Why is the universe so life-friendly? It is a question
that has haunted and fascinated physicists for years. Presenting
his unique vision of cosmic coincidences, superhuman
intelligence, and baby universes, science writer James Gardner
spins a celestial tale, arguing that human life may be a crucial
and necessary step in the evolving architecture of our amazing
WHAT IS ENLIGHTENMENT: It seems like every day we
learn something new about the universe, with incredible pictures
of distant stars, strange nebulae, or colliding galaxies that
dazzle astronomers. If we take a bird's-eye view on the subject
of cosmology, what do you feel is being revealed about the
universe we live in?
JAMES GARDNER: There are two important things going on
right now in the field of cosmology. The first is a growing
sophistication in observational technology. This era will be
viewed in retrospect as the dawn of precision
cosmology—incredible new instruments are showing us a
level of detail that was inconceivable a couple of decades ago.
We are learning what the universe looks like, how it evolved,
and what patterns have driven its evolution. Practically every
day, there is a new instrument coming on-line that essentially
constitutes a better set of eyes for the human race as it looks
back in time and out in space.
The second related development is ironically in almost the
opposite direction. The clearer that our picture of the universe
is becoming, the more mysterious it is growing. In particular,
we now know with a high degree of certainty that in the
“cosmic budget”—what actually makes up the
cosmos—the largest entry by far, constituting over fifty
percent of the stuff in the cosmos, is neither ordinary matter
nor ordinary energy nor even dark matter. It's a mysterious
force called “dark energy,” which is a kind of
antigravity, variously termed “cosmological
constant” or “quintessence.” It's the force
that appears at the very largest scale to be propelling the
universe outward. Dark energy is the generic name for it. No one
has a clue as to what it is. It's literally antigravity, a force
similar to what Einstein, before the advent of the Big Bang
theory, put into his equations as the “cosmological
constant” and then later bemoaned as the biggest blunder
of his career. In fact, it turned out to be perhaps his greatest
WIE: Would this also potentially be the force that
gave birth to the Big Bang?
Gardner: Yes; it might be a scaled-down version of the
force that propelled the Big Bang. So that's one huge mystery.
Another has to do with the most successful theoretical attempt
to unify general relativity and quantum mechanics and arrive at
a “theory of everything,” which is called
“M-theory,” formerly known as string theory. It
postulates that all the subatomic particles are different modes
of vibration of tiny one-dimensional strings of energy. In order
to be mathematically consistent, M-theory requires there to be
one dimension of time but ten dimensions of space,
because you need that many dimensions to encode the information
that is worked into the characteristics of fundamental
Physicists had hopes that M-theory would yield a single
solution, in line with the standard model of particle physics.
But instead, a great surprise has happened. The number of
solutions allowed by M-theory, which essentially corresponds to
different types of universes with different kinds of subatomic
particles and physical constants, is literally astronomical.
It's measured not in the millions, billions, or trillions, but
in googols or googolplexes. A googol is ten to the hundredth
power. And a googolplex is ten to a googol power. Those numbers
far exceed the number of subatomic particles in our particular
universe. That's how big they are.
WIE: So the only way that the mathematics
of string theory can begin to work is if you suddenly allow for
this incredible infusion of all these dimensions and potential
universes beyond ours?
Gardner: Yes. There are all of these potential
solutions to the mathematics, and none of the solutions appear
to be mathematically favored, let alone dictated. Do you
remember Einstein's famous question as to whether God had any
choice in designing the laws of physics? The answer, under this
interpretation of string theory, is that He had an enormous
range of choices, literally an astronomical degree of choice.
Our most advanced and sophisticated cosmological science seems
to be telling us that the physical creation of the cosmos could
have turned out in any number of ways that would have yielded a
universe very different from the one we inhabit.
Now, that gets to the next point: Why did our particular
universe, out of odds of perhaps a googolplex to one, have the
cards shuffled in just such a way—as a result of a
presumably random process—that they happened to yield a
life-friendly cosmos? Nothing in the fundamental principles of
M-theory would indicate that there was any mathematical
predisposition for things to come out so strangely well tuned.
