Complexity theory has become a popular frame for conceptualizing and analyzing cities. The theory proposes that certain large systems are characterized by the nonlinear, dynamic interactions of their many constituent parts. These systems then behave in novel and unpredictable ways—ways that cannot be divined by examining the components of the system. Complexity theory problematizes traditional reductionist, linear methods of scientifically analyzing and predicting cities. It also opens up a new world of scholarship to researchers keen to formulate new kinds of sciences that take complexity into account (e.g., Wolfram 2002). These attempts usually follow Kuhn’s (1962) theory of paradigm shifts: new evidence and modes of thinking undermine an established science, and a new science emerges to replace it.
In The New Science of Cities (2013), Michael Batty argues that we need a new kind of science to understand cities as complex systems of networks and flows between people, goods, resources, and institutions.