The majority of physics problems are impossible to solve by analytic means. Various strategies have been developed to cope with the highly non-linear nature of many of these problems. Dimensional analysis provides a powerful tool for addressing many complex problems, suggesting the form the solutions must have. Examples include the non-linear pendulum, explosions, flow at high Reynolds number and the law of corresponding states. The study of chaotic phenomena became feasible with the development of high speed computers and revealed regularities despite the apparent unpredictability of the systems. Scaling laws for extremely complex and non-linear problems lead to the concept of self-organised criticality, illustrated by the model computations for rice and sand piles.

In this chapter I show that it is possible to identify across a range of different thinkers a shared analytical investment in collective behaviour that allows one to distil the notion of social avalanches or social avalanching. The fundamental claim I make is that Durkheim, Simmel, Tarde and many others sought to respond to an experience that gained particular prominence in the late nineteenth and early twentieth centuries: various forms of social change increasingly produced situations in which individuals felt the ground disappearing beneath them, carrying them away in a collective turbulence which, once set in motion, acquired its own self-organising properties. In addition to developing the notion of social avalanching from late-nineteenth-century social theory, this chapter explores the prosocial character of avalanches. Elaborating on the concept of social avalanching, I examine the extent to which a metaphor such as ‘avalanche’ merits inclusion in the realm of proper sociological concepts and connect it to discussions within physics about self-organised criticality. Finally, I discuss the notion of social avalanching in relation to social action as conceived in the sociology of Max Weber.