EFTA00285909.pdf

Praise for The Greatest Story Ever Told—So Far "In every debate I've done with theologians and religious believers, their knock-out final argument always comes in the form of two questions: Why is there something rather than nothing? and Why are we here? The presumption is that if science provides no answers then there must be a God. But God or no, we still want answers. In A Universefrom Nothing Lawrence Krauss, one of the biggest thinkers of our time, addressed the first question with verve, and in The Greatest Story Ever Told he tackles the second with elegance. Both volumes should be placed in hotel rooms across America, in the drawer next to the Gideon Bible —Michael Shermer, publisher of Skeptic magazine, columnist for Scientific American, and author of The Moral Arc "Discovering the bedrock nature of physical reality ranks as one of humanity's greatest collective achievements. This book gives a fine account of the main ideas and how they emerged. Krauss is himself close to the field and can offer insights into the personalities who have led the key advances. A practiced and skilled writer, he succeeds in making the physics 'as simple as possible but no simpler: I don't know a better book on this subject? —Martin Rees, author of Just Six Numbers "It is an exhilarating experience to be led through this fascinating story, from Galileo to the Standard Model and the Higgs boson and beyond, with lucid detail and insight, illuminating vividly not only the achieve- ments themselves but also the joy of creative thought and discovery, 2P_Glealer-StoryEverTold_Atirdd I 12/16116 3:06 PIA EFTA00285909  enriched with vignettes of the remarkable individuals who paved the way. It amply demonstrates that the discovery that 'nature really follows the simple and elegant rules intuited by the twentieth- and twenty-first- century versions of Plato's philosopher? is one of the most astonishing achievements of the human intellect." —Noam Chomsky, Institute Professor & Professor of Linguistics (emeritus), MIT "Charming ... Krauss has written an account with sweep and verve that shows the full development of our ideas about the makeup of the world around us.... A great romp." —Walter Gilbert, Nobel laureate in chemistry 1 loved the fight scenes and the sex scenes were excellent." —Eric Idle 2P_GlealerASIonEverTold_Atirdd 2 1211&I6 3:06 PIA EFTA00285910  ALSO BY LAWRENCE M. KRAUSS A Universefrom Nothing The Fifth Essence Fear of Physics The Physics of Star Trek Beyond Star Trek Hiding in the Mirror Quintessence Atom Quantum Man 2P_Glealer-StoryEverTold_Atirdd 3 12/1&I6 3:06 PIA EFTA00285911 1 1._ 11. 1,, EFTA00285912 THE GREATEST STORY EVER TOLD-SO FAR WHY ARE WE HERE? Lawrence M. Krauss ATRIA BOOKS NEWS YORH . . •0130,,, . ,,.NEV . \EW' DELHI EFTA00285913  ATRIA BOOKS An Imprint of Simon & Schuster, Inc. 1230 Avenue of the Americas New York, NY 10020 Copyright 0 2017 by Lawrence Krauss All rights reserved, including the right to reproduce this book or portions thereof in any form whatsoever. For information, address Atria Books Subsidiary Rights Department. 1230 Avenue of the Americas, New York, NY 10020. First Atria Books hardcover edition March 2017 ATRIA BOOKS and colophon are trademarks ofSimon & Schuster, Inc. For information about special discounts for bulk purchases, please contact Simon & Schuster Special Sales at 1-866-506-1949 or The Simon & Schuster Speakers Bureau can bring authors to your live event. For more information or to book an event, contact the Simon & Schuster Speakers Bureau at 1-866-248-3049 or visit our website at Interior design by Dana Sloan Manufactured in the United States of America 109 8 7 6 543 2 1 Library of Congress Cataloging-in-Publication Data ISBN 978-1-4767-7761-0 ISBN 978-1-4767-7763-4 (ebook) 2P_Glealer-StoryEverrold_Atirdd 6 12/16116 3:06 PIA EFTA00285914  For Nancy 2P_Glealer-StoryEverTold_AC.irdd 7 128616 06 PM EFTA00285915 2P_Gtealer-StoryEverTold_Atirdd S 12/16116 3:06 PM EFTA00285916  These are the tears of things, and the stuff of our mortality cuts us to the heart. —VIRGIL 2P_Glealer-SoryEverTold_Atirdd 9 12/1&16 3:06 Pt, EFTA00285917 2P_GreatestSteryEverrold_AC.indd 10 12/16/16 3:06 PM EFTA00285918  CONTENTS Prologue 1 Part One: Genesis Chapter 1: From the Armoire to the Cave 9 Chapter 2: Seeing in the Dark 19 Chapter 3: Through a Glass, Lightly 33 Chapter 4: There, and Back Again 45 Chapter S: A Stitch in Time 55 Chapter 6: The Shadows of Reality 71 Chapter?: A Universe Stranger than Fiction 83 Chapter 8: A Wrinkle in Time 97 Chapter 9: Decay and Rubble 113 Chapter 10: From Here to Infinity: Shedding Light on the Sun 125 Part Two: Exodus Chapter 11: Desperate Times and Desperate Measures 139 Chapter 12: March of the Titans 151 Chapter 13: Endless Forms Most Beautiful: Symmetry Strikes Back 167 xl 2P_Glealer-StoryEverrold_Atirdd 11 12/18118 3:08 MA I EFTA00285919  xi' CONTENTS Chapter 14: Cold, Stark Reality: Breaking Bad or Beautiful? 