The Cosmic Landscape (2 page)

Then the cargo hold opened, and Curt’s wife, Chantal, bounded out of the plane, threw up her arms, and joyously yelled back, “It’s about as cold as a winter day in New Jersey.” And so it was. It stayed that way for the whole day while we frolicked in the snow.

Sometime during that night the beast awoke. By morning Antarctica had unleashed its fury. I went outside for a couple of minutes to get a taste of what Shackleton and his shipwrecked men had endured. Why hadn’t they all perished? Not a single member of the expedition was lost. Freezing cold and soaking wet for more than a year, why didn’t they all die of pneumonia? Out there in the blast of the storm, I knew the answer: nothing survives—not even the microbes that give men colds.

The other alien “planet” I’d mentioned to Victor was Death Valley—another lifeless place. No, not quite lifeless. But I wondered how much hotter it would have to get to fry all protoplasm. What Antarctica has in common with Death Valley is extreme dryness. It’s too cold for much water vapor to be suspended in the air—that and the complete lack of light pollution make it possible, in both extremes, to see the stars in a way that modern man rarely can. Standing there in the Antarctic starlight, it occurred to me how lucky we humans are. Life is fragile: it thrives only in a narrow range of temperatures between freezing and boiling. How lucky that our planet is just the right distance from the sun: a little farther, and the death of the perpetual Antarctic winter—or worse—would prevail; a little closer, and the surface would truly fry anything that touched it. Victor, being Russian, took a spiritual view of the question. “Was it not,” he asked, “God’s infinite kindness and love that permitted our existence?” My own “mindless” explanation will become clear in good time.

In fact we have much more to be thankful for than just the earth’s temperature. Without the right amount of carbon, oxygen, nitrogen, and other elements, a temperate climate would be wasted. If the sun at the center of our solar system were replaced by the more common binary star system,
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planetary orbits would be too chaotic and unstable for life to have evolved. There are endless dangers of this kind. But on top of all these are the laws of nature themselves. All it takes is a small change in Newton’s laws, or the rules of atomic physics, and poof—life would either be instantly extinguished or would never have formed. It seems that our guardian angel not only provided us with a very benign planet to live on but also made the rules of existence—the laws of physics and cosmology—just right for us. This is one of the greatest mysteries of nature. Is it luck? Is it intelligent and benevolent design? Is it at all a topic for science—for metaphysics—for religion?

This book is about a debate that is stirring the passions of physicists and cosmologists but is also part of a broader controversy, especially in the United States, where it has entered the partisan political discourse. On one side are the people who are convinced that the world must have been created or designed by an intelligent agent with a benevolent purpose. On the other side are the hard-nosed, scientific types who feel certain that the universe is the product of impersonal, disinterested laws of physics, mathematics, and probability—a world without a purpose, so to speak. By the first group, I don’t mean the biblical literalists who believe the world was created six thousand years ago and are ready to fight about it. I am talking about thoughtful, intelligent people who look around at the world and have a hard time believing that it was just dumb luck that made the world so accommodating to human beings. I don’t think these people are being stupid; they have a real point.

The advocates of intelligent design generally argue that it is incredible that anything as complex as the human visual system could have evolved by purely random processes. It is incredible! But biologists are armed with a very powerful tool—the Principle of Natural Selection—whose explanatory power is so great that almost all biologists believe the weight of evidence is strongly in favor of Darwin. The miracle of the eye is only an apparent miracle.

I think the design enthusiasts are on better ground when it comes to physics and cosmology. Biology is only part of the story of creation. The Laws of Physics and the origin of the universe are the other part, and here again, incredible miracles appear to abound. It seems hopelessly improbable that any particular rules accidentally led to the miracle of intelligent life. Nevertheless, this is exactly what most physicists have believed: intelligent life is a purely serendipitous consequence of physical principles that have nothing to do with our own existence. Here I share the skepticism of the intelligent-design crowd: I think that the dumb luck needs an explanation. But the explanation that is emerging from modern physics is every bit as different from intelligent design as Darwin’s was from “Soapy” Sam Wilberforce’s.
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The debate that this book is concerned with is not the bitter political controversy between science and creationism. Unlike the debate between “Darwin’s Bulldog” Thomas Huxley and Wilberforce, the present argument is not between religion and science but between two warring factions of science—those who believe, on the one hand, that the laws of nature are determined by mathematical relations, which by mere chance happen to allow life, and those who believe that the Laws of Physics have, in some way, been determined by the requirement that intelligent life be possible. The bitterness and rancor of the controversy have crystallized around a single phrase—the
Anthropic Principle
—a hypothetical principle that says that the world is fine-tuned so that we can be here to observe it! By itself I would have to say that this is a silly, half-baked notion. It makes no more sense than saying that the reason the eye evolved is so that someone can exist to read this book. But it is really shorthand for a much richer set of concepts that I will make clear in the chapters that follow.

But the controversy among scientists does have repercussions for the broader public debate. Not surprisingly, it does overflow the seminar rooms and scientific journals into the political debates about design and creationism. Christian Internet sites have leapt into the fray:

The Bible says:

“From the time the world was created, people have seen the earth and the sky and all that God made. They can clearly see His invisible qualities—His eternal power and divine nature. So they have no excuse whatsoever for not knowing God.”

This is as true today as it ever has been—in some ways, with the discovery of the Anthropic Principle, it is more true now than ever before. So the first kind of evidence that we have is the creation itself—a universe that carries God’s signature—a universe “just right” for us to live in.

And from another religious site:

In his book “The Cosmic Blueprint,” the astronomer professor Paul Davies concludes that the evidence for design is overwhelming:

Professor Sir Fred Hoyle—no sympathizer with Christianity—says that it looks as if a super-intellect has monkeyed with physics as well as with chemistry and biology.

