Consciousness: A User’s Guide

Adam Zeman
Copyright Date: 2002
Published by: Yale University Press
Pages: 416
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  • Book Info
    Book Description:

    This engaging and readable book provides an introduction to consciousness that does justice both to the science and to the philosophy of consciousness, that is, the mechanics of the mind and the experience of awareness. The book opens with a general discussion of the brain and of consciousness itself. Then, exploring the areas of brain science most likely to illuminate the basis of awareness, Zeman focuses on the science of sleep and waking and on the science of vision. He describes healthy states and disorders-epilepsy, narcolepsy, blindsight and hallucinations after stroke-that provide insights into the capacity for consciousness and into its contents. And he tracks the evolution of the brain, the human species, and human culture and surveys the main current scientific theories of awareness, pioneering attempts to explain how the brain gives rise to experience.Zeman concludes by examining philosophical arguments about the nature of consciousness. A practicing neurologist, he animates his text with examples from the behavioral and neurological disorders of his patients and from the expanding mental worlds of young children, including his own. His book is an accessible and enlightening explanation of why we are conscious.

    eISBN: 978-0-300-13531-2
    Subjects: Psychology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-ix)
  3. A note to the reader
    (pp. x-x)
  4. Preface
    (pp. xi-xii)
  5. Introduction
    (pp. 1-10)

    While I write I can just make out the steady patter of the rain on the lawn. A grey light slants through the window. There is a fire rumbling in the grate, scenting the air with wood smoke. My chair is hard, and when my attention wanders from my work I feel the pressure of my elbows on its arms, the support from its straw seat, the resistance my feet encounter from the stone floor. I take a sip of coffee, warm, bitter, yet sweet from the milk. In spite of the fire, the English summer’s day is chilly, and...

  6. Part I: Introducing consciousness
    • 1 As sweet by any other name? Consciousness, self-consciousness and conscience
      (pp. 13-36)

      Consciousness is in fashion, among scientists and philosophers on both sides of the Atlantic. It has been ‘regained’, ‘rediscovered’, ‘reconsidered’, and even ‘explained’.² AJournal of Consciousness Studiescarries forward the debate between students of psychology, physiology, anatomy, computation, artificial intelligence, religion and philosophy. The University of Arizona at Tucson plays host to a major biannual conference, ‘Toward a Science of Consciousness’;³ the Association for the Scientific Study of Consciousness⁴ promotes its investigation. Recently, interest has spread beyond the circle of learned journals and societies. The editors of magazines and daily papers, the producers of programmes on the sciences and...

    • 2 ‘The nerves in the brain, oh damn’em’: a sketch of the human nervous system
      (pp. 37-74)

      We need two sets of introductions if we are to get a hold on the relationship between consciousness and events in the brain. Chapter 1 has introduced you to the senses of consciousness. The aim of this chapter is to introduce you to the brain.

      I shall assume that you know nothing about biology or science. I sympathise if you do not, as I emerged from 12 years of otherwise perfectly good British schooling without ever being taught a syllable of biology. I got to grips with it years later, awkwardly dissecting my first frog in a handsome Victorian university...

  7. Part II: The capacity for consciousness
    • 3 The springs of awareness: the structural basis of consciousness (i)
      (pp. 77-110)

      In the course of a lifetime we spend about 20 years asleep. As we wake, each day, we must create our world of experience anew. The regular annihilation and renewal of awareness is one of the ordinary miracles of life: we take it entirely for granted, until a night or two of insomnia reminds us how essential, yet how elusive, sleep can be.

      The regular alternation of waking and sleep seems a natural place to start trying to understand the biology of awareness. It is also a rewarding point of departure, as a succession of remarkable discoveries over the past...

