Stefano Moroni and Stefano Cozzolino
The chapter deals with the limits of regulation in complex systems, and is structured around three main questions. (i) Why is the city a complex system? Aside from the city having multiple objects and elements it is complex due to the fact that ‘the city is action’. The city is the emergent result of actions and continuous interaction over time. While actions are intentional behaviours with their own internal logic, the interactions of plural actions imply the emergence of unintentional socio-spatial configurations and an overall uncertainty of the system. By acting, we (intentionally) bring about certain things, while (unintentionally) provoking other things. (ii) What are the conditions within which actions take place? ‘Conditions’ for actions change from place to place. We will distinguish different kinds of conditions for action according to two main variables: first, we consider their nature, which can be ‘social’ or ‘material’; second, we focus on their genesis, which can be independent from human intervention or dependent on human activity. (iii) On which conditions can planners (effectively) intervene (and how)? Although planning rules are only one of the many conditions that influence actions in space, they represent the only condition that can be directly altered by planners to avert or favour certain situations in complex systems. It is exactly because the city is a complex system that only certain types of rules are better suited to deal with it. This brings us to two types of rules: directional rules to directly obtain a given order of urban actions, and relational rules to indirectly foster self-coordination of urban actions. This reasoning brings to the fore regulations that are relevant for the planner to consider when dealing with a dynamic city in action.