Giulio Tononi - Phi: A Voyage from the Brain to the Soul

Copyright 2012 by Giulio Tononi

All rights reserved. Published in the United States by Pantheon Books, a division of Random House, Inc., New York, and in Canada by Random House of Canada Limited, Toronto.

Pantheon Books and colophon are registered trademarks of Random House, Inc.

Grateful acknowledgment is made to Alfred A. Knopf for permission to reprint b o d y copyright 1995 by James Merrill, from A Scattering of Salts by James Merrill. Used by permission of Alfred A. Knopf, a division of Random House, Inc.

LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Tononi, Giulio. Phi : a voyage from the brain to the soul/Giulio Tononi. p. cm. eISBN: 978-0-307-90722-6 1. ConsciousnessPhysiological aspects.2. Brain physiology.3. Mind and body.I. Title. QP411.T66 2012 612.8dc23 2011041620

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Cover design by Giulio Tononi

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Every night, when we fall into dreamless sleep, consciousness fades. With it fades everyones private universepeople and objects, colors and sounds, pleasures and pains, thoughts and feelings, even our own selves dissolveuntil we awake, or until we dream.

What is consciousness, and what does it mean? How is it related to the world around us? What is it made of, and how is it generated inside the brain? Can science shed some light on it? Perhaps, but consciousness cannot just rest inside the shroud of science. Because consciousness is more than an object of science: it is its subject too.

What follows is a story where an old scientist, Galileo, goes through a journey in search of consciousness. In his time, Galileo removed the observer from nature and opened the way for the objectivity of science. Perhaps this is why Galileo is engaged to return the observer to nature, to make subjectivity a part of science. Or perhaps because Galileo was a master of thought experiments, of which this book makes much use.

During his journey, Galileo meets people from his and other times, learns many lessons, thinks many thoughts, and sometimes wonders, too, whether he is awake or dreaming. But each chapter makes some kind of statement, building on the previous ones, and Galileos understanding grows. So in the first part of the book, he learns the facts of consciousness and the brainwhy certain parts of the brain are important but not others, or why consciousness fades with sleep. In the second part, he sees how these facts can be unified and understood through a scientific theory of consciousnessa theory that links consciousness to , the symbol of integrated information that gives the book its title. And finally, in the third part of the book, he realizes some of the theorys implications, and sees that they concern us all, because consciousness is everything we have, and everything we are. Each experience, Galileo realizes, is a unique shape made of integrated informationa shape that is maximally irreduciblethe shape of understanding. And it is the only shape thats