By George Johnson
George Johnson is the author of "In the Palaces of Memory." His book "Fire in the Mind: Science, Faith and the Search for Order" will be published next year.

THE PHYSICS OF IMMORTALITY
Modern Cosmology, God and the Resurrection of the Dead.
By Frank J. Tipler.
528 pp. New York:
Doubleday. $24.95.

EVEN more than the separation of church and state, the separation between church and laboratory is supposed to be absolute. Science is to concentrate on describing how the universe works, leaving questions of who or what created it and why it exists to the dens of the metaphysicians. Once they agree to play by these rules, scientists the world over can worship different gods while contemplating the same equations.

The one area of science where this fire wall most often threatens to crumble is cosmology. Scientists almost all agree that the universe began with a "Big Bang." But what detonated the explosion? And why did the primordial mass unfold into this particular universe, with furnaces called stars cooking hydrogen into the carbon needed to make astronomers and theologians who can contemplate the meaning of it all?

If the expansion rate of the universe were a little slower, the Big Bang would have been stillborn. A little faster and there would not have been the leisure for any kind of matter to coalesce. If something called the fine structure constant (the square of the charge of the electron divided by the speed of light multiplied by Planck's constant) were slightly different, atoms would not exist. Our very existence seems to be either a miracle or a fluke.

Why should we be so lucky? Some cosmologists propose that there are actually an infinity of universes, each of which was created with slightly different initial conditions. Finding ourselves in one that happens to support life would be no more amazing than the fact that cities tend to arise on the banks of rivers. There are still vast deserts where no life blooms. Followers of the so-called strong anthropic principle argue that life is not incidental but necessary, that a universe must have observers in order to exist.

Theoretical extravagances like these have become so commonplace that one expects popular books on cosmology to read like science fiction. Even so, it is startling to pick up a book by a respected cosmologist who promises to explain the miracle of human existence by providing no less than "a testable physical theory for an omnipresent, omniscient, omnipotent God who will one day in the far future resurrect every single one of us to live forever in an abode which is in all essentials the Judeo-Christian heaven."

Frank J. Tipler reassures us in "The Physics of Immortality: Modern Cosmology, God and the Resurrection of the Dead" that "if any reader has lost a loved one, or is afraid of death, modern physics says: 'Be comforted, you and they shall live again.' "

It's tempting to close the book at this point and dismiss it as a self-conscious effort to manufacture a best seller: Science offers new hope for the dead. But by the time I finished the first chapter, I was surprised to find myself succumbing to Mr. Tipler's strange charm. As farfetched as they seem, his ideas are propounded with such deadpan earnestness that it is hard not to keep on reading. What finally emerges is a wonderfully ambitious, painfully sincere tour de force -- an attempt, sometimes brilliant, sometimes absurd, to stretch scientific reasoning to its breaking point.

"Either theology is pure nonsense, a subject with no content," Mr. Tipler writes, "or else theology must ultimately become a branch of physics."

In some regards, the effort brings to mind Roger Penrose's book "The Emperor's New Mind." Begin with a gut feeling of what you know must be true (Mr. Penrose: the brain cannot be a digital computer; Mr. Tipler: life is everlasting), then try to rationalize it with an elaborate superstructure of physics and mathematics. Ultimately the authors may succeed in convincing no one but themselves, but along the way the reader is taken on a thrilling ride to the far edges of modern physics.

MR. TIPLER'S argument begins with the familiar warning that the earth itself is doomed, fated to be burned to a cinder with the inevitable expansion of the sun. The only hope is to embark on a mammoth project to colonize other worlds. Robotic space vehicles equipped with antimatter engines can travel to the nearest star systems at nine-tenths the speed of light, the author calculates, homesteading the planets or, where there are no planets, constructing orbiting space stations. Using information from the Human Genome Project, the robots can create living inhabitants and simulate human minds with artificial intelligence.

Once these outposts have been established, they can be used as bases to build more robots to colonize more star systems, and from there still more automated expeditions can fan out. Through an exponential explosion of exploration, life will take over more and more of the universe.

Sounding sometimes like a dutiful Government accountant for the Office of Technology Assessment, Mr. Tipler estimates, in overwhelming detail, that the necessary expertise (including the ability to simulate the human brain) will be available by the middle of the next century. After that, we will take about 600,000 years to make the Milky Way as dense with life as the suburbs of Los Angeles. Then it's off to Andromeda, which can be taken over in three million years, then to the Virgo Cluster, which will require 70 million years to subdue. By the time 10,000,000,000,000,000,000 (10 billion billion, or 10 to the 19th power) years have passed, life will have seized control of the whole universe.

AND just in the nick of time. By the time the entire universe is colonized, Mr. Tipler estimates, the Big Bang will be running out of steam, and the universe will begin collapsing into what is sometimes called the "Big Crunch." This, it might seem, would spell doom for any kind of creature, real or artificial. But remember: life is now ubiquitous. It is no longer simply along for the ride. Having filled every nook and cranny of the cosmos, we can control its destiny.

