Prediction Cities

http://www.nytimes.com/2010/12/19/magazine/19Urban_West-t.html?ref=magazine&pagewanted=all# One most significant omission I noted was the failure to mention the traditional role of cities as population sinks. Before 1900 or so all cities had negative internal population growth because the disease burden was high enough to kill most people before adulthood. These days the expense and space restrictions of cities tend to limit fertility rates, leading to the same result. Result: economic growth may be more sustainable than suspected since fertility rates are declining and, eventually, it may be possible to grow without increased per capita use of physical resources. The derivation of mathematical "laws" from animal metabolism and corporations is also interesting. Abstraction is leverage--but, at the cost of estrangement. Only a certain measure of immersion in the concrete details can put the abstractions in practical perspective and render them robust. Reagan appears to have understood this: did you know he read and answered 20 random letters from citizens each week to achieve this type of immersion?