observed system of the

agent’s choice about how to act is mathematically

specified, the manner in which this choice itself is

determined is not specified. This means that, in the

treatment of experimental data, the choices made by

human agents must be treated as freely chosen input

variables, rather than as mechanical consequences of

Model of mind–brain interaction

J. M. Schwartz and others 7

Phil. Trans. R. Soc. B

any known laws of nature. Quantum theory thereby

converts science’s concept of us from that of a

mechanical automaton, whose conscious choices are

mere cogs in a gigantic mechanical machine, to that of

agents whose conscious free choices affect the physically

described world in a way specified by the theory.

The approximation that reduces quantum theory to

classic physics completely eliminates the important

element of conscious free choice. Hence, from a physics

point of view, trying to understand the connection

between mind/consciousness and brain by going to the

classic approximation is absurd: it amounts to trying to

understand something in an approximation that

eliminates the effect we are trying to study.

This original formulation of quantum theory was

created primarily at an institute in Copenhagen

directed by Niels Bohr and is called ‘the Copenhagen

interpretation’. Owing to the strangeness of the properties

of nature entailed by the new mathematics, the

Copenhagen strategy was to refrain from making any

ordinary sort of ontological claims, but instead to take

an essentially pragmatic stance. Thus, the theory was

formulated

basically as a set of practical rules for how

scientists should go about the tasks of acquiring,

manipulating and using knowledge. Claims about

‘what the world out there is really like’ were considered

to lie beyond

science.

This change in perspective is captured by Heisenberg’s

famous statement:

The conception of the objective reality of the elementary

particles has thus evaporated not into the cloud

of some obscure new reality concept, but into

the transparent clarity of a mathematics that represents

no longer the behavior of the particle but rather our

knowledge of this behavior.

(

Heisenberg 1958, p. 100).

A closely connected change is encapsulated in Niels

Bohr’s dictum that ‘in the great drama of existence we

ourselves are both actors and spectators’ (

Bohr 1963,

p. 15;

1958, p. 81). The emphasis here is on ‘actors’: in

classic physics we were mere spectators. The key idea is

more concretely expressed in statements such as:

The freedom of experimentation, presupposed in

classic physics, is of course retained and corresponds

to the free choice of experimental arrangement for

which the mathematical structure of the quantum

mechanical formalism offers the appropriate latitude.

(

Bohr 1958, p. 73)

Copenhagen quantum theory is about how the

choices made by conscious human agents affect the

knowledge they can and do acquire about the physically

described systems upon which these agents act. In

order to achieve this re-conceptualization of physics the

Copenhagen formulation separates the physical universe

into two parts, which are described in two

different languages. One part is the observing human

agent plus itsmeasuring devices. This extended ‘agent’,

which includes the devices, is described in mental

terms—in terms of our instructions to colleagues about

how to set up the devices and our reports of what we

then ‘see’, or otherwise consciously experience. The

other part of nature is

the system that the agent is acting

upon

. That part is described in physical terms—in

terms of mathematical properties assigned to tiny

space–time regions. Thus, Copenhagen quantum

theory brings ‘doing science’ into science. In particular,

it brings a crucial part of doing science, namely our

choices about how we will probe nature, directly into

the causal structure. It specifies the effects of these

probing actions upon the systems being probed.

This approach works very well in practice. However,

the body and brain of the human agent, and also their

devices, are composed of atomic constituents. Hence a

complete theory ought to be able to describe these

systems in physical terms.

The great mathematician and logician John von

Neumann formulated quantumtheory in a rigorous way

that allows the bodies and brains of the agents, along

with their measuring devices, to be shifted into the

physically described world. This shift is carried out in a

series of steps, each of which moves more of what the

Copenhagen approach took to be the psychologically

described ‘observing system’ into the physically

described ‘observed system’. At each step the crucial

act of choosing or deciding between possible optional

observing actions remains undetermined by the physical

observed system. This act of choosing is always ascribed

to the observing agent. In the end all that is left of this

agent is what von Neumann calls his ‘abstract ego’. It is

described in psychological terms, and is, in practice, the

stream of consciousness of the agent.

At each step the direct effect of the conscious act is

upon the part of the physically described world that is

closest to the psychologically described world. This

means that, in the end, the causal effect of the agent’s

mental action is on their own brain, or some significant

part of their brain.

von Neumann makes the logical structure of

quantum theory very clear by identifying two very

different processes, which he calls process 1 and

process 2 (

von Neumann 1955, p. 418). Process 2 is

the analogue in quantum theory of the process in classic

physics that takes the state of a system at one time to its

state at a later time. This process 2, like its classic

analogue, is

local and deterministic. However, process 2

by itself is not the whole story: it generates a host of

‘physical worlds’, most of which do not agree with our

human experience. For example, if process 2 were,

from the time of the big bang, the

only process in

nature, then the quantum state (centre point) of the

moon would represent a structure smeared out over a

large part of the sky, and each human body–brain

would likewise be represented by a structure smeared

out continuously over a huge region. Process 2

generates a

cloud of possible worlds, instead of the one

world we actually experience.

This huge disparity between properties generated by

the ‘mechanical’ process 2 and the properties we

actually observe is resolved by invoking process 1.

Any physical theory must, in order to be complete,

specify how the elements of the theory are connected to

human experience. In classic physics this connection is

part of a

metaphysical superstructure: it is not part of the

dynamic process. But in quantum theory a linkage of

the mathematically described physical state to human

experiences is contained in the mathematically

8 J.M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

specified dynamic. This connection is not passive. It is

not a mere

witnessing of a physical feature of nature.

Instead,

it injects into the physical state of the system being

acted upon specific properties that depend upon choices made

by the agent

.

Quantum theory is built upon the practical concept

of intentional actions by agents. Each such action is a

preparation

that is expected or intended to produce

an experiential response or feedback. For example, a

scientist might act to place a Geiger counter near a

radioactive source and expect to see the counter either

‘fire’ during a certain time-interval or not ‘fire’ during

that interval. The experienced response, ‘Yes’ or ‘No’, to

the question, ‘Does the counter fire during the specified

interval?’, specifies one bit of information. Quantum

theory is thus an information-based theory built upon

the preparative actions of information-seeking agents.

Probing actions of this kind are not only performed

by scientists. Every healthy and alert infant is continually

engaged in making wilful efforts that produce

experiential feedbacks and he or she soon begins to

form expectations about what sorts of feedbacks are

probable to follow from some particular kind of effort.

Thus, both empirical science and normal human life

are based on paired realities of this action–response

kind, and our physical and psychological theories are

both basically attempting to understand these linked

realities within a rational conceptual framework.

The basic building blocks of quantum theory are,

then, a set of intentional actions by agents and for each

such action an associated collection of possible ‘Yes’

feedbacks, which are the possible responses that the

agent can judge to be in conformity to the criteria

associated with that intentional act. For example, the

agent is assumed to be able to make the judgement

‘Yes’ the Geiger counter clicked, or ‘No’ the Geiger

counter did not click. Science would be difficult to

pursue if scientists could make no such judgements

about what they are experiencing.

