Physicist Geoffrey West argues that simple, mathematical laws govern the properties of cities -- that wealth, crime rate, walking speed and many other aspects of a city can be deduced from a single number: the city's population. In this fascinating presentation, he shows how this works and how similar laws are true for both organisms and corporations:

Dr West was trained as a theoretical physicist, but in recent years, he has studied the inner workings of more concrete things, like ... animals. In a 1997 paper in Science [DOI: 10.1126/science.276.5309.122; abstract; free PDF], he and his team uncovered what he sees as a surprisingly universal law of biology -- the way in which heart rate, size and energy consumption are related, consistently, across most living animals. (Though not all animals: "There are always going to be people who say, 'What about the crayfish?' " he says. "Well, what about it? Every fundamental law has exceptions. But you still need the law or else all you have is observations that don't make sense.")

A past president of the multidisciplinary Santa Fe Institute (after decades working in high-energy physics at Los Alamos and Stanford), Dr West now studies the behavior and development of cities. In his newest work, he proposes that one simple number, population, can predict a stunning array of details about any city, from crime rate to economic activity. It's all about the plumbing, he says, the infrastructure that powers growth or dysfunction. His next target for study: corporations.

He says: "Focusing on the differences [between cities] misses the point. Sure, there are differences, but different from what? We've found the what."

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