The Greatest Story Ever Told—So Far

by Lawrence M. Krauss

  While the religious allusion in Lewis’s story is clear, we can also interpret it in another way—as an allegory, not for the existence of God or the devil, but rather for the remarkable and potentially terrifying possibilities 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. Possibilities 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 example, 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 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 shadows 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.

  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, ultimately 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 happen. First, because his eyes would no longer be accustomed to the darkness, he would be less able to distinguish the shadows and recognize them, and his compatriots would view him as handicapped at best, and 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 anything, 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 different 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 author 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 scientific 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 empirical 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 pol
icies 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, discussion, 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 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, theocratic, 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:

  What would the prisoners infer from all of this? Presumably, that concepts such as length or direction have no absolute meaning. The objects 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 prisoners. 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 certain 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 community by stressing attractive characteristics associated with his claim: behavior that on the surface appears to be complex and arbitrary can be shown to result from 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 exactly 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 fundamental scales of space, time, and matter. We too have had to escape the shackles of our prior experience to uncover profound and beautiful 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.

  Chapter 2

  * * *

  SEEING IN THE DARK

  Let there be light: and there was light.

  —GENESIS 1:3

  In 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 awareness of the vast universe surrounding us. When we nod and say, “I 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 temporarily blind the freed prisoner and then illuminate the real world for him. Like the prisoners in the cave, we too are prisoners of light—almost everything we learn about the world we learn from what we see.

  While the most significant words in the Western religious canon may be Let there be light, in the modern world this phrase now has a completely different significance from what it once did. Human beings may be prisoners of light, but so is the universe. What once appeared as a whim of a Judeo-Christian God, or other gods before that one, we now understand to be required by the very laws that allow both heaven, and more important, Earth, to exist. You cannot have one without the other. Earth, or matter, follows light.

  This change in perception underlies almost every development in the edifice we call modern science. I am writing these words as I stare out from a ship at one of the Galápagos Islands, which Charles Darwin made famous, and which made him famous in return, as he changed our perception of life and its diversity with a single brilliant realization: that all living species developed through the natural selection of small inherited variations that are passed along to future generations by survivors. As surely as the understanding of evolution changed everything about our understanding of biology, our changing understanding of light changed everything about our physical understanding of our place in the universe. As a useful fringe benefit, this change resulted in virtually all of the technology on which the modern world is based.

  The extent to which our observations of the world imprison our minds, and frame our description of the fabric of the universe, remained unappreciated for more than twenty centuries following Plato. Once serious minds began to investigate in detail the hidden nature of the universe, it took over four centuries for them to fully resolve the question What is light?

  Perhaps the most serious modern mind, although certainly not the first, to ask this question was also one of the most famous—and oddest—scientists in history: Isaac Newton. It is not inappropriate to classify Newton as a modern mind—after all, his seventeenth-century Principia: Mathematical Principles of Natural Philosophy uncovered the classical laws of motion and laid the basis for his theory of gravity, both of which form the foundation of much of modern physics. Nevertheless, as John Maynard Keynes pointed out:

  Newton was not the first of the age of reason, he was the last of the magicians, the last of the Babylonians and Sumerians, the last great mind that looked out on the visible and intellectual world with the same eyes as those who began to build our intellectual inheritance rather less than 10,000 years ago.

  The truth of this statement reflects the revolutionary importance of Newton’s work. After the Principia, no rational person could view the world the same way the ancients had viewed it. But it also reflects the character of Newton himself. He devoted far more time, and far more ink, to
writing about the occult, alchemy, and searching for hidden meanings and codes in the Bible—focusing in particular on the Book of Revelation and mysteries associated with the ancient Temple of Solomon—than he did to writing about physics.

  Newton was also one in a long line of people, which extends before and after him, who felt that he had been specifically chosen by God to help reveal the true meaning of the Scriptures. To what extent his studies of the universe derived from his fascination with the Bible is not clear, but it does seem reasonable to conclude that his primary interest was in theology, and that natural philosophy came in well below that, and probably below alchemy as well.

  Many individuals point to Newton’s fascination with God as evidence of the compatibility between science and religion, and to assert that modern science owes its existence to Christianity. This confuses history with causality. It is undeniable that many of the early giants of modern Western natural philosophy, from Newton onward, were deeply religious, although Darwin lost much, if not all, of his religious belief later in life. But remember that during much of this period there were primarily two sources of education and wealth: the Church and the Crown. The Church was the National Science Foundation of the fifteenth, sixteenth, and seventeenth centuries. All institutions of higher learning were tied to various denominations, and it was unthinkable for any educated person to not be affiliated with the Church. And as Giordano Bruno and later Galileo discovered, it was unpleasant at best to counter its doctrine. It would have been remarkable for any of these leading early scientific thinkers to have been anything but religious.