How the Brain Creates the Mind
We have long wondered how the conscious mind comes to be. Greater understanding
of brain function ought to lead to an eventual solution
At the start of the new millennium, it is apparent that one question towers above all
others in life sciences: How does the set of processes we call mind emerge from the
activity of the organ we call brain? The question is hardly new. It has been f ormulated
in one way or another for centuries. Once it became possible to pose the question and
not be burned at the stake, it has been asked openly and insistently. Recently the
question has preoccupied both the experts--neuroscientists, cognitive scien tists and
philosophers-and others who wonder about the origin of the mind, specifically the
The question of consciousness now occupies center stage because biology in general
and neuroscience in particular have been so remarkably successful at unraveling a
great many of life's secrets. More may have been learned about the brain and the m ind
in the 1990s--the so-called decade of the brain--than during the entire previous history
of psychology and neuroscience. Elucidating the neurobiological basis of the conscious
mind--a version of the classic mind-body problem--has become almost a resi dual
Contemplation of the mind may induce timidity in the contemplator, especially when
consciousness becomes the focus of the inquiry. Some thinkers, expert and amateur
alike, believe the question may be unanswerable in principle. For others, the rele ntless
and exponential increase in new knowledge may give rise to a vertiginous feeling that
no problem can resist the assault of science if only the theory is right and the
techniques are powerful enough. The debate is intriguing and even unexpected, as no
comparable doubts have been raised over the likelihood of explaining how the brain is
responsible for processes such as vision or memory, which are obvious components of
the larger process of the conscious mind.
I am firmly in the confident camp: a substantial explanation for the mind's emergence
from the brain will be produced and . perhaps soon. The giddy feeling, however, is
tempered by the acknowledgment of some sobering difficulties.
Nothing is more familiar than the mind. Yet the pilgrim in search of the sources and
mechanisms behind the mind embarks on a journey into a strange and exotic
landscape. In no particular order, what follows are the main problems facing those who
se ek the biological basis for the conscious mind.
The first quandary involves the perspective one must adopt to study the conscious mind
in relation to the brain in which we believe it originates. Anyone's body and brain are
observable to third parties; the mind, though, is observable only to its owner. Multiple
individuals confronted with the same body or brain can make the same observations of
that body or brain, but no comparable direct third-person observation is possible for
anyone's mind. The body and its brain are public, exposed, externa l and unequivocally
objective entities. The mind is a private, hidden, internal, unequivocally subjective entity.
How and where then does the dependence of a first-person mind on a third-person
body occur precisely? Techniques used to study the brain include refined brain scans
and the measurement of patterns of activity in the brain's neurons. The naysayers argue
that the exhaustive compilation of all these data adds up to correlates of mental states
but nothing resembling an actual mental state. For them, detailed observation of living
matter thus leads not to mind but simply to the details of living matte r The
understanding of how living matter generates the sense of self that is the hallmark of a
conscious mind--the sense that the images in my mind are mine and are formed in my
perspective--is simply not possible. This argument, though incorrect, tends to silence
most hopeful investigators of the conscious mind.
To the pessimists, the conscious-mind problem seems so intractable that it is not even
possible to explain why the mind is even about something--why mental processes
represent internal states or interactions with external objects. (Philosophers. r efer to
this representational quality of the mind with the confusing term "intentionality.") This
argument is false.
The final negative contention is the reminder that elucidating the emergence of the
conscious mind depends on the existence of that same conscious mind. Conducting an
investigation with the very instrument being investigated makes both the definit ion of
the problem and the approach to a solution especially complicated. Given the conflict
between observer and observed, we are told, the human intellect is unlikely to be up to
the task of comprehending how mind emerges from brain. This conflict is r eal, but the
notion that it is insurmountable is inaccurate.
In summary, the apparent uniqueness of the conscious-mind problem and the difficulties
that complicate ways to get at that problem generate two effects: they frustrate those
researchers committed to finding a solution and confirm the conviction of others who
intuitively believe that a solution is beyond our reach.
Evaluating the Difficulties
THOSE WHO CITE the inability of research on the living matter of the brain to reveal
the "substance of mind" assume that the current knowledge of that living matter is
sufficient to make such judgment final. This notion is entirely unacceptable. Th e current
description of neurobiological phenomena is quite incomplete, any way you slice it. We
have yet to resolve numerous details about the function of neurons and circuits at the
molecular level; we do not yet grasp the behavior of populations of ne urons within a
local brain region; and our understanding of the large-scale systems made up of
multiple brain regions is also incomplete. We are barely beginning to address the fact
that interactions among many noncontiguous brain regions probably yield highly
complex biological states that are vastly more than the sum of their parts.
