Incognito: The Secret Lives Of The Brain

Also by David Eagleman Sum Why the Net Matters Wednesday Is Indigo Blue Copyright © 2011 by David Eagleman All rights reserved. Published in the United States by Pantheon Books, a division of Random House, Inc., New York. Originally published in Great Britain by Canongate Books Ltd., Edinburgh. Pantheon Books and colophon are registered trademarks of Random House, Inc. Figure on this page © Randy Glasbergen, 2001. Figures on this page © Tim Farrell (top) and Ron Rensink (bottom). Figure on this page © Springer. Figure on this page © astudio. Figures on this page © Fotosearch (left) and Mark Grenier (right). Figure on this page © Elsevier. Library of Congress Cataloging-in-Publication Data Eagleman, David. Incognito : the secret lives of the brain / David Eagleman. p. cm. Includes bibliographical references and index. eISBN: 978-0-307-37978-8 1. Subconsciousness. 2. Brain. I. Title. BF315.E25 2011 153—dc22 2010053184 www.pantheonbooks.com Jacket design by Peter Mendelsund v3.1 Man is equally incapable of seeing the nothingness from which he emerges and the infinity in which he is engulfed. —Blaise Pascal, Pensées Contents Cover Other Books by This Author Title Page Copyright Epigraph 1. There’s Someone In My Head, But It’s Not Me 2. The Testimony of the Senses: What Is Experience Really Like? 3. Mind: The Gap 4. The Kinds of Thoughts That Are Thinkable 5. The Brain Is a Team of Rivals 6. Why Blameworthiness Is the Wrong Question 7. Life After the Monarchy Appendix Acknowledgments About the Author Notes Bibliography Index There’s Someone in My Head, But It’s Not Me Take a close look at yourself in the mirror. Beneath your dashing good looks churns a hidden universe of networked machinery. The machinery includes a sophisticated scaffolding of interlocking bones, a netting of sinewy muscles, a good deal of specialized fluid, and a collaboration of internal organs chugging away in darkness to keep you alive. A sheet of high-tech selfhealing sensory material that we call skin seamlessly covers your machinery in a pleasing package. And then there’s your brain. Three pounds of the most complex material we’ve discovered in the universe. This is the mission control center that drives the whole operation, gathering dispatches through small portals in the armored bunker of the skull. Your brain is built of cells called neurons and glia—hundreds of billions of them. Each one of these cells is as complicated as a city. And each one contains the entire human genome and traffics billions of molecules in intricate economies. Each cell sends electrical pulses to other cells, up to hundreds of times per second. If you represented each of these trillions and trillions of pulses in your brain by a single photon of light, the combined output would be blinding. The cells are connected to one another in a network of such staggering complexity that it bankrupts human language and necessitates new strains of mathematics. A typical neuron makes about ten thousand connections to neighboring neurons. Given the billions of neurons, this means there are as many connections in a single cubic centimeter of brain tissue as there are stars in the Milky Way galaxy. The three-pound organ in your skull—with its pink consistency of Jell-o— is an alien kind of computational material. It is composed of miniaturized, self-configuring parts, and it vastly outstrips anything we’ve dreamt of building. So if you ever feel lazy or dull, take heart: you’re the busiest, brightest thing on the planet. Ours is an incredible story. As far as anyone can tell, we’re the only system on the planet so complex that we’ve thrown ourselves headlong into the game of deciphering our own programming language. Imagine that your desktop computer began to con