181 Chapter 15: Living inside a Superconductor 191 Chapter 16: The Bearable Heaviness of Being: Symmetry Broken, Physics Fixed 201 Part Three: Revelation Chapter 17 The Wrong Place at the Right Time 211 Chapter 18: The Fog Lifts 219 Chapter 19: Free at Last 231 Chapter 2O: Spanking the Vacuum 249 Chapter 21: Gothic Cathedrals of the Twenty-First Century 259 Chapter 22: More Questions than Answers 275 Chapter 23: From a Beer Party to the End of Time 289 Epilogue: Cosmic Humility 301 Acknowledgments 307 Index 309 2P_GrealestSloryEverTald_AC.indd 12 12/16116 3:06 PIA EFTA00285920 EFTA00285921 rgd 93:C 90141 CI Prur0Y-PRIAm3koiSaM0,0 4C LI VA OS C1101 2:13/V3 _LSA_LVAL10 '3H1 2P_Gtealer-StoryEverTold_Atincld 14 12/16116 3:06 PM EFTA00285922  PROLOGUE The hardest thing of all to see Is what Is really there. -J. A. BAKER, THE PEREGRINE L the beginning there was light. But more than this, there was gravity. After that, all hell broke loose.... This is how the story of the greatest intellectual adventure in history might properly be introduced. It is a story of science's quest to uncover the hidden realities underlying the world of our experience, which required marshaling the very pinnacle of human creativity and intellectual bravery on an unparalleled global scale. This process would not have been possible without a willingness to dispense with all kinds of beliefs and preconcep- tions and dogma, scientific and otherwise. The story is filled with drama and surprise. It spans the full arc of human history, and most remarkably, the current version isn't even the final one—just another working draft. It's a story that deserves to be shared far more broadly. Already in the first world, parts of this story are helping to slowly replace the myths and superstitions that more ignorant societies found solace in centuries or millennia ago. Nevertheless, thanks to the directors George Stevens and David Lean, the Judeo-Christian Bible is still sometimes referred 2P_Glealer-StoryEverTold_Atirdd I 12/16116 3:06 PIA EFTA00285923  2 PROLOGUE to as "the greatest story ever told." This characterization is astounding because, even allowing for the frequent sex and violence, and a bit of poetry in the Psalms, the Bible as a piece of literature arguably does not compare well to the equally racy but less violent Greek and Roman epics such as the Aeneid or the Odyssey-even if the English translation of the Bible has served as a model for many subsequent books. Either way, as a guide for understanding the world, the Bible is pathetically inconsis- tent and outdated. And one might legitimately argue that as a guide for human behavior large swaths of it border on the obscene. In science, the very word sacred is profane. No ideas, religious or otherwise, get a free pass. For this reason the pinnacle of the human story did not conclude with a prophet's sacrifice two thousand years ago, any more than it did with the death of another prophet six hundred years later. The story of our origins and our future is a tale that keeps on telling. And the story is getting more interesting all the time, not due to revelation, but due to the steady march of scientific discovery. Contrary to many popular perceptions, this scientific story also en- compasses both poetry and a deep spirituality. But this spirituality has the additional virtue of being tied to the real world—and not created in large part to appease our hopes and dreams. The lessons of our exploration into the unknown, led not by our de- sires, but by the force of experiment, are humbling. Five hundred years of science have liberated humanity from the shackles of enforced igno- rance. By this standard, what cosmic arrogance lies at the heart of the assertion that the universe was created so that we could exist? What myopia lies at the heart of the assumption that the universe of our expe- rience is characteristic of the universe throughout all of time and space? This anthropocentrism has fallen by the wayside as a result of the story of science. What replaces it? Have we lost something in the pro- cess, or as I shall argue, have we gained something even greater? I once said at a public event that the business of science is to make people uncomfortable. I briefly regretted the remark because I worried 2P_Glealer-StoryEverTold_Atincld 2 12/16116 3:06 PIA EFTA00285924  PROLOGUE 3 that it would scare people away. But being uncomfortable is a virtue, not a hindrance. Everything about our evolutionary history has primed our minds to be comfortable with concepts that helped us survive, such as the natural teleological tendency children have to assume objects exist to serve a goal, and the broader tendency to anthropomorphize, to as- sign agency to lifeless objects, because clearly it is better to mistake an inert object for a threat than a threat for an inert object. Evolution didn't prepare our minds to appreciate long or short time- scales or short or huge distances that we cannot experience directly. So