In fact, the explanation of the physics related to biological events is still incomplete.
Consequently, declaring the conscious-mind problem insoluble because we have
studied the brain to the hilt and have not found the mind is ludicrous. We have not yet
fully studied either neurobiology or its related physics. For example, at the finest level of
description of mind, the swift construction, manipulation and superposition of many
sensory images might require explanation at the quantum level. Incid entally, the notion
of a possible role for quantum physics in the elucidation of mind, an idea usually
associated with mathematical physicist Roger Penrose of the University of Oxford, is not
an endorsement of his specific proposals, namely that consciou sness is based on
quantum-level phenomena occurring in the microtubules--constituents of neurons and
other cells. The quantum level of operations might help explain how we have a mind,
but I regard it as unnecessary to explain how we know that we own tha t mind--the issue
I regard as most critical for a comprehensive account of consciousness.
The strangeness of the conscious mind problem mostly reflects ignorance, which limits
the imagination and has the curious effect of making the possible seem impossible.
Science-fiction writer Arthur C. Clarke has said, "Any sufficiently advanced t echnology
is indistinguishable from magic." The "technology" of the brain is so complex as to
appear magical, or at least unknowable. The appearance of a gulf between mental
states and physical/biological phenomena comes from the large disparity between two
bodies of knowledge--the good understanding of mind we have achieved through
centuries of introspection and the efforts of cognitive science versus the incomplete
neural specification we have achieved through the efforts of neuroscience. But there is
no reason to expect that neurobiology cannot bridge the gulf. Nothing indicates that we
have reached the edge of an abyss that would separate, in principle, the mental from
Therefore, I contend that the biological processes now presumed to correspond to mind
processes in fact are mind processes and will be seen to be so when understood in
sufficient detail. I am not denying the existence of the mind or saying that on ce we
know what we need to know about biology the mind ceases to exist. I simply believe
that the private, personal mind, precious and unique, indeed is biological and will one
day be described in terms both biological and mental.
The other main objection to an understanding of mind is that the real conflict between
observer and observed makes the human intellect unfit to study itself. It is important,
however, to point out that the brain and mind are not a monolith: they h ave multiple
structural levels, and the highest of those levels creates instruments that permit the
observation of the other levels. For example, language endowed the mind with the
power to categorize and manipulate knowledge according to logical princip les, and that
helps us classify observations as true or false. We should be modest about the
likelihood of ever observing our entire nature. But declaring defeat before we even
make the attempt defies Aristotle's observation that human beings are infinit ely curious
about their own nature.
Reasons for Optimism
MY PROPOSAL for a solution to the conundrum of the conscious mind requires
breaking the problem into two parts. The first concern is how we generate what I call a
"movie-in-the-brain." This "movie" is a metaphor for the integrated and unified compo
site of diverse sensory images-visual, auditory, tactile, olfactory and others--that
constitutes the multimedia show we call mind. The second issue is the "self" and how
we automatically generate a sense of ownership for the movie-in-the-brain. The two
parts of the problem are related, with the latter nested in the forme r. Separating them is
a useful research strategy, as each requires its own solution.
Neuroscientists have been attempting unwittingly to solve the movie-in-the brain part of
the conscious-mind problem for most of the history of the field. The endeavor of
mapping the brain regions involved in constructing the movie began almost a c entury
and a half ago, when Paul Broca and Carl Wernicke first suggested that different
regions of the brain were involved in processing different aspects of language. More
recently., thanks to the advent of ever more sophisticated tools, the effort has begun to
reap handsome rewards.
Researchers can now directly record the activity of a single neuron or group of neurons
and relate that activity to aspects of a specific mental state, such as the perception of
the color red or of a curved line. Brain-imaging techniques such as P ET (positron
emission tomography) scans and fMR (functional magnetic resonance) scans reveal
how different brain regions in a normal, living person are engaged by a certain mental
effort, such as relating a word to an object or learning a particular face . Investigators
can determine how molecules within microscopic neuron circuits participate in such
diverse mental tasks, and they can identify the genes necessary for the production and
deployment of those molecules.