All known physical theories involve idealizations of

one kind or another. In quantum theory the main

idealization is not that every object is made up of

miniature planet-like objects. It is rather that there are

agents that perform intentional acts each of which can

result in feedback that may or may not conform to a

certain criterion associated with that act. One piece of

information is introduced into the world in which that

agent lives, according to whether or not the feedback

conforms to that criterion. The answer places the agent

on one or the other of two alternative possible branches

of the course of world history.

These remarks reveal the enormous difference

between classic physics and quantum physics. In

classic physics the elemental ingredients are tiny

invisible bits of matter that are idealized miniaturized

versions of the planets that we see in the heavens and

that move in ways unaffected by our scrutiny, whereas

in quantum physics the elemental ingredients are

intentional preparative actions by agents, the feedbacks

arising from these actions and the effects of these

actions upon the physically described states of the

probed systems.

This radical restructuring of the form of physical

theory grew out of a seminal discovery by Heisenberg.

That discovery was that in order to get a satisfactory

quantum generalization of a classic theory one must

replace various

numbers in the classic theory by

actions

(operators). A key difference between

numbers and actions is that if A and B are two

actions then AB represents the action obtained by

performing the action A upon the action B. If A and

B are two different actions then generally AB is

different from BA: the order in which actions are

performed matters. But for numbers the order does

not matter: AB

ZBA.

The difference between quantum physics and its

classic approximation resides in the fact that in the

quantum case certain differences AB–BA are proportional

to a number measured by Max Planck in

1900, and called Planck’s constant. Setting those

differences to zero gives the classic approximation.

Thus quantum theory is closely connected to classic

physics, but is incompatible with it, because certain

non-zero

quantities must be replaced by zero to obtain

the classic approximation.

The intentional actions of agents are represented

mathematically in Heisenberg’s space of actions.

A description of how it operates follows.

Each intentional action depends, of course, on the

intention of the agent

and upon the state of the system

upon which this action acts. Each of these

two aspects of

nature

is represented within Heisenberg’s space of

actions by an

action. The idea that a ‘state’ should be

represented by an ‘action’ may sound odd, but

Heisenberg’s key idea was to replace what classic

physics took to be a ‘being’ with a ‘doing’. We shall

denote the

action (or operator) that represents the state

being acted upon by the symbol

S.

An intentional act is an action that is intended to

produce a feedback of a certain conceived or imagined

kind. Of course, no intentional act is certain: one’s

intentions may not be fulfilled. Hence the intentional

action merely puts into play a process that will lead

either to a confirmatory feedback ‘Yes’, the intention is

realized, or to the result ‘No’, the ‘Yes’ response did not

occur.

The effect of this intentional mental act is represented

mathematically by an equation that is one of

the key components of quantum theory. This equation

represents, within quantum mathematics, the effect of

process 1 action upon the quantum state

S of the

system being acted upon. The equation is:

S

/S0 ZPSPCðI KPÞSðI KPÞ:

This formula exhibits the important fact that this

process 1 action changes the state

S of the system being

acted upon into a new state

S0, which is a sum of two

parts.

The first part,

PSP, represents in physical terms, the

possibility in which the experiential feedback called

‘Yes’ appears and the second part, (

IKP)S(IKP),

represents the alternative possibility ‘No’, this ‘Yes’

feedback does not appear. Thus, an effect of the

probing action is injected into the mathematical

description of the physical system being acted upon.

The operator

P is important. The action represented

by

P, acting both on the right and on the left of S, is the

Model of mind–brain interaction

J. M. Schwartz and others 9

Phil. Trans. R. Soc. B

action of eliminating from the state

S all parts of S

except the ‘Yes’ part. That particular retained part is

determined by the choice made by the agent. The

symbol

I is the unit operator, which is essentially

multiplication by the number 1, and the action of

(

IKP), acting both on the right and on the left of S is,

analogously, to eliminate from

S all parts of S except

the ‘No’ parts.

Notice that process 1 produces the

sum of the two

alternative possible feedbacks, not just one or the

other. Since the feedback must either be ‘Yes’ or

‘No

ZNot-Yes’, one might think that process 1, which

keeps both the ‘Yes’ and the ‘No’ possibilities, would do

nothing. But that is not correct. This is a key point. It

can be made absolutely clear by noticing that

S can be

written as a sum of four parts, only two of which survive

the process 1 action:

S

ZPSPCðI KPÞSðI KPÞCPSðI KPÞCðI KPÞSP:

This formula is a strict identity. The dedicated reader

can quickly verify it by collecting the contributions of

the four occurring terms

PSP, PS, SP and S, and

verifying that all terms but

S cancel out. This identity

shows that the state

S is a sum of four parts, two of which

are eliminated by process 1

.

But this means that process 1 has a non-trivial

effect

upon the state being acted upon: it eliminates the two

terms that correspond neither to the appearance of a

‘Yes’ feedback nor to the failure of the ‘Yes’ feedback to

appear.

This result is the

first key point: quantum theory has a

specific causal process, process 1, which produces a

non-trivial effect of an

agent’s choice upon the physical

description of the system being examined. (‘Nature’

will eventually choose between ‘Yes’ and ‘No’, but we

focus here on the prior process 1,

the agent’s choice.

Nature’s subsequent choice we shall call process 3.)

(

a) Free choices

The second key point is this: the agent’s choices are

‘free choices’,

in the specific sense specified below.

Orthodox quantum theory is formulated in a

realistic and practical way. It is structured around the

activities of human agents, who are considered able to

freely elect to probe nature in any one of many possible

ways. Bohr emphasized the freedom of the experimenters

in passages such as the one already quoted

earlier, or the similar:

The foundation of the description of the experimental

conditions as well as our freedom to choose them is

fully retained.

(

Bohr 1958, p. 90)

This freedom of choice stems from the fact that in

the original Copenhagen formulation of quantum

theory the human experimenter is considered to

stand outside the system to which the quantum laws

are applied. Those quantum laws are the only precise

laws of nature recognized by that theory. Thus,

according to the Copenhagen philosophy,

there are no

presently known laws that govern the choices

made by the

agent/experimenter/observer about how the observed

system is to be probed. This choice is thus,

in this very

specific sense

, a ‘free choice’. The von Neumann

generalization leaves this freedom intact. The choices

attributed to von Neumann’s ‘abstract ego’ are nomore

limited by the known rules of quantum theory than are

the choices made by Bohr’s experimenter.

(

b) Nerve terminals, ion channels and the need

to use quantum theory in the study of the

mind–brain connection

Neuroscientists studying the connection of mind

and consciousness to physical processes in the brain

often assume that a conception of nature based on

classic physics will eventually turn out to be adequate.

That assumption would have been reasonable during

the nineteenth century. But now, in the twenty-first

century, it is rationally untenable. Quantum theory

must be used in principle because the behaviour of the

brain depends sensitively upon atomic, molecular and

ionic processes, and these processes in the brain often

involve large quantum effects.

To study quantum effects in brains within an

orthodox (i.e. Copenhagen or von Neumann) quantum

theory one must use the von Neumann formulation.

This is because

Copenhagen quantum theory is

formulated in a way that leaves out the quantum

dynamics of the human observer’s body and brain. But

von Neumann quantum theory takes the physical

system

S upon which the crucial process 1 acts to be

precisely the brain of the agent, or some part of it. Thus

process 1 describes here an interaction between a

person’s stream of consciousness, described in mentalistic

terms, and an activity in their brain, described in

physical terms.