And the physical laws and constants of this universe are, in
fact, extraordinarily well tuned for life. In physics, attempts
to explain this mystery are classified as different variations
of what is called the “anthropic principle.”
There are four primary versions of the anthropic principle.
First, the weak anthropic principle says that since we
inhabit this particular cosmos, it must necessarily be
life-friendly, or else we would not be here to observe it. Some
physicists have said that the weak anthropic principle is really
little more than a tautology, and I agree. It hardly deserves to
be called a principle.
The second is the strong anthropic principle. It
says that the laws and constants of physics actually encode
within them the emergence of life and intelligence. This is an
almost quasi-religious notion that few scientists subscribe to.
And there are two others that are interesting. One is called
the participatory anthropic principle, which was first
articulated by John Wheeler at Princeton. Using the strange
properties of quantum mechanics, it asserts that the very act of
observing the universe summons it into existence and gives it
the structure and the properties that we observe. And then there
is a fourth anthropic principle that John Barrow and Frank
Tipler have articulated. It's called the final anthropic
principle, and it advances the claim that once life has
arisen anywhere in this or any other universe, its
sophistication and pervasiveness will expand inexorably and
exponentially until life's domain is conterminous with the
boundaries of the cosmos itself.
So those are the four versions of the anthropic principle.
Now the fact that the universe appears to be exquisitely
fine-tuned in just such a way as to render it life-friendly is
really not very controversial anymore. The set of coincidences
is just too stunning to escape the notice of any but the most
diehard dogmatic opponents of the term
“anthropic”—the “A-word.” But the
explanations for this phenomenon vary dramatically.
I happen to think that this utterly mysterious phenomenon
poses the biggest of the big questions currently outstanding in
all of science. It is certainly the deepest question in
cosmology: Why is the universe life-friendly?
The two most popular attempts by cosmologists to account for
the bio-friendly quality of the universe both involve enlisting
the weak version of the anthropic principle. One approach is
favored by people such as the famous physicist Steven Weinberg.
It says that the Big Bang didn't just happen once. There are
countless “big bangs” going off all the time in
inaccessible regions that we simply cannot perceive. It is
called “eternal chaotic inflation,” and it's really
the consensus view now.
WIE: So there are “big bangs” going
off everywhere, and our universe is just one of hundreds of
millions or so?
Gardner: Yes, hundreds of millions of googols of
them. Under this view, generating a life-friendly cosmos is
simply a matter of randomly reshuffling the fundamental
parameters and values of physics a sufficient number of times
until a particular big bang yields that result—until,
against odds of a googolplex to one, a permutation just happens
to be bio-friendly. It's kind of like assuming that if you wait
long enough, a Boeing 747 will assemble itself out of the dust
in the asteroid belt. Yes, it could happen. Nothing in
the laws of physics says it can't, but it's not what I
would call a parsimonious hypothesis. To be blunt, in my view,
it's just giving up. It's just throwing in the towel. It
represents a failure to recognize that just as the appearance of
a seemingly well-tuned natural world constituted a vital set of
clues for Darwin to follow, so, too, does the appearance of a
seemingly well-tuned cosmos constitute a vital set of clues that
should be pursued.
The second common explanation—and this is the one
favored by Stephen Hawking—basically says that the origin,
and evolution, of the universe is a quantum phenomenon and that
every possible quantum state of the cosmos exists
simultaneously. But we're limited to those quantum states in
which human beings can exist. It's really a very close cousin of
the weak anthropic principle. It essentially asserts that we'll
never be able to observe any branch of the quantum wave function
other than the one that we inhabit. They're unobservable, and of
course, we inhabit a life-friendly branch because otherwise we
wouldn't be here to observe it. It's another kind of
tautological non-explanation in my view.
Both of these approaches violate what's called the
“mediocrity principle,” which is a statistically
based rule of thumb that says that without extraordinary
evidence to the contrary, our universe should be assumed to be
relatively typical. The Weinberg approach, in particular, flouts
that principle. His approach takes refuge in a brute,
unfathomable mystery—the conjectured lucky role of the
dice. It declines to probe seriously into the possibility of the
existence of a naturalistic (as opposed to supernatural) cosmic
evolutionary process that could yield a life-friendly set of
physical laws and constants.