it is no wonder that some of the remarkable discoveries of the scientific method, such as evolution and quantum mechanics, are nonintuitive at best, and can draw most of us well outside our myopic comfort zone. This is also what makes the greatest story ever told so worth telling. The best stories challenge us. They cause us to see ourselves differently, to re- align our picture of ourselves and our place in the cosmos. This is not only true for the greatest literature, music, and art. It is true of science as well. In this sense it is unfortunate that replacing ancient beliefs with modern scientific enlightenment is often described as a "loss of faith." How much greater is the story our children will be able to tell than the story we have told? Surely that is the greatest contribution of science to civilization: to ensure that the greatest books are not those of the past, but of the future. Every epic story has a moral. In ours, we find that letting the cosmos guide our minds through empirical discovery can produce a great rich- ness of spirit that harnesses the best of what humanity has to offer. It can give us hope for the future by allowing us to enter it with our eyes open and with the necessary tools to actively participate in it. • • • My previous book, A Universe from Nothing, described how the revolu- tionary discoveries over the past hundred years have changed the way we understand our evolving universe on its largest scales. This change has led science to begin to directly address the question Why is there something 2P_Glealer-StoryEverrold_Atirdd 3 12/16116 3:06 PIA EFTA00285925  4 PROLOGUE rather than nothing?"—which was formerly religious territory—and re- work it into something less solipsistic and operationally more useful. Like A Universefrom Nothing, this story also originated in a lecture I presented, in this case at the Smithsonian Institution in Washington, DC, which generated some excitement at the time, and as a result I was once again driven to elaborate upon the ideas I started to develop there. In con- trast to A Universefrom Nothing, in this book I explore the other end of the spectrum of our knowledge and its equally powerful implications for under- standing age-old questions. The profound changes over the past hundred years in the way we understand nature at its smallest scales are allowing us to similarly co-opt the equally fundamental question Why are we here?" We will find that reality is not what we think it is. Under the surface are "weird: counterintuitive, invisible inner workings that can chal- lenge our preconceptions of what makes sense as much as a universe arising from nothing might. And like the conclusion I drew in my last book, the ultimate lesson from the story I will tell here is that there is no obvious plan or purpose to the world we find ourselves living in. Our existence was not preordained, but appears to be a curious accident. We teeter on a precarious ledge with the ultimate balance determined by phenomena that lie well beneath the surface of our experience—phenomena that don't rely in any way upon our existence. In this sense, Einstein was wrong: "God" does appear to play dice with the universe, or universes. So far we have been lucky. But like playing at the craps table, our luck may not last forever. • • • Humanity took a major step toward modernity when it dawned in our ancestors' consciousness that there is more to the universe than meets the eye. This realization was probably not accidental. We appear to be hardwired to need a narrative that transcends and makes sense of our own existence, a need that was probably intimately related to the rise of religious belief in early human societies. 2P_Glealer-StoryEverTold_Atincld 4 12/16116 3:06 PIA EFTA00285926  PROLOGUE 5 By contrast, the story of the rise of modern science and its divergence from superstition is the tale of how the hidden realities of nature were uncovered by reason and experiment through a process in which seem- ingly disparate, strange, and sometimes threatening phenomena were ultimately understood to be connected just beneath the visible surface. Ultimately these connections dispelled the goblins and fairies that had earlier spawned among our ancestors. The discovery of connections between otherwise seemingly dispa- rate phenomena is, more than any other single indicator, the hallmark of progress in science. The many classic examples include Newton's connection of the orbit of the Moon to a falling apple; Galileo's recogni- tion that vastly different observed behaviors for falling objects obscure that they are actually attracted to the earth's surface at the same rate; and Darwin's epic realization that the diversity of life on Earth could arise from a single progenitor by the simple process of natural selection. None of these connections was all that obvious, at first. However, after the relationship comes to light and becomes clear, it prompts an "Ahar experience of