ALSO BY BRIAN GREENE Icarus at the Edge of Time The Fabric of the Cosmos The Elegant Universe THIS IS A BORZOI BOOK PUBLISHED BY ALFRED A. KNOPF Copyright © 2011 Brian Greene All rights reserved. Published in the United States by Alfred A. Knopf, a division of Ran- dom House, Inc., New York, and in Canada by Random House of Canada Limited, Toronto. www.aaknopf.com Knopf, Borzoi Books, and the colophon are registered trademarks of Random House, Inc. 5/1131 Library of Congress Cataloging-in-Publica- tion Data Greene, B. (Brian), [date] The hidden reality parallel universes and the deep laws of the cosmos / by Brian Greene.—1st ed. p. cm. eISBN: 978-0-307-59525-6 1. Physics—Philosophy. 2. Quantum theory. 3. General relativity (Physics) 4. Cosmology. I. Title. QC6.G6885 2011 530.12—dc22 2010042710 Jacket design by Peter Mendelsund v3.1 To Alec and Sophia Contents Cover Other Books by This Author Title Page Copyright Dedication Preface 1. The Bounds of Reality On Parallel Worlds 2. Endless Doppelgängers The Quilted Multiverse 8/1131 3. Eternity and Infinity The Inflationary Multiverse 4. Unifying Nature’s Laws On the Road to String Theory 5. Hovering Universes in Nearby Dimensions The Brane and Cyclic Multiverses 6. New Thinking About an Old Constant The Landscape Multiverse 7. Science and the Multiverse On Inference, Explanation, and Prediction 8. The Many Worlds of Quantum Measurement The Quantum Multiverse 9. Black Holes and Holograms 9/1131 The Holographic Multiverse 10. Universes, Computers, and Mathem- atical Reality The Simulated and Ultimate Multiverses 11. The Limits of Inquiry Multiverses and the Future Notes Suggestions for Further Reading About the Author Preface If there was any doubt at the turn of the twentieth century, by the turn of the twenty- first, it was a foregone conclusion: when it comes to revealing the true nature of reality, common experience is deceptive. On reflec- tion,that’snotparticularlysurprising.Asour forebears gathered in forests and hunted on the savannas, an ability to calculate the quantum behavior of electrons or determine the cosmological implications of black holes would have provided little in the way of sur- vival advantage. But an edge was surely