Quantum Theory of the Human Person.

This article is a written version of my conference talk. 
That talk was based on sixteen slides. Accordingly, this version
will be divided into sixteen sections, each beginning with a slide.  
Each slide either identifies the themes, or gives some quotation related to,
the associated portion of my talk. 

The overall organization of  the talk is built around five related themes. 
They are listed in the first slide.

Slide 1: Quantum Theory of the Human Person

 1. The most important development in science in the twenty-first century 
    will be about the nature of human beings. 
 2. The basic unsolved question there is the nature of the causal relationship 
    of mind to brain. 
 3. Von Neumann’s Processes I and II, applied to the human person, constitute
    genuine causal top-down and bottom-up mind-brain connections.
 4. Process I involves "Free Choices."
 5. These "Free Choices" Can Influence Behavior. 

Theme 1 concerns "importance." By `most important' I mean most important to 
human beings. Physicists have generally shied away from the problem of human 
beings because they are so complex. This difficult problem has been set aside 
for some later time. But that time has now arrived. The needed technologies, 
funding, and interest are all at hand. Moreover, the advances in technology 
already allow scores of laboratories to participate, and the number will 
soon grow at least to hundreds, and probably to thousands: the data will 
come from diverse sources, not just a few billion dollar facilities. 
 
A second reason why physicists have shunned the problem of human beings 
is that physicists are interested in basic problems, whereas human beings 
seem at first to be just complicated physical systems the study of which 
will not illuminate any basic issue. However, there is a very basic 
dynamical question that arises first in the study of human beings.   

Theme 2 is that this basic problem is the nature of the causal connection 
between the experiential (phenomenal) aspects of nature and the 
physical (geometrical) aspects .
 
Theme 3 is the core of the talk: Von Neumann's quantum theory has two distinct
processes. This contrasts with the single dynamical process that governs
everything in classical physics. These two quantum processes, von Neumann's 
Processes I and II, constitute, in the context of the study of human beings, 
genuine "top down" and "bottom up" causal connections, respectively. 

The terms "top down" and "bottom up" are often used in discussions of the 
causal structure of a system. A `bottom up' connection is one in which 
macroscopic processes are controlled by microscopic processes: 
a `top down' process is one in which macroscopic processes control aspects 
of the microscopic processes. 

Roger Sperry (of split brain fame) uses the motion of a wheel to illustrate 
the idea of a top down causal connection: the overall large-scale motion of 
the wheel controls certain aspects of the motions of the atoms that make up 
the wheel. However, in classical physics this top down causal connection 
is a redundant re-expression of the bottom up causal connections: 
it is not genuinely different from the botton up connections. On the other 
hand, von Neumann's Process I is a top down process that IS genuinely different
from the bottom up process II: Process I is a not determined, controlled, 
or governed by Process II! 

Theme 4 is the claim that Process I involves "free choices." 
I must make clear the nature of this `freedom'.

Theme 5 is the claim that these 'free choices' can influence behavior. 
Thus the laws of quantum physics naturally accomodate an influence of human 
volition on human behavior. In contrast to the situation in classical physics 
this quantum top down influence is not controlled by the the bottom up process.

The actual mechanism of this influence will be described: it does not 
involve any biasing of the quantum statistical rules, but follows from strict 
adherence to all the laws and rules of von Neumann quantum theory.


Slide 2: The Most Important Question

   Human Beings Are More Important To Human Beings Than Quarks Or Big 
   Bangs.
   Physical and Mental Health Funding Is Big and Growing (16% vs 2.8% of GNP).
   The Mind-Brain Question is of "Towering Importance" in Neuroscience, and is
   important also in Psychology/Psychiatry.
   Its Legal/Cultural/Institutional/Moral Ramifications Control Human Destiny.


In an era of shrinking budgets funding will probably be channeled increasingly 
to research fields that are perceived to be vital to human needs. Already one 
sixth of the US GNP goes to the health industry, as contrasted to 2.8% to 
education and research. So that is a big pot from which to fund research into 
the nature of human beings and their connection to the rest of nature. 

The next slide will give two quotations indicating the "towering" importance
of the mind-brain question in neuroscience. Moreover, the cutting-edge research
in psychology and psychiatry is increasingly being tied to neuroscience, and 
hence to studies of the mind-brain connection. 

