On a winter evening in 1927, a small group gathered for a dinner party at the home of the famous German-Jewish publisher Samuel Fischer. A middle-aged Albert Einstein was there, as were novelist Gerhart Hauptmann, critic Alfred Kerr, and patron of the arts Count Harry Kessler, who recorded the night's events in his diary. "Professor!" Kerr reportedly called out to Einstein as discussion heated up. "I hear that you are supposed to be deeply religious." To that, the story goes, Einstein replied: "Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible concatenations, there remains something subtle, intangible, and inexplicable. Veneration for this force beyond anything that we can comprehend is my religion. To that extent I am, in point of fact, religious."
"Religious," but without a traditional God. Einstein did not pray, nor did he have faith in a deity who interfered in day-to-day life. Rather, as he told Rabbi Herbert Goldstein of the Institutional Synagogue in 1929, he believed in "Spinoza's God, who reveals himself in the orderly harmony of what exists." By the time he was fifty, Einstein's view of God had been so greatly influenced by the seventeenth-century Jewish philosopher Baruch Spinoza-who had altogether rejected the Judeo- Christian personal God-that he, too, believed it was the universe that was ultimately divine.
Spinoza had used the word "God" to describe the impersonal laws of nature-laws he believed to be beautiful, harmonious, and universally obeyed. It was this humble view of the world that Einstein admired: Man was not the focus of God's attention. Instead, humans must surrender to "the sublimity and marvelous order which reveal themselves both in nature and in the world of thought," he wrote in "Religion and Science," a 1930 New York Times Magazine article. Only then could they reach a "cosmic religious feeling."
Yet his loyalty to Spinoza may have led to what Einstein called his greatest blunder. According to Israeli physicist Max Jammer, who knew Einstein personally and wrote the book Einstein and Religion, there are those who believe Einstein adjusted his equations-which initially predicted expansion or contraction of the universe-with the cosmological constant in order to accommodate a static universe. The reason: Spinoza believed that God, and therefore nature, is immutable.
Of course, in the late 1920s, astronomer Edwin Hubble measured a universe that expands. And in the decades since, as telescopes have seen farther and cosmologists have refined their theories, the science of the stars has advanced beyond what Einstein could have imagined. We now know the universe started with some kind of big bang close to 14 billion years ago. We know that black holes are collapsed stars from which even light cannot escape; that galaxies could not form were it not for the presence of cold dark matter filling space; that there was likely a period of quick expansion soon after the universe was born.
"It is phenomenal how well cosmology has come along in the last twenty to thirty years," says Sandra Faber, an astrophysicist at the University of California, Santa Cruz and a self-described vehement atheist. "If you had told me as a graduate student that we'd [understand what happened] 10-35 seconds after the big bang, I would have said, `Don't be ridiculous.'"
Still, many unanswered questions remain. Would the universe as we know it, and life within it, have formed under the influence of a different set of physical laws? In other words, as Einstein asked, did God have a choice in creating the universe? What happened before the big bang? Why is time a one-way arrow? Will there be a "big crunch" at some point in the future, or will the universe expand forever? Why are the laws of physics the way they are?
We do not understand why the laws exist as they do, but still we can claim they are special-an argument known as the anthropic principle. According to one version of the anthropic principle, the laws of physics and the numbers we use to describe our world-which have been discovered rather than devised- are fine-tuned. Even small deviations from basic constants like the speed of light, the mass of an electron, and the strength of nuclear forces would mean stars and galaxies could not have formed. As a result, we would not be here to observe them.
Perhaps it is mere coincidence that the universe so particularly evolved to the point at which carbon-based life forms could survive. Or perhaps there is another explanation. Some scientists believe that many universes with different properties exist, and that we inhabit one compatible with our presence. Or it could be, as some cosmologists continue to believe in this age of skepticism, that the universe is the work of a divine creator.
In attempts to understand how humans came to be in the universe, most theologians and many scientists have invoked God. Yet the way they have done so has changed over time. Natural theology used to look to effects, such as the existence of life or the complexity of the eye, for evidence of God's existence. No more, explains British particle physicist and ordained Anglican priest the Reverend Doctor John Polkinghorne in his book Belief in God in an Age of Science. Polkinghorne highlights a theology that now looks back to the causes-the laws of physics-that made our world possible.
"New-style natural theology in no way seeks to be a rival to scientific explanation but rather it aims to complement that explanation," he writes. "Science rejoices in rational accessibility of the physical world...but it is unable of itself to offer any reason why [the laws of nature] take the particular form that they do, or why we can discover them through mathematical insight." For Polkinghorne, the most satisfying answer to the question of how the universe came to be special enough to spawn self-conscious life is that God created it and is present in it.
