ABSTRACT
A hierarchical and Cartesian notion of scale has been fundamental to the geographic imagination, with geographers developing ideas about how changes on one scale inform processes operating on others. This chapter explores notions of connectivity and mobility and argues that this literature on world cities provides some important clues as to how we might rework urban theory to better acknowledge the complex and stretched-out spatialities of the city. In urban studies, distance has traditionally been understood as a kind of 'friction' or impediment between locations. The adoption of new experimental approaches to comparing cities seems particularly important in an era when many urbanists have made the case for a fundamental renewal of urban theory in an era of planetary urbanism. Hierarchical distinctions between leading and secondary world cities are not derived from measures of population size or the presence of corporate headquarters, but the relative importance of a city's advanced producer service firms.