But perhaps even more important than these issues are the cultural 
ramifications. We live immersed in a world of ideas, and the nature of these 
ideas are, today, at least as important to human destiny as our immediate 
physical conditions. These ideas are based upon our conception of what we 
ourselves are, and how we are connected to the rest of nature. 

The main contributors to the development of this world of ideas are science, 
philosophy, and religion. The voice of science is strong in the construction
of this cultural milieu, but the message of science is undercut by the fact 
that it is based mainly on classical physics, which proclaims us to be 
mechanical automata, in direct opposition to the deep intuitive 
idea of ourselves that is the basis of our lives. 

The next slide gives two quotations from a recent special issue of 
Scientific American devoted to the subject of the mind-brain connection. 
The lead article is by Antonio Damasio, a prestigious neuroscientist who 
wrote the book "Descartes' Error." Damasio begins his lead article with the
words:


Slide 3: Mind and Brain in Neuroscience

   "At the start of the new millennium, it is apparent that one question 
    towers above all others in the life sciences: How does the set of 
    processes we call mind emerge from the activity of the organ we call 
    brain?" 
    Antonio Damasio

   "The overwhelming question in neurobiology today is the relationship 
    between the mind and the brain." 
    Francis Crick and Christoph Koch

The second quote begins another article in that magazine. These quotes give 
the flavor of the enthusiasm for reasearch in this field. Furthermore, 
cutting-edge psychology and psychiatry are increasinly being linked to 
neuroscience. Philosophy is also deeply involved. But since the core issue is 
the nature of the pertinent causal connections it is evident that physics is 
also relevant.


Slide 4: Legal, Cultural, Institutional, Moral

   Australian Supreme Court Justice David Hodgson’s book "The Mind Matters" 
   describes the growing effects upon The Law of the concepts of classical 
   physics. 
   (Recall the infamous `Twinkie Defense’ of Dan White for the murders of SF 
   Mayor George Moscone and Supervisor Harvey Milk.)

   The thesis that Genes + Environment determine behavior is not backed up by 
   the evidence. (Books by S. Pinker and by J. Schwartz and S. Begley)

I shall not go here into the important cultural ramifications of our conception
of what we are and how we are linked to the rest or nature. But the book by 
David Hodgson gives a discussion of the impact of the ideas of classical 
physics upon our legal system. 

In California we all remember well the case of a man who walked into the office
of the Mayor of San Francisco, shot him dead, walked down the hall and into the
office of a Supervisor and shot him dead, and got off with five years on the 
basis of the defense that eating junk food had rendered him not responsible 
for his actions.  
 
The ideas of classical physics have led to the idea that a person is just 
the causal consequence his genes plus his environment. However, the empirical 
facts do not support that conclusion. The recent book "The Blank Slate" by 
Steven Pinker cites studies of twins that confirm that the genes are very 
important. But the environment seems less important than individual
"personality." Thus the empirical facts certainly do not rule out a
causal role for a nonmechanical mind in the functioning of the brain

The recent book "The Mind and The Brain" by Jeffrey Schwartz and Sharon Begley 
documents the strong effects upon the structure of the brain of therapies based
on the encouragement of appropriately directed mental effort.
Thus the concept of "efficacious mental effort" that can strongly affect brain 
activity is currently a key element of scientific medical approaches to the 
mind-brain question. The data are compatible with---and most easily understood 
in terms of---the idea that mental effort is an experiential reality that can 
influence physical brain activity. 
 

Slide 5: The Problem of Causation

   Classical physics reduces us to robots.
   Intuition insists that mental effort matters. 
   This conflict is the basis of much philosophical debate: Materialism vs 
   Idealism vs Pragmatism.
   The issue colors all aspects of our lives. 
   The basic question is the nature of causal connection between mind and 
   brain.
   "Bottom up" verses "Top Down" causation.

This slide 5 summarizes the introductory remarks. Classical physics leaves our 
minds out of its dynamically complete causal description: it deals with 
geometric and numeric concepts, in contrast to "feelings," to which it has no 
rational connection. This absence of any rational or dynamical connection 
between a person's mind and his brain means that classical physics provides 
no satisfactory rational conception of what a human person is. My aim here is 
to contrast that essentially mechanical conception of man to one that 
arises naturally from von Neumann quantum mechanics.  

