The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind

249 Pages·2018·1.54 MB·English

by  Michael S. Gazzaniga

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Table of Contents
A Note About the Author
Copyright Page

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For Leonardo,
consciousness unfolding if I ever saw it
INTRODUCTION
IMAGINE, IF YOU CAN, being conscious of only one moment—right now. This
moment exists without a past or a future. Now imagine life being a series of
these moments, each existing in some kind of isolation from all other moments,
not connected by subjective time. Imagine being temporarily frozen in each of
the moments that together make up normal living. It is hard to imagine this
scenario because our minds travel back and forth through time so fluidly, like a
ballerina in The Nutcracker. One moment serves as the grist for the next planned
action, which is in turn weighed in the present against our past experience. It is
hard to imagine this ever not being true. And yet, conk your head in the right
way and that might be you, still able to understand the idea of having a past and
future, but unable to place yourself in your own past or future. Weird, if true. No
past, no future, only the present.
In this book I will take you on a journey through a world where hard-to-
imagine alterations in what we call conscious experience are commonplace. The
neurologic ward of every hospital is replete with disruptions of normal conscious
experience. Each of these cases tells us something about how our brains are
organized to deliver up our cherished consciousness, moment by moment. Each
example of disruption cries out to be understood, to be used to deduce a coherent
story about how our brains build and produce the everyday joys of being
conscious. In the past, folks were content to tell stories of these bizarre
phenomena. Here in the twenty-first century, it is not enough to simply describe
the basketful of intriguing disorders. In this book, my goal is to move forward on
the problem of consciousness, and I will try to illuminate how our exquisitely
evolved brain is organized to do its magic. In short, I want to examine how
matter makes minds.
A few years back, a work trip found me passing through customs at
Heathrow in London. The passport control officer, an attentive British civil
servant, dutifully asked me my name and business and reason for coming to the
United Kingdom. I told him I did brain research and was on my way to Oxford
for a meeting. He asked if I was aware of the two different functions of the
cerebral hemispheres, the left and the right. I somewhat proudly said that not
only had I heard about it, I was in part responsible for the work. As he perused
my passport, he asked what the meeting in Oxford was going to be about. I
responded, with an air of authority, “About consciousness.”
The agent closed the passport and, handing it back, asked, “Have you ever
thought about quitting while you are ahead?”
Apparently not. Some of us are naturally incautious in our desire to wonder
about our nature. Working away in the mind/brain sciences as I have for sixty
years makes me painfully aware that we humans have not yet grasped the
problem in its fullness. Still, it is in our nature to think about who and what we
are and what it means to be conscious. Once bitten by the question, we spend our
lives gnawed by the desire for an answer. Yet, when we try to grab hold of the
problem of consciousness, it seems to dissolve like fog. Why has the quest to
understand consciousness been so difficult? Do the lingering ideas of the past
block us from seeing clearly how it comes about? Is consciousness just what
brains do? Just as a pocket watch with all of its gears tells us the time, do brains
with all their neurons just give us consciousness? The history of the topic is vast,
swept by pendulum swings between the pure mechanists and the hopeful
mentalists. Surprisingly, twenty-five hundred years of human history have not
resolved the question or taught our species how to frame an understanding of our
personal conscious experience. Indeed, our core ideas have not changed that
much. While thinking explicitly about consciousness was ignited by Descartes
three hundred years ago, two overarching and contradictory notions—that the
mind either is part of the brain’s workings or works somehow independently of
the brain—have been around seemingly forever. Indeed, these ideas are still with
us.
In recent years the topic of consciousness has become red-hot once again. At
the same time, and despite the modern avalanche of new data, there are few, if
any, generally accepted proposals on how the brain builds a mind and, with it,
conscious experience. The goal of this book is both to break free from this
quagmire and to present a new view of how to conceptualize consciousness. Our
journey includes knowledge gained not only from neurology but also from
evolutionary and theoretical biology, engineering and physics, and, of course,
psychology and philosophy. Nobody said the search was going to be easy. But
the goal—understanding how nature pulls off the trick of turning neurons into
minds—is attainable. So hold on to your hat!