The equations governing the expansion and contraction of the universe are chaotic, Mr. Tipler tells us, making them hypersensitive to the slightest nudge. Using the famous butterfly effect (a flapping of wings in Rio sets off a hurricane in Bangladesh), we can steer the course of the collapse with strategically placed explosions. If the universe contracts faster in some directions than in others, the result will be a vast reservoir of potential energy (in the form of temperature differentials) that can be tapped as we surf the waves of the great implosion.

What do we use the energy for? To bring about the Resurrection. By the time the universe is contracting, Mr. Tipler calculates, it will have enough computing power to perfectly simulate -- to emulate -- every creature that ever existed or could conceivably exist. As the universe continues to collapse to a final singularity of infinite density and infinite temperature (the Omega Point, he calls it, borrowing from the French theologian Pierre Teilhard de Chardin), all creatures great and small can be brought back to life inside computers, along with all their memories.

Even though there is a finite amount of time until the Omega Point -- the final crunch -- is reached, enough energy can be tapped to perform an infinite amount of information processing, Mr. Tipler says. Viewed from outside, the universe would seem finite in duration, but from within, the simulated life forms would have the subjective sense of lasting forever.

There you have it. Resurrection and life everlasting. Since this bounty flows from the Omega Point, we can think of it as God. "The Omega Point loves us," Mr. Tipler writes (precisely defining love by appealing to sociobiological theories of altruism and economic game theory). With its omnipotent computational powers, the Omega Point will create for each of us the best possible world. In fact, Mr. Tipler writes, "it would be possible for each male to be matched not merely with the most beautiful woman in the world, not merely with the most beautiful woman who has ever lived, but to be matched with the most beautiful woman whose existence is logically possible." And vice versa.

All this would be small comfort if the author were simply describing something that might happen if we only had the technological resolve to pull it off. After all, Congress won't even finance the Superconducting Supercollider, whose abandoned tunnels are being considered for use as a commercial mushroom farm. But Mr. Tipler does not simply argue that it is conceivable life could take over the universe and bring about the Resurrection. He says that it is inevitable.

Why? Because life must take these steps in order to survive the Big Crunch and live forever. O.K. But why must life survive? Here the argument depends on Mr. Tipler's version of the strong anthropic principle, which he outlined in the book he wrote with John D. Barrow, "The Anthropic Cosmological Principle" (1986): There are an infinite number of possible universes that can conceivably exist, depending on how the knobs were set at the time of the Big Bang. But while all these universes can be said to exist logically, for them to exist physically, Mr. Tipler argues, they must contain observers to behold and appreciate them. Our universe obviously exists, so it must -- by his definition -- behave in a way that sustains life forever.

This rather circular argument might sound about as convincing as the attempts of medieval theologians to deduce the existence of God from first principles. As a reminder that we are to take this as science, not religion, Mr. Tipler declares that his theory has certain testable consequences. To allow for the kind of information processing necessary to sustain the computational Resurrection, such hypothetical particles as the long-sought Higgs boson and the top quark must have certain masses. The Omega Point Theory also predicts that the universe must be found to contain enough mass to collapse eventually and not go on expanding forever, as some cosmologists believe it will.

It's left for Mr. Tipler's fellow cosmologists to evaluate these claims. To make his book as accessible as possible, he has relegated the mathematical proofs of many of his assertions to a 123-page, equation-filled "Appendix for Scientists." It is here that he shows, for example, how an infinite amount of information can be processed in a finite amount of time. To really appreciate this section, Mr. Tipler concedes, one must have the equivalent of at least three Ph.D.'s -- in global general relativity, theoretical particle physics and computer complexity theory. The author has a doctorate in the first of these fields; getting up to speed in the other two, he says, took 15 years. Mr. Tipler sounds like a trustworthy sort, and we can believe that he has done his calculations carefully. But finally we must trust in the wisdom of the high priests.

"THERE is nothing supernatural in the theory," he insists, "and hence there is no appeal, anywhere, to faith." But all of mankind's grand systems are ultimately built on a platform of belief. At some point we must stop calculating and take the Kierkegaardian leap. Even the few who can thoroughly understand the equations are being asked to assume, as a postulate of the theory, that a fundamental feature of the universe is the ability to sustain life forever. What makes Mr. Tipler so very sure?

His book is dedicated to his wife's grandparents, who were killed in the Holocaust. In the first chapter he tells how a visit to a Nazi death camp reinforced his conviction "that there is nothing uglier than extermination."

For a moment the curtains are pulled back and we see what motivates this herculean effort. "We physicists know that a beautiful postulate is more likely to be correct than an ugly one," he writes, taking another leap of faith. "Why not adopt this Postulate of Eternal Life, at least as a working hypothesis?"

Would finding the wrong mass for the Higgs boson or the top quark really overturn so unshakable a conviction? One imagines Mr. Tipler would find a way to tweak a variable here or add a postulate there, as he strains to find a rationale for the one thing he, and all of us, want so desperately to believe.

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