Slide 6: Von Neumann’s Process I

   Process II Generates a Continuum of Overlapping Possibilities. 
   Environmental Decoherence Does Not Resolve The Problem!
   The Experimenter Chooses A Particular Action From A Continuum Of 
   Possibilities!
   S --> S’ =PSP + (I-P)S(I-P)
   Discrete Possibilities: `Yes’ or `No’
   Geiger Counter `Clicks’ or `Doesn’t Click’


A key innovation of the founders of quantum theory was to bring human agents
into basic physical theory in a fundamental way. This was a radical move 
because the successes of the earlier classical theory were due in large measure
to the policy of keeping human agents out. But in orthodox Copenhagen quantum 
theory the mentally directed actions of agents are an essential part of the 
theory. In John von Neumann's rigorous reformulation of the theory, each 
such action is called a Process I intervention. 

Process II is the quantum analog of the classical process of motion and, 
like it, is governed by laws that are both local and deterministic. 
Process II is constructed from its classical counterpart by "quantization," 
which replaces 'values' by 'actions.' The effect of this change is to smear 
out values: it turns the physical state into a smeared out collection of 
overlapping possibilities. (This feature is not undone by the much-studied 
environmental decoherence effect, which effectively wipes out certain 
off-diagonal interference terms of the density matrix but does not restrict 
the evolution of the important diagonal elements.)

In order to tie this smeared out mathematical state S to probabilities for 
various alternative possible experiences to occur an experimenter must act. 
By virtue of his efforts some particular experimental situation will be 
created: e.g., a Geiger counter will be set in some particular place. 
This action causes the state S to jump to the state 

S' = PSP + (I-P)S(I-P), 

where the first term corresponds to the possibility that the 
feedback from nature will be a human experience of seeing the Geiger Counter 
fire, whereas the second term corresponds to the failure of that experiential 
feedback to occur. This Process I action by the agent involves a selection 
of a projection operator P from a continuum of alternative possibilities. 
This selection is construed, by Bohr and the other founders of quantum theory, 
to be a free choice on the part of the experimenter/agent.     


Slide 7:  Process I "Free Choice"

   "The freedom of experimentation, presupposed in classical 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" 
    N. Bohr

This notion that the experimenter's choice is "free" is connected to Bohr's 
idea that the state contains information about all of the *complementary* 
possible experiments that the agent might choose to perform on the system 
being examined.

Slide 8: The Process I Free Choice

    In Copenhagen QT the experimenter stands outside the quantum system.
    Thus the Experimenter’s Choice is not determined by any known law.
    Process I is essential to von N QT.
    Von Neumann’s approach pushes the Process I choice unto the "Abstract 
    Ego."
    No known law determines the Experimenter’s Free Choice!
 
The reason why, in Copenhagen QT, the agent's choice must regarded as "free," 
in the specific sense that it is controlled by no *known* law, is that in the 
Copenhagen formulation the experimenter stands outside the system that is being
examined. But the only known exact laws are the quantum laws that govern the 
system that is being examined. Thus in the Copenhagen formulation the actions 
of the human experimenters are not contolled by the known laws of nature. 

Copenhagen quantum theory separates the dynamically unified physical world
into two systems, the physical system being examined, and the agent who is 
doing the examination. This works well in practice, but means that the theory 
cannot be viewed as a possible description of nature: it must be viewed as 
merely a set of rules for computing predictions pertaing to relationships 
between our observations. 

It can be argued that the capacity to make predictions of this kind is all 
that science should aspire to. But this ad hoc sundering of the physical 
world and the radical restriction to subjective human experience does not
adequately accommodate theories about the cosmos, and our role in the cosmos.
Von Neumann's approach is to treat the entire physical world, including our 
own bodies and brains as belonging to the dynamically unified world described 
by the quantum laws. This tack circumvents the need to separate the 
dynamically unified physical world into two differently described
subsystems. 

In this treatment the brain/body of the agent becomes both the system being 
examined AND the measuring device, and also the physical aspect of the agent. 
The evolution of this full system is assumed to be governed by Process II 
when no Process I intervention is occurring. But Process I is still needed
in order to tie the mathematics to statistical predictions pertaining to
empirical (i.e., experiential) facts. And this Process I is still, just as in
Copenhagen quantum theory, not determined by the local deterministic process, 
Process II. 