understanding and familiarity. One feels like saying, 1 should have thought of that!" Our modern picture of nature at its most fundamental scale—the Standard Model, as it has become called—contains an embarrassment of riches, connections that are far removed from the realm of everyday experience. So far removed that it is impossible without some ground- ing to make the leap in one step to visualize them. Not surprisingly, such a single leap never occurred historically, ei- ther. A series of remarkable and unexpected and seemingly unrelated connections emerged to form the coherent picture we now have. The mathematical architecture that has resulted is so ornate that it almost seems arbitrary. "Ahar is usually the furthest thing from the lips of the noninitiated when they hear about the Higgs boson or Grand Unifica- tion of the forces of nature. To move beyond the surface layers of reality, we need a story that 2P_Glealer-StoryEverTold_Atirdd S 12/16116 3:06 PM EFTA00285927  6 PROLOGUE connects the world we know with the deepest corners of the invisible world all around us. We cannot understand that hidden world with in- tuitions based solely on direct sensation. That is the story I want to tell here. I will take you on a journey to the heart of those mysteries that lie at the edge of our understanding of space, time, and the forces that operate within them. My goal is not to unnecessarily provoke or offend, but to prod you, just as we physicists ourselves have been prodded and dragged by new discoveries into a new reality that is at once both un- comfortable and uplifting. Our most recent discoveries about nature's fundamental scales have chillingly altered our perception of the inevitability of our presence in the universe. They provide evidence too that the future will no doubt be radically different from what we might otherwise have imagined, and they too further decrease our cosmic significance. We might prefer to deny this uncomfortable, inconvenient reality, this impersonal, apparently random universe, but if we view it in an- other context, all of this need not be depressing. A universe without purpose, which is the way it is as far as I can tell, is far more exciting than one designed just for us because it means that the possibilities of existence are so much more diverse and far ranging. How invigorating it is to find ourselves with an exotic menagerie to explore, with laws and phenomena that previously seemed beyond our wildest dreams, and to attempt to untangle the knotted confusion of experience and to search for some sense of order beneath. And how fascinating it is to discover that order, and to piece together a coherent picture of the universe on scales far beyond those that we may ever directly experience—a picture woven together by our ability to predict what will happen next, and the consequent ability to control the environment around us. How lucky to have our brief moment in the Sun. Every day that we discover some- thing new and surprising, the story gets even better. 2P_Glealer-StoryEverTold_Atirdd S 12/16116 3:06 PIA EFTA00285928  Part One GENESIS EFTA00285929 2P_Gtealer-StoryEverTold_Atirdd S 12/16116 3:06 PM EFTA00285930  Chapter 1 FROM THE ARMOIRE TO THE CAVE The simple inherit folly, but the prudent are crowned with knowledge. -PROVERBS 14:18 Lmy beginning there was light. Surely there was light at the beginning of time, but before we can get to the beginning of time, we will need to explore our own beginnings, which also means exploring the beginning of science. And that means returning to the ultimate motive for both science and religion: the longing for some- thing else. Something beyond the universe of our experience. For many people, that longing translates into something that gives meaning and purpose to the universe and extends to a longing for some hidden place that is better than the world in which we live, where sins are forgiven, pain is absent, and death does not exist. Others, however, long for a hidden place of a very different sort, the physical world beyond our senses, the world that helps us understand how things behave the way they do, rather than why. This hidden world underlies what we ex- perience, and the understanding of it gives us the power to change our lives, our environment, and our future. 