The Accidental Universe: The World You Thought You Knew

by Alan Lightman

two theories in physics, called “eternal inflation” and “string theory,” now indicate that the same fundamental principles, from which the laws of nature derive, lead to many different self-consistent universes,

According to the current thinking of many physicists, we are living in one of a vast number of universes. We are living in an accidental universe. We are living in a universe uncalculable by science.

the multiverse idea does explain one aspect of our universe that has unsettled some scientists for years: according to various calculations, if the values of some of the fundamental parameters of our universe were a little larger or a little smaller, life could not have arisen.

In sum, the strengths of the basic forces and certain other fundamental parameters in our universe appear to be fine-tuned to allow the existence of life.

anthropic principle, which states that the universe must have many of the parameters it does because we are here to observe it.

If these fundamental parameters were much different from what they are, it is not only we human beings who would not exist. No life of any kind would exist.

The multiverse offers another explanation. If there are zillions of different universes with different properties—for example, some with nuclear forces much stronger than in our universe and some with nuclear forces much weaker—then some of those universes will allow the emergence of life and some will not.

Physicists call the energy associated with this unexpected cosmological force dark energy. No one knows what it is. Not only invisible, dark energy apparently hides out in empty space. Yet, based on our observations of the accelerating rate of expansion, dark energy comprises a whopping three-quarters of the total energy of the universe. Dark energy is the ultimate éminence grise. Dark energy is the invisible elephant in the room of science.

(A negative value for dark energy means that it acts to decelerate the universe, in contrast to what is observed.)

If the theoretically possible values for dark energy were marked out on a ruler stretching from here to the sun, the value of dark energy actually found in our universe (10–8 ergs per cubic centimeter) would be closer to the zero end than the width of an atom.

If the amount of dark energy in our universe were only a little bit different than what it actually is, then life could never have emerged. A little larger, and the universe would have accelerated so rapidly that matter in the young universe could never have pulled itself together to form stars and hence complex atoms made in stars.

out of all the possible amounts of dark energy that our universe might have, the actual amount lies in the tiny sliver of the range that allows life.

A vast number of universes may exist, with many different values of the amount of dark energy. Our particular universe is one of the universes with a small value, permitting the emergence of life.

string theory postulates that the smallest constituents of matter are not subatomic particles, like the electron, but extremely tiny one-dimensional “strings” of energy.

These elemental strings can vibrate at different frequencies, like the strings of a violin, and the different modes of vibration correspond to different fundamental particles and forces.

There are, in fact, a vast number of ways that the extra dimensions in string theory can be folded up, a little like the many ways that a piece of paper can be folded up, and each of the different ways corresponds to a different universe with different physical properties.

all of reality would be a manifestation of the vibrations of elemental strings. String theory would then represent the ultimate realization of the Platonic ideal of a fully explicable cosmos in terms of a few fundamental principles.

string theory does not predict a unique universe, but a vast number of possible universes with different properties. It has been estimated that the “string landscape” contains 10500 different possible universes. For all practical purposes, that number is infinite.

Not only must we accept that basic properties of our universe are accidental and uncalculable. In addition, we must believe in the existence of many other universes. But we have no conceivable way of observing these other universes and cannot prove their existence. Thus, to explain what we see in the world and in our mental deductions, we must believe in what we cannot prove.

I don’t know why we long so for permanence, why the fleeting nature of things so disturbs. With futility, we cling to the old wallet long after it has fallen apart. We visit and revisit the old neighborhood where we grew up, searching for the remembered grove of trees and the little fence. We clutch our old photographs. In our churches and synagogues and mosques, we pray to the everlasting and eternal. Yet, in every nook and cranny, nature screams at the top of her lungs that nothing lasts, that it is all passing away.

Physicists call it the second law of thermodynamics. It is also called the arrow of time. Oblivious to our human yearnings for permanence, the universe is relentlessly wearing down, falling apart, driving itself toward a condition of maximum disorder.

Our sun, for example, will last another five billion years before its fuel is spent. Then it will expand enormously into a red gaseous sphere, enveloping the Earth, go through a series of convulsions, and finally settle down to a cold ball made largely of carbon and oxygen.

In past eons, new stars have replaced the dying stars by the action of gravity pulling together cosmic clouds of gas. But the universe has been expanding and thinning out since its Big Bang beginning, large concentrations of gas are gradually being disrupted, and in the future the density of gas will not be sufficient for new star formation. In addition, the lighter chemical elements that fuel most stars, such as hydrogen and helium, will have been used up in previous generations of stars. At some point in the future, new stars will cease being born. Slowly but surely, the stars of our universe are winking out.

Anicca, or impermanence, they call it. In Buddhism, anicca is one of the three signs of existence, the others being dukkha, or suffering, and anatta, or non-selfhood.

To my mind, it is one of the profound contradictions of human existence that we long for immortality, indeed fervently believe that something must be unchanging and permanent, when all of the evidence in nature argues against us.

