The second law of thermodynamics states that a closed system can become more disordered (or stay the same), but it cannot become less disordered. The entropy of a gas reaches its maximum in its equilibrium state when the particles are random both with respect to the distribution of their positions and to their velocities. Under such “messy” conditions, observing an unusual combination of particles or any interesting configuration is rare. The first deal in a game of poker (that is, with one deck of cards that are thoroughly shuffled) is unlikely to yield a winning hand. There is a smaller probability of a chance encounter with a sociology colleague on a vacation than at the annual sociology meetings. Most people, in fact, arrange their lives to maximize the probabilities of interesting configurations. Social arrangements are, by definition, nonrandom. On varieties of social, economic, and political dimensions, cities have relatively much structure and they vary in the composition of people who live in them. However, on dimensions of culture we find that American cities vary surprisingly little, and that cultural patterns are not so highly structured.