9 2P_Gtealer-StoryEverTold_Atincld 9 12/16116 3:06 PIA EFTA00285931  10 THE GREATEST STORY EVER TOLD-SO FAR The contrast between these two worlds is reflected in two very dif- ferent works of literature. The first, The Lion, the Witch and the Wardrobe, by C. S. Lewis, is a twentieth-century children's fantasy with decidedly religious overtones. It captures a childhood experience most of us have had—looking under the bed or in the closet or in the attic for hidden treasure or evidence that there is more out there than what we normally experience. In the book, several schoolchildren discover a strange new world, Narnia, by climbing into a large wardrobe in the country house outside London where they have been sequestered for their protection during the Second World War. The chil- dren help save Narnia with the aid of a lion, who lets himself be humiliated and sacrificed, Christlike, at an altar in order to conquer evil in his world. While the religious allusion in story is clear, we can also in- terpret it in another way—as an allegory, not for the existence of God or the devil, but rather for the remarkable and potentially terrifying possi- bilities of the unknown, possibilities that lie just beyond the edge of our senses, just waiting for us to be brave enough to seek them out. Possibili- ties that, once revealed, may enrich our understanding of ourselves or, for some who feel a need, provide a sense of value and purpose. The portal to a hidden world inside the wardrobe is at once safe, with the familiar smell of oft-worn clothes, and mysterious. It implies the need to move beyond classical notions of space and time. For if nothing is revealed to an observer who is in front of or behind the wardrobe, and something is revealed only to someone inside, then the space experienced inside the wardrobe must be far larger than that seen from its outside. Such a concept is characteristic of a universe in which space and time can be dynamical, as in the General Theory of Relativity, where, for ex- ample, from outside the "event horizon" of a black hole—that radius inside of which there is no escape—a black hole might appear to comprise a small volume, but for an observer inside (who has not yet been crushed to smithereens by the gravitational forces present), the volume can look quite different. Indeed, it is possible, though beyond the domain where we 2P_GrealestSloryEverTold_AC.indd 10 12/10/16 3:06 PIA EFTA00285932  From the Armoire to the Cave 11 can perform reliable calculations, that the space inside a black hole might provide a portal to another universe disconnected from our own. But the central point I want to return to is that the possibility of universes beyond our perception seems to be tied, in the literary and philosophical imagination, at least, to the possibility that space itself is not what it seems. The harbinger of this notion, the "ur" story if you will, was written twenty-three centuries before Lewis penned his fantasy. I refer to Plato's Republic, and in particular to my favorite section, the Allegory of the Cave. But in spite of its early provenance, it illuminates more directly and more clearly both the potential necessity and the potential perils of searching for understanding beyond the reach of our immediate senses. In the allegory, Plato likens our experience of reality to that of a group of individuals who live their entire lives imprisoned inside a cave, forced to face a blank wall. Their only view of the real world is that wall, which is illuminated by a fire behind them, and on which they see shad- ows moving. The shadows come from objects located behind them that the light of the fire projects on the wall. I show the drawing below, which came from the high school text in which I first read this allegory, in a 1961 translation of Plato's dialogues. 2P_Glealer-StoryEverTold_Atirdd t1 12.'1&16 3:C8 PM EFTA00285933  12 THE GREATEST STORY EVER TOLD-SO FAR The drawing is amusing because it clearly reflects as much about the time it was drawn as it does the configuration of the cave described in the dialogue. Why, for example, are the prisoners here all women, and scantily clad ones at that? In Plato's day, any sexual allusion might easily have displayed young boys. Plato argues that the prisoners will view the shadows as reality and even give them names. This is not unreasonable, and it is, in one sense, as we shall soon see, a very modern view of what reality is, namely that which we can directly measure. My favorite definition of reality still is that given by the science fiction writer Philip K. Dick, who said, "Reality is that which, when you stop believing in it, doesn't go away." For the prisoners, the shadows are what they see. They are also likely to hear only the echoes of noises made behind them as the sounds bounce off the wall. Plato likened a philosopher to a prisoner who is freed from bondage and forced, almost against his will, to not only look at the fire, but to move past it, and out to the daylight beyond. First, the poor soul will be in distress, with the glare of the fire and the sunshine beyond the cave hurting his eyes. Objects will appear completely unfamiliar; they will not resemble their shadows. Plato argues that the new freeman may still imagine the shadows that he is used to as truer representations than the objects themselves that are casting the shadows. If the individual is reluctantly dragged out into the sunshine, ulti- mately all of these sensations of confusion and pain will be multiplied. But eventually, he will become accustomed to the real world, will see the stars and Moon and sky, and his soul and