Von Neumann associates Process I with an "Abstract Ego,"  but gives no rules 
for determining how the crucial choice of the operator P is made. Thus neither 
the Copenhagen nor the von Neumann formulations give rules for determining 
this choice of P. This choice is, then, in this very specific sense of not 
being fixed or specified by *known* laws, a "free Choice."
  
Slide 9: Effort and Feedback

   The experimenter exerts an effort that he expects will produce a direct 
   experiential feedback, and perhaps a "response."
   A human being exerts an effort that he expects will produce the feeling and 
   sight of moving his finger towards the stove, and perhaps the feel of the 
   hot  stove. 
   Infants, children, and adults learn by trial and error what sort of 
   "feeling of effort" will produce what sort of feedbacks,
   and possible feedbacks.

In the quantum context the Process I intervention of the agent involves an 
effort on the part of the agent to, say, put the Geiger Counter in some 
particular place. He expects his effort to produce, first, the experiential 
feedback of seeing his arms and hands placing the device in the chosen spot, 
and he may expect a later possible experiencing of "the counter firing." 

But this scenario carries over to our normal activity in life.

I may make an effort to reach out toward the stove, and I expect that effort to
cause me to see and feel my hand moving toward the stove, and I may also expect
to feel a certain sensation of hotness when my finger touches the stove. 

Thus Process I intervention need not be restricted to the actions of scientists
in pursuit of scientific knowledge.

We all learn by trial and error which feelings of effort will normally produce 
which sorts of experiences pertaining to bodily movement, and also which 
possible responses a certain kind of effort effort might elicit from nature. 

This sort of connection between experienced effort and experienced feedback
is a basic feature of human life.

Slide 10: Mind_Brain Interaction

   There is a seeming causal connection between "feeling of effort" and 
   experiential feedback.
   Non-Interactive Parallelism? (Synchronized clocks: Geulincx, Occasionalism)
   Monism? (Mind is Matter is Mind!) But how are `feelings’ connected to 
   geometry?
   Interactive Dualism! (Science has two kinds of descriptions. Von Neumann’s 
   Process I connects them dynamically.)

There is apparently a causal relationship between our mental efforts and the
subsequent experiential feedbacks. But how are the observed connections WITHIN 
the realm of experiences connected to the external physical world?

This problem had become acute already in the context of Descartes' philosophy, 
and one of his disciples, Geulincx, proposed the "Two Clocks Solution":
The physical and mental worlds are likened to two clocks that are set by God 
to run perpetually in synchrony. This possible solution is, today, probably 
believed by no one at all.

More popular now is the idea that the mental world is just an aspect of the
physical world. But this proposal is difficult to understand if the physical 
world is what classical physics claims it to be. For that world is described 
exclusively in terms of geometric and numeric concepts, and these concepts 
have no logical or rational link to the "feelings" that are the basis of our 
experiential lives.

Moreover, in classical physics the connection to mind is not dynamical: 
the classical dynamical laws are complete within an ontology that makes no 
mention of experiential realities.

Orthodox (Von Neumann) quantum theory provides a rationally coherent way out. 
It is built around the intervention of Process I in the mathematically 
described physical world.


Slide 11: Quantum Psycho-Physical Theory

   Each conceivable-to-the-agent course of action is represented in QT by a 
   projection operator P that specifies an associated pattern of brain 
   activity.
   Effortful attention on the action represented by P causes rapid repetition 
   of the Process I specified by P.
   William James’s ideo-motor theory:
   Effortful attention on an intended action normally elicits or sustains the 
   brain activity that produces the expected action.

Let me place von Neumann's Process I into a general Quantum Psycho-Physical 
framework.

I propose that each possible course of action that is conceivable to---and 
executable by---an agent is represented in the brain of the agent by a 
pattern of brain activity.

This pattern is specified by a projection operator P, which is therefore 
associated with the idea of an action. Each Process I intervention is 
instantaneous in von Neumann's theory. 

However, attention lasts! So let it be assumed that effortful attention to 
this idea of an intended action causes a rapid repetition of the Process I 
intervention associated with this operator P. 

This proposal ties naturally into William James's ideo-motor theory of the 
connection between Volition and Action. According to that theory, Willful 
action is associated with prolonged attention to the idea of the intended 
action.    
 