    • 4 The brothers of death: pathologies of consciousness
      (pp. 111-152)

      Consciousness is a vulnerable biological achievement. It has a host of preconditions besides the patterning of arousal which we explored in the last chapter. The brain is constantly in need of oxygen and glucose, ferried in by the bloodstream, propelled headwards by the heart: any interruption to supply makes itself known within seconds, and consciousness rapidly fades. The less precipitous failure of our other organs, such as the liver or kidneys, creates an unfavourable chemical milieu for the nervous system, leading, untreated, to coma. Coma also results from careless use of the many drugs with which we enjoy upsetting our...

  8. Part III: The contents of consciousness
    • 5 From darkness into light: the structural basis of consciousness (ii)
      (pp. 155-196)

      While we are conscious at all, we are always conscious ofsomething. I have chosen vision to illustrate the scientific approach to the content of consciousness. Sight has a special place in our lives, even if a rich human existence is perfectly possible without it. Its importance reflects our ancestry: about half the brain of the African monkey is given over to sight.

      The challenge posed by vision for the scientist is evident enough. Just look around: the shapes and colours, depth and movement which meet your effortless gaze are all created by the brain.² How? Answering this simple question...

    • 6 ‘I cannot see you Charley, I am blind’: clear-sighted blindness and blindsight
      (pp. 197-240)

      The commonest causes of blindness reside in the eye. This might seem obvious – until one realises that the process of vision has only just begun when a focused image falls upon the retina. Disorders of the brain also give rise to many pathologies of sight.

      One of these will be within the personal experience of about one reader in ten. Attacks of migraine are often ushered in by a zigzagging intrusion in the field of vision, known as the ‘fortification spectrum’ from its resemblance to a set of battlements. Vivid, scintillating, this unwelcome guest usually makes its way across a...

  9. Part IV: The origins of consciousness
    • 7 The history of everything
      (pp. 243-276)

      We can ask four fundamental questions about each part and activity of an organism: how does it work, what is it for, how does it develop and how did it evolve? Biologists refer to these as questions of mechanism, function, ontogeny and phylogeny (ontogeny concerns the development of the individual, phylogeny the development of the species over many generations). We can reasonably ask these questions about consciousness. So far I have concentrated largely on the first, the mechanisms of the waking state and vision, with only brief excursions into questions of growth and evolution.

      This chapter will redress the balance....

  10. Part V: Consciousness considered
    • 8 Scientific theories of consciousness
      (pp. 279-302)

      The renaissance of interest in consciousness over the past two decades has encouraged scientists and philosophers to propose general theories of its mechanisms, its functions and its nature. In this chapter I shall concentrate on the scientists’ contributions, turning to the philosophers in the following chapter. Some have focused on the neurobiology of awareness, nominating candidates for the ‘NCC’, the neural correlate of consciousness. Any given moment of visual awareness, they suppose, depends on activity in a network of brain regions: butwhichbrain regions and whatkindof activity? Others, grounded in computer science, have asked what role consciousness...

    • 9 The nature of consciousness
      (pp. 303-342)

      Two simple facts inspired this book: the first is that we are richly conscious of our world and of ourselves, the second that this consciousness depends upon events within our brains. These facts raise questions which have refused to surrender completely to many centuries of philosophical attack. This chapter will introduce you to contemporary thinking on three issues at the heart of the debate: what is the nature of the relationship between conscious states and the neural activity associated with them? Is there any bar, in principle, to the construction of a conscious machine? What are the implications of the...

  11. Epilogue
    (pp. 343-347)

    How do the events in our brains give rise to those in our minds? How does the intricate activity of 100,000 million nerve cells generate consciousness? To gain a long perspective on the ground we have traversed, I would like to close by asking an even simpler question:whyare we conscious? Despite its simplicity, this question can be attacked in several different ways.

    A first approach is to outline the mechanisms of consciousness: what makes awareness possible?

    We know a good deal about the mechanisms ofthe waking state, as we saw in Chapter 3. The ‘electricity of the...

  12. Glossary
    (pp. 348-363)
  13. Notes
    (pp. 364-387)
  14. Suggestions for further reading
    (pp. 388-389)
  15. List of figures and tables
    (pp. 390-395)
  16. Index
    (pp. 396-404)