mind will be liberated of the illusions that had earlier governed his life. If the person returns to the cave, Plato argues, two things would hap- pen. First, because his eyes would no longer be accustomed to the dark- ness, he would be less able to distinguish the shadows and recognize them, and his compatriots would view him as handicapped at best, and 2P_GrealestStrayE-verTold_AC.indd 12 12/18/18 3:08 PIA EFTA00285934  From the Armoire to the Cave 13 dim at worst. Second, he would no longer view the petty and myopic priorities of his former society, or the honors given to those who might best recognize the shadows and predict their future, as worthy of his respect. As Plato poetically put it, quoting from Homer: "Better to be the poor servant of a poor master, and to endure any- thing, rather than think as they do and live after their manner." So much for those whose lives are lived entirely in illusion, which Plato suggests includes most of humanity. Then, the allegory states that the journey upward—into the light—is the ascent of the soul into the intellectual world. Clearly in Plato's mind only a retreat to the purely "intellectual world," a journey reserved for the few—aka philosophers—could replace illusion with reality. Happily, that journey is far more accessible today using the techniques of science, which combine reason and reflection with empirical inquiry. Nevertheless, the same challenge remains for scientists today: to see what is behind the shadows, to see that which, when you drop your preconceptions, doesn't disappear. While Plato doesn't explicitly mention it, not only would his fellow prisoners view the poor soul who had ventured out and returned as handicapped, but they would likely think he was crazy if he talked about the wonders that he had glimpsed: the Sun, the Moon, lakes, trees, and other people and their civilizations. This idea is strikingly modern. As the frontiers of science have moved further and further away from the world of the familiar and the world of common sense as inferred from our direct experience, our picture of the reality underlying our experience is getting increasingly difficult for us to comprehend or accept. Some find it more comforting to retreat to myth and superstition for guidance. But, we have every reason to expect that "common sense," which first evolved to help us cope with predators in the savannas of Africa, might lead us astray when we attempt to think about nature on vastly differ- 2P_Glealer-StoryEverTold_Aairdd 13 12/16116 3:06 PIA EFTA00285935  14 THE GREATEST STORY EVER TOLD-SO FAR ent scales. We didn't evolve to intuitively understand the world of the very small, the very big, or the very fast. We shouldn't expect the rules we have come to rely on for our daily lives to be universal. While that myopia was useful from an evolutionary perspective, as thinking beings we can move beyond it. In this regard, I cannot resist quoting one last admonition in Plato's allegory: "In the world of knowledge the idea of good appears last of all and is seen only with an effort; and, when seen, is also inferred to be the au- thor of all things good and right, parent of light, and ... the immediate source of reason and truth." Plato further argues that this is what those who would act rationally should strive for, in both public and private life—seeking the "good" by focusing on reason and truth. He suggests that we can only do so by exploring the realities that underlie the world of our direct experience, rather than by exploring the illusions of a reality that we might want to exist. Only through rational examination of what is real, and not by faith alone, is rational action—or good—possible. Today, Plato's vision of "pure thought" has been replaced by the sci- entific method, which, based on both reason and experiment, allows us to discover the underlying realities of the world. Rational action in public and private life now requires a basis in both reason and empiri- cal investigation, and it often requires a departure from the solipsistic world of our direct experience. This principle is the source of most of my own public activism in opposition to government policies based on ideology rather than evidence, and it is also probably why I respond so negatively to the concept of the "sacred"—implying as it does some idea or admonition that is off-limits to public questioning, exploration, dis- cussion, and sometimes ridicule. It is hard to state this view more strongly than I did in a New Yorker piece: 'Whenever scientific claims are presented as unquestionable, they undermine science. Similarly, when religious actions or claims 2P_Glealer-StoryEverTold_Atirdd 14 12/16116 3:06 PIA EFTA00285936  From the Armoire to the Cave 15 about sanctity can be made with impunity in our society, we undermine the basis of modern secular democracy. We owe it to ourselves and to our children not to give a free pass to governments—totalitarian, theo- cratic, or