"The elegant order and beauty of the universe, to me, seems to point to an intelligent creator of it," says University of Alberta cosmologist Don Page, an evangelical Christian who studied with physicist Stephen Hawking at Cambridge University and lived with him for a time. "It seems simpler to believe that this ordered universe was created by an intelligent being than to believe that it exists just by itself." Page, whose work in quantum cosmology investigates what happened when the universe was so small that quantum mechanics would have applied, reads the Bible and believes God listens to his prayers.
Cosmologists, like the rest of us, run the gamut from atheist to devout. Some believe the universe is fascinating enough without attributing to it any divine intervention. "I love and admire life and the world around me, from small flowers in the backyard to friends and colleagues to galaxies at the end of the observable universe. It's enough for me," says Princeton University cosmologist Jim Peebles, who was raised in the Anglican Church of Canada but is now agnostic. For those who feel otherwise, says cosmologist John Barrow, a professor of mathematical sciences at the University of Cambridge, "the scope of modern cosmology is so broad that I don't think it really places strong constraints on any particular system of religious beliefs." Allan Sandage, a leader in measuring the rate of the universe's expansion, is a Christian, and South African George Ellis, who won the 2004 Templeton Prize, is a Quaker.
In the world of science, cosmologists may have more room for religious faith than do their peers in other fields. "Evolution, with its great wastefulness, is maybe hard for a biologist to come to terms with from a religious perspective," says Harvard University astronomer and historian of science Owen Gingerich. Cosmology's purview encompasses the unimaginably immense scale of space and time; a cosmological proof, unlike a fossil, cannot be held in your hand. "The thing about cosmologists is that we're open-minded because we're fumbling with the deepest issues," says theoretical physicist Paul Davies.
But even cosmologists like Sandage, Ellis, and Page usually keep their faith from tiptoeing on their science, and vice versa. "I am skeptical of claims that from science, one can prove or disprove various religious statements," Page says, adding, however, that his belief in the theory of evolution does influence the way he interprets Scripture. "And I am skeptical of claims that from religion, one can prove or disprove various scientific statements."
The challenge for religious cosmologists is no different than the one facing scientists everywhere: to develop theoretical models that not only make predictions about nature, but match empirical observations as well. The big bang theory, for example, which implies that the universe had a well-defined beginning point, is a natural extrapolation of observational data. If the present universe has always increased in both size and age, but is neither infinitely large nor infinitely old, it must have had a starting point-a smallest size and an earliest time.
Cosmological investigation of the early universe requires Einstein's theory of general relativity to deal with its large mass and quantum mechanics to deal with its tiny size. The two theories don't fit together very well, but the places where they do intersect have turned out to be fertile ground for esoteric mathematical speculation. Still, the countless mathematical models often compete with each other, and when coupled with the enormous challenges posed by trying to observe the early universe, they have left philosophically inclined cosmologists both intrigued and puzzled by the universe's birth.
In the early 1980s, Hawking, the Lucasian Professor of Mathematics at Cambridge University, attempted to combine aspects of general relativity and quantum mechanics in a no-boundary universe-one that is self-contained and did not begin with a singularity (a point where space and time are infinitely compressed), as a big-bang universe might have. Hawking has claimed that the no-boundary universe requires no creator. This theory may have merit, but, says Page, it doesn't get rid of God, who was not only present in the beginning, but also sustains the universe and is everywhere at all times. Whether the universe has a beginning, claims Page, has "no relevance to the question of its creation."
Davies, who works at the Australian Centre for Astrobiology in Sydney, believes that people need to be persuaded to "abandon their fixation with the origin of things." While Davies describes himself as having "faith," he does not practice an organized religion or use the word "God"; where Page would see a creator, sustaining the universe from outside, Davies, like Einstein, sees the eternal laws of physics. "I hate the idea of a God who upsets the natural order of things," he says, choosing instead to see God as "underpinning the natural order" of a universe with a purpose. "[To say] these laws exist reasonlessly-are grounded in absurdity-is not satisfactory to me," he adds. "The universe is about something. It seems to be doing something significant."
What exactly it is doing, and of what exactly it is composed, is hard to know. Cosmologists speculate that the universe accelerates in its expansion because of a mysterious "dark energy." String theorists claim there are far more dimensions hidden beyond the three dimensions of space and one dimension of time that we live in.
Joel Primack, a cosmologist at the University of California, Santa Cruz and a practicing Jew who participates with his wife in Friday night Shabbat prayers and candlelighting, spends much of his time looking at cold dark matter. Primack says it's unusual for Jews to see conflict with science the way Christians sometimes do because Jews don't have a particular dogma. "There are Jewish fundamentalists," he admits, "but I've never met one." On the one hand, he says, he has his religion, and on the other hand, he has his science, and the two don't seem to overlap. "Cosmology," Primack says, "is producing the true history of the universe."
