Can Silicon Valley invent public space as it has reinvented public life online? If the cultish ideas about serendipity and chance encounters have any value, a new urbanism (with a small n, small u) betwixt the metropolis and the ‘burbs, can only lead to more billion-dollar ideas, more employed people, and a healthier environment. And if that doesn’t occur, maybe they have been worshipping a false, groupthink god all along.