THE INFLATIONARY UNIVERSE: The Quest for a New Theory of Cosmic Origins.<i> By Alan Guth</i> . <i> Addison-Wesley: 368 pp., $25</i> : GOODBYE, DESCARTES: The End of Logic and Search for a New Cosmology of the Mind.<i> By Keith Devlin</i> .<i> John Wiley & Sons: 320 pp., $27.95</i>
Almost 20 years ago, I tagged along with the great physicist Victor Weisskopf as he talked to a Cambridge, Mass., high school class about the Big Bang, the explosive origin of the universe. One student asked him what happened before the Bang, what caused the Bang? That question, said Weisskopf, fell outside the realm of physics. It was a question for God.
Not anymore. Today, some scientists, it seems, just won’t take no for an answer. The more impossible the task, the more it appeals, perhaps because these scientists sense that the most exciting discoveries lie beyond established boundaries. The physics of how the universe came into being from an unstable speck of nothing is highly respectable work, thanks in large part to MIT cosmologist Alan Guth, who has concluded that the universe is just one of an infinite number of universes, forever bubbling up out of nothing at all.
A kindred spirit is mathematician Keith Devlin, who gave up a career as a respected logician at the University of Lancaster in England to explore the appalling proposition that 2,000 years of logic, developed by Aristotle, Rene Descartes and George Boole, simply won’t do when trying to program computers.
Both these scientists have taken on big, almost breathtaking, questions. Guth wants to know why there is matter and how the universe came into being. “Where did all this come from?” he calmly asks as he cooks up recipes for creating universes from his lab at MIT, where he is now the V.F. Weisskopf professor of physics.
Devlin, on the other hand, wants to develop a mathematics of thought to encode common sense into computers. Working from St. Mary’s College of California, he believes that logic is inadequate to understand thought because thought isn’t logical. That’s why computers can’t think. Ultimately, the road to intelligence is not reason, he’s concluded, arguing for an entirely new kind of mathematics--an “algebra of conversation”--that will grasp the essentials of the mind.
“Modern science has been remarkably successful in understanding the inner workings of the atom, the structure of distant stars and the origins of the universe,” he writes in “Goodbye, Descartes.” “And yet we have been far less successful in understanding the thought processes involved in the everyday use of language. Why?”
Both scientists are suitably humbled by the difficulty of their tasks. “How much can we know, I asked myself, about the first seconds of the existence of the universe?” Guth writes early in his discovery process in “The Inflationary Universe.” “At the time, cosmology seemed to me to be the kind of subject about which you can say anything you like--how can anyone prove you wrong?”
Devlin recognizes that his discussion and conclusions are likely to be dismissed by some scientists, and he jokes about the problems his book will pose for librarians and bookstore owners who will have to decide under what category to file it: Math? Philosophy? Linguistics? Psychology?
Both men have written rich, satisfying accounts of their intellectual explorations, food for thought that is likely to prove indigestible for some casual readers. Guth’s book requires coming to terms with such arcane concepts as curved space, false vacuums, Higgs fields, magnetic monopoles and negative gravity. Devlin’s is a thinking person’s book about thinking that requires a willingness to play difficult mind games.
But it is in these sometimes excruciating details that Devlin’s work rises above speculation and that Guth proves why, to physicists, the Big Bang is more than just a cartoon. Read together, both books present a confident picture of the validity of these ideas, no matter how subtly they are presented. Luckily for the reader, both scientists are also lively, lucid and frequently amusing.
Of the two books, “The Inflationary Universe” is the more personal. Guth includes diary entries (“Hell of a Good Day.” “Damn it. How did I miss that?”) and the advice from Chinese fortune cookies that he’s followed. He portrays the pressures of being a post-doctoral researcher, struggling to publish in “a very marginal position” while juggling personal medical emergencies, lawsuits, cross-country moves and young children. After ignoring entreaties from his colleague Henry Tye, he came to the study of creation when Nobel laureate Steven Weinberg visited Cornell, where he was then a post-doctoral researcher. “I was shown that a respectable (and even highly respected) scientist could think about things as crazy as . . . the universe at 10 (to the minus 39th power) seconds. . . . In hindsight, my reluctance to work with Henry was foolish.”
