What Is the Form of a City, and How Is It Made?

Abstract

Three branches of theory endeavor to explain the city as a spatial phenomenon. One, called “planning theory,” asserts how complex public decisions about city development are or should be made. Since these understandings apply to all complex political and economic enterprises, the domain of this theory extends far beyond the realm of city planning, and it has been well developed in those other fields. So it has a more general name: “decision theory.” The second branch, which I call “functional theory,” is more particularly focussed on cities, since it attempts to explain why they take the form they do and how that form functions. This is a reasonably thick theoretical limb—if not as robust as decision theory—and engages renewed interest today. I have summarized its leading ideas in appendix A, and there, from a safe distance, point to some of the more common blemishes on this limb. The third branch, spindly and starved for light, but on which so many actions are hung, is what I would call “normative theory.” It deals with the generalizable connections between human values and settlement form, or how to know a good city when you see one. This is our concern. As on any healthy tree, the three branches should spring securely from a common trunk. Unlike the branches of trees we know, they should not diverge. They should interconnect and support each other at many points. A comprehensive theory of cities would be a mat of vegetation, and some day the branches will no longer exist in separate form. While working perilously far out on the weakest branch, we must be aware of the other two and look for favorable places to insert a graft. So this chapter scans planning theory and functional theory, the two companion branches to our own. It also sets forth what I mean by the “form” of the city. Otherwise, what are we talking about?