Based on what was said during the first day of class, I understand emergence to be the study of complex systems in which the final outcome for the system is determined by the state of a multitude of variables that interact in complex, unpredictable, and chaotic ways. As a Cities major concerned primarily with issues of planning and policy in modern American cities, my interest in emergence lies mainly in using the concept to understand cities as the product of large numbers of independent and unpredictable actors. For instance, one could view cities as a collection of a large number of individual citizens, or a large collection of economic agents and actors, or a large set of built structures--all of which represent examples of emergence theory that could be used to define a city. Thinking about cities as emergent systems raises intriguing opportunities to use these insights about cities as systems to model, simulate, and predict changes in the urban system to support planning decisions. From what I'm able to tell from a few cursory Google searches, not much has been done in using emergence theories to understand the dynamics of modern cities. But it seems that there is a bit of existing research (incuding this paper examining the size of cities as an emergent system and this site, which indirectly uses the concept of emergence to explain the relationship between "city-systems" and the "world-system") that has been working to apply concepts of emergence in order to understand the evolution and development of cities and urban form.