A lot of commentary about contemporary cities has it that our economy is no longer an economy in which things are made, but an economy of service, a "knowledge economy," an economy in which value is added through the production of software, websites, prototypes, manipulation of symbolic knowledge systems and processes of control. This view, popularized by writers such as Richard Florida, has affected ideas about city planning and city "branding;" it has contributed greatly to a particular view of the contemporary city that is characterized by warehouses and factories, left over from the industrial economy, that have been converted into "hives" and offices for creative people, with hip coffee shops and restaurants at the street. In this view of the city, places where most goods are sold—Walmart and Costco stores, Kroger supermarkets and CVS pharmacies, Home Depot and Target stores—are located outside the creative core in suburban locations with plenty of parking. And the places where the goods sold in Walmart, Costco, Kroger and CVS are made are not part of the city at all.
What is understood to be "urban"—and understood to be the contemporary urban ideal—has a lot to do with spaces that accommodate this "knowledge work" along with dwellings that are in nearby, dense neighborhoods.
This picture of the city is not inaccurate. In the spirit of von Thunen or Burgess, we can think of it, very roughly, as having two concentric rings: an inner ring, which is the "creative core," and an outer ring, which is the "service ring" of Walmarts and suburban housing developments.
But there is in fact a third, outermost ring, which is not usually talked about at all in describing the "city of knowledge." It is the ring in which things are made and in which food is grown, and it may be geographically quite distant from the ring of Walmarts and suburban tract developments. This ring includes factory farms in the San Joaquin Valley, banana plantations in Central America, shoe factories in Vietnam, clothing factories in Bangladesh, factories making every conceivable kind of item, from zippers to toilet-bowl brushes, in China.
But even more so than the suburban ring, this last ring is invisible. People don't drive through it, they don't work there, they don't know anyone who does work there. It is out of sight, and therefore may be out of mind, not part of our model of the city.
But this is a colonialist attitude. By itself, the “creative core” represents an incomplete city, and in fact depends on the "hinterlands" in which labor is cheap and from which transport costs are also cheap. It is the same phenomenon described by William Cronon with respect to Chicago in Nature's Metropolis, but extended to a global dimension.
Another way of putting this is that this invisibility represents an artificial severing of a holistic phenomenon—the phenomenon that is concerned with the cycle of production and consumption. In order to maintain a holistic understanding of that phenomenon—in function as well as in physical form—we have to include the outermost ring, even if it is invisible in people's everyday lives.
In the same way that William Cronon saw Chicago as inextricably linked to its hinterland of the American West, we have to see the contemporary city as linked to its "global hinterland." The idea that the contemporary city is characterized primarily by a "service economy" or particularly by a "knowledge economy" is true only if it is described to be artificially separated from an essential functional component—that of production.
The city cannot be thought of only as a physical thing, or only as a particular geographical area. It has to be thought of as a system that has very particular relationships with systems outside itself, that need to be defined, specified and understood when the city is described.
Another way of putting this is that production and consumption need to be thought about as part of a single ecological system, in which inputs and outputs, the adding of value and the increased organization of the system are necessarily understood together. The idea that our cities are characterized only by "knowledge economies" is superficially true, but only if the city's boundary is limited by its political or geographic definition. It is not true if the city or its economic functions are viewed in terms of their actual functions, or flows of material, money, labor or knowledge.