Resumo:
The paper presents the Jane Jacobs´ understanding on urban vitality, derived from the theories of organized complexity. Cities are an expression of the universal phenomenon of development, the growing order that expels entropy, where the very term vitality is not a metaphor, but the very root of the phenomenon, governed by few and inexorable principles. The Birth is the emergence of a new type of order, different from the sum of the parts, with the formation of increasingly intricate connections. To Jacobs the Growth is quantitative (the expansion) and qualitative (the differentiation) in a continuous co-development, fuelled by the various forms of positive and negative feedback in an unstable universe over time. The Death is the loss of complexity in the system, in this case the cities, and Jacobs exposes the causes and ways of the incapacity to respond to changing circumstances, reviewing the concept of efficiency. She still tries to demonstrate the conditions for it Survival through innovations in the bifurcations, despite the uncertain and unexpected results. And precisely because of this uncertainty, constitutive of reality, Jane Jacobs will oscillate between despair and hope.
