Gabriel Garcia for the Santa Fe Institute

In an essay in New Scientist magazine's Big Ideas section, SFI Professor Luis Bettencourt explains how cities are like stars -- in one sense, both are implosions of interaction -- and offers four principles for understanding cities.

"The key is not to think of cities just as a collection of buildings or people, but as a web of social interactions embedded in space," he writes, introducing his first principle for understanding cities: that cities develop so citizens can, in theory, meet anybody else in the city.

Principles 2-4: 

  • Urban mobility is essential for social mixing
  • City infrastructural networks grow incrementally and this growth is decentralize
  • Human effort is bounded by human cognitive ability and human personal energy

These principles can be combined into a mathematical model to make predictions about urban environments, he says.

Read Bettencourt's article in New Scientist (December 9, 2013, subscription required)