Progress in this field has been swift ever since David H. Hubel and Torsten Wiesel of
Harvard University provided the first clue for how brain circuits represent the shape of a
given object, by demonstrating that neurons in the primary visual cort ex were
selectively tuned to respond to edges oriented in varied angles. Hubel and Margaret S.
Livingstone, also at Harvard, later showed that other neurons in the primary visual
cortex respond selectively to color but not shape. And Semir Zeki of Univer sity College
London found that brain regions that received sensory information after the primary
visual cortex did were specialized for the further processing of color or movement.
These results provided a counterpart to observations made in living neuro logical
patients: damage to distinct regions of the visual cortices interferes with color perception
while leaving discernment of shape and movement intact.
A large body of work, in fact, now points to the existence of a correspondence between
the structure of an object as taken in by the eye and the pattern of neuron activity
generated within the visual cortex of the organism seeing that object [see illustration on
Further remarkable progress involving aspects of the movie-in-the-brain has led to
increased insights related to mechanisms of learning and memory. In rapid succession,
research has revealed that the brain uses discrete systems for different types of
learning. The basal ganglia and cerebellum are critical for the acquisition of skills--for
example, learning to ride a bicycle or play a musical instrument. The hippocampus is
integral to the learning of facts pertaining to such entities as people, p laces or events.
And once facts are learned, the long-term memory of those facts relies on
multicomponent brain systems, whose key parts are located in the vast brain expanses
known as cerebral cortices.
Moreover, the process by which newly learned facts are consolidated in long-term
memory goes beyond properly working hippocampi and cerebral cortices. Certain
processes must take place, at the level of neurons and molecules, so that the neural cir
cuits are etched, so to speak, with the impressions of a newly learned fact. This etching
depends on strengthening or weakening the contacts between neurons, known as
synapses. A provocative finding by Eric R. Kandel of Columbia University and Timothy
P. Tully of Cold Spring Harbor Laboratory is that etching the impression requires the
synthesis of fresh proteins, which in turn relies on the engagement of specific genes
within the neurons charged with supporting the consolidated memory.
These brief illustrations of progress could be expanded with other revelations from the
study of language, emotion and decision making. Whatever mental function we
consider, it is possible to identify distinct parts of the brain that contribute to the
production of a function by working in concert; a close correspondence exists between
the appearance of a mental state or behavior and the activity of selected brain regions.
And that correspondence can be established between a given macroscopically
identifiable region (for example, the primary visual cortex, a language-related area or an
emotion-related nucleus) and the microscopic neuron circuits that constitute the region.
Most exciting is that these impressive advances in the study of the brain are a mere
beginning. New analytical techniques continuously improve the ability to study neural
function at the molecular level and to investigate the highly complex large- scale
phenomena arising from the whole brain. Revelations from those two areas will make
possible ever finer correspondences between brain states and mental states, between
brain and mind. As technology develops and the ingenuity of researchers grows, th e
fine grain of physical structures and biological activities that constitute the movie-in-the-
brain will gradually come into focus.
Confronting the Self
THE MOMENTUM of current research on cognitive neuroscience, and the sheer
accumulation of powerful facts, may well convince many doubters that the neural basis
for the movie-in-the-brain can be identified. But the skeptics will still find it diffic ult to
accept that the second part of the conscious-mind problem--the emergence of a sense
of self--can be solved at all. Although I grant that solving this part of the problem is by
no means obvious, a possible solution has been proposed, and a hypothes is is being
The main ideas behind the hypothesis involve the unique representational ability of the
brain. Cells in the kidney or liver perform their assigned functional roles and do not
represent any other cells or functions. But brain cells, at every level of the nervous
system, represent entities or events occurring elsewhere in the organism. Brain cells
are assigned by design to be about other things and other doings. They are born
cartographers of the geography of an organism and of the events that take place within
that geography. The oft-quoted mystery of the "intentional" mind relative to the
representation of external objects turns out to be no mystery at all. The philosophical
despair that surrounds this "intentionality" hurdle alluded to earlier- -why mental states
represent internal emotions or interactions with external objects--lifts with the
consideration of the brain in a Darwinian context: evolution has crafted a brain that is in
the business of directly representing the organism and indire ctly representing whatever
the organism interacts with.
The brain's natural intentionality then takes us to another established fact: the brain
possesses devices within its structure that are designed to manage the life of the
organism in such a way that the internal chemical balances indispensable for survival
are maintained at all times. These devices are neither hypothetical nor abstract; they
are located in the brain's core, the brain stem and hypothalamus. The brain devices that
regulate life also represent, of necessity, the constantly changing states of the organism
as they occur. In other words, the brain has a natural means to represent the structure
and state of the whole living organism.
