Download consciousness as an afterthought

A SPECULATIVE ESSAY ON THE QUEST for
CONSCIOUSNESS
(final version, Feb 14) (Doug’s edit)
“Nullius in verba” *
F. Eugene Yates, M.D**
Ralph and Marjorie Crump Professor of Medical Engineering (Emeritus)/ UCLA
Scientific Advisor, The John Douglas French Alzheimer’s Foundation
* Motto of the Royal Society since 1660: “Take nobody’s word for it”
CONTENTS
I.Introduction
II. Targets for a consciousness detector
III. Some bottom-up views
IV. Emergence
V. Some top –down views
VI. Social Networks
VII. What’s missing?
VIII. Appendices
A. Becoming human: brain developments in the hominid to hominin
(Genus Homo) evolutionary transition
B. A relevant theme from quantum mechanics?
** In my capacity as a Medical Engineer, I seek a scientific connection between
normal brains and minds. In my capacity as Scientific Advisor to the John
Douglas French Alzheimer’s Foundation, I seek ways to support or restore lost
minds.
This essay is background for my talk on February 26, 2010 in the University of
California Multi-Campus Series on Complexity.
I am indebted to my son Gregory Barnett Yates for providing ideas, criticisms
and sources for this essay.
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I.
INTRODUCTION
The synoptic and engaging book by Christof Koch (with Francis Crick) lays an
unsurpassed foundation for studies of consciousness (1). It has 429 pages, sixty
of which are references. In addition, Gerald Edelman has produced a wonderful
series on consciousness of great value (26) that has strongly influenced my
thinking. In this short essay I try to find my own independent “voice” on the topic,
knowing that I’ll merely add some bits and pieces of newer data, and some
idiosyncratic personal perspectives.
The mystery of consciousness has been vigorously studied from the “lower”,
reductionistic views and methods of modern molecular and cell biology,
biophysics, and neurophysiology, as well as from the more holistic, “higher”
levels of philosophy, psychology, social sciences, anthropology and evolution.
Between the domains of these two approaches lies an explanatory gap. This
essay addresses that gap from many perspectives. The details of top-down and
bottom-up scientific data and concepts are necessary but not sufficient to
characterize consciousness. That characterization may require a bridge between
the two approaches to close the huge explanatory gap between them.. It is
commonly held that mental states, including consciousness, emerge from
physical states in brains (or ganglia).
Living systems are famously complex. In contrast to machines, complex systems
have no overarching model from which all subsystem models can be derived,
and successful reductionistic analysis does not imply a path for successful
synthesis. Analysis and synthesis are not inverses in complex systems. As a
result, descriptions of complex systems require multiple models and levels of
observations and the models cannot always be formally reduced to each other.
Jacques Monod (2) pointed out that living systems have three essential
characteristics: 1. Autonomus morphogenesis, 2. Nearly invariant reproduction
with hereditary transmission of characteristics, and 3. teleonomic (goal-directed)
behaviors - that look to us like signs of intentionality. However, Intentionality does
not imply consciousness, though it is a regular feature of consciousness when it
is present.
The concept of emergence (3) could provide the required bridge mentioned
above, but the search for a “bridging principle”, that was fashionable several
decades ago, has failed to illuminate the quest and has recently been largely
abandoned. Instead, candidate processes like 40 Hz oscillations in the cerebral
cortex or quantum coherence in microtubules or loops of kinase enzymes and
synaptic chemistries have all been proposed to account for the highly subjective
qualia of consciousness, and to firmly anchor the thoughts of an immaterial and
conscious mind in material, biophysical processes. These proposals have also
failed. The Quest for consciousness would be helped if we had a device, sensor
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or program that could detect consciousness, without false positives, in any entity.
I shall comment on possible targets for the detector later.
The “mind” is usually pursued using the norms of Western science that, following
Aristotle, emphasize “agency” , but an Eastern path might emphasize “harmony”
as the key (4). The following story is an example:
A troubled man came to a monk and said: “Please, Master, give me peace of
mind”. The monk replied: “Show me your mind and I shall give it peace.” The
troubled man went away and looked everywhere for his mind -by one account in
the ten directions: North, East, South, West; in the intermediate points and up
and down. He also looked in the seven places, and eventually he returned and
reported: “ I searched everywhere but cannot find my mind .” “There”, responded
the monk: “I have given it peace.”
(The relevance of this story to my topic becomes apparent when the word
consciousness is substituted for mind. That there is no such fixed thing as a mind
is a common understanding in zen. A source is: The Gateless Barrier. Robert
Aiken trans. The Wu-men Kuan (Mumonkan) 1990 North Point Press, NY NY p
248. )
essay accepts the Scottish Enlightenment (1730-1800) and the Logical
Positivism of the 1920s and 1930s as a standard base for starting out on a quest
for a reductionistic, objective, scientific account of consciousness. (I studied
symbolic logic under Hans Reichenbach, a member of the Vienna Circle of
Positivists.) Historically, in the intensely reductionistic, “hard” physical sciences,
many of the most productive questions have been those having binary (yes/no)
answers to sharply defined queries, that support strong inferences. Some
classical examples from physics:
 Is spin parity conserved?
 Does a light ray bend near massive objects?
 Is the velocity of light in a vacuum a limiting velocity in all reference
frames?
 Can the position and momentum of an electron be simultaneously
observed?
My
In contrast we find that in the so-called “soft” sciences: e.g., biology, psychology,
evolution, economics, sociology….more nebulous questions abound, and among
them are: a. What was the earliest terrestrial life-form - self-replicating molecules
(e.g., RNAs serving as information )?, or metabolism – a quasi-stable
arrangement of catalyzed reactions, locally bounded, that yield abundant
thermodynamic free-energy for creating new reactions and forms? b. What are
the lineages of extant life-forms? c. What are the “mechanisms” of evolution? d.
Is Homo sapiens predominantly a cooperative or an aggressively competitive
species? e. Does “free will” exist? f. How should we define and identify
consciousness?
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Consciousness (some definitions)
I proceed mindful that J.B. Watson (5) in declared in 1913 “The time has come
when psychology must discard all reference to consciousness…Its sole task is the
prediction and control of behavior (i.e., observable activities) and introspection can
form no part of its method.” Skinner’s operant conditioning later drove that position to
the limit.
Consciousness is a special mental state. The simplest definition of waking
consciousness is that it is synonymous with awareness. A fuller definition would add
that it is awareness with focused attention and a mix of memories. Because
consciousness is so personal I have little hope of finding a standard definition.
However, here is a labored one from the neurophysiologist E.R. John (around 1980):
“Consciousness is a process in which information about multiple individual
modalities of sensation and perception are combined into a unified,
multidimensional representation of the state of the system and its environment,
and integrated with information about memories and the needs of the organism,
generating emotional reactions and programs of behavior to adjust the organism
to its environment.”
Mental states are an immaterial, emergent property of physical states of a
material brain. Not all mental states are conscious: some are unconscious (and in
humans, these can be powerfully influential on behaviors and beliefs). In fact,
consciousness may often be an “afterthought” of the unconscious mind (6). Other
non-conscious mental states are instincts – relatively direct, stimulus-response,
semi-automatic behaviors and processes.
Varieties of consciousness include: waking consciousness; REM sleep; hypnotic
states, reveries, musings and daydreaming, and the suspended attention state such
as we experience when driving a car on a familiar commute, arriving at the
destination with no detailed memory of the details of the trip. A few of these types
will be discussed.
Having invoked “brains” and “minds” above, I offer a few comments about them.
Brains
The human brain looked at materially is an unpromising object. In adults, it
typically weighs about 1350 grams, comprising 1 to 2% of body weight. It has a
volume of about 1300 cc which means it has a density of about 1.0. Compositionally,
it is full fat and water. Energetically it is commonly said to be “expensive” because it
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consumes about 18% of resting oxygen consumption – the highest fraction of any
organ. But, that opinion is somewhat misleading because the absolute metabolic
rate for a human being quietly sitting is under 100 watts and the brain is then
expending only 25 watts. It is a dim bulb. And yet, if a supercomputer had to
compute what the brain does well (and much of what it does well is transcomputable), it would melt down its switches unless it were cooled very severely.
The brain, in contrast, is cooled rather cheaply by a low flow of a sticky fluid offering
only the heat capacity of water at 37°C to carry off its modest heat. Its trick, as we all
recognize, is having a large number of varied types of neurons, and almost ten times
that number of varied classes of glial cells that interact with them and their dynamic,
dendritic-synaptic connections that are of stupendous number and varieties, forming
modules and networks.
All members of Class Mammalia have brains of a common global design, but, of
course, the detailed anatomy varies widely within the Class. Some “lower” animals
have clusters of neurons with a very different layout (e.g., ganglia) much less
complicated than brains. All brains of members of Class Mammalia (excepting a few
with severe developmental anomalies) are presumed to be endowed with the
capacity for consciousness, on the grounds of many similarities in their neural
organizations, and the many common behaviors, e.g., grooming, playing, REM and
SWS types of sleep - discussed later. A big question concerns the phylogenetic
distribution of that capacity beyond Class Mammalia.
