Fewer, Richer, Greener

11Cities

What is a city? Isn’t it just a bunch of buildings that are close together?

No. Blow up or burn down a city and it springs right back where it was. Even Hiroshima couldn’t be wiped out: today it has a thriving population of 1,196,274. Chicago, Dresden, New Orleans, you name it—whether destroyed by fire in 1871, war in 1945, or flood in 2005, a city regrows itself like a patch of injured skin, almost exactly in the pattern that existed before the destruction.

The reason is that a city is not a collection of buildings (those are the symptom, not the cause) but a network of human connections. Knowledge connections. In the more or less urban neighborhood where I live, there is a shoe repairman named Mike. (See Figure 11.1.)

Figure 11.1 The locus of a network of knowledge connections. 

Source: J. Needham.

What makes him a good shoemaker? Not just his personal skill, but the network of connections he’s developed: he knows where to buy leather, get the tools of his trade repaired, and acquire the paraphernalia that all trades have in common—a credit card acceptance system, a telephone line, and so forth. He can (and did) locate on a crowded block with lots of foot traffic. And, because he’s in a city, he can comparison shop among competing suppliers without traveling immense distances, so the supplies are affordable.¹

The other network Mike needs is on the demand side: ...