A key question is the

quantitative magnitude of

quantum effects in the brain. They must be large in

order for deviations from classic physics to play any

significant role. To examine this quantitative question

we consider the quantum dynamics of nerve terminals.

Nerve terminals are essential connecting links

between nerve cells. The general way they work is

reasonably well understood. When an action potential

travelling along a nerve fibre reaches a nerve terminal, a

host of ion channels open. Calcium ions enter through

these channels into the interior of the terminal. These

ions migrate from the channel exits to release sites on

vesicles containing neurotransmitter molecules. A

triggering effect of the calcium ions causes these

contents to be dumped into the synaptic cleft that

separates this terminal from a neighbouring neuron,

and these neurotransmitter molecules influence the

tendencies of that neighbouring neuron to ‘fire’.

At their narrowest points, calcium ion channels are

less than a nanometre in diameter (

Cataldi et al. 2002).

This extreme smallness of the opening in the calcium

ion channels has profound quantum mechanical

implications. The narrowness of the channel restricts

the lateral

spatial dimension. Consequently, the lateral

velocity

is forced by the quantum uncertainty principle to

become large. This causes the

quantum cloud of

possibilities

associated with the calcium ion to fan out

over an increasing area as it moves away from the tiny

channel to the target region where the ion will be

absorbed as a whole, or not absorbed at all, on some

small triggering site.

10 J. M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

This spreading of this

ion wave packet means that the

ion may or may not be absorbed on the small triggering

site. Accordingly, the contents of the vesicle may or

may not be released. Consequently, the quantum state

of the brain has a part in which the neurotransmitter is

released and a part in which the neurotransmitter is not

released. This quantum splitting occurs at every one of

the trillions of nerve terminals. This means that the

quantum state of the brain splits into a vast host of

classically conceived possibilities, one for each possible

combination of the release-or-no-release options at

each of the nerve terminals. In fact, because of

uncertainties on timings and locations, what is generated

by the physical processes in the brain will be not a

single discrete set of non-overlapping physical possibilities

but rather a huge

smear of classically conceived

possibilities. Once the physical state of the brain has

evolved into this huge smear of possibilities one must

appeal to the quantum rules, and in particular to the

effects of process 1, in order to connect the physically

described world to the streams of consciousness of the

observer/participants.

This focus on the motions of calcium ions in nerve

terminals is not meant to suggest that this particular

effect is the

only place where quantum effects enter into

the brain process, or that the quantum process 1 acts

locally at these sites. What is needed here is only the

existence of

some large quantum of effect. The focus

upon these calcium ions stems from the facts that (i) in

this case the various sizes (dimensions) needed to

estimate the

magnitude of the quantum effects are

empirically known, and (ii) that the release of

neurotransmitter into synaptic clefts is known to play

a significant role in brain dynamics.

The brain matter is warm and wet and is continually

interacting intensely with its environment. It might be

thought that the strong

quantum decoherence effects

associated with these conditions would wash out all

quantum effects, beyond localized chemical processes

that can be conceived to be imbedded in an essentially

classic world.

Strong decoherence effects are certainly present, but

they are automatically taken into account in the von

Neumann formulation employed here. These effects

merely convert the state

S of the brain into what is

called a ‘statistical mixture’ of ‘nearly classically

describable’ states, each of which develops in time (in

the absence of process 1 events), in an almost classically

describable way.

The existence of strong decoherence effects makes

the main consequences of quantum theory being

discussed here more easily accessible to neuroscientists

by effectively reducing the complex quantum state of

the brain to a collection of almost classically describable

possibilities. Because of the uncertainties introduced

at the ionic, atomic, molecular and electronic

levels, the brain state will develop not into one single

classically describable macroscopic state, as it does in

classic physics, but into a continuous distribution of

parallel virtual states of this kind. Process 1 must then

be invoked to allow definite empirical predictions to be

extracted from this continuous smear of parallel

overlapping almost-classic possibilities generated by

process 2.

(

c) Quantum brain dynamics

A principal function of the brain is to receive clues

from the environment, to form an appropriate plan of

action and to direct and monitor the activities of the

brain and body specified by the selected plan of action.

The exact details of the plan will, for a classic model,

obviously depend upon the exact values of many noisy

and uncontrolled variables. In cases close to a

bifurcation point, the dynamic effects of noise might

even tip the balance between two very different

responses to the given clues, for example, tip the

balance between the ‘fight’ or ‘flight’ response to some

shadowy form. It is important to realize that the exact

values accounting for what in classic physics models are

called ‘dynamic effects of noise’ are unknowable in

principle. The contemporary physical model accounts

for these uncertainties in brain dynamics.

The effect of the independent ‘release’ or ‘do not

release’ options at each of the trigger sites, coupled with

the uncertainty in the timing of the vesicle release at

each of the trillions of nerve terminals, will be to cause

the quantum mechanical state of the brain to become

a smeared-out cloud of different macroscopic possibilities,

some representing different alternative possible

plans of action. As long as the brain dynamic is

controlled wholly by process 2—which is the quantum

generalization of the Newtonian laws of motion of

classic physics—all of the various alternative possible

plans of action will exist in parallel, with no one plan of

action singled out as the one that will actually be

experienced.

Some process beyond the local deterministic process

2 is required to pick out one experienced course of

physical events from the smeared-out mass of possibilities

generated by all of the alternative possible

combinations of vesicle releases at all of the trillions

of nerve terminals. As already emphasized, this other

process is process 1. This process brings in a

choice that

is not determined by any currently known law of

nature, yet has a definite effect upon the brain of the

chooser. The process 1 choice picks an operator

P and

also a time

t at which P acts. The effect of this action at

time

t is to change the state S(t) of the brain, or of some

large part of the brain, to

PS

ðtÞP CðI KPÞSðtÞðI KPÞ:

The action

P cannot act at a point in the brain, because

action at a point would dump a huge (in principle

infinite) amount of energy into the brain, which would

then explode. The operator

P must, therefore, act nonlocally,

over a potentially large part of the brain.

In examining the question of the nature of the effect

in the brain of process 2 we focused on the separate

motions of the individual particles. But the physical

structures in terms of which the action of process 1 is

naturally expressed are not the separate motions of

individual particles. They are, rather, the

quasi-stable

macroscopic degrees of freedom

. The brain structures

selected by the action of

P must enjoy the stability,

endurance and causal linkages needed to bring the

intended experiential feedbacks into being.

These functional structures are probably more like

the lowest-energy state of the simple harmonic

Model of mind–brain interaction

J. M. Schwartz and others 11

Phil. Trans. R. Soc. B

oscillator, which is completely stable, or like the states

obtained from such lowest-energy states by spatial

displacements and shifts in velocity. These shifted

states tend to

endure as oscillating states. In other words,

in order to create the needed causal structure the

projection operator

P corresponding to an intentional

action ought to pick out functionally pertinent quasistable

oscillating states of macroscopic subsystems of the

brain

. The state associated with a process 1 preparatory

intervention should be a functionally important brain

analogue of a collection of oscillating modes of a

drumhead, in which large assemblies of particles are

moving in a coordinated way. Such an enduring

structure in the brain can serve as a trigger and

coordinator of further coordinated activities.