Minds
For comprehensive reports on studies of animal minds see (6 – 9). Some
invertebrates with brain structures very different from ours (e.g., octopuses) show
high intelligence by tests we accept as suitable for the purpose, and in many
invertebrates there is more there than simple stimulus-response, instinctive
behaviors. It is now incontrovertible that honey bees have a truly abstract language
(no quotation marks needed for the word language). More than that, using eyes of
very different construction from ours, and working with only one million neurons,
bees recognize human faces, and do so in the same way we do (10). However, most
insects express only purposeful, instinctive behaviors arising from elementary
stimulus-response systems that are not likely to be mindful, even when the behavior
seems elaborate. Though they are obviously goal-directed, the limited repertoires of
instinctive behaviors require no fancy interpretations involving mental states. They
are automatic. The superb, now classical studies of insect societies by E.O. Wilson,
including ants, (11) can be appreciated by his delightful fictional (but not really
fiction) story Trailhead, that is featured in the Jan. 25, 2010 issue of The New
Yorker. After reading it, you will know what it is like to be an ant!
A test for the presence of a mind is adaptability to a wide range of unforeseen
circumstances. A surprising adaptation by an animal only doubtfully mindful, is the
hermit crab. It has three pairs of side legs plus a pair of antennae up front. When it
tries to occupy an empty shell, the crab grasps the margins of the entrance with its
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rear pair of legs, braces in the sand, on which the empty shell is located, using its
front legs and then scoops itself backwards into the shell using its middle pair. That
is its standard behavior. Remarkably, if the middle pair of legs is cut off, the crab still
gets into the waiting shell, but by a novel technique. It again grasps the shell with the
rear legs, but braces itself with now- lowered antennae and scoops backwards with
its front legs. I have seen a convincing video of this instantaneously adaptive
performance, the existence of which I would be otherwise be inclined to doubt. The
crab’s unlearned behavior, appearing immediately as needed, has suggested to
some that there must be a mindless repertoire of automatic “motor tapes” available.
The origin of that proposed and controversial repertoire is unexplained.
Successful modifications of behaviors by Pavolvian conditioned responses, or by
Skinnerian operant conditioning, though they require active attention, do not imply or
require the presence of consciousness, and may be demonstrated even in primitive
animals. An organism exposed to a repetitive stimulus to which it gives a nonrandom, regular response may or may not be conscious. Circus-trained bears and
dancing elephants, though surely conscious – being mammals - manifest the effects
of operant conditioning and their tricks are not spontaneous nor signs of their
consciousness. In contrast, the famous You-Tube video of a parrot dancing to music
revealed a unique, spontaneous behavior not put in by a trainer. (That bird may well
be conscious.)
II. SOME PLAUSIBLE TARGETS FOR DESIGN OF AN OBJECTIVE
“CONSCIOUSNESS-DETECTOR”
. The need for such a detector is imperative in some uncommon clinical
cases such as the “vegetative states” and the “locked-in” syndromes. (For the
latter see the renowned and dramatic book by Jean-Dominique Bauby entitled
The Diving Bell and the Butterfly first published in French in 1997 as Le
scaphandre et le papillon.) For the mammalian brain to be awake and aware, the
neocortex requires inputs from lower levels of organization including hindbrain
(brainstem) and midbrain structures, rather than from direct sensory inputs.
Some structures supporting awareness states in the neocortex are the reticular
formation, ventral pons, mesencephalic tegmentum, subthalamus, hypothalamus
and internal capsule. H.W. Magoun in 1952 (12)defined “An ascending reticular
activating system in the brain stem”, since abbreviated as RAS. The RAS can be
damaged in many ways (e.g., trauma in auto accidents) but a stroke involving the
basilar artery of the brain supplying the pons is a common cause. Such patients
are conscious and may have no loss of cognitive powers (we now know) but can
barely communicate (sometimes only with eye blinks). They can’t move or speak
and superficially they seem to be unconscious. In contrast, persistent vegetative
states usually result from damage to higher levels of the brain and
consciousness is definitely lost, though the EEG is not flat.
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The recent (Feb. 3) online issue of The New England J. of Medicine
(www.NEJM.org) has a detailed article by Martin. M. Monti et al. entitled Willful
modulation of brain activity in disorders of consciousness with an accompanying
Editorial by A.H. Ropper entitled “Cogito ergo sum by MRI”. These have strong
bearing on the use of fMRI as a consciousness detector. Fifty-four patients with
disorders of consciousness were studied. One of them was a patient with
traumatic brain injuries that put him into a chronic, clinical “vegetative state” as
determined by bedside testing. No responses of any kind. He was put into an
MRI machine and (with appropriate control data from normal subjects available
for comparison) instructed to imagine himself in either of two scenes – playing
tennis (motor test) or navigating the streets of a familiar city or walking from room
to room in his home (spatial imagery test). Data from normal subjects showed
that the motor test would activate the supplementary motor area whereas the
spatial test would activate the parahippocampal gyrus. This clinically
unresponsive patient was told to think of one scene to indicate a “yes” answer to
a Y/N question, and the other scene to indicate “no”. The correct answers to
questions asked were not known to the interrogators. Evidently the patient could
hear, because with a high degree of accuracy he actually carried out the
instructions and gave correct answers. Sample question: Do you have any
brothers? In spite of these results indicating that he was in a “minimally
conscious state” rather than a true vegetative state, no communication at the
bedside could be established. The content of that minimal conscious state could
have been at a very low, reflexive level, without self-awareness. There is no way
for an observer to judge. As might be expected, these data raise ethical issues
about when to “pull the plug” on patients who cannot communicate at all at the
bedside. What has been found here is an fMRI-dependent signal for very minimal
communication that has no practical value. The Editorial by Ropper shows proper
caution in evaluating the significance of these findings.
A “consciousness – detector” should report only on objective phenomena
of a kind that any appropriately educated scientist could observe and record.
Three kinds of such data have been frequently sought in consciousness studies:
1) certain behaviors, 2) brain images – especially, these days, as mentioned
above, from fMRI scans that measure increases in local oxygenation via blood
flows as indicator of neural activity and 3) communication (human speech – or
signing – having no rival for effectiveness in this regard). The difficulty is that
minds and consciousness are subjective and private whereas brain events are
objective and public. Mental events violate the requirements of the scientific
enterprise that is fundamentally committed to the position that private
experiences don't count as evidence. Only publicly accessible and repeatable
experiences have that status. By running scans on conscious subjects who can
tell what they are thinking and experiencing under test conditions (limited by what
can be attempted while inside a scanner), all three kinds of data can sometimes
be simultaneously obtained. While the subject’s comments describe mental
states, their behaviors and scan data give a view of the associated physical brain
states.
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Some objective markers of consciousness
1) Self-Recognition Protocol: secretly put a mark on the forehead of a
sleeping or distracted subject and after its awakening place a mirror
before it. Is there any behavioral evidence indicating that the mark has
been noticed in the reflection and referred to self by attempts to touch it or
scrape it off? So far, only humans (after about one year of age),
elephants, chimpanzees, dolphins, and magpies have passed this selfrecognition test.
2) Pointing test. A human who is well known to the test subject (animal, baby
or adult human) suddenly points to some object or location in the room
without saying anything, except, maybe, Look! Only humans, starting at
about age two years, and domestic dogs can follow the point. Even other
canines such as wolves fail to get it. The assumption is that as dogs
became domesticated from wolves, starting about 135,000 years ago,
there was a strong selection by their keepers for those who showed
certain aptitudes – such as following hand signals to guide a retriever to a
downed bird. I have frequently marveled at the extraordinary recoveries by
black Labrador retrievers on duck hunts when the dog hadn’t marked the
shot bird down. Hearing the command: “Get the bird”, the dog looks to its
owner for a hand signal (point) to choose a course for retrieval (often into
rushes that obscure the downed bird). As it nears the target area, if the
bird is not immediately located, the dog looks back toward its master in the
duck blind for another fix by hand signal. This performance goes way
beyond the famous “Clever Hans” trick in which a horse (Hans) was
supposedly able to count or answer yes/no questions put to it by its
handler, who was unobtrusively and unconsciously giving it specific
signals when it chose the right answer out of a selection. Even the excited
responses of the audience as the horse tapped on choices and came near
the right answer, when the handler was shielded so Hans couldn’t see
him, were sufficient to clue the horse in good light. In dim light it lost its
“amazing ability”.
3) Speech, signing, reading. Whether or not Chomsky is right that human
language skills arise from fixed innate structures in the brain (an opposing
view emphasizes the mounting evidence for plasticity in the brain), the use
of symbolic language is, of course, a very strong indication of
consciousness. In spite of decades of efforts to teach apes some form of
language, be it by gestures or visual symbols, there has been no
noteworthy success (but much hype). One of the prerequisites of
language is the ability to imitate sounds created by someone else. Chimps
and bonobos can’t do it to any extent, but whales (by singing!), many
parrots and songbirds are striking vocal mimics. Nevertheless, using
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speech or vocal mimicry as a convincing test of consciousness is too
narrow a criterion,
4) Tool fabrications and uses of symbols. Besides us, some primates and
birds can make the triangulated abstraction associating me, it and function
between. More advanced abstractions appear, to a limited extent, in some
chimpanzees, gorillas, dolphins and birds who can count, add, subtract,
string short lists of symbols together in a “meaningful” way, plan ahead, or
play games to deceive others. The African gray parrot Alex was the
subject of 30 years of scientific study during which he learned more than
100 words and could distinguish colors and numbers.
