More than a book, this is an intellectual curiosity. Philip Ball, a science writer of some distinction, has persuaded a publisher to let him argue, over 650 densely packed pages, that the laws of physics can help solve social problems.
Ball starts by presenting us with aerial views of the way a throng of visitors fills up a crowded art gallery, or the way that cars move along a crowded motorway. Because the direction which each art lover takes is determined by a subtle negotiation with each of his fellows, and because each driver on the motorway modifies his speed in response to what the driver ahead does, Ball concludes that there are some things which cannot be reduced to the sum of individual actions and which can only be understood within groups. The modern discipline of economics treats people as discrete individuals who are only out for what they can get. Within the "softer" social sciences like sociology, on the other hand, individuals are often stuck together in a kind of formless glue, mutually suffocated by the weight of culture and tradition.
Between those two caricatures, Ball suggests, lies a whole world of human interaction in which the activities of human groups cannot be explained by adding up the sum of their parts. Since physicists are accustomed to thinking in terms of the interaction between things rather than about things themselves, their methods can add something distinctive to our understanding of society. Collective social processes, in short, can be seen to have their own physical laws of shape and form.
Ball wants to press his "social physics" in the service of improving the human condition. "The more we can understand and predict the ways in which we instinctively want to move around our environment," he says, "the better we are likely to be able to create places where people feel relaxed, comfortable and considerately housed." He is not shy of drawing attention to his distinguished antecedents. The idea that the methods of physics and the other natural sciences might help us understand human affairs, he points out, was a natural outgrowth of the heady ambitions of Enlightenment thought. The abstractions and ruthless logic through which the classical political economists sought to understand society might be simplifications, he argues, but it is rather cheap to suggest that they are inhuman. The search for the mechanism which can explain how society works has been most enthusiastically pursued by liberals and radicals - men like Adam Smith and Karl Marx - whose concern was to understand society as a means of improving it.
Despite all the graphs and bar charts in this exquisitely produced and painstakingly researched book, there is the sneaking suspicion that we have been here before. In his recent book The Tipping Point, Malcolm Gladwell sought to explain how fashions change and crime rates suddenly vary using techniques drawn from psychology and epidemiology. In Butterfly Economics, Paul Ormerod used biology to much the same effect. Now Ball comes along to tell us, for example, that sudden changes in the way that crowds behave are akin to "phase transitions" in the world of physics. A long line of cars on a motorway, for example, is presented by Ball as a relatively stable physical body. But just as steam abruptly condenses to water, or snowflakes suddenly appear when water vapour freezes into ice, a random movement by one car can convert the whole entity into a congested state.
Ball writes patiently and eloquently about both the history of political economy and developments in modern physics, but there is a degree of recoil when he brings both together. …