Commentary

Urban planning as a field is ill defined in contents and in scope, and the public hardly knows what to expect of its prac-titioners.1 This essay is a proposal for a common understand-ing of what urban planning is, of the dilemmas that planners face, and of the norms we can use to assess their practice. It does not do justice to the diversity of the field (for instance, in terms of geographic differences), but it does touch on the main issues that planners in practice and in academia must address to explain what they do and why they do it. I argue that urban planning is both challenged and enriched by a number of contradictions and tensions at its heart. Some of these are specific to the field; others are not. Some can be resolved; others cannot. Whether or not they are particular to planning and whether or not they are amenable to resolution, these dualities are a given of urban planning. The position