Some members of the corvids (crows, rooks) have substantial intelligence,
as seen when they spontaneously, without prior training or clues, drop
stones into a tube with some water near the bottom on which a worm is
floating. They keep adding stones until the water level is high enough for
them to get the food. New Caledonian crows (captive) can figure out how
to manipulate three wooden sticks of different lengths, in sequence, to pry
out food. They select a short stick, from a tube, that is suitable to retrieve
a longer stick out of another tube, which is suitable to retrieve a still longer
stick, out of another tube, that reaches the food. Orangutans solve the
floating food (a peanut) problem by taking a mouthful of water and spitting
it into the tube to raise the water level to a point that they get the peanut.
In the hominin evolutionary line (Genus Homo), crude stone tools first
appeared around 2.5 million years ago (H. habilis, H. erectus). (For details
about the hominid to hominin evolution see Appendix A.)
5) Brain size and organization
Darwin believed that consciousness was a graduated phenomenon
among primates and perhaps other animals, present in most or all, but
reaching its greatest elaboration in us. Others claim that to be accorded
consciousness an animal must manifest highly developed cognitive systems
behaviorally and anatomically along the lines I have been discussing above.
Members of Class Mammalia alive today range in body mass from the
smallest (e.g., the shrew) to the largest – the blue whale (the largest animal
that has ever lived). The shrew weighs about 3 grams, and the blue whale
has a mass of 100,000 kg. This mass range for the Class is an extraordinary
eight orders of magnitude! If, as seems very likely, all mammals have the
brain circuitry for consciousness, then absolute brain size alone cannot be a
reliable marker for consciousness.
The classical allometric scaling for brain size as a function of body size is
given by:
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Y = YoMb where Yo is a normalization constant, M is the independent
variable body mass, and b is the scaling exponent.
A linear graph is given by:
log Y = logYo + b log M with b as slope of the line
For eutherian mammals, there are good data indicating a value for Yo of
11.24 and b=0.76 when M is body mass in kg and Y is brain mass in grams.
For most of the animals the data lie on or close to a line with a slope of
(rounded) 3/4 which is identical to the slope for their metabolic rate. Some
primates (chimpanzees) and marine mammals (dolphins) are an exceptiontheir brains are bigger than their size or metabolic rate would predict from the
allometric relation for other mammals. Humans are farther above the line than
any other animals. This fact suggests that an important indicator for what
might be called cognitive power, including consciousness, is brain size as a
relatively large fraction of body size. Octopuses share this important trait with
some mammals and some birds: a high brain to body mass ratio – an
example of “convergent evolution”. But large brain/body size ratio is also too
narrow a criterion for consciousness, as is vocal mimicry mentioned above.
Though providing strong evidence for the presence of consciousness, both
criteria exclude too many animals that pass other tests. It is sobering to
realize that Neanderthals had bigger brains we do, for similar body size. In
the other direction, the skull of miniature Homo floresiensis (“fossil hobbits”)
held a chimp size brain, but with enlarged frontal lobes. Some interpret this
finding to mean that this hominid species (if it is that) had neural
reorganization that allowed its members to think much as people do, in spite
of its small size.
6) Brain imaging
EEG, fMRI, PET, CAT are prominent methods, used separately and in
some combinations, to peek at brain structure and function in living brains. All are
in clinical use. Of course each has its own special value and limitation (that I
won’t detail here). Recently, reading the brain’s spontaneous magnetic fields is
also being explored. The new science of optogenetics (2002) has matured to the
point that light-driven experiments are now probing the brains of mice, fruit flies,
zebra fish, and nematodes, as well as human neurons growing in dishes, “to get
the neural code for complex things such as reward” (Karl Deisseroth, Stanford
University).
When imaging views can be obtained from conscious subjects, it is
possible to get some idea of which brain regions are most active under highly
specified test circumstances. (A particularly interesting question is where the
most intense activity is when a bilingual person is reading, first a text in his/her
native language, and then in a language acquired later.)
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Imaging approaches can provide some crude empirical patterns
associated with claimed mental states, but they can’t discover the content of
those mental states, nor provide a clue as to how they emerged from brain
states. The images do reveal that consciousness in humans has a physical
substrate in the thalamo-cortical complex that begins to be detectable between
the 24th and 28th week of the ~ 40 week human gestation. By the third trimester
the fetus is continually in either one of two sleep states, called active and quiet,
corresponding to rapid-eye-movement (REM) and slow-wave sleep (SWS)
common to all mature mammals. Imaging has also revealed that the dorsal
lateral prefrontal cortex in humans is not fully formed and active until about age
20 years, and that surprising fact has suggested that mature judgments are not
supported until that age. (Companies insuring teen-age drivers have taken note
of these data.) Homo sapiens has a long childhood and adolescence – the
longest of all in the homin line (Appendix A).
Christof Koch, who has outstanding credentials regarding the quest
for consciousness (1), advises that we should “measure more, argue less” (13).
He based his demand on the study of a patient like that discussed above. He
also cites studies that show that in certain tricky protocols, relying on “people’s
instinct (?) to make money”, there was evidence that something in the brain could
guide the subjects to make “good” choices using unconscious processing that did
not force subjects to focus their consciousness on what they are conscious of.
This effort tested the philosophical theory of consciousness, called higher-order
thought, that specifies when you are conscious of something you can confidently
judge what you saw. The results confounded these expectations.
7) Sleep states
The literature on sleep has become vast since the discovery of its stages
through EEGs. It is clear that consciousness during sleep is lost in SWS yet still
present, in modified form, during dreaming (mostly in REM). Uniquely among
mammals, the Cetacea (whales, dolphins) enter sleep with only one side of their
brains at a time. Sleepwalking is a recognized clinical condition of great interest
because during episodes the subjects are unconscious, as proved by their total
lack of recall of events after they are awakened. During this unconscious mode
people may do very complicated and distinctively human things -- talk, make
phone calls, get into a car and drive off, or even play musical instruments. Mat
Cartmill comments: “This makes it much harder for us to find out anything about
animal awareness. How do we know that animals are not simply sleepwalking all
the time, even when they appear to be awake? Do wolves hunt and horses
gallop in their sleep, in the same way that a human somnambulist gets into the
car and drives off on the freeway at 65 miles an hour?”
Regarding the normal functions of sleep and dreaming, there are too
many theories to detail here. But there is one for dreaming (REM) that I like:
dreams keep the attention circuits tuned up. SWS seems to support the setting of
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long-term memories and modifications of dendritic trees and it cleans up the
metabolic ashes of wakefulness (possibly by removing an accumulation of
adenosine).
I turn now to views of different levels of neural organizations that may
support consciousness.
III.
SOME BOTTOM-UP VIEWS
Are single neurons, or very small clusters, “smart”?
Firing of a single neuron can modify global brain states. Cheng-yu T. Li
Mu-ming Poo and Yang Dan (14) asked whether or not the activity of a single
neuron could switch between two global brain states, resembling SWS and REM,
in anesthetized rats. Whole - cell patch clamps were placed on superficial layers
of visual or somatosensory cortex. Recordings were first made to show that there
were indeed two global brain states, resembling the two sleep states, detectable
in the firing patterns of the single cell. Then different frequency stimulations were
delivered to the single neurons and a global pattern could be switched, as
confirmed by examining local field potentials remote from the stimulated cell.
Previous studies by others had shown that that stimulation of a single motor
cortical neuron could evoke whisker movement and that spiking of a single
somatosensory cortical neuron could induce behaviorally reportable effects. This
study showed that burst spiking of a single neuron can trigger a switch among
global brain states. They conclude that these results underscore the functional
importance of individual neuronal activity. However, these important results do
not necessarily impute “smarts” to the individual neuron providing the switch.
Complex fields in nonlinear systems often have singularities at which a small
input – even noise- can reorganize the field into a new quasi-stable dynamic
state. I believe this study may show an instance of such an effect.
E.Z. Macosko et al. (15) studying the nematode C. elegans, reported that
regulated feeding behavior of this simple animal with only 302 neurons depends
upon a pair of cells (RMG) whose activity is essential for all aspects of their
social behavior. Differences in the foraging styles of this organism can be
explained by variations in the gene NPR-1 whose protein is found associated
with the RMG neurons and these are potent in their global behavioral effects.
That potency arises through gap junction connections to seven other neurons in
a hub- and - spoke arrangement with RMG at the center.
This study confirms that small clusters of neurons can have amplified
effects on whole-animal behaviors. However, a recent report challenges the
conventional view that dense local connectivity in visual cortex of primates forces
nearby cortical neurons to share common inputs, and that sharing must lead to
strong correlations among them. Ecker et al (27), studying the visual cortex of
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monkeys, discovered that even nearby neurons, with similar orientation tuning,
show little if any correlated variability. They conclude that either adjacent neurons
share only a few percent of their inputs, or that “their activity is actively
decorrelated”. In addition, Renart et al simulated recurrent neural networks and
showed that they can generate an asynchronous state characterized by low
mean spiking correlations despite substantial amounts of shared inputs (28 ).
(deletions) Within a network neurons are cooperating, but correlated electrical
activity is not a signature of that cooperation.
Below are two kinds of valuable data that I think have created some misinterpretations (not by their authors) that I call “myths”. Experts in neuroscience
have never endorsed these mistaken views, but in lay publications I have often
encountered them so I expose them here.