But how is it possible to move from such a biological self to the sense of ownership of
one's thoughts, the sense that one's thoughts are constructed in one's own perspective,
without falling into the trap of invoking an all-knowing homunculus who interprets one's
reality? How is it possible to know about self and surroundings? I have argued in my
book The Feeling of What Happens that the biological foundation for the sense of self
can be found in those brain devices that represent, moment by mom ent, the continuity
of the same individual organism. Simply put, my hypothesis suggests that the brain
uses structures designed to map both the organism and external objects to create a
fresh, second-order representation. This representation indicates th at the organism, as
mapped in the brain, is involved in interacting with an object, also mapped in the brain.
The second-order representation is no abstraction; it occurs in neural structures such as
the thalamus and the cingulate cortices.
Such newly minted knowledge adds important information to the evolving mental
process. Specifically, it presents within the mental process the information that the
organism is the owner of the mental process. It volunteers an answer to a question
never posed: To whom is this happening? The sense of a self in the act of knowing is
thus created, and that forms the basis for the first-person perspective that characterizes
the conscious mind.
Again from an evolutionary perspective, the imperative for a sense of self becomes
clear. As Willy Loman's wife says in Arthur Miller's Death of a Salesman: "Attention
must be paid!" Imagine a self aware organism versus the same type of organism l
acking it. A self-aware organism has an incentive to heed the alarm signals provided by
the movie-in-the-brain (for instance, pain caused by a particular object) and plan the
future avoidance of such an object. Evolution of self rewards awareness, which is dearly
a survival advantage.
With the movie metaphor in mind, if you will, my solution to the conscious mind problem
is that the sense of self in the act of knowing emerges within the movie. Self-awareness
is actually part of the movie and thus creates, within the same frame, the "seen" and the
"seer," the "thought" and the "thinker." There is no separate spectator for the movie-in-
the-brain. The idea of spectator is constructed within the movie, and no ghostly
homunculus haunts the theater. Objective brain processes knit th e subjectivity of the
conscious mind out of the cloth of sensory mapping. And because the most
fundamental sensory mapping pertains to body states and is imaged as feelings, the
sense of self in the act of knowing emerges as a special kind of feeling--th e feeling of
what happens in an organism caught in the act of interacting with an object.
I WOULD BE FOOLISH TO mare predictions about what can and cannot be discovered
or about when something might be discovered and the route of a discovery.
Nevertheless, it is probably safe to say that by 2050 sufficient knowledge of biological
phenom ena will have wiped out the traditional dualistic separations of body/brain,
body/mind and brain/mind.
Some observers may fear that by pinning down its physical structure something as
precious and dignified as the human mind may be downgraded or vanish entirely. But
explaining the origins and workings of the mind in biological tissue will not do aw ay with
the mind, and the awe we have for it can be extended to the amazing microstructure of
the organism and to the immensely complex functions that allow such a microstructure
to generate the mind. By understanding the mind at a deeper level, we will see it as
nature's most complex set of biological phenomena rather than as a mystery with an
unknown nature. The mind will survive explanation, just as a rose's perfume, its
molecular structure deduced, will still smell as sweet.
MORE TO EXPLORE
Eye, Brain, and Vision. David H. Hubel. Scientific American Library [W.H. Freeman],
The Engine of Reason, the Seat of the Soul; A Philosophical Journey into the Brain.
Paul M. Churchland. MIT Press, 1995.
Consciousness Explained. Daniel C. Dennett. Little, Brown, 1996.
The Feeling of What Happens: Body and Emotion in the Making of Consciousness.
Antonio R. Damasio. Harcourt Brace, 1999.
Looking for Spinoza: Joy, Sorrow and the Human Brain. Antonio R. Damasio. Harcourt
By Antonio R. Damasio
ANTONIO R. DAMASIO is M. W. Van Allen Distinguished Professor and head of the
department of neurology at the University of Iowa College of Medicine and adjunct
professor at the Salk Institute for Biological Studies in San Diego. He was born in Port
nal Academy of Sciences and of the American Academy of Arts and Sciences, Damasio
is the author of Descartes' Error: Emotion, Reason, and the Human Brain [ 1994}, The
Feeling of What Happens: Body and Emotion in the Making of Consciousness [ 1999]
and Lo oking for Spinoza [forthcoming].
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