(Phoenix, AZ) In my forays into social science (I am trained as a philosopher), I tend to read and write about variables that can be attributed to individual human beings. Individuals vote or don’t, they graduate from high school or drop out, they live in Massachusetts or Texas, they support or oppose health care reform. I am interested in the distribution of these variables across populations, how they interrelate, and what causes them to change.

Reading Dynamics of Contention by Doug McAdam, Sidney Tarrow, and Charles Tilly (2001) helpfully reminds me that there is more to life than that. These authors are concerned with the causes and courses of “contentious politics”: social movements, revolutions and revolts, secession, communal violence, and waves of strikes.

They analyze mechanisms, processes, and episodes. Episodes are large historical events like the collapse of the Soviet Union or the achievement of political rights by African Americans. Mechanisms are specific phenomena that occur during episodes, such as competition among factions, repression by authorities, radicalization, or the diffusion of unrest from one community to another. A specific example (as an illustration) would be “cultural appropriation.” When the French revolutionaries beheaded aristocrats and displayed their heads on pikes, they were appropriating the ancient ritual of execution used for treasonous nobles. When African American pastors began calling volunteers to the front of the church for civil disobedience, they were appropriating the traditional “invitation” period at the end of a revival meeting. These acts of appropriation were mechanisms within episodes.

In between mechanisms and episodes are processes, which are concatanations of mechanisms. For example, the Civil Rights struggle in the American South between 1955 and 1964 was a complex process that included many mechanisms (diffusion, violent repression, recruitment, brokering among groups, etc.). McAdam, Tarrow, and Tilly emphasize that mechanisms combine in various unpredictable ways to create processes, whose outcomes are also unpredictable. There is no general pattern, such as rise-and-fall or radicalization-followed-by-collapse. But the mechanisms have general properties and logics.

For students of social change, the lesson is to look not only at individual attributes but also at group-level phenomena. A survey might never identify a historically momentous process, because only a small number of people may be involved, and even they may not know what they are doing until it is all over. The Patriots at Lexington and Concord knew they were defending some weapons; they had no idea they were creating a new nation. A survey taken in 1775 would have missed the process entirely.

For activists who want to change the world, the lesson is not only to promote changes in populations or in members of specific groups and programs. We must also use the best available and practicable mechanisms in the best combinations to achieve good outcomes. Learning to identify appropriate recipes seems an essential task for both research and practice.