Given this plausible rudiment of a psycho-physical theory we can ask:
Can such a freely chosen sequence of Process I interventions have any 
effect on bodily action?

The answer in von Neumann QT is a resounding Yes! Such a sustained focus of 
attention can exert a huge effect on brain activity, and thence on the 
bodily behavior of the person. This effect is an automatic consequence of:


Slide 12: The Quantum Zeno Effect

   Suppose S describes slowly changing degrees of freedom of the brain.
   Suppose a sequence of "freely chosen" Process I events consist of a rapid 
   repetition of events with the same P.
   Then S’ is trapped in the subspace of states of the form PXP if the original 
   state has this form: transitions to the other possibility (I-P)Y(I-P) are 
   suppressed:

          (I-P)exp-iHt(PXP)expiHt(I-P)=O(t squared)


Consciousness should be associated with slowly changing degrees of freedom. 
Let S represent the slowly changing the degrees of freedom of the brain that 
are associated with consciousness.

Supposed the "free choices" associated with Process I activate a 
rapid repetition of Process I events all associated with the same P.

If the first event has landed you in the subspace PSP then if the repetition
rate is sufficiently fast there will be hardly any transitions to the 
"No" states of the form (I-P)Y(I-P), for any Y. 

One verifies this by noting that the relevant transitions are of order 
t squared. This result follows from the fact that a replacement of either 
of the two exponentials by the zeroth order term "unity" gives a null 
contribution to the transition probability. [P(I-P)=(I-P)P=0]  

The lowest order term is therefore of second order in t.

This means that: 

Slide 13: Willful Effort Influences Action

   The rapid repetition of Process I with the same P (or slowly changing P) 
   holds the state in the form PXP!
 
   "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.” 
        Wm. James.

    "Everywhere, then, the function of effort is the same: to keep affirming 
     and adopting the thought which, if left to itself would slip away."  
        Wm. James.

This is the key point: The concentration of attention actually MODIFIES
the activity of the brain. It confines the brain in the associated subspace 
PXP, in spite of perhaps very strong ordinary forces that would otherwise
quickly the move the state out of that small subspace. 

This situation is totally different from what happens in classical physics, 
where there is no second process that is controlled by mental "free choices,"
and that is mathematically able to override the bottom up mechanical process.

William James clearly recognized the difficulty within classical physics
of allowing mental effort to make a physical difference, and he seems to 
have sensed that therefore classical physics must be wrong. The final and 
prescient words of his book "Psychology: The Briefer Course" are: 


Slide 14: Wm. James Quote

   "...understand how great is the darkness in which we grope, and never 
    forget that the natural-science assumptions with which we started are 
    provisional and revisable things."
    Wm. James, The final words of "Psychology: Briefer Course"

The development of the needed new physical theory was, at that time, 
just beginning. But psychology could not wait, and turned impatiently to 
behaviorism. Even today  psychology, and also neuroscience and philosophy, 
remaining largely uninformed about the enormous possible relevance the 
quantum revolution to brain dynamics, are still busy trying to do what 
James seemed to recognize as impossible, namely to reconcile the causal 
efficacy of mind with a classical conception of the brain.


Slide 15: Effort and Top-Down Causation

   Within classical physics the efficacy of effort is an illusion: 
   the feeling of effort "accompanies" the apparent effect, but the causal 
   structure is completely explained, in principle, in terms of geometric 
   concepts with no rational or logical link to "feelings of effort."
   Quantum theory allows "free choices" by the agent to produce top-down 
   causal effects on the brain.

So the main conclusion here is that whereas according to classical physics 
all brain activity is completely controlled by a bottom up mechanical process, 
quantum theory has a second process, Process I, that involves "free choices", 
and that can significantly modify the brain activity that is generated by 
the bottom up process. It does this by holding in place and sustaining 
certain conditions that would rapidly be lost if no Process I 
interventions occur.

Slide 16: Conclusions


   Von Neumann QT brings basic physics in line with our intuition that our 
   thoughts can influence our actions. 
   We need not be the robots that classical physics proclaimed us to be.
   The philosophically corrosive conclusion of Classical Physics is nullified.
   This opens the door to a deeper level of science-based understanding of 
   ourselves.

According to classical physics the atoms control everything.
But according to von Neumann's formulation here is a top down Process I 
that can overide the microlocal Process II.