1) The myth of “Grandmother neurons”
This term was invented by Jerry Lettvin of MIT , a brilliant neuroscientist with
a proclivity to dramatize aspects of the sciences.
Recently, Moran Cerf et al. at the California Institute of Technology have
shown in epileptic patients with implanted electrodes, that single brain cells can
fire selectively to specific thoughts. The electrodes were able to record activity
from single brain cells in the medial temporal lobe, in a region important for
memory, attention and perception. In each patient the researchers found about
five neurons that fired when the subject viewed an image of a certain person or
object. (e.g., grandmother). Once these neurons were identified, the researchers
wanted to know if the patients could control each cell by merely thinking about
that certain person or object. Indeed, they could. With practice the patients
became increasingly adept at controlling individual neurons with specific
thoughts. To me, this remarkable result does not necessarily mean that the
individual neuron by itself was able to carry out the whole recognition, but only
that when the thought was present the particular cell was a regular participant in
the response. Furthermore, properties of temporal lobe neurons are
extraordinarily plastic - they respond to many different input stimuli. The expert
Charles G. Gross calls attention to these realities in a recent book review
(Science 327:524-525, 2010.)
2) The myth of “mirror neurons”
In the late 1980s and early 1990s, neuroscientists found a population of
cells that fired whenever a monkey prepared to act - but also when it merely
watched another animal act. They called these cells “mirror neurons." However,
we cannot generalize directly from other animals to people. The evidence for
individual mirror neurons comes mostly from studies of macaque monkeys.
Because the studies require placing an electrode in single neurons they are not
likely to be repeated in human beings. Furthermore, it does not follow that mirror
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neurons were structurally and specifically determined in advance during the
development of the brain. Neurons are shaped by experience. In spite of these
striking and interesting data, I remain doubtful that a single type of cell can be
responsible for a single type of experience. Even something as simple as seeing
an edge, results from a very complex pattern of interactions among many
different types of neurons. There are no neurons that by themselves are uniquely
and only “edge detectors”.
Small clusters of neurons supporting a thought that can move matter
Recently, Jose M. Carmena et al. showed that monkeys can learn to move a
computer cursor with their thoughts, using just one set of instructions and a small set
of 75-100 neurons. With training the number of neurons required decreased, and,
remarkably, the same set was used on subsequent days. Furthermore a smaller set
(10-15 neurons) could learn a different task, and later switch from one task to the
other without interference. Thus, the brain can acquire multiple skills using the same
small set of neurons to carry out movements. Again, neuronal networks are plastic.
Genes - Why can’t chimps speak?
Katherine S. Pollard recently summarized DNA sequences that are distinctive in
humans as compared to chimpanzees (Scientific American, May 2009. pp 44-49).
Her list includes FOXP2, HAR1, AMY1, ASPM, LCT, HAR2 and each of these
supports a different process that puts humans at an advantage.
Although our genetic relation to chimps superficially seems close, it does not take
many changes to produce a new species. In the case of speech, the amino acid
composition of the protein that is the gene product of FOXP2 changed rapidly
around the time that language emerged in modern humans. All animals have the
gene, but the human version’s product differs in only 2 of its 740 units from that of
chimpanzees. From study of a large family, half of whose members have severe
problems in articulating and understanding speech, it seemed that this gene was
essential for normal speech production and comprehension, and they had a mutant
version. That importance of FOXP2 has since been confirmed. Daniel Geschwind, at
UCLA, put the chimp version of the gene into cultures of human neurons, and found
that at the cellular level the gene did not do just one thing – but controlled the activity
of at least 116 other genes (see Nature Nov 12, 2009). But there must be more to
the origin of the capacity for speech because the FOXP2 network is present and
equally active on both sides of the human brain, whereas the language facility is
asymmetric.
And, at the very bottom, quantum mechanics (QM) and consciousness
Some serious attempts have been made to anchor consciousness in quantum-level
phenomena. There are two books with a quantum perspective that I have found
informative. The curious reader may enjoy looking at these as an introduction to the
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issues (16,17). Nevertheless, I had never warmed to the idea that quantum physics
could serve as a useful platform for understanding consciousness. Its appeal
seemed to me to arise from the following absurd syllogism:
 Quantum physics is very mysterious and no one really understands it.
 Consciousness is also very mysterious and no one understands it.
 Therefore there must be a quantum-physical foundation for
consciousness.
I had felt that scale differences between macroscopic brain structure and function
and the microscopic dynamics of quantum physics constituted a mismatch, but on
further study I noticed what physicists have always recognized, viz., that some
phenomena and entities are to be best understood simultaneously as both a
classical (macroscopic) system and a quantum system. (Crystals are a common,
simple example. In them micro = macro.) Quantum theory is not restricted to the
explanation of microscopic phenomena only (18).
I have come to respect (some) efforts to present a quantum-physical theory of
consciousness, and in Section VII, I use a concept fundamental to QM, in my
attempt to reconcile the profound differences between brain states and mind states.
(See also Appendix B ).
The common assumption in studies of immaterial consciousness and mental states
is that physical, material, brain states are associated with them, and their source.
That is, they emerge from the material brain. I mentioned earlier that the notion of
emergence has come in and out of favor in neuroscience (and in physics too).
Nevertheless, on page 10 of his splendid book (1), Koch accepts the usefulness of
the term and concept. So do I. Below I examine it. For an argument that emergence
can’t be a proper description of how brain states create mental states, see Galen
Strawson et al.(19) and its rebuttal by Jerry Fodor (20).
IV. EMERGENCE
Brain states are material and therefore susceptible to analysis through normal
principles and procedures of physics, chemistry, and neurophysiology. All
emergent properties, material or immaterial themselves, have an associated
physical, material state or states associated with them at a lower structural and
functional level, consisting of atoms and molecules, cells, reactions and flows.
There are two kinds of emergent phenomena of relevance to consciousness.
They differ in the degree of our ignorance, rather like the differences between the
deeply probabilistic (and profoundly mysterious) quantum mechanics, and the
less mysterious, more trivially probabilistic, statistical mechanics. The first is the
emergence of a new material structure with functions from a material
physiological state similarly constituted. That is the normal condition in the
developing human brain that ultimately has more synaptic connections than can
be specified by its genetic details. The scales are too different. About 50% of the
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total human genome, of at most 25,000 genes, is active, or potentially so, in the
brain, whereas the number of synaptic connections is uncountably large. It has
been estimated to be in the trillions, and ever-changing. The brain is not “hardwired” in advance; its structure emerges. We rely on the current and familiar
activities of interested scientists from cell and molecular biology, biochemistry,
biophysics, neurophysiology, information and computation, brain scans as well
as methods of tissue-section analyses, to advance further our understanding of
material structure → emergent material structures.
This first kind of emergence appears even in statistical mechanics. The
founders of statistical mechanics showed that macroscopic observables were
averages over microscopic states and thus the two intensive thermodynamic
variables, pressure and temperature, were emergent properties of mean field
theories. In contrast to the first kind of emergence is a second kind - that of
immaterial mind from the material brain. This emergence cannot arise directly
from the material to immaterial by any known, normal-science pathways. The
classical reductionist approach leaves us continually to seek solutions at lower
and lower hierarchical levels. To move conceptually in the other direction, we
must apply pruning algorithms at the lower level and look for emergent properties
including new entities that become new agents for behaving according to new
rules at a higher hierarchical level of organization.
Emergence is thus the opposite of reduction
Below I introduce some top-down perspectives, and later will consider whether or
not the concept of emergence bridges the gap between them and the bottom-up
perspectives.
V.TOP-DOWN VIEWS of Brains, Minds and Consciousness
.
Reaching the human mind by introspection
Because introspection is by definition private, it lacks scientific status. However, it
has possibilities. My son Gregory provides this thought experiment based on his
actual experience in a neuroscience laboratory. He presents it as a story:
Late one night a skeptical scientist probed the activity of nerve cells cultured in a
glass dish. Micro-electrodes and flashing fluorescent dyes revealed the complex
activity of the neural web on the bench before him. The scientist studied and
recorded the scintillating patterns closely, gaining ever-deeper understanding of the
network’s functioning. The scientist then had an odd thought:
“Watching these flickering patterns must be causing activity in my own brain. If I had.
myriad micro-electrodes to study the activity of my own brain ( a healthy wholebrain), what cascades and patterns of activity I might then see! But wait. What are
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my own neurons but elaborately ramified micro-electrodes monitoring the activity of
my own brain? If I am in large measure a brain, then what is introspection but
literally “seeing within” – observing the activity of my own brain using neural
microelectrodes? Others may not be able to verify my introspective observations, but
if I am careful to shun my own biases might I not use introspection as a powerful tool
to formulate hypotheses about brain function – hypotheses that could then be tested
in mutually observable ways?”
Boredom. What does your mind do when you are “doing nothing”?
According to some scientists, boredom may be useful as an important source of
creativity. (Watson remarked in The Double Helix that for creative work it helps to be
slightly under-employed.) Data from people lying quietly in an fMRI or other scanner,
waiting to be given a mental task as part of a psychology experiment, reveal that
their brains are then very active in regions presumed to be involved in
autobiographical memories, imagining the thoughts and feelings of others, and
making up hypothetical events. This is a default mind-mode that uses almost as
much energy as does active attention to tasks. It is currently believed to be based on
a network having two major hubs: the posterior cingulate gyrus (with the precuneus)
and the medial prefrontal cortex. It screens a show on our inward eye with scenes
and scripts - imaginative, creative, or foolish.