democratic—that endorse, encourage, enforce, or otherwise legitimize the suppression of open questioning in order to protect ideas that are considered 'sacred.' Five hundred years of science have liberated humanity from the shackles of enforced ignorance! Philosophical reflections aside, the prime reason I am introducing Plato's cave here is that it can provide a concrete example of the nature of the scientific discoveries at the heart of the story I want to tell. Imagine a shadow that our prisoners might see on the wall, displayed by an evil puppeteer located on a ledge in front of the fire: This shadow displays both length and directionality, two concepts that we, who are not confined to the cave, take for granted. However, as the prisoners watch, this shadow changes: Later it looks like this: And again later like this: And later still, like this: 2P_Glealer-StoryEverTold_Atirdd 15 12/16116 3:06 PIA EFTA00285937  16 THE GREATEST STORY EVER TOLD-SO FAR What would the prisoners infer from all of this? Presumably, that concepts such as length or direction have no absolute meaning. The ob- jects in their world can change both length and directionality arbitrarily. In the reality of their direct experience, neither length nor directionality appears to have significance. What will the natural philosopher, who has escaped to the surface to explore the richer world beyond the shadows, discover? He will see that the shadow is first of all just a shadow: a two-dimensional image on the wall cast from a real, three-dimensional object located behind the pris- oners. He will see that the object has a fixed length that never changes, and that it's accompanied by an arrow that is always on the same side of the object. From a vantage point slightly above the object, he sees that the series of images results from the projection of a rotating weather vane onto the wall: When he returns to join his former colleagues, the philosopher- scientist can explain that an absolute quantity called length doesn't change over time, and that directionality can be assigned unambiguously to cer- tain objects as well. He will tell his friends that the real world is three- dimensional, not two-dimensional, and that once they understand, all of their confusion about the seemingly arbitrary changes will disappear. Would they believe him? It would be a tough sell because they won't have an intuitive idea of what a rotation is (after all, with an intuition based purely on two-dimensional experience, it would likely be difficult to "picture" mentally any rotations in a third dimension). Blank stares? Probably. The loony bin? Maybe. However, he might win over the com- munity by stressing attractive characteristics associated with his claim: behavior that on the surface appears to be complex and arbitrary can be 2P_Glealer-StoryEverTold_Atindd 18 12/16116 3:06 PIA EFTA00285938  From the Armoire to the Cave 17 shown to resultfrom a much simpler underlying picture of nature, and seemingly disparate phenomena are actually connected and can be part of a unified whole. Better still, he could make predictions that his friends could test. First, he could argue that, if the apparent change in length of the shadows measured by the group is really due to a rotation in a third dimension, whenever the length of the object briefly vanishes, it will immediately reemerge with the arrow pointing in the opposite direction. Second, he could argue that as the length oscillates, the maximum length of the shadow when the arrow is pointing in one direction will always be ex- actly the same as the maximum length of the shadow when it is pointing in the other direction. Plato's cave thus becomes an allegory for far more than he may have intended. Plato's freed man discovers the hallmarks of the remarkable true story of our own struggle to understand nature on its most fun- damental scales of space, time, and matter. We too have had to escape the shackles of our prior experience to uncover profound and beauti- ful simplifications and predictions that can be as terrifying as they are wonderful. But just as the light beyond Plato's cave is painful to the eyes at first, with time it becomes mesmerizing. And once witnessed, there is no going back. 2P_Glealer-Storgverrold_Atirdd 17 12/16116 3:06 PIA EFTA00285939 2P_GreatestSlowEverrold_AC.indd 18 1211&18 3:06 PM EFTA00285940  Chapter 2 SEEING IN THE DARK Let there be light: and there was light -GENESIS 1:3 L the beginning there was light. It is no coincidence that the ancients imagined in Genesis that light was created on the first day. Without light, there would be little aware- ness of the vast universe surrounding us. When we nod and say, 1 see," to a friend who is trying to explain something, we convey far more than just an observation, but rather a fundamental understanding. Plato's allegory was appropriately centered on light—light from a fire to cast the shadows on the cave wall and light from the outside to tempor