THE END OF PHYSICS The Myth of a Unified Theory. By David Lindley. 275 pp. New York: Basic Books. $25.
SAMUEL C. C. TING, a Nobel Prize-winning experimental physicist, once said this about his theoretical colleagues: “I am happy to eat Chinese dinners with theorists, but to spend your life doing what they tell you is a waste of time.”
“The End of Physics,” by David Lindley, is filled with many of the important ideas theorists have had over the past century. The price of the book is $25. Regrettably, this does not include a Chinese dinner.
The phrase “the end of physics” has been around almost since the beginning of physics. In its orthodox interpretation, it is an optimistic concept, referring to the time when physicists will know the basic principles of the universe, how it works and what it is made of. This will be the end, because there will be nothing left for physicists to do except write their memoirs — at least for those precious few who haven’t already done so. The end of publishing will quickly follow.
Over the past century and a half, many physicists have boldly (and stupidly) declared that the end of physics was near. In 1958, Werner Heisenberg, of uncertainty fame, declared on a radio show that he and his colleague Wolfgang Pauli had all but perfected a unified field theory. Only a few technicalities needed to be ironed out. Pauli, furious at Heisenberg over this hubris, mailed his friends little pencil-drawn black rectangles. “This is to show the world I can paint like Titian,” he wrote beneath each rectangle. “Only technical details are missing.”
Earlier this year Steven Weinberg, a Nobel laureate and one of the deepest of the so-called deep theorists, published “Dreams of a Final Theory,” in which he convincingly held out the possibility that such a theory is attainable, if not necessarily imminent, thus proving that while the end of physics may be in sight, there certainly is no end of end-of-physics books.
And now here comes this book by Mr. Lindley, a former research fellow in the Theoretical Astrophysics Group at the Fermi National Accelerator Laboratory (Fermilab). But “the end of physics” means something completely different to him. Mr. Lindley, who is currently a senior editor at Science magazine, is not talking about something that’s going to happen in the future. He’s saying that physics is kaput — right here, right now — because of its very dependence on elegant mathematical theories that purport to describe conditions of the early universe, but that can never be verified by experiment. Such theories are altogether plausible, Mr. Lindley says. But physics means experiment, and without verification, these theories are meaningless. The quasi-religious search for a unified theory by Einstein, Heisenberg, Pauli, Mr. Weinberg and others, Mr. Lindley says, has propelled physics into the realm of theology.
Mr. Lindley begins by challenging the very foundation of theory: mathematics. The people working in theoretical physics, the most mathematical of all the sciences, often ask why nature chose math as its language. Why is it that the overarching principles of the universe can be broken down into equations? What the theorists are also saying, implicitly, is that they speak nature’s language and the rest of us don’t. Mr. Lindley is not awe-struck by the connection of math and physics. “The puzzle becomes a tautology,” he explains. “Mathematics is the language of science because we reserve the name ‘science’ for anything that mathematics can handle.”
The author then goes on to show how physicists have used math to wreak havoc not only on their own discipline but on other sciences as well. In the 19th century, Lord Kelvin (William Thomson) declared that the world was only 100 million years old, much to the consternation of the geologists and biologists who thought the world needed much more time than that for the development of continents and the animals that roamed them. The 100-million-year figure, based on newly formulated principles of energy conservation and thermodynamics, was of course absurd, but Kelvin spoke math and the opposition didn’t, and he thus prevailed. Imagine the plight of poor Charles Darwin, given a mere scintilla of time in which to explain how the great apes evolved from primordial ooze, when the rocks upon which the ooze first slithered had already used up Kelvin’s meager allotment of years.
Mr. Lindley next attacks the idea of “beautiful” mathematics, the belief, held by Mr. Weinberg, Paul Dirac, Einstein and many other theorists, that one should be guided by esthetics, that the beautiful, symmetrical theory is probably the right theory. Isn’t it pretty to think so, Mr. Lindley replies, and then proceeds to rip this idea to shreds, pointing out that the Pythagoreans felt the same way and produced a pile of lovely but useless theories (reincarnation, for one), and that Johannes Kepler worked for years to keep the orbits of the planets circular — the circle was a sacred form — before he accepted that the dowdier ellipse was what the data called for.
