Illustration by Hubert Blanz
Excerpts from the article at the New York Times: A Physicist Solves the City. By Jonah Lehrer.
¨Although (Geoffrey) West worked for decades as a physicist at Stanford University and Los Alamos National Laboratory, he started thinking about leaving the field after the financing for the Texas superconducting supercollider was canceled by Congress in 1993. West, however, wasn’t ready to retire, and so he began searching for subjects that needed his skill set.
Eventually he settled on cities: the urban jungle looked chaotic — all those taxi horns and traffic jams — but perhaps it might be found to obey a short list of universal rules. “We spend all this time thinking about cities in terms of their local details, their restaurants and museums and weather,” West says. “I had this hunch that there was something more, that every city was also shaped by a set of hidden laws.”
And so West set out to solve the City. As he points out, this is an intellectual problem with immense practical implications. Urban population growth is the great theme of modern life, one that’s unfolding all across the world, from the factory boomtowns of Southern China to the sprawling favelas of Rio de Janeiro. As a result, for the first time in history, the majority of human beings live in urban areas. (The numbers of city dwellers are far higher in developed countries — the United States, for instance, is 82 percent urbanized.) Furthermore, the pace of urbanization is accelerating as people all over the world flee the countryside and flock to the crowded street.
Illustration by Hubert Blanz
This relentless urban growth has led to a renewed interest in cities in academia and in government. In February 2009, President Obama established the first White House Office of Urban Affairs, which has been told to develop a “policy agenda for urban America.” Meanwhile, new perspectives have come to the field of urban studies. Macroeconomists, for instance, have focused on the role of cities in driving gross domestic product and improving living standards, while psychologists have investigated the impact of city life on self-control and short-term memory. Even architects are moving into the area: Rem Koolhaas, for one, has argued that architects have become so obsessed with pretty buildings that they’ve neglected the vital spaces between them.
But West wasn’t satisfied with any of these approaches. He didn’t want to be constrained by the old methods of social science, and he had little patience for the unconstrained speculations of architects. (West considers urban theory to be a field without principles, comparing it to physics before Kepler pioneered the laws of planetary motion in the 17th century.) Instead, West wanted to begin with a blank page, to study cities as if they had never been studied before. He was tired of urban theory — he wanted to invent urban science.
For West, this first meant trying to gather as much urban data as possible. Along with Luis Bettencourt, another theoretical physicist who had abandoned conventional physics, and a team of disparate researchers, West began scouring libraries and government Web sites for relevant statistics. The scientists downloaded huge files from the Census Bureau, learned about the intricacies of German infrastructure and bought a thick and expensive almanac featuring the provincial cities of China. (Unfortunately, the book was in Mandarin.) They looked at a dizzying array of variables, from the total amount of electrical wire in Frankfurt to the number of college graduates in Boise. They amassed stats on gas stations and personal income, flu outbreaks and homicides, coffee shops and the walking speed of pedestrians.
After two years of analysis, West and Bettencourt discovered that all of these urban variables could be described by a few exquisitely simple equations. For example, if they know the population of a metropolitan area in a given country, they can estimate, with approximately 85 percent accuracy, its average income and the dimensions of its sewer system. These are the laws, they say, that automatically emerge whenever people “agglomerate,” cramming themselves into apartment buildings and subway cars. It doesn’t matter if the place is Manhattan or Manhattan, Kan.: the urban patterns remain the same. West isn’t shy about describing the magnitude of this accomplishment. “What we found are the constants that describe every city,” he says. “I can take these laws and make precise predictions about the number of violent crimes and the surface area of roads in a city in Japan with 200,000 people. I don’t know anything about this city or even where it is or its history, but I can tell you all about it. And the reason I can do that is because every city is really the same.” After a pause, as if reflecting on his hyperbole, West adds: “Look, we all know that every city is unique. That’s all we talk about when we talk about cities, those things that make New York different from L.A., or Tokyo different from Albuquerque. But focusing on those differences misses the point. Sure, there are differences, but different from what? We’ve found the what.”
There is something deeply strange about thinking of the metropolis in such abstract terms. We usually describe cities, after all, as local entities defined by geography and history. New Orleans isn’t a generic place of 336,644 people. It’s the bayou and Katrina and Cajun cuisine. New York isn’t just another city. It’s a former Dutch fur-trading settlement, the center of the finance industry and home to the Yankees. And yet, West insists, those facts are mere details, interesting anecdotes that don’t explain very much. The only way to really understand the city, West says, is to understand its deep structure, its defining patterns, which will show us whether a metropolis will flourish or fall apart. We can’t make our cities work better until we know how they work. And, West says, he knows how they work. (....)
The mathematical equations that West and his colleagues devised were inspired by the earlier findings of Max Kleiber. In the early 1930s, when Kleiber was a biologist working in the animal-husbandry department at the University of California, Davis, he noticed that the sprawlingly diverse animal kingdom could be characterized by a simple mathematical relationship, in which the metabolic rate of a creature is equal to its mass taken to the three-fourths power. This ubiquitous principle had some significant implications, because it showed that larger species need less energy per pound of flesh than smaller ones. For instance, while an elephant is 10,000 times the size of a guinea pig, it needs only 1,000 times as much energy. Other scientists soon found more than 70 such related laws, defined by what are known as “sublinear” equations. It doesn’t matter what the animal looks like or where it lives or how it evolved — the math almost always works.
West’s insight was that these strange patterns are caused by our internal infrastructure — the plumbing that makes life possible. By translating these biological designs into mathematics, West and his co-authors were able to explain the existence of Kleiber’s scaling laws. “I can’t tell you how satisfying this was,” West says. “Sometimes, I look out at nature and I think, Everything here is obeying my conjecture. It’s a wonderfully narcissistic feeling.”
Not every biologist was persuaded, however. In fact, West’s paper in Science ignited a flurry of rebuttals, in which researchers pointed out all the species that violated the math. West can barely hide his impatience with what he regards as quibbles. “There are always going to be people who say, ‘What about the crayfish?’ ” he says. “Well, what about it? Every fundamental law has exceptions.¨
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