In the bright sunshine filtering through Caltech’s blooming jacaranda trees, there is little to distinguish the plump, middle-aged physicist from the knot of faculty and students outside the university auditorium, save the tiny StarTac cellular phone clipped to his baggy black trousers, his laptop computer-the thinnest money can buy-and the attentive publicist who carries it for him.Working up his nerve, a 17-year-old Caltech physics major edges up to the man and asks him to autograph a set of computer disks. The physicist is Stephen Wolfram. The disks contain a computer program he designed called Mathematica, the centerpiece of the $100 million company he founded after leaving academia in 1986.
As Wolfram scribbles his signature with a modest flourish, he seems to savor a moment of perfect personal equilibrium, such as a tightrope artist might enjoy after a back flip on the high wire, kept aloft solely by his faith in himself. Indeed, many consider Wolfram one of the most intriguing high-wire acts in physics today.
Working without a net-the security of an academic position or the collaboration of colleagues-Wolfram is using the pattern-generating capacities of computers to try to uncover fundamental rules underlying the extraordinary, chaotic complexity of the universe. In doing so, he says, he is rebuilding physics from the bottom up by developing techniques that rival the mathematical equations conventional physicists use to describe and predict events in the world around us.
To physicists, mathematics is a language. It offers a vocabulary-geometry, calculus, and quadratic equations-that allows them to describe many of the properties of the universe, from the relationship between the radius and the circumference of a circle to the behavior of subatomic particles. Its most famous epigram-E=mc2-conveys in poetic shorthand the frozen energy of mass and the power to destroy cities.
But traditional physics has been unable to explain many common phenomena in nature, from the singularity of snowflakes to the self-organizing properties of neural networks in the human brain. Simply put, they are too complex. To investigate these phenomena, many scholars, including Wolfram, have turned to the emerging field of complexity theory. Complexity theory seeks explanations for apparently unpredictable phenomena-the flight of a swarm of bees, the ebb and flow of the stock market-in the interplay of their myriad simple components. In each case, individual actors-bees or brokers-make separate decisions based on simple rules; taken together, their actions create dynamic, apparently random patterns.
Wolfram and his colleagues believe the complexity of the universe belies an underlying simplicity in which a few basic rules give rise to complicated and unpredictable behavior. Indeed, if one conceives of God as a clever programmer, then one can imagine our vast, expanding universe as the elaborate consequence of an algorithm that set the conditions of the cataclysm known as the Big Bang. Everything that has followed-from black holes and organic chemistry to the rise of human consciousness and the spontaneous melody of a jazz improvisation-is an inevitable result.
Some of the rules that govern the behavior of the universe, we know: the laws of motion, the speed of light, the relationship between matter and energy. Others, however, may be embedded in systems so complex that they defy conventional analysis. To investigate the universe from this new perspective, scientists like Wolfram use computer simulations the way previous generations of scientists used microscopes, radio telescopes, cyclotrons, and particle accelerators. To the extent that the universe may behave like a computer obeying a programmer’s instructions, they argue, computer models are the best device for learning how it works.
Wolfram says the computer experiments he has been conducting after hours at Wolfram Research in Champaign, Ill., have led him into a new world of basic science. The problem is, he won’t tell anyone what he has discovered there. He has not published a formal research paper in years, nor has he presented his findings at any scientific conference though he does promise eventually to publish them in a book. Even close colleagues say they know only the general outlines of his work.
“Is there a simple computer that is the universe-a logical representation of how the universe fundamentally works?” Wolfram asks. “I will admit to having made quite a lot of progress on that question. It strongly encourages me to say the answer is yes.”
But for now, that is about as much as he will reveal of his research.
With almost any other scientist, Wolfram’s secretive midnight computer hacking might be dismissed as eccentricity or-less charitably-as the activity of someone unwilling to accept the consequences of his career choices. His erudite patter on the future of physics, modulated by his soft British accent, might seem just so much high-tech hyperbole, the kind of self-promotion that is as much a part of software packaging as shrink-wrap plastic. (This is, after all, a man whose corporate press release describes him as “one of the world’s most original scientists.”) So why is anyone listening?
“If I were less well known, people would just say, The guy is a nut case. Forget him,’” Wolfram admits.
But a remarkable number of respected computer scientists, physicists, and mathematicians seem, for the moment, to have suspended their disbelief. Some say they take Wolfram seriously because of his published record as a physicist, his work developing Mathematica, and the strength of his intellect. “Everybody, himself included, has been looking to him for a major contribution,” says physicist Norman Packard, who helped Wolfram establish the Center for Complex Systems at the University of Illinois. The founder of a financial analysis firm in Santa Fe, N.Mex., Packard now applies complexity theory to help Swiss banks play the stock market.
Others stress the potential of the emerging field of computational physics. Neuroscientist Terry Sejnowski, who researches complex neural networks at the Salk Institute for Biological Studies in La Jolla, Calif., says Wolfram offers a “vision of the future of science”-a science “based on computational principles rather than the classical mathematical tools that so many generations of scientists have relied on.”
“I think what he is doing goes to the bedrock of particle physics,” Sejnowski says. “He is talking about a computational [model of the] universe based on quite new principles.”
“If he succeeds he will make us rethink the world we are in,” says Steven Levy, author of Artificial Life, an introduction to the emerging field of computer-driven complexity studies. “I think he has a shot at it.”