(

d) Templates for action

The brain process that is actualized by the transition

S

(t)/PS(t)P is the neural correlate of the psychologically

intended action. It is the brain’s template for the

intended action. It is a pattern of neuroelectrical

activity that, if held in place long enough, will tend to

generate a physical action in the brain that will tend to

produce the intended experiential feedback.

(

e) Origin of the choices of the process 1 actions

It has been repeatedly emphasized here that the

choices by which process 1 actions actually occur are

‘free choices’ in the sense that they are not specified by

the currently known laws of physics. On the other hand,

a person’s intentions are surely related in some way to

their historical past. This means that the laws of

contemporary orthodox quantum theory, although

restrictive and important, do not provide a complete

picture. In spite of this, orthodox quantum theory,

while making no claim to ontological completeness, is

able to achieve a certain kind of

pragmatic completeness.

It does so by treating the process 1 ‘free choices’ as the

input variables of experimental protocols, rather than

mechanically determined consequences of brain

action.

In quantum physics

the ‘free choices’ made by human

subjects are regarded as subjectively controllable input

variables

. Bohr emphasized that ‘the mathematical

structure of the quantum mechanical formalism offers

the appropriate latitude’ for these free choices. But the

need for this strategic move goes deeper than the mere

fact that contemporary quantum theory fails to specify

how these choices are made. For if in the von Neumann

formulation one does seek to determine the cause of the

‘free choice’ within the representation of the physical

brain of the chooser, one finds that one is

systematically

blocked from determining the cause of the choice by

the Heisenberg uncertainty principle, which asserts

that the locations and velocities of, say, the calcium

ions, are simultaneously unknowable to the precision

needed to determine what the choice will be. Thus, one

is not only faced with merely a practical unknowability

of the causal origin of the ‘free choices’, but with an

unknowability in principle

that stems from the uncertainty

principle itself, which lies at the base of quantum

mechanics. There is thus a deep root in quantum

theory for the idea that the origin of the ‘free choices’

does not lie in the physical description alone and also

for the consequent policy of treating these ‘free choices’

as empirical inputs that are selected by agents and enter

into the causal structure via process 1.

(

f) Effort

It is useful to classify process 1 events as either

‘active’ or ‘passive’.

Passive process 1 events are

attentional events that occur with little or no feeling

of conscious effort.

Active process 1 events are

intentional and involve effort. This distinction is given

a functional significance by allowing ‘effort’ to enter

into the selection of process 1 events in a way that will

now be specified.

Consciousness probably contributes very little to

brain dynamics compared with the contribution of the

brain itself. To minimize the input of consciousness,

and in order to achieve testability, we propose to allow

mental effort to do nothing but control ‘attention

density’, which is the rapidity of the process 1 events.

This allows effort to have only a very limited kind of

influence on brain activities, which are largely controlled

by physical properties of the brain itself.

The notion that only the attention density is

controlled by conscious effort arose from an investigation

into what sort of conscious control over process

1 action was sufficient to accommodate the most

blatant empirical facts. Imposing this strong restriction

on the allowed effects of consciousness produces a

theory with correspondingly strong predictive power.

In this model all significant effects of consciousness

upon brain activity arise exclusively from a well-known

and well-verified strictly quantum effect known as the

‘quantum Zeno effect’ (QZE).

(

g) The quantum Zeno effect

If one considers only passive events, then it is very

difficult to identify any empirical effect of process 1,

apart from the occurrence of awareness. In the first

place, the empirical averaging over the ‘Yes’ and ‘No’

possibilities in strict accordance with the quantum laws

tends to wash out all effects that depart from what

would arise from a classic statistical analysis that

incorporates the uncertainty principle as simply lack

of knowledge. Moreover, the passivity of the mental

process means that we have no empirically controllable

variable.

However, the study of effortfully controlled intentional

action brings in two empirically accessible

variables, the intention and the amount of effort. It

also brings in the important physical QZE. This effect is

named for the Greek philosopher Zeno of Elea, and

was brought into prominence in 1977 by the physicists

Misra & Sudarshan (1977)

. It gives a name to the fact

that repeated and closely spaced observational acts can

effectively hold the ‘Yes’ feedback in place for an

extended time-interval that depends upon the

rapidity

at which the process 1 actions are happening

. According to

our model, this rapidity is controlled by the amount of

effort being applied. In our notation, the effect is to

keep the ‘Yes’ condition associated with states of the

form

PSP in place longer than would be the case if no

effort were being made. This ‘holding’ effect can

override very strong mechanical forces arising from

process 2.

12 J. M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

The ‘Yes’ states

PSP are assumed to be conditioned

by training and learning to contain the template for

action which if held in place for an extended period will

tend to produce the intended experiential feedback.

Thus, the model allows intentional mental efforts to

tend to bring intended experiences into being. Systems

that have the capacity to exploit this feature of natural

law, as it is represented in quantum theory, would

apparently enjoy a tremendous survival advantage over

systems that do not or cannot exploit it.

6. SUPPORT FROM PSYCHOLOGY

A person’s experiential life is a stream of conscious

experiences. The person’s experienced ‘

self’ is part of

this stream of consciousness: it is not an extra thing that

lies outside what the person is conscious of. In James’s

words (

1890, p. 401) ‘thought is itself the thinker, and

psychology need not look beyond’. The experiential

‘self ’ is a slowly changing ‘fringe’ part of the stream of

consciousness. This part of the streamof consciousness

provides an overall background cause for the central

focus of attention.

The physical brain, evolving mechanically in accordance

with the local deterministic process 2, can domost

of the necessary work of the brain. It can do the job of

creating, on the basis of its interpretation of the clues

provided by the senses, a suitable response, which will

be controlled by a certain pattern of neural or brain

activity that acts as a

template for action. However, owing

to its quantum character, the brain necessarily generates

an amorphous mass of overlapping and conflicting

templates for action. Process 1 acts to extract from

this jumbled mass of possibilities some particular

template for action. This template is a feature of the

‘Yes’ states

PSP that specifies the form of the process 1

event. But the quantum rules do not assert that this

‘Yes’ part of the prior state

S necessarily comes into

being. They assert, instead, that if this process 1 action

is triggered (for example, by some sort of ‘consent’)

then this ‘Yes’ component

PSP will come into being

with probability Tr

PSP/Tr S, and that the ‘No’ state

will occur if the ‘Yes’ state does not occur, where the

symbol Tr represents a quantum mechanical summation

over all possibilities.

If the rate at which these ‘consents’ occur is assumed

to be

increasable by conscious mental effort, then the

causal efficacy of ‘will’ can be understood. Conscious

effort can, by activation of the QZE, override strong

mechanical forces arising from process 2 and

cause the

template for action to be held in place longer than it

would be if the rapid sequence of process 1 events were

not occurring. This sustained existence of the template

for action can increase the probability that the intended

action will occur.

Does this quantum-physics-based concept of the

origin of the causal efficacy of ‘will’ accord with the

findings of psychology?

Consider some passages from

Psychology: the briefer

course

, written by William James. In the final section of

the chapter on attention, James (

1892, p. 227) writes:

I have spoken as if our attention were wholly

determined by neural conditions. I believe that the

array of

things we can attend to is so determined. No

object can

catch our attention except by the neural

machinery. But the

amount of the attention which an

object receives after it has caught our attention is

another question. It often takes effort to keep the mind

upon it. We feel that we can make more or less of the

effort as we choose. If this feeling be not deceptive, if

our effort be a spiritual force, and an indeterminate

one, then of course it contributes coequally with the

cerebral conditions to the result. Though it

introduce no

new idea, it will deepen and prolong the stay in

consciousness of innumerable ideas which else would

fade more quickly away.

