This article is the product of reflections on the consequences of the latest discoveries in complexity science upon the practice of urban design. Its intent is to establish a foundation for a new debate in urban design, which is trapped in production processes inherited from a failed ideology, modernism, but has had no scientific alternative until the last decade. It will not argue over the superiority of one urban design morphology over another, the debate that many urban designers are engaged in, but make the counter-intuitive claim that urban design morphology is an unimportant determinant of the life and sustainability of a city, and that the relevant determinant is the process through which the city is grown. From the starting point that spontaneous city growth is absolutely necessary for sustainability, techniques to produce large-scale geometric order are reintroduced that respect this condition and produce order out of the random actions of large numbers of individuals, a phenomenon known as emergence. With this insight, urban design is explained as the selection of urban growth processes that emerge desirable patterns.
Hélie, Mathieu. "Conceptualizing the Principles of Emergent Urbanism," in ArchNet-IJAR: International Journal of Architectural Research, vol. 3, issue 2 (2009).