What Can Mechanisms Do for You? Mechanisms and the Problem of Confounders in the Social Sciences

The idea that mechanisms are crucially important to differentiate between genuine and spurious causal relations is ubiquitous both in the philosophical and in the social scientific literature. Yet philosophers of the social sciences have seldom attempted to spell out systematically the way in which mechanistic reasoning or evidence are concretely used to deal with spurious association and the problem of confounders in the social sciences. In this paper, we analyze two recent such accounts, proposed by Harold Kincaid and Daniel Steel. We show how these two accounts radically differ in their notion of mechanism (a process account, and a complex system account, respectively), and how this ultimately impacts in the way in which they understand the inferential role of mechanisms in the social sciences. We then confront both accounts with the details of a well-known controversy around the purportedly causal association between the legalization of abortion and the subsequent fall in criminality in the United States. We show the limitations of both accounts in representing accurately the role of mechanistic evidence and hypotheses in practice.