In the chapter on will, in the section entitled

‘Volitional effort is effort of attention’, James (

1892,

p. 417) writes:

Thus we find that we reach the heart of our inquiry into

volition when we ask by what process is it that the

thought of any given action comes to prevail stably in

the mind.

And, later:

The essential achievement of the will, in short, when it

is most ‘voluntary,’ is to attend to a difficult object and

hold it fast before the mind.

.Effort of attention is thus

the essential phenomenon of will.

Still later, James says:

Consent to the idea’s undivided presence, this is effort’s

sole achievement

.Everywhere, then, the function of

effort is the same: to keep affirming and adopting the

thought which, if left to itself, would slip away.

This description of the effect of will on the course

of mental–cerebral processes is remarkably in line

with

what had been proposed independently from purely

theoretical considerations of the quantum physics of this

process

. The connections specified by James are

explained

on the basis of the same dynamic principles

that had been introduced by physicists to explain

atomic phenomena. Thus the whole range of science,

from atomic physics to mind–brain dynamics, has the

possibility of being brought together into a single

rationally coherent theory of an evolving cosmos that

is constituted not of

matter but of actions by agents. In

this conceptualization of nature, agents could naturally

evolve in accordance with the principles of

natural selection, owing to the fact that their efforts

have physical consequences. The outline of a possible

rationally coherent understanding of the connection

between mind and matter begins to emerge.

In the quantum theory of mind/consciousness–brain

being described here, there are altogether three processes.

First, there is the purely mechanical process

called process 2. As discussed at length in the book,

Mind, matter, and quantum mechanics

(Stapp 1993/2003,

p. 150), this process, as it applies to the brain, involves

important dynamic units that are represented by

complex patterns of brain activity that are ‘facilitated’

(i.e. strengthened) by use and are such that each unit

tends to be activated as a whole by the activation of

several of its parts. The activation of various of these

complex patterns by cross referencing—that is, by

activation of several of its parts—coupled to feedback

loops that strengthen or weaken the activities of

Model of mind–brain interaction

J. M. Schwartz and others 13

Phil. Trans. R. Soc. B

appropriate processing centres, appears to account for

the essential features of the mechanical part of the

dynamics in a way that is not significantly different from

what a classic model can support, except for the

existence of a host of parallel possibilities that according

to the classic concepts, cannot exist simultaneously.

The second process, von Neumann’s process 1, is

needed in order to pick out from a chaotic continuum

of overlapping parallel possibilities some particular

discrete possibility and its complement. (The complement

can be further divided, but the essential action

is present in the choice of one particular ‘Yes’ state

PS

(t)P from the morass of possibilities in which it is

imbedded.) The third process is nature’s choice

between ‘Yes’ and ‘No’. Nature’s choice conforms to

a statistical rule, but the agent’s choice is, within

contemporary quantum theory, a ‘free choice’ that can

be and is consistently treated as an input variable of the

empirical protocol.

Process 1 has itself two modes. The first is passive,

and can produce temporally isolated events. The

second is active and involves mental effort.

Active

process 1 intervention has, according to the

quantum model described here, a distinctive form. It

consists of a sequence of intentional purposeful

actions, the rapidity of which can be increased with

effort. Such an increase in attention density, defined as

an increase in the number of observations per unit

time, can bring into play the QZE, which tends to hold

in place both those aspects of the state of the brain

that are fixed by the sequence of intentional actions

and also the felt intentional focus of these actions.

Attention density is not controlled by any physical rule

of orthodox contemporary quantum theory, but is

taken both in orthodox theory and in our model, to be

subject to subjective volitional control. This application

in this way of the basic principles of physics to

neuroscience constitutes our model of the mind–brain

connection.

(

a) Support from psychology of attention

A huge amount of empirical work on attention has

been done since the nineteenth century writings of

William James. Much of it is summarized and analysed

in

Harold Pashler’s (1998) book The psychology of

attention

. Pashler organizes his discussion by separating

perceptual processing from post-perceptual processing.

The former type covers processing that, first of all,

identifies such basic physical properties of stimuli as

location, colour, loudness and pitch and, secondly,

identifies stimuli in terms of categories ofmeaning. The

post-perceptual process covers the tasks of producing

motor actions and cognitive action beyond mere

categorical identification. Pashler emphasizes that the

empirical ‘findings of attention studies

.argue for a

distinction between perceptual attentional limitations

and more central limitations involved in thought and

the planning of action’ (p. 33). The existence of these

two different processes with different characteristics is a

principal theme of Pashler’s book (e.g. pp. 33, 263,

293, 317, 404).

A striking difference that emerges from the analysis

of the many sophisticated experiments is that the

perceptual processes proceed essentially in parallel,

whereas the post-perceptual processes of planning and

executing actions form a single queue. This is in line

with the distinction between ‘passive’ and ‘active’

processes. The former are essentially a passive stream

of essentially isolated process 1 events, whereas the

‘active’ processes involve effort-induced rapid

sequences of process 1 events that can saturate a

given capacity. This idea of a limited capacity for serial

processing of effort-based inputs is the main conclusion

of Pashler’s book. It is in accord with the quantumbased

model, supplemented by the condition that there

is a limit to how many effortful process 1 events per

second a person can produce during a particular stage

of their development.

Examination of Pashler’s book shows that this

quantum model accommodates naturally all of the

complex structural features of the empirical data that

he describes. Of key importance is his chapter 6, in

which he emphasizes a specific finding: strong empirical

evidence for what he calls a central processing

bottleneck associated with the attentive selection of a

motor action. This kind of bottleneck is what the

quantum-physics-based theory predicts: the bottleneck

is precisely the single linear sequence of mind–brain

quantum events that von Neumann quantum theory

describes.

Pashler describes four empirical signatures for this

kind of bottleneck and describes the experimental

confirmation of each of them (p. 279). Much of part II

of Pashler’s book is a massing of evidence that supports

the existence of a central process of this general kind.

The queuing effect is illustrated in a nineteenth

century result described by Pashler: mental exertion

reduces the amount of physical force that a person can

apply. He notes that ‘This puzzling phenomenon

remains unexplained’ (p. 387). However, it is an

automatic consequence of the physics-based theory:

creating physical force by muscle contraction requires

an effort that opposes the physical tendencies generated

by the Schro¨dinger equation (process 2). This opposing

tendency is produced by the QZE and is roughly

proportional to the number of bits per second of central

processing capacity that is devoted to the task. So, if

part of this processing capacity is directed to another

task, then the applied force will diminish.

The important point here is that there is in principle,

in the quantum model, an essential dynamic difference

between the unconscious processing done by the

Schro¨dinger evolution, which generates by a local

process an expanding collection of classically conceivable

experiential possibilities and the process associated

with the sequence of conscious events that

constitute the wilful selection of action. The former

are not limited by the queuing effect, because process 2

simply develops all of the possibilities in parallel. Nor is

the stream of essentially isolated passive process 1 events

thus limited. It is the closely packed active process 1

events that can, in the von Neumann formulation, be

limited by the queuing effect.