Plainly stated, I believe consciousness is an instinct. Many organisms, not
just humans, come with it, ready-made. That is what instincts are, something
organisms come with. Living things have an organization that allows life and
ultimately consciousness to exist, even though they are made from the same
materials as the non-living natural world that surrounds them. And instincts
envelop organisms from bacteria to humans. Survival, sex, resilience, and
walking are commonly thought to be instincts, but so, too, are more complex
capacities such as language and sociality—all are instincts. The list is long, and
we humans seem to have more instincts than other creatures. Yet there is
something special about the consciousness instinct. It is no ordinary instinct. In
fact, it seems so extraordinary that many think only we humans can lay claim to
it. Even if that’s not the case, we want to know more about it. And because we
all have it, we all think we have insight into it. As we will see, it is a slippery,
complex instinct situated in the universe’s most impenetrable organ, the brain.
The word “apple” is a noun; it signifies a real, physical object. The word
“democracy” is a noun as well, and it describes something a little harder to pin
down, a state of societal relationships. It is easy for me to show you an apple, its
physical reality. It is hard for me to show you the physical reality of a
democracy. How about “instinct,” another noun? All three are definable
somethings, whether they are objects or concepts, managed by the brain. We
have lots of these somethings, but where are they in the brain? Are some best
represented as actual structures in the brain and others best represented by the
processing actions of structures? Indeed, what is the physical reality of an
instinct? Is it tangible, like an apple, or elusive, like a democracy?
Complex instincts are more like democracies; they are identifiable but not
easily localized. They emerge from the interaction of simple instincts but are not
those things themselves—just as an intricate pocket watch chugs away at
keeping time, yet time itself is impossible to find in the watch. In order to
understand how the watch relates to time, you have to describe its principles of
design, its architecture, not just list all its springs and gears. The same is true of
the consciousness instinct. Don’t think that if consciousness is an instinct, there
will be a single, unitary, discrete brain network generating that phenomenal self-
aware state we all relish. It is not like that at all. When we visit the neurologic
wards, armed with our ideas, you’ll recognize right away that patients who suffer
from dementia, even severe dementias, are conscious. These patients with
widely distributed brain lesions, a level of disruption vast enough to bring any
computing machine to its knees, remain conscious. In one hospital room after
another, each harboring a patient with a focal or a diffuse brain impairment,
consciousness purrs along. After a tour of the wards, it begins to look like
consciousness is not a system property at all. It is a property of local brain
circuits.
In this book’s first section, we will see how nature became an “it,” a thing
separate from us that can be studied and understood in objective terms. We trace
this idea all the way through Descartes up to modern times and the dawn of
modern biology. Surprisingly, most modern scientific thinking has looped back
to build on the ideas of the ancient Greeks, and holds essentially the same
models, which link the mental and physical inexorably together in one system.
Modern science has started to pursue the same goal the Greeks sought, but so far
it, too, has fallen short. Again, new ideas are needed, and this book takes a shot.
In Part II, some modern principles of brain functioning are introduced that I
feel should guide our journey into how neurons produce minds. It is amazing to
me how the “brain as a machine” metaphor, first proposed by Descartes and
wholly adopted by most of modern science, has led us to believe that the entire
machine is needed to perform many of its functions. In fact, we are each a
confederation of rather independent modules, orchestrated to work together. To
understand how those modules collaborate, we need to know about the overall
architecture of the system, an architecture called “layering” that will be familiar
to many readers, such as computer scientists. And finally, we’ll pay that visit to
the neurologic clinic to test this formulation. There we will discover that our
modular brain with its layered architecture is managing our consciousness
from … everywhere in its local tissues, over and over again. There is not one
centralized system working to produce the grand magic of conscious experience.
It is everywhere, and you can’t seem to stamp it out, not even with a wide-
ranging brain disease like Alzheimer’s.
In Part III, I confront that nagging issue at the core of this mind/brain
business: How do neurons gin up mind? How do those squishy bundles of wet
tissue make you and me mental? It turns out there are gaps throughout our
understanding of the physical world. We study one level of organization and
then another, but in fact we don’t understand how the two different levels work