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
something new and surprising, the story gets even better.
͢͝
P a r t O n e
G E N E S I S
ͣ͝
C h a p t e r 1
F R O M
T H E
A R M O I R E
T O
T H E C AV E
The simple inherit folly, but the prudent are crowned with
knowledge.
—PROVERBS 14:18
In my 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 something 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 experience, and the
understanding of it gives us the power to change our lives, our
environment, and our future.
The contrast between these two worlds is reflected in two very
different 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 children 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 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 represent
ations 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 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, 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
project
ion 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
Lawrence Krauss - The Greatest Story Ever Told--So Far Page 2