Jacques Barzun claimed that the mark of an educated person was the ability to sit
quietly alone in a bare room for an hour – and not be bored! A “daydreaming” or
musing person can be far from “spaced-out”, and even creative. The rich rewards
available from this default mode of the brain come most easily to a person feeling
well rested and not sleep deprived. But, there are some who take a different view. In
his unfinished novel The Pale King, David Foster Wallace deliberately introduces
boredom as part of the plot. In a note left with his manuscript he wrote: “Bliss – a
second-by -second joy and gratitude at the gift of being alive, conscious – lies on the
other side of crushing, crushing boredom.“ He likened release from boredom to
“stepping from black and white into color. Like water after days in the desert. Instant
bliss in every atom.”
The mesmerized mind
Research shows that when people act on a hypnotic suggestion, they actually see,
hear and feel differently. When told to see colors, the color-processing parts of their
brains “light up” in scans – despite the absence of any real color in view. In this
mysterious state of mind the subject may seem quiet, but the scans show that the
brain is actually focused and super-attentive. Other studies indicate that hypnosis
can measurably change how the brain works. During color-text conflict tests (e.g.,
the word “red” is displayed colored blue), highly hypnotizable subjects show
diminished activity in the anterior cingulate cortex that is active when people are
trying to sort out conflicting information from different sources. (The fMRI scans were
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done at Weill Medical College of Cornell University and published in Proc Nat Acad
Sci in 2005).
Peter W. Halligan of Cardiff University, in collaboration with Quinton Deeley of King’s
College London, has evidence that hypnosis boosts activity in the prefrontal cortex,
and Yann Cojann (Geneva) found that when a hypnotized subject was told that one
hand was paralyzed, and later directed to use that hand, the motor cortex failed to
send signals to motor execution regions in the normal way, but instead sent them to
the precuneus. (As mentioned above, it is believed that the precuneus is a center for
self-consciousness and mental imagery.) Evidently, hypnosis definitely can alter
mind-body relationships in both an objective and a subjective fashion.
Sleep and sleepwalking
These mental states have already been discussed.
Multiple minds – three views
1. The unconscious normal mind (consciousness as an “afterthought)
Freud’s vision of a tripartite mind, consisting of super-ego, ego and (hidden) id, no
longer commands respect (it tends to turn everyone into a clinical case needing
therapy), but no one doubts that some vigorous mental processing is ongoing of
which the conscious mind, by definition, seems unaware. That busy unconscious (or
subconscious) mind unobtrusively biases the conscious mind, creating and
maintaining various fixed notions such as racial prejudices, sexual preferences,
political positions, and even altruism – all of which reach conscious awareness as
compelling “afterthoughts” (for which the conscious mind takes credit). Steven
Harnad (21) has even suggested that, in general, consciousness is itself a continual
afterthought.
2. The triune brain
Another well-known partitioning of the brain, that has implications for different
classes of brain functioning and mental states, comes from an evolutionary view of
the origins of modern mammalian brain structure. McLean has called it a triune brain
– reptilian, paleomammalian (limbic system), neomammalian. Anatomically they are
the hindbrain, midbrain and neocortex (22).The neocortex is uniquely mammalian - a
sheet-like, six-layered structure, found in all mammals and only in mammals and is
required for their consciousness.
3.Split brains/split minds
The careful studies of epileptic patients who have undergone section of the corpus
collosum have dramatized the correctness of the view that the brain has a
profoundly modular construction. There is a broken symmetry between the two
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hemispheres, each with a “personality” and capacity uniquely its own. The details
are so well known that I won’t recap them here, except to say that it is too easy to
over-interpret the data and over- invest in the view that we have two minds, not one.
Connected, the two normal hemispheres coordinate to establish one coherent
mental state of awareness. Were that not so, we would all suffer from a “paralysis
cogitans”! There are rare instances of people born with a congenital failure to
develop a corpus collosum, and they are less inconvenienced than might be
expected from the split-brain clinical syndrome induced in normally-developed
brains. (Presumably the congenitally defective brain arrives at compensatory
pathways during its development that are not available to normally-developed
brains.)
4. Altered minds (other than by trauma)
Schizophrenia, bipolar disease, autism, addictions and numerous other distortions of
“normal” mental states abound. The mind-altering effects of many common
chemicals such as nitrous oxide, ether, alcohol, caffeine, cocaine, marijuana,
modern centrally-acting general anesthetics, LSD, as well as uncommon therapeutic
drugs of many classes …..demonstrate dramatically the existence of a
physical/chemical foundation from which non-physical mind emerges. (Those who
like to believe that the mind lives in “another world”, separate from the body, might
profitably take notice that it stands in that other world with feet of clay!)
At this point, having presented some samples from both bottom- up and top-down
views, and also the possibly bridging concept of emergence, I now mention an old
issue in the field of consciousness studies.
The interaction problem between brains and minds
In this essay, up to now, I have focused on the conventional problem of deriving
(emergent, higher-level) mental states from (lower-level) brain states. But the
inverse problem – the ability of mental states to affect brain and body states is
equally formidable. Many studies have shown that how we process information
depends not just on our brains, but on our entire body. The famous James-Lange
theory of emotions proposed that brain/body states cause the mental states of
emotions. But, it was opposed by the Cannon – Bard theory, from two very
distinguished physiologists, who theorized instead that bodily changes associated
with emotions were caused by the emotions. The issue of interactions between
brains and minds remains a central problem in neuroscience today. In Section VII I
shall return to this issue.
At this point I have arrived at the conclusion, based on known structures and some
functions, that we can justifiably claim: All mammals possess consciousness – an
ability to be aware of themselves as an individual, and of others in a kinship group,
and to play. Playing may in some cases be a rehearsal for hunting or other foodgathering behavior, but it is more than that in its seemingly gratuitous excess
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capacity for fooling around, teasing, competing in mock fights. But only a few
mammals have been proven to be able to read the minds and intentions of others,
as living in organized social groups requires.
.
SOCIAL NETWORKS
As the audience for this Lecture Series knows well, modeling of small networks has
become basic to “computational social science”, as can be seen in the titles of
recently scheduled presentations. They include: Social Networks and Human Social
Complexity (D. White), How Cooperation Emerges from Conflict: an Agent-Based
Model of Security Network Formation (Zeev Maoz), Power and Exploitation in
Exchange Networks (P. Bonacich), Large Scale Structure in Complex Networks
(Joerg Reichardt). My attention was initially drawn to small world networks by the
work of Steven Strogatz and Duncan Watts. Networks with properties between
completely ordered and completely random appear widely, from neural networks of
nematodes to the power grid of the United States. In the case of human social
networks, the advent of mobile phones tied to the internet generate data about
networks of contacts rich enough and fast enough to permit robust theory building
and testing.
In his now –classic Sociobiology : The New Synthesis, E.O. Wilson set the scene for
subsequent discussions of social mechanisms, symbioses, evolution and much
more. He examined “societies” ranging through slime molds and colonial bacteria,
insects, cold-blooded vertebrates, birds, mammals, non-human primates and
humans. There is no need for me to try to add to that masterpiece with a synoptic
view of my own. Instead, I’ll offer some comments on the importance of networks as
underlying structure of advanced social groups, that makes them much more
than mere aggregates, or kinships. By “advanced” I mean that the members of the
social group must have awareness of, and sensitivity to, the states of minds and
intentions of others. That restriction eliminates from consideration here of most of
the “societies” of other animal life, including hives ,herds, flocks, schools,
prides….etc. In fact, on the available evidence, I claim that it leaves only members of
the hominin line (genus Homo) and requires language. Behaviors and feelings must
be able to travel and disperse through an advanced network to constitute a culture.
.
What can we learn about social networks from comparing signs of consciousness in
apes and in us?
Although the phenomenon of conscious awareness clearly extends to more animals
than just humans and chimps, it has been customary to look closely at the
differences between humans and chimps, both of whose genomes have been
largely decoded, for clues to the character of consciousness, given that ours is
uniquely expanded in potential compared to that of chimps. The comparisons usually
take a top-down view of three contrasts: 1. Distinctive mental processes, 2.
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Evolutionary histories including tool use, 3. Aggressive versus cooperative
behaviors. (Speech is another contrast that I already discussed under “genes” in
Bottom-Up Section III.)
1. Distinctive human mental processes
Marc Hauser recently suggested that there are four key and unique ingredients of
the human mind: 1. generative computation, 2. promiscuous combination of ideas, 3.
mental symbols to encode sensory experience, 4. abstractions permitting
contemplation of things beyond what we can see, hear touch, taste or smell.
(Scientific American Sept. 2009, pp 44 – 51). I would add music explicitly to
Hauser’s list. It has “a language of its own” (24).
Although we do not know exactly when the modern human mind took shape, it is
clear from the archeological record that a major transformation occurred during the
relatively brief period of evolutionary history, starting approximately 800,000 years
ago and accelerating 45,000 to 50,000 years ago (when evidence of hearths and
community gatherings around a fire, and cooking appear). The selection pressures
that may have been forcing the advances are currently thought to be climate
variability.
2. Evolutionary histories: Becoming human- some timelines. ( See Appendix A.)
Working with three nearly complete human genomes, Chad D. Huff and Lynn B.