If against our wishes and hopes, we are stuck with mortality, does mortality grant a beauty and grandeur all its own? Even though we struggle and howl against the brief flash of our lives, might we find something majestic in that brevity? Could there be a preciousness and value to existence stemming from the very fact of its temporary duration?

Starting with these axioms, we can say that science and God are compatible as long as the latter is content to stand on the sidelines once the universe has begun. A God that intervenes after the cosmic pendulum has been set into motion, violating the physical laws, would clearly upend the central doctrine of science. Of course, the physical laws could have been created by God before the beginning of time. But once created, according to the central doctrine, the laws are immutable and cannot be violated from one moment to the next.

We can categorize religious beliefs according to the degree to which God acts in the world. At one extreme is atheism: God does not exist, period. Next comes deism. A prominent belief in the seventeenth and eighteenth centuries and partly motivated to incorporate the new science with theological thinking, deism holds that God created the universe but has not acted thereafter.

immanentism: God created the universe and the physical laws and continues to act but only through repeated application of those fixed laws.

immanentism differs philosophically from deism, it is functionally equivalent because God does not perform miracles in the world, and the central doctrine of science is upheld.

Most religions, including Christianity, Judaism, Islam, and Hinduism, subscribe to an interventionist view of God.

Except for a God who sits down after the universe begins, all other Gods conflict with the assumptions of science.

falsifying the arguments put forward to support a proposition does not falsify the proposition.

In my opinion, Dawkins has a narrow view of faith, and of people. I would be the first to challenge any belief that contradicts the findings of science. But, as I have said earlier, there are things we believe in that do not submit to the methods and reductions of science.

Richard Dawkins stopped being credible the second he started playing Devil’s advocate on the matter of eugenics

Consider the verses of the Gitanjali, the Messiah, the mosque of the Alhambra, the paintings on the ceiling of the Sistine Chapel. Should we take to task Tagore and Handel and Sultan Yusuf and Michelangelo for not thinking? For believing in nonsense, to use Dawkins’s language? Reaching beyond art to the world of public affairs, should we label as nonthinkers Abraham Lincoln, Mahatma Gandhi, and Nelson Mandela because of their religious beliefs, because of their faith in some things that cannot be proved? Can we not accept their value as powerful thinkers and doers even if we do not agree with all of their beliefs?

Faith, in its broadest sense, is about far more than belief in the existence of God or the disregard of scientific evidence. Faith is the willingness to give ourselves over, at times, to things we do not fully understand. Faith is the belief in things larger than ourselves. Faith is the ability to honor stillness at some moments and at others to ride the passion and exuberance that is the artistic impulse, the flight of the imagination, the full engagement with this strange and shimmering world.

“Were one to characterize religion in the broadest and most general terms possible, one might say that it consists of the belief that there is an unseen order, and that our supreme good lies in harmoniously adjusting ourselves thereto.”

Science indeed has a level of practice that is personal and human, but it also has an additional level of authentication, which is entirely impersonal and objective, and that additional level, existing outside of our minds, is what makes science science.

Science also engages in a few beliefs without proof: for example, belief in the central doctrine of science, as discussed in part I. There is no way that we can prove that the same laws of nature hold everywhere in the universe, since we cannot collect data from all parts of the universe.

Another tenet of faith in science is that the laws of nature are ultimately discoverable by us human beings.

Some people believe that there is no distinction between the spiritual and physical universes, no distinction between the inner and the outer, between the subjective and the objective, between the miraculous and the rational. I need such distinctions to make sense of my spiritual and scientific lives. For me, there is room for both a spiritual universe and a physical universe, just as there is room for both religion and science. Each universe has its own power. Each has its own beauty, and mystery.

It takes roughly a trillion collisions between protons to coax one Higgs into existence, and, once created, the particle hangs around for less than a billionth of a trillionth of a second before changing into other subatomic particles. Clearly, a particle with such a fleeting acquaintance cannot be spotted directly. Rather, its existence is inferred by observing the other particles that it morphs into.

The essence of the electroweak theory is the postulate that nature is symmetrical with respect to the particles that convey the weak and electromagnetic forces, known as Ws and Zs and photons, respectively. That is, you can exchange some of these particles with the others, and the fundamental forces act in the same way. In terms of the unified electroweak force, these particles are equivalent.

Some physicists believe that nature is even more symmetrical than we have yet discovered, that at high enough energy all four of the fundamental forces become essentially identical, with the same strength.

“we must ultimately be able to account for the most basic fact of aesthetic experience, the fact that delight lies somewhere between boredom and confusion. If monotony makes it difficult to attend, a surfeit of novelty will overload the system and cause us to give up.”

Beauty and symmetry and minimum principles are not qualities we ascribe to the cosmos and then marvel at in their perfection. They are simply what is, just like the particular arrangement of atoms that make up our minds. We are not observers on the outside looking in. We are on the inside too.