And the astronomer George Greenstein says:

As we survey all the evidence, the thought insistently arises that some supernatural agency, or rather Agency, must be involved. Is it possible that suddenly, without intending to, we have stumbled upon scientific proof of the existence of a supreme being? Was it God who stepped in and so providentially created the cosmos for our benefit?
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Is it any wonder that the Anthropic Principle makes many physicists very uncomfortable?

Davies and Greenstein are serious scholars, and Hoyle was one of the great scientists of the twentieth century. As they point out, the
appearance
of intelligent design is undeniable.
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Extraordinary coincidences
are
required for life to be possible. It will take us a few chapters to fully understand this “elephant in the room,” but let’s begin with a sneak preview.

The world as we know it is very precarious, in a sense that is of special interest to physicists. There are many ways it could go bad—so bad that life as we know it would be totally impossible. The requirements that the world be similar enough to our own to support conventional life fall into three broad classes. The first class involves the raw materials of life: chemicals. Life is, of course, a chemical process. Something about the way atoms are constructed makes them stick together in the most bizarre combinations: the giant crazy Tinkertoy molecules of life—DNA, RNA, hundreds of proteins, and all the rest. Chemistry is really a branch of physics: the physics of the valence electrons, i.e., those that orbit the nucleus at the outer edges of the atom. It’s the valence electrons hopping back and forth or being shared between atoms that gives the atoms their amazing abilities.

The Laws of Physics begin with a list of elementary particles like electrons, quarks, and photons, each with special properties such as mass and electric charge. These are the objects that everything else is built out of. No one knows why the list is what it is or why the properties of these particles are exactly what they are. An infinite number of other lists is equally possible. But a universe filled with life is by no means a generic expectation. Eliminating any of these particles (electrons, quarks, or photons), or even changing their properties a modest amount, would cause conventional chemistry to collapse. This is obviously so for the electrons and for the quarks that make up protons and neutrons. Without these there could be no atoms at all. But the importance of the photon may be less obvious. In later chapters we will learn about the origin of forces like electric and gravitational forces, but for now it’s enough to know that the electric forces that hold the atom together are consequences of the photon and its special properties.

If the laws of nature seem well chosen for chemistry, they are also well chosen for the second set of requirements, namely, that the evolution of the universe provided us with a comfortable home to live in. The large-scale properties of the universe—its size; how fast it grows; the existence of galaxies, stars, and planets—are mainly governed by the force of gravity. It’s Einstein’s theory of gravity—the General Theory of Relativity—that explains how the universe expanded from the initial hot Big Bang to its present large size. The properties of gravity, especially its strength, could easily have been different. In fact it is an unexplained miracle that gravity is as weak as it is.
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The gravitational force between electrons and the atomic nucleus is ten thousand billion billion billion billion times weaker than the electrical attraction. Were the gravitational forces even a little stronger, the universe would have evolved so quickly that there would have been no time for intelligent life to arise.

But gravity plays a very dramatic role in the unfolding of the universe. Its pull causes the material in the universe—hydrogen, helium, and the so-called dark matter—to clump, into galaxies, stars, and finally planets. However, for this to happen, the very early universe must have been a bit lumpy. If the original material of the universe had been smoothly distributed, it would have stayed that way for all time. In fact, fourteen billion years ago, the universe was just lumpy enough—a bit lumpier or a bit less lumpy, and there would have been no galaxies, stars, or planets for life to evolve on.

Finally, there is the actual chemical composition of the universe. In the beginning there were only hydrogen and helium: certainly not sufficient for the formation of life. Carbon, oxygen, and all the others came later. They were formed in the nuclear reactors in the interiors of stars. But the ability of stars to transmute hydrogen and helium into the all-important carbon nuclei was a very delicate affair. Small changes in the laws of electricity and nuclear physics could have prevented the formation of carbon.

Even if the carbon, oxygen, and other biologically important elements were formed inside stars, they had to get out in order to provide the material for planets and life. Obviously we cannot live in the intensely hot cores of stars. How did the material escape the stellar interior? The answer is that it was violently ejected in cataclysmic supernova explosions.

Supernova explosions themselves are remarkable phenomena. In addition to protons, neutrons, electrons, photons, and gravity, supernovae require yet another particle—the ghostly neutrino previously mentioned. The neutrinos, as they escape from the collapsing star, create a pressure that pushes the elements in front of them. And, fortunately, the list of elementary particles happens to include neutrinos with the right properties.

As I said, a world full of biological phenomena is by no means a generic expectation. From the point of view of picking elementary-particle lists and strengths of forces, it is the very rare exception. But how exceptional—exceptional enough to warrant a radically new paradigm including the Anthropic Principle? If we were to base our opinions on only the things that I’ve explained so far, opinions would be mixed, even among those who are open to anthropic ideas. Most of the individual fine-tunings needed for life are not so very precise that they couldn’t just be lucky accidents. Perhaps, as physicists have always believed, a mathematical principle will be discovered that explains the list of particles and constants of nature and a lot of lucky accidents will prove to be just that: a lot of lucky accidents. But there is one fine-tuning of nature that I will explain in chapter 2 that is incredibly unlikely. Its occurrence has been a stupendous puzzle to physicists for more than half a century. The only explanation, if it can be called that, is the Anthropic Principle.

A paradox then: how can we ever hope to explain the extraordinarily benevolent properties of the Laws of Physics, and our own world, without appeal to a supernatural intelligence? The Anthropic Principle, with its placement of intelligent life at the center of the explanation for our universe, would seem to suggest that someone, some Agent, is looking out for humankind. This book is about the emerging physical paradigm that does make use of the Anthropic Principle but in a way that offers a wholly scientific explanation of the apparent benevolence of the universe. I think of it as the physicist’s Darwinism.