Jorde reported that from Alu insertions and the amount of variation seen in the DNA
immediately surrounding the insertions, they could calculate the size of the human
population (Homo sapiens) about 1.2 million years ago, from which everyone in the
world is descended. Their estimate is from 600 to 18,500 people. The beginning of
the hominin line, of which modern humans (Homo sapiens ) is the latest version, has
recently been pushed back (controversially) to 4.4 million years ago (mya) by the
publication of analyses of the fossil skeleton named “Ardi” ( from Ardipithecus
ramidus). (See Appendix A.) Previously “Lucy” (Australopithecus afarensis) held the
record at about 3.5 mya.
As mentioned above (Tools) members of the human evolutionary family are known
to have made and used stone tools of increasing complexity since about 2.5 mya.
(Homo habilis – the first member of Genus Homo.) Recently, a new field, “primate
archeology”, merges contributions from archeology, anthropology, primatology and
psychology, to explore past material cultures among apes and, perhaps, other
nonhuman animals. Modern chimps crack nuts in a series of steps that imply an
awareness with focused attention to details: First, lug large rocks to a spot near a
nut-bearing tree; next, gather nuts and place them on the rocks; then, obtain a
smaller, graspable rock; and finally, smash the nuts open. Early hominids had
chimp-sized brains, making comparisons appropriate. A new analysis of previously
21
unearthed sites of hominid fossils (Olduvai Gorge in Tanzania) reveals evidence of
stone-on-stone pounding. In the hominid line techniques seem to have been passed
from one generation to another. Modern chimps show some tendency to do the
same, but it isn’t known how long ago they acquired that inclination. The emerging
speculation is that at the time when hominins had chimp-sized brains, they may also
have had a chimp-like “culture”.
For amusing speculations, consider that our advanced cultures may evolve further,
possibly reaching the famous “Omega Point” of Pierre Teilhard de Chardin.
3. Aggressive versus cooperative behaviors
The literature on this subject, full of anthropocentric projections, can’t decide
whether chimps are basically peaceful and empathetic, or dangerously harmful.
Gorillas are known to be “gentle giants”. The Bonobo apes have sometimes been
presented as a delightful yet irrelevant side branch of our family tree, whereas we
are more like the blustering chimps. They can be killers. They have fearsome fangs.
(Ardi did not, so maybe the chimps are outliers?) Cooperative behavior and signs of
caring for others does appear occasionally among chimps, and the new field of
“behavioral economics” notes that not only humans, but monkeys, elephants and
dolphins do not always seek maximum benefits for themselves in social settings. But
apes and monkeys make dangerous pets. The have a propensity for jealousy and
misunderstanding of human body language that has led to vicious, destructive and
even lethal attacks with little warning. Furthermore, apes and monkeys manifest a
range of behaviors that we might interpret as covering the whole range of our “seven
deadly sins”: pride, greed, lust, sloth, envy, gluttony and avarice. They are surely
conscious.
The history of weapons documents stone tools, as mentioned above, to 2.5 mya.
Stone, as well as fire-hardened wood, tips of spears appear 250,000 – 100,000
BCE. So did bows and arrows and more effective knives with sharper edges. These
were hunting tools. It is not certain exactly when these tools began to be used
against humans. Signs of warfare are evident from bodies killed with stone-bladed
weapons at Jebel Sahaba (now Egypt) 12,000 – 5,000 BCE. At that time humans
were making transitions from hunter-gatherer to agriculture, and living in settled
communities. Jericho (now Israel) and Catal- Hüyük (now Turkey) had fortress walls
7,000-6,000 BCE, that imply wars (though some think that they have been merely
mud-guards!). By that time the city-states had become empires fielding armies of
professionals with weapons made especially for killing humans. Are we like the
chimps, or not?
Advanced social networks generate a “culture” of shared knowledge. That fact offers
an explanation of the seemingly peculiar consequence that the new Homo sapiens is
the last species of the hominin line still alive today. Consider that H. erectus lasted
from almost 2 million years ago to the near present ~50,000 years ago. Homo
erectus spawned both H. sapiens and H. neanderthalensis (via H. heidelbergensis –
22
see Appendix A) about 300,000 – 400,000 years ago, and the Neanderthals lasted
until about 25,000 years ago. Why are they all extinct while we are survivors?
Survivors of what? Climate variability. The evidence is compelling that in the past
200,000 years the climate of the earth has had abrupt and huge swings between hot
and cold, wet and dry, in many regions. During that time getting sufficient calories for
maintenance became increasingly difficult. Species with specialized diets (e.g.,
carnivores, as the Neanderthals were) had trouble adapting. H. sapiens did not, and
found new ways to hunt (throwing spears, bows and arrows) and as coastal regions
of Africa offered a mellower climate than inland regions, H. sapiens learned to get
food from the sea. . Doing that successfully required noticing some connection
between phases of the moon and tidal processes. H. erectus and H.
neanderthalensis made no significant change in their tools, locations, diets or
strategies for over 2 milllion years. In contrast, 50,000 years ago H. sapiens already
had hearths, speech, and gatherings around pit fires where they cooked food (easier
to digest) and no doubt, shared experiences. Modern human consciousness was
forming in full strength out of that cultural network – a likely time and place for the
birth of philia, - friendship, comradeship or brotherly love. Climate variability forced
cultural adaptations that only H. sapiens could make.
And yet, minds and thoughts still seem uncomfortably distant from all that we learn
about the material brain. Below are two ideas that have occurred to me as pointing
toward a reconciliation across the phenomenological gap.
VII. Summing Up – Two missing themes may help “explain” consciousness
First Theme: Complementary conjugates
The Principle of Complementarity from quantum mechanics (QM) (see Appendix B)
asserts that some features of physical reality come in conjugate pairs. With a
“prepared system” of measurement (observation) you the observer can address only
one at a time. What you discover with each separate view cannot invalidate
whatever you discover with the other view, using a different prepared system to
access it. Separately considered, the two views may seem contradictory in the
(limited) mind of the observer. The famous example, of course, is the wave/particle
duality of an electron. There is no bridge between the two views and no interactions.
They just have to accepted for what they are – complementary conjugates, equally
valid versions of some otherwise inaccessible deeper reality.
All attempts to build a rational, reductionistic, formal bridge, using normal science (
in Kuhn’s sense), between brain states and mental states including consciousness,
having demonstrably failed, I suspect that they will continue to fail because they
frame the problem in the wrong way.
23
Here is a novel proposal that may succeed. It offers a new frame, analogizing from
QM principles. It asserts three propositions:
1. All mental states, conscious or not, are manifestations of complementary,
conjugate brain states.
2. Consciousness is a special instance of such a mental state manifestation of a
conjugate brain state.
3. Because the underlying reality is always, and only, brain states,
no “interaction” rule is required to connect mind states and brain states, and the
need for the concept of emergence is diminished.
The reason that immaterial mental states can affect the body is that they do so
through their associated brain-state conjugates which, like all other body states, are
material. In QM terms, we can speculate that an immaterial thought, when it
generates a perception or action, has “collapsed the wave function” so a material,
observable brain/body state results. (I can’t discuss here “collapse of the wave
function” during measurement or observation. It is a classical but not simple issue in
QM.)
There may be a notable difference between wave/particle duals and my proposed
brain- state/mind- state conjugates. The latter pair can be observed simultaneously
as individual aspects of reality, whereas the former cannot - except by
superposition, in which their separate identities are lost. By superpositioning, we
can see light, without noticing its photon conjugate pairs. I recall Penrose’s proposal
that superpositioning plays an essential role in consciousness (25).
NOTE: there are a few physical, “prepared systems” that can access brain states
directly (e.g.,electrical recordings, scans) but they do not give unique answers.
Recall that, as mentioned in Section II, sets of same neurons can participate in
different tasks at different times.
NOTE: Two “prepared systems” can probe mental states directly: 1. introspection on
the part of a human subject whose mental state is being assessed and 2.
communications from any subject, animal or human, to observers. The
communications can be by “languages” (speech, signing, specific gestures, signal
flags, waggle dances of honey bees), or by various sounds (screams of pain, Morse
code), pheromones (ants) or some motor actions using a special code. Recall the
locked-in syndrome of J-B Bauby (Section 1) who could demonstrate that he was
conscious and cognitively intact using only coded eye-blinks observed by a
confederate who set up the code. Though he appeared on casual observation to be
an example of the “living dead”, Bauby proved that he had full cognitive powers by
“writing” an amazing book. (See also the brain imaging subsection of Section III.)
Second Theme: The arts and the problem of qualia
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(The following discussion was strongly inflenced by a “Features” article in the
November/December 2007 issue of SEED Magazine.)
The epic questions that modern science must answer cannot be solved by science
alone. Karl Popper wrote: “It is imperative that we give up on the idea of ultimate
sources of knowledge, and admit that all knowledge is human; that it is mixed with
our errors, our prejudices, our dreams, and our hopes; that all we can do is grope for
truth even though it is beyond our reach.” Novelists can simulate the latest theory of
consciousness in their novels. Noam Chomsky has declared that “It is quite
possible- overwhelmingly probable, one might guess – that we will always learn
more about human life and personality from novels than from scientific psychology.”