Still, there is a place for God, a place similar to the one Einstein carved out: Primack's God is reflected in every aspect of the universe, but not beyond it. "I have faith that the universe is organized in a coherent and beautiful way that we scientists are going to understand," he says. "My faith is reinforced by success."
Some of that success came in April 1992, when scientists announced that the Cosmic Background Explorer, or COBE, satellite had observed subtle temperature changes in the cosmic background radiation. In the 1980s, Primack and his colleagues, including Sandra Faber, had shown how quantum fluctuations caused galaxies to form in some parts of the universe, but not in others. Now, the COBE discovered that these fluctuations were of the amount predicted by the scientists' theory of cold dark matter, which claims most of the matter in the universe cannot be observed by its electromagnetic radiation and is made up of particles moving slowly. "It was an amazing experience. I'd wake up at night in a cold sweat," Primack says, comparing the bliss of scientific success to a religious revelation. "We had been living in an imaginary universe, but we found out the dream world is real. It gives you a sense that you're reading the mind of God."
Without the whole story, however, some cosmologists have bypassed the strange uniqueness of our universe by imagining that ours is not the only one. The idea of multiple universes, or the "multiverse," has become increasingly popular in the last two decades, in part because it explains anthropic arguments. If there is an infinity of universes-be they separate or joined, big or little, and with all kinds of values of fundamental constants and varying life cycles-then it is not altogether bizarre that a universe like ours could, and should, exist.
The theory of the multiverse "removed the mystery of the fine-tuning of our universe, which is a serious mystery that we worry about," says cosmologist Sir Martin Rees, British Astronomer Royal and a "practicing but nonbelieving Christian" who attends church on occasion, but doesn't adhere to religious dogma. Rees is uncomfortable with the argument that our universe is one of a kind. "We used to think the Earth and solar system were indeed very special, and that was a mystery; but we now realize there are zillions of planets orbiting other stars, and we wouldn't be surprised to find some that have the special properties needed for the Earth," he says. "And it may turn out that that is the case with the universe."
Because it is nearly impossible to prove alternate universes exist, it is arguable that multiverse cosmology requires a nearreligious faith on the part of its followers. "Some people say that the multiverse is appealing to an infinite number of unseen things, which makes the multiverse explanation, in some sense, infinitely complex. This is equivalent to appealing to an infinite, unseen God," says Davies, who is working on a book about multiple universes. He takes the idea seriously, but says even if there is an infinity of universes, we cannot ignore the exceptionality of the one we live in-the one with conditions so improbably perfect that we humans came to be.
There are others who admit the idea of multiple universes requires a good dose of faith, although they believe this faith will, someday, be proven by science. Believers in God, however, do not seem to agree. Proof notwithstanding, "How does the multiverse get around the design question?" asks Gingerich, a Christian who believes God designed the universe and is using the evolutionary process to achieve larger goals.
Today, there are theoretical predictions of the multiverse. The cosmological theory of inflation devised by Massachusetts Institute of Technology cosmologist Alan Guth twenty-five years ago posits that for a brief time after the big bang, the universe expanded extremely quickly. One version of this theory speculates that the material driving inflation began to decay and bits of the decaying universe, still expanding exponentially, became their own pocket universes. "Right now, very little is known," admits Guth, who does not believe there is a God who had any involvement in the process.
The inflationary theory also accounts for some of the universe's perfection. At about one second after the big bang, the rate of expansion is fine-tuned to fifteen decimal places-a value so precise it means that had the universe swollen in size even the tiniest bit faster, it would have flown apart; the smallest bit slower, and it would have collapsed.
"Inflation fixes that problem and drives expansion to just the right value," says Guth. As for the other constants, Guth isn't sure their values are all that special. "We don't know yet how to calculate whether or not life would exist, [to] make a prediction about what the parameters of physics should be for there to be life," he says. "There could be lots of other forms of life."
Cosmology is filled with speculation. Mere decades ago, few considered it a legitimate scientific field because cosmologists knew little more than the humans who first contemplated the night sky. But in the last half-century, cosmology has come of age. While there remain many interesting questions-are there other life forms?- there is much we are confident about.
We have proof that planets orbit stars, stars form galaxies, and galaxies are organized into even larger structures. We understand that the early universe was composed almost entirely of hydrogen and helium and that carbon is created in nuclear reactions in stars-stars that are the source of all the atoms in our bodies. And we know with certainty that our life form exists under the laws of physics established by our world. We just might have to live with the fact that where those laws came from, and why, may always be a source of mystery and a matter of faith.