The very numerous experiments cited by Pashler all

seem to be in line with the quantum approach. It is

important to note that this bottleneck is not automatic

within classic physics. A classic model could easily

produce, simultaneously, two responses in different

14 J. M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

modalities, say vocal and manual, to two different

stimuli arriving via two different modalities, say

auditory and tactile: the two processes could proceed

via dynamically independent routes. Pashler notes that

the bottleneck is undiminished in split-brain patients

performing two tasks that, at the level of input and

output, seem to be confined to different hemispheres

(p. 308). This could be accounted for by the necessarily

non-local character of the projection operator

P.

An interesting experiment mentioned by Pashler

involves the simultaneous tasks of doing an IQ test and

giving a foot response to a rapidly presented sequence

of tones of either 2000 or 250 Hz. The subject’s mental

age, asmeasured by the IQ test, was reduced from adult

to 8 years (p. 299). This result supports the prediction

of quantum theory that the bottleneck pertains to both

‘intelligent’ behaviour, which requires complex effortful

processing, and the simple wilful selection of a

motor response.

Pashler also notes that ‘Recent results strengthen the

case for central interference even further, concluding

that memory retrieval is subject to the same discrete

processing bottleneck that prevents simultaneous

response selection in two speeded choice tasks’ (p. 348).

In the section on ‘mental effort’, Pashler reports

that ‘incentives to perform especially well lead subjects

to improve both speed and accuracy’, and that the

motivation had ‘greater effects on the more cognitively

complex activity’ (p. 383). This is what would be

expected if incentives lead to effort that produces

increased rapidity of the events, each of which injects

into the physical process, through quantum selection

and reduction, bits of control information that reflect

mental evaluation. Pashler notes ‘Increasing the rate at

which events occur in experimenter-paced tasks often

increases effort ratings without affecting performance.

Increasing incentives often raises workload ratings and

performance at the same time’ (p. 385). All of these

empirical connections are in line with the general

principle that effort increases attention density, with

an attendant increase in the rate of directed conscious

events, each of which inputs a mental evaluation and a

selection or focusing of a course of action.

Additional supporting evidence comes from the

studies of the stabilization or storage of information

in short-term memory (STM). According to the

physics-based theory, the passive aspect of conscious

process merely actualizes an event that occurs in

accordance with some brain-controlled rule and this

rule-selected process then develops automatically, with

perhaps some occasional monitoring. Thus, the theory

would predict that the process of stabilization or

storage in STM of a certain sequence of stimuli should

be able to persist undiminished while the central

processor is engaged in another task. This is what the

data indicate. Pashler remarks that ‘These conclusions

contradict the remarkably widespread assumption that

short-term memory capacity can be equated with, or

used as a measure of, central resources’ (p. 341). In the

theory outlined here, STM is stored in patterns of brain

activity, whereas consciously directed actions are

associated with the active selection of a sub-ensemble

of quasi-classic states. This distinction seems to

account for the large amount of detailed data that

bear on this question of the relationship of the

stabilization or storage of information in STM to the

types of task that require wilfully directed actions (pp.

337–341). In marked contrast to STM function,

storage or retrieval of information from long-term

memory (LTM) is a task that requires actions of just

this sort (pp. 347–350).

Deliberate storage in, or retrieval from, LTM

requires wilfully directed action and hence conscious

effort. These processes should, according to the theory,

use part of the limited processing capacity and hence be

detrimentally affected by a competing task that makes

sufficient concurrent demands on the central resources.

On the other hand, ‘perceptual’ processing that involves

conceptual categorization and identification without

wilful conscious selection should not be interfered with

by tasks that do consume central processing capacity.

These expectations are what the evidence appears to

confirm: ‘the entirety of

.front-end processing are

modality specific and operate independent of the sort of

single-channel central processing that limits retrieval

and the control of action. This includes not only

perceptual analysis but also storage in STM and

whatever processing may feed back to change the

allocation of perceptual attention itself ’ (p. 353).

Pashler speculates on the possibility of a neurophysiological

explanation of the facts he describes, but

notes that the parallel versus serial distinction between

the two mechanisms leads, in the classic neurophysiological

approach, to the questions of what makes these

two mechanisms so different, and what the connection

between them is (pp. 354–356, 386–387).

After considering various possible mechanisms that

could cause the central bottleneck, Pashler concludes

that ‘the question of why this should be the case is quite

puzzling’ (pp. 307–308). Thus, the fact that this

bottleneck and its basic properties seem to follow

automatically from the same laws that explain the

complex empirical evidence in the fields of classic and

quantum physics means that the theory being presented

here has significant explanatory power for the

experimental data of cognitive psychology. Further, it

coherently explains aspects of the data that have

heretofore not been adequately addressed by currently

applicable theoretical perspectives.

These features of the phenomena may be claimed by

some to be potentially explainable within a classicalphysics-

based model. But the possibility of such an

explanation is profoundly undermined by the absence

from classic physics of the notion of conscious choice

and effort. These consciousness-connected features, so

critical to a coherent explanation of the psychology of

human attention, however, already exist and are

specified features of the causal structure of fundamental

contemporary physical theory.

7. APPLICATION TO NEUROPSYCHOLOGY

The quantum model is better suited to the analysis of

neuropsychological data than models based on the

classic approximation. For, just as in the treatment of

atomic systems, the quantum approach brings the

phenomenologically described data

directly into the

dynamics in place of microscopic variables that are, in

Model of mind–brain interaction

J. M. Schwartz and others 15

Phil. Trans. R. Soc. B

principle, unknowable. Quantum theory injects

directly into the causal structure the phenomenal

descriptions that we human beings use in order to

communicate to our colleagues the empirical facts. It

thereby specifies a useful and testable causal structure,

while evading the restrictive classic demand that the

causal process be ‘bottom up’, i.e. expressible in terms

of local mechanical interactions between tiny mindless

entities. The Heisenberg uncertainty principle renders

that ideal

unachievable in principle and the banishment

of that microlocal ‘bottom up’ determinism opens the

door to the quantum alternative of injecting the

phenomenologically described realities directly into

the causal structure in the way that is both allowed and

described by contemporary physical theory.

Quantum physics works better in neuropsychology

than its classic approximation precisely because it

inserts knowable choices made by human agents into

the dynamics in place of unknowable-in-principle

microscopic variables. To illustrate this point we

apply the quantum approach to the experiment of

Ochsner

et al. (2002).

Reduced to its essence, this experiment consists first

of a training phase in which the subject is taught how to

distinguish, and respond differently to, two instructions

given while viewing emotionally disturbing visual

images: ‘attend’ (meaning passively ‘be aware of, but

not try to alter, any feelings elicited by’) or ‘reappraise’

(meaning actively ‘reinterpret the content so that it no

longer elicits a negative response’). Second, the

subjects perform these mental actions during brain

data acquisition. The visual stimuli, when passively

attended to, activate limbic brain areas, and when

actively reappraised, activate prefrontal cerebral

regions.