The image of the theoretician that emerges from “The End of Physics” is of a surprisingly unsophisticated individual who must anthropomorphize nature to understand it: I like symmetry and beauty; ergo, nature likes symmetry and beauty. It reminds one of the Parisian animal trainer who teaches his bear to respond to voice commands and concludes that bears speak French.
Mr. Lindley is kindest to the theory called the standard model, the bizarre array of particles named leptons and quarks combined with their antiparticles and then further combined with the three forces of the universe — electromagnetism, strong and weak forces — and their subsequent particles, called bosons. The standard model is thus far the best summary of all the data that have come out of all the experiments physicists have done since Galileo dropped his two weights from the Leaning Tower of Pisa. But it has often been criticized as overcomplicated (too many particles), clumsy and inelegant, which of course it is. Mr. Lindley defends it, saying the standard model explains what has been revealed by experiment. “If particle physics is a mess,” he concludes, “it is because that is the way the world appears to work.”
Mr. Lindley rolls on and on, flattening every unified theory in his path. Especially amusing is his chapter entitled “March of the Superlatives,” in which he dispatches three of the most ambitious theories — supergravity, supersymmetry and superstrings. No one, not even Stephen Hawking in his wheelchair, is spared in the onslaught.
If there is any quibble with Mr. Lindley’s brave and important book, it is with the title. We’re talking here about the end of theory, and maybe the end of theorists, but not the end of physics. I suspect Mr. Lindley knows that, but by concentrating on the theory he fortifies the popular notion that theory and physics are one and the same. In doing so, he mistakes the map for the territory. Since Galileo, it is the experimenters who have driven physics, extracting secrets from nature by hand, often with little regard for theory or theorists.
Is Mr. Lindley right? He concludes: “We are already at the point where experiments are becoming impossible for technological reasons and unthinkable for social and political reasons. An accelerator bigger than the supercollider would be a vast technical challenge. . . . Experiments to test fundamental physics are at the point of impossibility.” Physicists, he says, seem to be returning to the days of the ancient Greeks, who did physics “by means of thought alone.”
Maybe he doesn’t know about the Livingston curve. Mr. Lindley, I’m sure, would hate the Livingston curve. It’s one of those mathematical curiosities that are probably meaningless. In the 1950’s, a physicist named Stanley Livingston drew a line on a graph that plotted the energy available in laboratories from the time of J. J. Thomson (circa 1897) to his own era, then extended it into the future. He found a logarithmic relationship: the energy increased by roughly a factor of 10 every 10 years. The Livingston curve has accurately predicted accelerator energies in the 1960’s, 70’s, 80’s and 90’s. Extrapolated to the future, it predicts that we’ll have what is called Planck-scale energy in the lab by the year 2150. A Planck-scale accelerator would be powerful enough to prove one of the most popular unified theories, superstring theory. According to one of the theories that Mr. Lindley destroys, the inflationary-universe theory, such high energies are also capable of popping new universes into existence. Two scientists, Leon Lederman and David Schramm, point out, tongue in cheek, that perhaps we are just the products of some previous universe’s accelerator experiments.
Think of a world long ago and far away. A physicist sits at a console, as his Planck-scale accelerator crashes massive particles. In one collision, just one of a billion trillion that occur every second in the machine, a peculiar singularity is produced. This singularity contains within it all the mass and energy needed to create our universe, encompassing our galaxy, our solar system, this week’s issue of The New York Times Book Review, a nice Chinese dinner for Samuel Ting and the manuscript of “The End of Physics,” which states that none of this is possible. Think of it. And please pass the sweet-and-sour shrimp.
Dick Teresi is the co-author, with the physicist Leon Lederman, of “The God Particle.”