"This remarkable equation is why people move to the big city," West says. "Because you can take the same person, and if you just move them to a city that's twice as big, then all of a sudden they'll do 15 percent more of everything that we can measure." While Jacobs could only speculate on the value of our urban interactions, West insists that he has found a way to "scientifically confirm" her conjectures. "One of my favorite compliments is when people come up to me and say, 'You have done what Jane Jacobs would have done, if only she could do mathematics,' " West says. "What the data clearly shows, and what she was clever enough to anticipate, is that when people come together, they become much more productive."
But I think there is a deeper explanation for the persistent misreadings of Jacobs. She was the first to apply a dawning new human understanding of the natural world to cities - an understanding that even now is slow to be grasped by built environment professions. It's an understanding of "organized complexity," as she called it - the dynamic inter-relationships of systems, of processes, of self-organization.
Some may be surprised to hear PPS echoing a version of the modernist mantra "form ever follows function" (see principle 9), but it's important for us to remember what that phrase is really all about. When it was first coined by Louis Sullivan, it was a humanist idea: that the form of a building should serve first and foremost the human uses that animate it. But over time, as Jane Jacobs observed, the idea of function underwent a "drift from humanism to gimmickry."
This is what Jane Jacobs taught us long ago in her book The Economy of Cities. This is what the Nobel Prize winning economist Robert Lucas meant when he formalized Jacob's argument into a theory of "human capital externalities" that stem from the dense clustering of people in cities as the basic mechanism of economic growth. Cities themselves power economic progress, driving artistic, technological, and overall economic growth at one and the same time.