From the classic materialist point of view this is

essentially a conditioning experiment where, however,

the ‘conditioning’ is achieved through linguistic access

to cognitive faculties. But how do the cognitive realities

involving ‘knowing’, ‘understanding’ and ‘feeling’ arise

out of motions of the miniature planet-like objects of

classic physics, which have no trace of any experiential

quality? How do the vibrations in the air that carry the

instructions get converted into feelings of understanding?

And how do these feelings of understanding get

converted to conscious effort, the presence or absence

of which determine whether the limbic or frontal

regions of the brain will be activated?

Within the framework of classic physics these

connections between feelings and brain activities

remain huge mysteries. The materialist claim (Karl

Popper called this historicist prophecy ‘

promissory

materialism

’) is that someday these connections will be

understood. But the question is whether these connections

should reasonably be expected to be understood

in terms of a physical theory that is known to be false,

and to be false in ways that are absolutely and

fundamentally germane to the issue. The classic

concept demands that the choices made by human

agents about how they will act be determined by

microscopic variables that according to quantum

theory are indeterminate in principle. The reductionist

demand that the course of human experience be

determined by local mechanical processes is the very

thing that is most conclusively ruled out by the

structure of natural phenomena specified by contemporary

physical theory. To expect the mind–brain

connection to be understood within a framework of

ideas so contrary to the principles of physics is

scientifically unsupportable and unreasonable.

There are important similarities and also important

differences between the classic and quantum explanations

of the experiments of

Ochsner et al. (2002). In

both approaches the atomic constituents of the brain

can be conceived to be collected into nerves and other

biological structures and into fluxes of ions and

electrons, which can all be described reasonably well

in essentially classic terms. In the classic approach the

dynamics must in principle be describable in terms of

the local deterministic classic laws that, according to

those principles, are supposed to govern the motions of

the atomic-sized entities.

The quantum approach is fundamentally different.

In the first place the idea that all causation is

fundamentally mechanical

is dropped as being prejudicial

and unsupported either by direct evidence or by

contemporary physical theory. The quantum model of

the human person is essentially dualistic, with one of the

two components being described in psychological

language and the other being described in physical

terms. The empirical/phenomenal evidence coming

from subjective reports is treated as data pertaining to

the psychologically described component of the person,

whereas the data from objective observations, or from

measurements made

upon that person, are treated as

conditions on the physically described component of the

person. The apparent causal connection

manifested in the

experiments

between these two components of the agent

is then explained by the causal connections between

these components

that are specified by the quantum laws.

The quantum laws, insofar as they pertain to

empirical data, are organized around

events that

increase the amount of information lodged in the

psychologically described component of the theoretical

structure. The

effects of these psychologically identified

events upon the physical state of the associated brain

are specified by process 1 (followed by ‘Nature’s

statistical choice’ of which the discrete options specified

by process 1 will be experienced). When no effort is

applied, the temporal development of the body/brain

will be approximately in accord with the principles of

classic

statistical mechanics, for reasons described

earlier in connection with the strong

decoherence effects.

But important departures from the classic statistical

predictions can be caused by conscious effort. This

effort can cause to be held in place for an extended

period, a pattern of neural activity that constitutes a

template for action

. This delay can tend to cause the

specified action to occur. In the experiments of

Ochsner the effort of the subject to ‘reappraise’

causes

the ‘reappraise’ template to be held in place and the

holding in place of this template

causes the suppression

of the limbic response. These causal effects are, by the

QZE, mathematical consequences of the quantum

rules. Thus the ‘subjective’ and ‘objective’ aspects of

the data are tied together by quantum rules that

directly

specify the causal effects upon the subject’s brain of the

choices made by the subject, without needing to specify how

16 J. M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

these choices came about

. The form of the quantum laws

accommodates a natural dynamic breakpoint between

the

cause of wilful action, which is not specified by the

theory, and its

effects, which are specified by the theory.

Quantum theory was designed to deal with cases in

which the conscious action of an agent—to perform

some particular probing action—enters into the

dynamics in an essential way. Within the context of

the experiment by

Ochsner et al. (2002), quantum

theory provides, via the process 1 mechanism, an

explicit means whereby the successful effort to ‘rethink

feelings’ actually causes—by catching and actively

holding in place—the prefrontal activations critical to

the experimentally observed deactivation of the

amygdala and orbitofrontal cortex. The resulting

intention-induced modulation

of limbic mechanisms

that putatively generate the frightening aversive feelings

associated with passively attending to the target stimuli

is the key factor necessary for the achievement of the

emotional self-regulation seen in the active cognitive

reappraisal condition. Thus, within the quantum

framework, the causal relationship between the mental

work of mindfully reappraising and the observed brain

changes presumed to be necessary for emotional selfregulation

is

dynamically accounted for. Furthermore,

and crucially, it is accounted for in ways that fully allow

for communicating to others the means used by living

human experimental subjects to attain the desired

outcome. The classic materialist approach to these

data, as detailed earlier in this article, by no means

allows for such effective communication. Analogous

quantum mechanical reasoning can of course be used

mutatis mutandis

to explain the data of Beauregard et al.

(2001) and related studies of self-directed neuroplasticity

(see

Schwartz & Begley 2002).

8. CONCLUSIONS

Materialist ontology draws no support from contemporary

physics and is in fact contradicted by it. The

notion that all physical behaviour is explainable in

principle solely in terms of a local mechanical process is

a holdover from physical theories of an earlier era. It

was rejected by the founders of quantum mechanics,

who introduced, crucially into the basic dynamical

equations, choices that are not determined by local

mechanical processes, but are rather attributed to

human agents. These orthodox quantum equations,

applied to human brains in the way suggested by John

von Neumann, provide for a causal account of recent

neuropsychological data. In this account brain behaviour

that appears to be caused by mental effort is

actually caused by mental effort: the causal efficacy of

mental effort is no illusion. Our wilful choices enter

neither as redundant nor epiphenomenal effects, but

rather as fundamental dynamical elements that have

the causal efficacy that the objective data appear to

assign to them.

A shift to this pragmatic approach that incorporates

agent-based choices as primary empirical input variables

may be as important to progress in neuroscience

and psychology as it was to progress in atomic physics.

The work of the second-named author (H.P.S.) was

supported in part by the Director, Office of Science, Office

of High Energy and Nuclear Physics, Division of High Energy

Physics, of the US Department of Energy under Contract

DE-AC03-76SF00098. The work of the third-named author

(M.B.) was supported in part by a scholarship from the Fonds

de la Recherche en Sante´ du Que´bec (FRSQ). We thank

Joseph O’Neill for his insightful comments about preliminary

versions of our manuscript.

APPENDIX A. OTHER INTERPRETATIONS

This work is based on the Copenhagen Interpretation

of quantum theory, and von Neumann’s extension of it.

The Copenhagen Interpretation is what is, in essence,

both taught in standard quantum physics courses and

used in actual practice. This interpretation brings the

human agent into the dynamics at a crucial point,

namely to resolve the ‘basis’ problem, i.e. to pose some

particular physical question. This entry of the agent’s

‘free’ choice is the basis of the present work.

Many of the physicists who are most acutely

interested in the logical and physical foundations of

quantum theory reject the Copenhagen Interpretation,

which is basically epistemological and have sought to

invent alternative formulations that can be regarded as

descriptions of what is really going on in nature. The

three most-discussed alternatives are the ones associated

with the names of Roger Penrose, Hugh Everett

and David Bohm. In order to provide a broader

conceptual foundation for understanding and assessing

the Copenhagen–von Neumann approach used here we

shall compare it with those other three.