Personal excursions help Guth weave together the profound and the ordinary and show how the paths to the most fundamental discoveries are strewn with the happenstance of everyday life: a chance encounter, a missed doctor’s appointment, a conversation over lunch. He also elucidates the tools physicists use to tackle problems sometimes too complex and messy for them to comprehend--for example, with “toy theories,” deliberately oversimplified scenarios that help them understand unwieldy situations.
When Guth came to cosmology, the Big Bang was already accepted as the probable origin of the universe, which is astonishing in itself: Forty years ago, the term “Big Bang” was a joke and no one thought to use “such a silly phrase in a dignified publication,” Guth admits. Today, physicists can say with confidence exactly what was going on one second after the universe began. Using equations to turn back the cosmic clock to the beginning of time, physicists can come up with remarkably accurate pictures of how the energy from the primordial explosion condensed into particles of light and matter and, eventually, evolved into galaxies and stars and the cosmologists who ponder them.
“If cosmologists are so smart, you might ask, why can’t they predict the weather?” Guth answers his own question: The early universe was a far simpler place than the world today. Still, there are questions even the Big Bang couldn’t answer. Why does the universe look the same everywhere you look? And where did all the magnetic monopoles (particles thought to have been created in the Big Bang but never seen) go?
It was in the course of trying to answer this last question that Guth stumbled upon answers to the others. He came to the conclusion that during the first fraction of a fraction of a second of time, the universe expanded furiously from a tiny seed, smoothing out the wrinkles and flattening the fabric of space like the rubber skin of a rapidly expanding balloon. This “inflationary universe” made the Big Bang a far more beautiful--and workable--theory.
It also gave rise to some unsettling implications, such as the idea that our entire grand all-encompassing universe is just the tiniest speck in a much bigger picture. If he’s correct, Guth’s idea will force a profound shift in the Judeo-Christian belief that creation was the beginning of everything.
“I believe that soon any cosmological theory that does not lead to the eternal reproduction of universes will be considered as unimaginable as a species of bacteria that cannot reproduce,” he writes.
Devlin, in some ways, is on far less-established ground in “Goodbye, Descartes.” At least cosmology can boast a well-developed set of mathematical tools. Indeed, the beginning of the universe seems almost concrete compared to the elusive nature of thought. As suits a logician, Devlin’s book also follows a more cerebral road with few excursions into the personal. In the process of his work, trying to give computers common sense, Devlin takes a cold hard look at logic, the study of the principles of reasoning, a process of deduction that Sherlock Holmes demonstrated so well.
The quality that gives formal logic its immense power is its total separation from context. If A is the opposite of B, then it remains opposite whether A and B are apples, oranges, universes or dreams. The theories of the 17th century philosopher Rene Descartes epitomize this kind of intelligence: the coolly rational man, the human calculator. Formal logic is thought divorced completely from emotion, the soul, the vague ooziness of the outside world. The truth or falsity of any statement can be proved, no matter what the statement is about, based purely on the logical structure of the argument. If Aristotle is a man, and men are mortal, then Aristotle must be mortal.
A wide-ranging and engaging book, “Goodbye, Descartes” takes the reader through 2,000 years of formal logic, computation, artificial intelligence, the linguistic revolution of Noam Chomsky (who developed a logic of language) and the cutting-edge study of language that consumed Devlin for the last 10 years during his work with Stanford’s Center for the Study of Language and Information.
So how then does Devlin propose to teach a computer common sense? Until recently, all efforts to duplicate human intelligence in computers involved trying to distill thought into a kind of mental calculation. It was a purely Cartesian endeavor. Devlin’s approach would blend logic with context--exactly that quality Cartesian thinkers consider the antithesis of clear thought. Context tells the brain whether “flies” is a noun or a verb in the sentences: Time flies like an arrow. Fruit flies like bananas. It tells the sweetheart how to interpret a message such as: “You are the cream in my coffee.” In the end, the mind’s language may be metaphor as much as logic.
Because context and languages are inextricable, Devlin proposes creating a new kind of mathematics, called “soft mathematics,” no longer divorced from psychology, sociology and neuroscience. It’s time to say “goodbye” to Descartes, he says.
Curiously, Guth comes to almost the same conclusion at one point. “The cold hard logic of science, we are told, has no place for intuition,” he writes. “Nothing could be farther from the truth!”
