The complexity of cities is a widely shared siren song amongst the vanguard of the new urban scientists. Yet nowhere is it being more fundamentally addressed than in the high desert of the American Southwest, where a handful of the world’s brightest physical theorists are trying to describe this complexity in precise detail at the Santa Fe Institute (SFI), established in 1984 to explore the then-new field of complexity. As useful as the boundless streams of data being produced by the world’s new urban research labs may be, without theory they may do little to advance our understanding of the bigger picture of urban evolution.
SFI’s interest in cities has its origins in the late 1990s when Geoffrey West at the Los Alamos National Laboratory became interested in the fundamental laws of scaling in biology. It had been known since Max Kleiber’s studies in the 1930s that as organisms grew larger, their metabolism slowed by a predicable and constant rate. A few years later, the study of scaling in biology was given a name — allometry. What West and his colleagues were able to do was not just inductively determine the law from observations like earlier investigators, they were able to deduce it from theoretical principles about the nature of the beings and processes themselves.
With this toolkit in hand, West moved down the street to the freewheeling Santa Fe Institute where he served as president from 2005–2009, it was not long before they began to apply it to connected complex systems of all kinds. According to West, “We conjectured that… highly complex self-sustaining systems — whether they are cells, organisms, ecosystems, cities, or corporations — require close integration of many constituent units that require an efficient supply of nutrients and the disposal of waste products. We suggested that this servicing — via circulatory systems in organisms or transport systems in cities — is accomplished through optimized, space-filling, fractal-like branching networks whose dynamical and geometric constraints are independent of specific evolved organismic design.” In short, West argues — “the key lies in the generic mathematical properties of networks.”[i]
The implications for cities were stunning, because they turned out to be a very different sort of network than an animal body or a corporation, which both tend to stagnate and decline as they expand. Instead, “with every doubling of city size, whether from 20,000 to 40,000 people or 2 [million] to 4 [million] people, socioeconomic quantities — the good, the bad, and the ugly — increase by approximately 15% per person with a concomitant 15% savings on all city infrastructure-related costs.” Think of it as a divine gratuity, bestowed upon cities as they are fruitful and multiply. But it wasn’t just the good news, or the clear and compelling explanation for why urbanization seemed to be gathering steam in its seemingly inevitable historic march across the planet — understanding scaling was an essential step in developing any science of cities, just as it was in every other field. As West put it, “Over the past 50 years, scaling arguments have led to a deeper understanding of the dynamics of tipping points and phase transitions (how, for example, liquids freeze into solids), chaotic phenomena (the mythical flapping of a butterfly’s wings in Brazil stimulating a hurricane in Florida), the discovery of quarks (the building blocks of matter), the unification of the fundamental forces of nature, and the evolution of the universe after the Big Bang.”[ii] SFI’s work on urban scaling, led by Luis Bettencourt, has proven remarkably robust — holding up against data describing from human settlements as different as pre-Colombian Mexico archaeological surveys to 21st century cell phone records.
Perhaps the most ironic thing about SFI is that, despite the unprecedented depth of its insights into the nature of urbanization, unlike the other leading centers of the new urban science we’ve looked at, it isn’t situated in a global city or a hub of higher education. But it is reaching out to the metropolis — in January 2015 building on its success SFI announced the creation of a joint research program with Arizona State University (where one of its key urban research collaborators Jose Lobo is a faculty member), the ASU-SFI Center for Biosocial Complex Systems which will study scaling and innovation in cities. This center represents SFI’s first formal collaboration with a university since its establishment over three decades ago.[iii]