All three of the alternative approaches accept von

Neumann’s move of treating the entire physical world

quantum mechanically. In particular, the bodies and

brains of the agents are treated as conglomerations of

such things as quantum mechanically described electrons,

ions and photons.

Penrose (1994)

accepts the need for consciousrelated

process 1 events, and wants to explain

when they

occur. He proposes an explanation that is tied to

another quantum mystery, that of quantum gravity.

Suppose the quantum state of a brain develops two

components corresponding to the ‘Yes’ and ‘No’

answers to some query. Penrose proposes a rule,

based on the gravitational interaction between these

two parts, that specifies approximately how long before

a collapse will occur to one branch or to the other. In

this way the question of

when the answer ‘Yes’ or ‘No’

occurs is given a ‘physical’ explanation.

Penrose and his

collaborator Hameroff (1996)

calculate estimates of

this typical time-interval on the basis of some detailed

assumptions about the brain. The result is a time of the

order of one-tenth of a second. They argue that the

rough agreement of this number with time-intervals

normally associated with consciousness lends strong

support to their theory.

The Penrose–Hameroff model requires that the

quantum state of the brain has a property called

macroscopic quantum coherence

, which needs to be

maintained for around a tenth of a second. But,

according to calculations made by

Max Tegmark

(2000)

, this property ought not to hold for more than

about 10

K13 s. Hameroff and co-workers (Hagen et al.

2002

) have advanced reasons why this number should

actually be of the order of a tenth of a second. But 12

Model of mind–brain interaction

J. M. Schwartz and others 17

Phil. Trans. R. Soc. B

orders of magnitude is a very big difference to explain

away and serious doubts remain about whether the

Penrose–Hameroff theory is technically viable.

If

all aspects of the collapse process were similarly

determined in an essentially mechanical way, then

there would be in quantum mechanics, as in classic

physics, nothing for consciousness to do. But

Penrose

(1994)

argues that the effects of consciousness cannot

be purely algorithmic: it cannot be governed by a finite

set of rules and operations. His argument is based

on the famous incompleteness theorem of Go¨ del.

However, the logical validity of his argument has been

vigorously challenged by many experts, including

Hillary

Putnam (1994), and Penrose’s conclusion

cannot be deemed absolutely secure. Also, it is peculiar

that the question of

when the event occurs should

be essentially algorithmic, while the process itself is

non-algorithmic.

However, Penrose’s overall aims are similar to those

of the approach made in this paper, namely to

recognize that the process-1-related features of quantum

mechanics are dynamically very different from the

local mechanistic dynamics of classic mechanics, or of

its quantum analogue, process 2. This differing

character of process 1, which is closely connected

to conscious awareness, seems, on its face, to be

signalling the entry of an essentially non-mechanical

consciousness-related element into brain dynamics.

Everett (1957)

proposed another way to deal with

the problem of how the quantum formulae are tied to

our conscious experiences. It is called the many-worlds

or many-minds approach. The basic idea is that nature

makes no choices between the ‘Yes’ and ‘No’ possibilities:

both options actually do occur. But, owing to

certain features of quantum mechanics, the two

streams of consciousness in which these two alternative

answers appear are dynamically independent: neither

one has any effect on the other. Hence the two

incompatible streams exist in parallel

epistemological

worlds, although in the one single ontological or

physical quantum world.

This many-minds approach is plausible within the

framework provided by quantum mathematics. It

evades the need for any real choices between the ‘Yes’

and ‘No’ answers to the question posed by the process

1 action. However, von Neumann never even mentions

any real choice between ‘Yes’ and ‘No’ and the

founders of quantum theory likewise focus attention

on the crucial

choice of which question shall be posed. It is

this

choice, which is in the hands of the agent, that the

present paper has focused upon. The subsequent

choice between ‘Yes’ and ‘No’, is normally deemed

to be made by nature. But it is enough that the latter

choice merely

seems to be made in accordance with the

quantum probably rules. The real problem with the

many-minds approach is that its proponents have not

yet adequately explained how one can evade the

process 1 choices. This difficulty is discussed in detail

in

Stapp (2002).

David Bohm’s pilot-wave model (

Bohm 1952)

seems at first to be another way of evading the problem

of how to tie the formulae of quantum mechanics to

human experiences. Yet in David Bohm’s book with

Basil Hiley (

Bohm & Hiley 1993) the last two chapters

go far beyond the reasonably well-defined pilot-wave

model and attempt to deal with the problem dealt with

in the works of

Stapp (1990) and of Gell-Mann &

Hartle (1989)

. This leads Bohm into a discussion of his

concept of the implicate order, which is far less

mathematically well-defined than his pilot-wavemodel.

Bohm saw a need to deal with consciousness and

wrote a detailed paper on it (

Bohm 1986, 1990). His

proposals go far beyond the simple well-defined pilotwave

model. It involves an infinite tower of pilot waves,

each controlling the level below. The engaging simplicity

of the original pilot-wave model is lost in this

infinite tower.

The sum of all this is that the structure of quantum

theory indicates the need for a non-mechanistic

consciousness-related process, but that the approaches

to quantum theory that go beyond the pragmatic

Copenhagen–von Neumann approach have serious

problems that have yet to be resolved. We, in this

paper, have chosen to stay on the safer ground of

orthodox pragmatic quantum theory and to explore

what can be said within that framework.

However, in this addendum we will now stray very

briefly from our strict adherence to the pragmatic

stance, in order to get a glimpse into what seems to us

to be the pathway beyond contemporary pragmatic

science that is pointed to by the structure of contemporary

physics.

The core message of quantum theory appears to be

that the basic realities are ‘knowables’ not ‘be-ables’:

they are things that can be known, not realities that exist

yet cannot be known. This conclusion can be strongly

defended by a detailed analysis of quantum theory, but

this is not place to do so. However, given this premise,

the programme of passing from the anthropocentric set

of pragmatic rules to a conception of the greater reality

in which our streams of human consciousness are

imbedded takes on a different complexion. If nature is

constructed of knowables, then the acts of knowing with

which we are familiar should be special cases of a

pervasive set of similar acts: the world should somehow

be constructed of such acts, and of a substrate that is

suited to be acted upon by such acts, but that supports,

as a matter of principle, only what can become known by

other acts. Acts of knowing become, then, the primitives

of nature, along with the substrate upon which they act.

Conscious acts of probing must also be encompassed.

This way of understanding the meaning of quantum

theory opens the door, in principle, to the formulation

of rules that allow the choices of which probing actions

are taken to depend not exclusively on the current

condition of the physically/mathematically described

substrate—that is, the current state of the brain—but

also on prior acts of knowing. Thus it could well be, as

James’s remarks suggest, that a mechanical rule

determines which thought is

initially caught, but that

felt properties of the consequent act of knowing can

influence the rapidity of follow-up repetitions of the

probing action.

It is not our intention to propose in this appendix

some testable proposal along these lines. We merely

note that quantum theory seems naturally to point to

this route for an understanding of the reality that lies

behind our human-knowledge-based science.

18 J. M. Schwartz and others

Model of mind–brain interaction

Phil. Trans. R. Soc. B

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