No scientific model of the mind will be wholly complete unless it includes what can’t
be reduced. Science rightly adheres to a strict methodology, relying on experimental
data and testability. But until science sees the brain from a more holistic perspective
such as those to be found in the artistic imagination, our scientific theories will be
detached from the way we see ourselves.
Our mind evolved in a simplified world, where matter is certain, time flows forward
and there are only three dimensions. When we venture beyond these innate
intuitions, we are forced to resort to metaphor. Einstein used moving trains;
Eddington compared the expansion of the universe to an inflated balloon; Maxwell
thought of magnetic fields as little whirlpools in space (vortices); the Big Bang is a
cosmic firecracker; and Schrödinger’s cat is neither alive or dead until we look. Bohr
said that quantum properties reminded him of cubist paintings - the form they took
depended on how you looked at them.
My point is that modern science has made little progress toward any unified
understanding of everything. Our unknowns have not dramatically receded, but in
many instances the opposite has happened. We don’t know the answers, and we
don’t always know how to frame the questions. In neuroscience we have fascinating
details and more to come, but they highlight an enigma which is that we don’t
experience these cellular details. It is ironic, but true, that the one reality
science cannot reduce is the only reality we will ever intimately know. And the
arts bring us closer to it than does science.
Considering that consciousness, besides expressing awareness, also draws heavily
on memories, it is appropriate to re-visit the opening paragraph of A la Recherche du
Temps Perdu (1911), variously translated as “In Search of Lost Time” or
“Remembrance of Things Past”. Proust is remembering eating a madeleine (a
buttery cookie flavored with lemon zest and shaped like a sea shell), and dipping it in
his tea:
No sooner had the warm liquid mixed with the crumbs touched my palate than a
shudder ran through me and I stopped, intent upon the extraordinary thing that was
happening to me. An exquisite pleasure had invaded my senses, something
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isolated, detached, with no suggestion of its origin. And at once the vicissitudes of
life had become indifferent to me, its disasters innocuous, its brevity illusory; it was
me. I had ceased to feel mediocre, contingent, mortal. Whence could it have come
to me, this all-powerful joy? I sensed that it was connected with the taste of the tea
and the cake, but that it infinitely transcended those savours, could not, indeed, be
of the same nature. Whence did it come? What did it mean? How could I seize it and
apprehend it?.....It is plain that the truth I am seeking lies not in the cup but in
myself.
I close with a poem by Robert frost:
We dance round in a ring and suppose,
But the Secret sits in the middle and knows.
The End
APPENDIX A. The hominid to hominin (Genus Homo) evolution.
An excellent recent account can be found in the PBS three-part series entitled
Becoming Human, available as a DVD disc. It provided a background for my
synopsis below and credits the scholars who developed the data and
interpretations.
Below is a list of the genera and species lineages plus approximate dates and
brain sizes (estimated from endocasts of skulls). Dates are estimated beginning
of a range for the species.
Hominids
!0 - 6 million years ago (mya) hominid line (Ardipithecus kadabba) separated
from ape line. Chimp brain size then and now ~ 400 cc.
4.6 mya. Ardipthecus ramidus (“Ardi”) brain size ~ 420 cc
4.2 mya. Australopthecus anamensis
Start of long period of steady climate.
3.8 mya Au. Afarensis, including “Lucy” 3.2 mya. First creatures remotely like us.
Walked upright much of the time. No other mammal does it. Note: bipedalism
believed to be the driving force of further brain development, not because of
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seeing further, but because it is more efficient locomotion and reduces caloric
requirement. Climbing trees is energetically expensive.
2.8 mya Au. Africanus
Start of highly variable climates that continued for next 1.5 million years.
That variability was the likely driving force for emergence of genus Homo.
Hominins: Genus Homo
2.3 mya H. habilis. Carpal navicular wrist bone like ours, indicative of more
supple hands and thumbs. Brain size 800 cc.. Still some ape-like features –
short.
1.8 mya H. erectus, “Turkana Boy” (TB) fossil 1.5 mya - brain 900 cc (twice that
of chimps); face structure more like ours. 5” 3” tall. Rapid maturation, short
childhood over by age 8. H. erectus was hanging on in Asia 50,000 years ago. H.
erectus was basically us, except that we have much longer brain
developmental time – up to age 20 years. TB’s fossil showed signs of an
enlarged Broca’s area, suggesting speech. That is what makes us human. TB
was hairless and could sweat (evidence from lice types!) Permanently bipedal. H.
erectus was built to run long distances without overheating. Hunted by running
game until the prey were exhausted from the heat. (Bushmen do that today.) H.
erectus had fire, cooking and advanced tools. They left Africa 1.8 mya. Skulls of
elderly without teeth indicate that they were being fed by others. H. erectus was a
caring species. There are other social animals, but none like us, as H. erectus
was.
500,000 years ago H. heidelbergensis. Hand axes found with many Homo bones
in a deep pit in Spain, perhaps indicating ceremonial burials; offerings; symbols
of beliefs?
By 250,000 years ago very specialized tools have appeared, with stone or firehardened tips of throwing spears, bows and arrows and flint knives. The human
ancestors that left Africa to explore the rest of the world may have done so
sooner than we have thought, and by sea as well as by land. On January 7, at
the 2010 meeting of The Archeological Institute of America, Thomas Strasser
presented data showing that stone hand axes unearthed on the island of Crete
indicate that an ancient Homo species – perhaps Homo erectus- had used rafts
to cross from northern Africa to Europe via some of the larger islands in between.
Many of these axes resemble those fashioned in Africa about 800,000 years ago
by H. erectus. Strasser said that “We’re just going to have to accept that as soon
as hominids left Africa, they were long-distance seafarers….” If so, they were
skilled tool makers and users.
250,000 years ago H. neanderthalensis Brain size 1400 cc. (larger than ours).
Endocasts show frontal lobes and Broca’s areas like ours. Lasted until 25,000
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years ago. Their tools did not evolve nor did their carnivorous diet ever change.
Last evidence was of a small population on Rock of Gibraltar. Genome now
decoded: FOXP2 speech gene same as ours. We and they have a common
ancestor – evidently H. heidelbergensis 300,000 – 400,000 years ago. No
interbreeding.
200,000 years ago H. sapiens. Brain size 1350 cc. Founding population was only
about 600 fertile members, about 1800 in all. Gene bottleneck –little diversity.
140,000 years ago most of Africa became uninhabitable – drought, except at
coasts. H. sapiens moved there and learned to fish – diet became diverse. Tools
evolved – fire hardened spear tips, cutting tools with thin, sharp blades. Could
get more out of the environment. Painted shells with holes suggest
ornamentation and symbolic art. Culture.
50,000 years ago – there were at least four different kinds of species Homo living
simultaneously, but without interbreeding.
30,000 years ago. Advanced cave paintings. Fully human minds at work. Culture.
18,000 years ago H. floresiensis (Hobbit”). Brain size only 400cc, but endocasts
of skull show brain reorganization compared to chimps with brain of same size.
Hints of speech capability.
APPENDIX B. Relevant Theme from Quantum Physics?
Quantum physics has four deep and fundamental principles that might be
invoked to help explain consciousness: Superposition, Heisenberg Uncertainty,
Bohr Correspondence, Bohr Complementarity, Two additional principles are
quantum coherence and “entanglement”, neither of which do I think pertains to
consciousness as a phenomenon. In the essay and here I use “QM” as a
shorthand for the larger domain of quantum theory that includes “classical”
(ending with the work of Paul Dirac around 1929), and the subsequent
developments of quantum field theory QFT, quantum electrodynamics QED. I
require only classical QM and QFT for my arguments. Below is a sketch of the
first four principles.
Superposition
A striking feature of quantum mechanics (QM) is the existence of superposition
states in which an object seems to be in different situations at the same time.
The existence of such states has been proved for small objects like atoms, ions,
electrons, photons and, even, molecules. Schrödinger’s famous live/dead cat
gedanken paradigm has become the archetype for provocative discussions of
superposition. It is a combination of basis states written:
aІ state 1› + bІ state 2› + …..
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Roger Penrose, in his Shadows of the Mind: a search for the missing science of
consciousness (25) (1994) Oxford Univ Press, argues for the trans - computable
character of mind, while still accepting that it arises from brain states. He calls for
some modification of physics to accommodate that claim. (Although he picks the
wrong biological platform for the response element to quantum physical thoughts
– microtubules - the book is otherwise a good account of the nature of the
consciousness problem. ) Penrose says we need to confront the concept of
superposition and imagine that it is the state of atoms and subatomic particles,
that we can’t see or even measure in functioning brains, that determines the
state of the mind. He proposes that it is this coherent superposition of particles
plus his newly-proposed, quantum wave function called “self-collapse”
(objective reduction), that constitute the QM basis of consciousness.
Heisenberg Uncertainty
The common form of this well-known principle states that it is not possible to
simultaneously determine the position and momentum of a particle. In its
compact form:
Δ xΔpx ≥ ½ħ
(Some forms use Planck’s constant h, instead of the preferred ħ, omitting the
factor of 2.) Heisenberg’s original paper in 1927 did not attempt to determine the
exact quantity on the right side of the inequality, but used a physical argument to
show that the uncertainty between conjugate quantum mechanical variables is
approximately h. (This principle has attracted the attention of a lay public that
regularly misrepresents it with sloppy generalizations.)
