Complexity: the evolution and planning of towns and cities

In this chapter we introduce the ideas of self-organization and of evolutionary dynamical models that explore how towns and cities evolve. And, this evolution concerns all levels of the system under studied ‚Ä" from that of the whole urban hierarchy, through neighbourhoods and different local zones, down to that of agents and families and how their concerns and desires change over time. Different models are arrived at as the result of making successive assumptions, so that models become simpler with additional assumptions, but may deviate too much from reality to be useful. Understanding, for a time, is achieved in this trade-off between simplicity and realism. The point is that decisions and plans have to be made in order to respond to the needs and desires of the people concerned, as well as the infrastructure, housing and business developments that are required. In such decisions, therefore, it is important to be able to explore the probable consequences of different possible actions and interventions in order to decide on the best course of action. In an evolving world, we develop a model that fits the facts as we currently know them and allows us to see when its predictions seem to deviate from reality. At this point we must try to modify our beliefs and the structure of our models and interpretive framework. But there is no scientific or unique way to modify our beliefs when they have failed, and so we are condemned to carry on throughout our lifetimes trying to ‚Äòmake sense‚Äô of what is going on, what it means and what might happen. This is an unending process. Even though the development and ‚Äòuse‚Äô of models as interpretive frameworks is always going to be imperfect, it is nevertheless better to have one than not to have one. This shows us how the new understanding of complexity and self-organization leads to a softer view of a changing world, in which there is a co-evolution of the problems we face and of the desires and plans that we have.