This talk has been about the quantum mechanics of the human person. 
But there is no reason why the same general dynamical considerations should 
not apply to all forms of life: von Neumann quantum theory removes in 
principle the anthropocentric bias of the Copenhagen formulation.


Discussion.

I made several comments during discussions about the connection of the 
von Neumann approach to approaches advocated by others at the conference.

A viewpoint strongly defended at the conference (particularly
by Simon Saunders) was the many-worlds interpretation. This theory has 
no Process I, yet claims to give the same predictions as the othodox theories,
whose predictive power is based crucially on Process I. The proponents of
the many-worlds approach have, I believe, not yet demonstrated the equivalence
of the predictions of that theory, which lacks a Process I, to those of 
the orthodox theories, whose connection to empirical (experiential) facts 
rests crucially upon Process I.
  
The consistent histories approach was much discussed at the conference. 
The original interest of Gell-mann was based on the hope that the initial 
condition of the universe might single out quasi classical states by means of
the consistent histories condition. This hope has not so far been borne 
out, and the significance of these completely imaginary histories has thus 
become questionable. However, it is not implausibe that within a von
Neumann ontology the "actual" history of the universe defined by using 
the actually occurring Process I interventions might define a coherent 
history. That would give some actual significance to the decoherent 
histories formalism.

It should be noted that von Neumann does not introduce Process III, the 
collapse or reduction to some single one of the possible outcomes specified
by Process I. Without that Process III reduction the von Neumann ontology 
looks very much like a decoherent histories many worlds ontology, with 
the actually occurring Process I interventions in place of the imaginary 
coarse graining `measurements' of consistent histories. 

It is worth stressing that with local properties defined by tracing over 
the variable associated with all other regions this von Neumann ontology 
become a local theory: Process I interventions in one region have no 
influence on properties localized in other regions. The desire to preserve
locality was probably one of the two principal motivations for going 
to a many-worlds ontology. But that motivation is undercut by the fact that
the von Neumann ontology is already local. 

The second principal motivation was to keep mind out of physics. But it 
is far from clear that this objective is in line with the actual nature 
of the world we inhabit, which seem to be partially controlled by mental
effort.

Gerald t'Hooft asserted, after my talk, that brain processes are 
classical processes. Time did not permit the exact meaning of his claim to be
determined, but it seems unlikely that he meant it in the literal sense that 
in (human) brains the atoms and ions are actually classical particles 
behaving according to classical rather than quantum laws. I assumed that he 
meant that although a human brain, like any other physical system, obeys the 
quantum laws, the net effects of various quantum processes is to allow a 
classical description to work quite well at some appropriate level of 
approximation. 

This is a quantitative issue. I explained that if one examines 
the dynamics of nerve terminals then one finds that quantum effects are 
very important. When an action potential pulse reaches a nerve terminal it
opens up a host of "ion channels," though which calcium ions enter into the
interior of the terminal. They then migrate, and may reach release sites on 
vesicles containing neurotransmitter. However, the ion channels are not much 
larger than the ions themselves. This lateral confinement gives the ions,
by virtue of the quantum uncertainty principle, significant lateral-velocity 
uncertainty. This uncertainty amounts to an uncertainty in the direction
of motion of about 1/300 radian. This uncertainty is important: it means that
the ion has a significant probability of missing the target site, in which 
case the vesicle will not release its neurotransmitter into the synaptic 
cleft that separates it from its neighbor. A vesicle is released only about
half of the time. This means that the state of the brain will rapidly 
decompose into a collection of alternative possible states that correspond 
to different combinations of vesicle release or non-release. 

The decoherence effect will convert this collection, almost instantaneously, 
into a statistical ensemble of states corresponding to different possible 
courses of action. But these decoherence effects do not reduce this ensemble 
to a single-location state. In a multi-dimensional configuration space the 
density matrix is reduced to almost-diagonal form. But the diagonal elements 
continue to evolve: the region of the diagonal where the density matrix 
is "large" evolves in accordance with the quantum equations of motion. 
The Quantum Zeno Effect can strongly affect the way these diagonal elements 
evolve. Consequently, mental effort can, by activating the Quantum Zeno 
Effect, influence brain activity, and thence bodily behavior, even in the 
presence of a strong environmental-decoherence effect that tends to reduce 
the density matrix of the brain to diagonal---hence quasi-classical---form.