Bohr Correspondence Principle
This is a fundamental hypothesis proposed by Bohr in the early 1920s, according
to which classical mechanics can be understood as a limiting case of quantum
mechanics; or conversely, many characteristic features in quantum mechanics
can be approximated on the basis of classical mechanics, provided the latter is
properly interpreted. Since 1925, because of the success of wave mechanics in
QM, the correspondence principle became diminished to a vague article of faith
among physicists. Today, however, it has regained significance in cases where
the traditional methods of QM are not very useful, and it is recognized that the
correspondence principle is still valid.
Bohr (Copenhagen) Complementarity
This principle states that sometimes an object can have several different
(apparently) contradictory properties (e.g., micro and macro views, wave or
particle). We can switch back and forth between the different views, but we can
never see both members of the pair at the same time, although in reality the
object exists in both at the same time. The wave/particle duality is the most
famous case. Every experiment (on a quantum particle) is an “interaction”
between the measuring apparatus and the particle. Example: the interaction
needed for a position measurement is not the same as that for a momentum
29
measurement. They are complementary (conjugate) quantities and measuring
one excludes measuring the other at the same time.
NOTE:To justify extending this principle to the proposed brain/mind conjugates
(which in special observational schemes can be viewed simultaneously) I find it
necessary to invoke superposition as well. Penrose did also.
Comments
These four principles are distinct and should not be confounded. Taken together,
Complementarity and Uncertainty dictate that all properties and actions in the
physical world must be non-deterministic to some degree. (It has been suggested
that “free will” takes advantage of that non-determinism.) Of the four principles,
only Complementarity seems to me to offer a new way of looking at the
brain/mind duality.
I was once invited to be a “ Celebration Speaker” at a huge gathering celebrating
Paul Dirac’s 80th birthday .( The organizers wanted to have a few tame biologists
there even if they couldn’t understand in formal detail, Dirac’s tremendous
achievements – all in mathematical form.) Dirac was a strong believer in the
beauty of mathematics, and therefore, he insisted, of Nature itself. He expressed
great distaste for philosophical interpretations of his discoveries and refused to
engage in arguments about interpretations. In a recent essay on Dirac , Freeman
Dyson explains: “Confusion arises from misguided attempts to translate the laws
from mathematics to human language. Human language describes the world of
everyday life, and lacks the concepts that could describe quantum processes
accurately.” (See Silent Quantum Genius, by Freeman Dyson, The New York
Review. February 25, 2010, pp20 -23.) Of course, I agree, and feel very diffident
about throwing words at the problem of brain/mind connections from a QM angle.
Unfortunately, I have to think metaphorically; it’s all I can do. Of the four
principles, Complementarity and Superposition, seem to me to offer a fresh way
of looking at the brain/mind duality. In the essay Section VII, where I suggest that
brain states and mental states are complementary conjugates that are
superimposable, I assume that we can explore them separately in different
observational settings , as we normally in do, but we also can detect both
simultaneously in special situations - as in talking to a subject while an fMRI scan
is being obtained, at which time, in QM language, it might be said that the “wave
functions” have already been “collapsed”.
.
REFERENCES – WITH SOME ANNOTATIONS
1. Koch 2004. The Quest for Consciousness – a Neurobiological Approach
.Roberts, Englewood, Colo.
2. Monod, J. Chance and Necessity (1971). Knopf, N.Y.
3. Morowitz, H.J. The Emergence of Everything; How the World became
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Complex. Oxford.
4. Nisbett, R.E. 2003. The Geography of Thought- How Asians and
Westerners Think Differently – and Why. Free Press, N.Y.
5. J.B.Watson. Psychology Review (1913) pp 158-167.
6. .Gould, J.L. and C.G. Gould: The Animal Mind (1994). ,Scientific American
Library, N.Y.
7. Edelman, D.B. and A.K. Seth. Animal consciousness: a synthetic
approach. Trends in Neuroscience. Sept. 2009;
8. Cartmill, M. The problem of animal consciousness. Natural History, March
1998
9., Griffin, D. Animal Minds: Beyond Cognition to Consciousness, 2003.
10. Giurfa, M. et al. J Exp. Biol. Feb 15, 2010).
11. Wilson, E.O. Insect Societies . (Updated): Holldobler, B. and E.O. Wilson.
The Superorganism: The Beauty, Elegance, and Strangeness of Insect
Societies. (2009). Norton, N.Y.
12. Magoun, H.W. (Am. Archives of Neurology and Psychiatry 67:145-154,
1952
13. Koch, C. Scientific American Mind February/March 2009 pp 16-17.
14. Cheng-yu T. Li Mu-ming Poo and Yang Dan (14) (Science 234:643-645,
2009)
15.. Macosko, E.Z. et al. (Nature 458: 1171- 1175, 2009)
16.Delbrück, M. Mind from Matter? An essay on evolutionary epistemology.
(1986). Blackwell, Palo Alto. This is a surprising contribution from a
physicist with a Nobel prize who later turned his attention to biology. The
book is not an easy read. The first 9 chapters deal with biology, but
chapters 10 – 18 require a knowledge of physics, mathematics, and logic
that will likely require hard study from most biologists.
17. Vitiello, G. My Double Unveiled: The dissipative quantum model of brain.
(2001), John Benjamins Publishing Co. Philadelphia. The author draws
attention to an important distinction between Quantum Mechanics (QM)
and Quantum Field Theory (QFT). He emphasizes that QFT usefully
dissolves the distinction between structure and function, and has the
capability for formally connecting certain macroscopic features of the
brain (collective properties) to collective modes born out of the
microscopic quantum dynamics.
18, Umezawa, H. et al. Advanced field theory -: micro, macro and thermal
concepts. (1993). American Institute of Physics. N.Y.
19. Strawson, G. et al. Consciousness and its Place in Nature. Imprint
Academic. 2006
20. Fodor, J. . London review of Books, 24 May, 2007 pp 9- 10.
21. Harnad, S. Consciousness – An Afterthought. J. Theoret. Biology
22 McLean, P. 1977. On the evolution of three mentalities. New Dimensions
in Psychiatry. Vol II. Wiley, N.Y.)
23. Wilson E O Sociobiology : The New Synthesis (Belknap Press, 1975),
24. Katz, R. , A Language of its Own. Univ. of Chicago Press, 2009.)
25 Penrose, R., Shadows of the Mind: a search for the missing science of
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consciousness(25) (1994) Oxford Univ Press
26. Edelman, G.
a. Neural Darwinism – The theory of neuronal group selection. (1987)
. Basic Books, N.Y
b.The Remembered Present – a Biological Theory of Consciousness.
(1989).Basic Books, N.Y.
c.(with G. Tonini) A Universe of Consciousness – How Matter becomes
Imagination. (2000).Basic Books, N.Y
d. Wider than the Sky – the phenomenal gift of consciousness. (2004).
Yale Univ. New Haven
e. Second Nature – brain science and human knowledge. (2006). Yale
Univ. New Haven.
27. Acker, A.S. et al. Decorrelated neuronal firing in cortical microcircuits
. Science: 327:584-587, 2010.
28. Renart, A. et al. The asynchronous state in cortical circuits. Science 327:
587-590. 2010.
29. Collini, E. et al. Coherently wired light-harvesting in photosynthetic marine
algae at ambient temperature. (Nature 463:644-647, 2010.
A few books about minds and mental states that open the door to the mysteries
I have over 50 books that address brains, minds and consciousness in my personal
library. Many are now old, but in my view some are still valuable for their outlining
the problems, their bibliographies, and their conjectures. Though progress in
neuroscience has been made in cell and molecular biology and brain imaging since
they were published, we still lack a deep understanding of how mental states arise
from brain states. I believe that mystery is just as intractable today as ever –
perhaps because we are looking in the wrong places or in the wrong way. (I’ll return
to that point in Section VII.)
Here is a small sampler of books, in no particular order, perhaps useful to anyone
starting out on a serious quest for a scientific account of minds and consciousness.
Most of them received extensive reviewing when they were new, and heavy
criticisms in some cases.
Gazzaniga, M. Mind Matters: How the mind and brain interact to create our
conscious lives. (1988) Houghton Mifflin Co. Boston. The author is well-known for
his studies of “split-brain” patients. Here he address in separate chapters the mental
states of pain, memory, intelligence, psychoses, anxiety, depression, obsessions
and compulsions, addiction, love, sleeping and dreaming, stress, healing. The
appeal of the book stems from the fact that Gazzaniga is a first-rate neuroscientist.
Humphrey, N. A History of the Mind. (1992). Harper Perennial. N.Y.
Schwartz, J.M. (with Sharon Begley). The Mind & The Brain: Neuroplasticity and the
power of mental force. (2002) Harper Collins, N.Y.
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Harth, E. Windows on the Mind. 1983. Quill, N.Y.
Hofstadter, D. and Dennett, D. (Editors) The Mind’s I – Fantasies and reflections of
self & soul. (1981). A collection of wildly varying essays by many authors. Basic
Books, N.Y..
Dennett, D. Kinds of Minds: Toward an understanding of consciousness. (1996).
Basic Books, N.Y.
Minsky, M. The Society of Mind. (1985). Simon and Schuster, N.Y.
Searle, J.R.The Mystery of Consciousness. (1997) including exchanges with Daniel
Dennett and David J. Chalmers. The New York Review of Books, N.Y.
J.Allan Hobson. Consciousness. (1999). Scientific American Library, N.Y.
33