When Numbers Turn into Streets

Thinking by Numbers
Throughout history cities have been great or humble, glorious or violent, pits of depravity or golden beacons of human civilisation. They are never just a collection of buildings but rather a repository of strength and a theatre of the possible beyond any one individual. We may build them but they soon grow out of our control. How do we even imagine a city in its entirety? Two authors from London, one an academic specialising in city modelling, the other a novelist, both wrestle with this question in very different ways.

Professor Michael Batty, Director of the Centre for Advanced Spatial Analysis at University College London has recently written Cities and Complexity (MIT Press). In this he takes the initial premise that cities form from the bottom up, in other words they evolve from a mass of interactions and factors rather than a process orchestrated from top-down management. This notion is then built into computer simulations of city growth, scraping away the mass of details to expose the raw underlying principals of formation using cellular automata and agent-based modelling.

Cities are never just a collection of buildings but rather a repository of strength and a theatre of the possible beyond any one individual. We may build them but they soon grow out of our control

Cities contain an almost infinite complexity in their structure which is why normal predictive techniques do not create realistic models. Due to the sheer scale of the task it is unfeasible to take into account all the factors involved and simulation designers are forced to take shortcuts. But if critical factors of city formation are ignored, and these are quite often the hardest to reduce to mathematical equations, we end up with disastrous urban planning. One only has to look at the capital of Brazil, Brasilia, to see the enormous gap between grand ideas and humble reality where human interaction is suppressed, throttling the city.

When creating models of cities it is important not just to look at them as collections of buildings and transportation networks but as organic, fractal entities with unique properties. A city will have memories for example, which might sound strange unless you think of it in the terms of an organism. Our immune system ‘learns’ to fight infectious diseases as it comes into contact with them. Cities likewise have this ‘path dependence,’ in-built mechanisms like train-tracks that retain continuity. Businesses will cluster in proximity to each other. In London for example the area of Hoxton is well-know for its contemporary art galleries and so draws in not only art customers but also new galleries, continuing the cycle. Likewise neighbourhoods form along ethnic or socio-economic lines because people gravitate towards those that are similar to themselves.

In these non-linear models an important element to be factored in is generic uncertainty. This simulates to a degree the ‘unknowablility’ of specific events, an approximation of detail. Batty is quick to point out that these models do not provide an accurate picture of one city as it stands today but rather are organic simulations displaying the underlying principles that might have carved out these environments. By 2025 60% of the world’s population will live in cities as opposed to 40% today. In a hundred years that figure is predicted to rise to 90% so it is critical that we understand those shaping forces.

“Cities and Complexity” contains a birds-eye view of a metropolis, calibrated through the lens of equations, random number generators and simulations. The view is altogether different when it is at ground-level, amongst the cracked paving stones, the jostling crowds and the struggle to find ones identity within the context of the whole. Simon Ings, a novelist, found the gritty, jarring back-drop of London and war-torn, destitute Beira in Mozambique seeping into his latest work. The Weight of Numbers (Random House) is a tangled web of half a dozen narratives, conjuring up a disparate community of characters and placing them in a familiar world made strange. For each of the main characters it is purely a question of the weight of numbers; one driven mad by the tantalising hope that mathematical equations may provide a logical heaven, another with the very pounds and ounces of her own flesh. Ings takes the reader from gruesome tragedy to the sinister reality of every day life, in which it isn’t fate or chance that controls our lives, but numbers and their absolute indifference to pain and suffering.

For Ings the only interesting city is a broken one, of which London is a perfect example, the result of multiple attempts at social planning and disastrous housing schemes. It is alive through its sheer resilience as organism-like it evolves and sustains itself. But it still holds its character, glued together as Ings says, by the fact it is a ‘travelling community.’ Working in London invariably means travelling. By coming into contact with vast numbers of people on the street or in the Tube one plays a part in this reality. This echoes the writing of Jane Jacobs in The Death and Life of Great American Cities, a seminal text on urban development written in the 1960’s. In it she makes the forceful argument that the lifeblood of a city is to be found in the interactions of its inhabitants, particularly in its public spaces. Take away the chance for people to interact, even fleetingly and you kill the city.

Side by side the positions of these two London authors may seem polar opposites but in fact there is an over-lap. Both hold on to a scepticism that it is possible to know the details of human interaction and the fallacy that we may be able to control our lives through the Cartesian, mechanical application of direct cause and effect. Both acknowledge that the one irreducible element, the random component of any city equation, is, to put it simply, us. Humans. We may have the tools to form dreams of the world around us but as people we are the stuff of nightmares.