Imagine the perfect city. If you have a clear picture in mind, you’re not alone. Tsars, emperors, and prophets have been trying to build perfect cities for millennia. With the emergence of the field of urban planning and modern social science, everyone from stenographers to industrialists to independent architects have joined in. For Ebenezer Howard, the perfect city was the Garden City, a corporate-owned residential satellite on the outer edge of town. For Le Corbusier, it was the Ville Radieuse, full of “skyscrapers in the park” and elevated highways. For Frank Lloyd Wright, it was Broadacre City, a dispersed anti-city full of single-family homes on one-acre lots. Each reflects a distinct vision of urban life, and each seems to have as many opponents as it does proponents.

Thankfully, few of these plans have ever been implemented in full on a mass scale. Yet “perfect city” thinking—the view that one particular vision of urban form should be imposed by planners—has manifested itself in small ways in cities around the world through the construction and enforcement of specific theories of how a city should work. This approach to urban form involves expanding urban planning beyond prudentially managing infrastructure and mitigating destructive negative externalities and toward enforcing and preserving particular lifestyle and aesthetic preferences.

Consider: while Ville Radieuse was never built, many cities bulldozed traditional urban neighborhoods to construct the urban elevated highways of Le Corbusier’s dreams. While Broadacre City never moved beyond the model stage, many suburban communities still zone minimum lot sizes of one acre and heavily restrict apartments, a reflection of Wright’s peculiar view of the ideal urban life. The immodesty of thinking that one plan can be imposed on the millions of plans developed by residents lives with us today in every Euclidian zoning ordinance and every urban freeway.