On the Survival of Butterflies in the Jungle of Urban Systems

Sanders, Lena [CNRS, UMR Géoraphie-Cités, Paris] Thomas, Isabelle [UCL] Vacchiani-Marcuzzo, Céline [Université de Reims Champagne-Ardenne]

As suggested by the title, this contribution is inspired by Gilles Duranton’s and Andrés Rodriguez-Pose’s paper of 2005 entitled “When economists and geographers collide, or the tale of the lions and the butterflies”. Comparing economical (the lions’) and geographical (the butterflies’) scientific approaches, they pointed out their radically different ways of proceeding and the lack of cross-fertilization between these two disciplines. Looking at the geography of cities, our aim is to continue the discussion through pointing out some differences in points of view. First we discuss what seems to be a “necessity” for lions, that of rooting the approach in methodological individualism for understanding the dynamics of a system of cities. Indeed, this seems to be the mainstream position in economy when butterflies explore different ways of flying from one scale to another. We build on philosophers’ tools in order to explore more deeply the meaning of methodological individualism and the relevance of different kinds of “objects” when modelling cities’ dynamics. We then focus on the question of delineation of spatial objects like cities, building on an empirical approach to discuss how proper scale choice associated to a multiscale approach favors comparison. At last, we expose the feedback of an interdisciplinary experience where the city delineation played a crucial role when developing a LUTI model.As a conclusion,we are convinced that more opening and interactions between butterflies, lions (and tigers!), will help the scientific ecosystem to be more resilient.