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Chapter 3. What Are Causal Mechanisms?
- University of Michigan Press
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23 Chapter 3 What Are Causal Mechanisms? This chapter focuses on debates about the nature of causality and the understanding of causal mechanisms that form the ontological and epistemological underpinnings of all three process-tracing variants. This chapter introduces the reader to the ontological debates within the philosophy of science that deal with the nature of causality itself to understand how the mechanismic understanding of causality used in process-tracing analysis differs from the other understandings of causality that are prevalent in social science, particularly large-n statistical analysis and comparative case study research. As this book is not a treatise on the lengthy philosophical debates on causality—a topic that has been the subject of heated exchanges since ancient Greece— the chapter only briefly reviews two key debates about the ontology (nature of) causality that are necessary to grasp how causal mechanisms are understood within theory-centric and case-centric process-tracing variants. The first debate relates to whether we should understand a causal relationship in a skeptical, neo-Humean fashion, where causality is seen purely in terms of patterns of regular association (regularity), or whether causality refers to a deeper connection between a cause and effect (e.g., a mechanism). The second debate deals with whether causal relations should be understood in a deterministic or probabilistic fashion. The chapter then discusses the nature of causal mechanisms. After defining causal mechanisms in the mechanismic understanding, we identify a common core regarding how causal mechanisms are understood within process-tracing methods and how they differ from an understanding where mechanisms are seen as either empirical events or intervening variables. However, significant differences exist within process-tracing depending on the variant chosen. In case-centric analyses, a mechanism is often considered a loose conglomerate of systematic and nonsystematic parts that together ac- 24 Process-Tracing Methods count for a particular outcome. In contrast, theory-centric analyses operate with relatively simple causal mechanisms that include only systematic parts that can be generalized beyond the confines of the single case. The chapter concludes with an in-depth discussion of several key points of contention about the nature of causal mechanisms. These points include the ontological debate about whether mechanisms should be understood as operating solely at the micro/actor level or whether macro/structural mechanisms also have a reality of their own as well as more epistemological debates about whether we can directly observe causal mechanisms or whether we can only observe the implications of their existence. 3.1.The Ontology of Causality in the Social Sciences This section provides a brief overview of the main lines of debate in the philosophy of science regarding the nature of causality itself (mechanisms or regular association) and whether causality should be understood in a probabilistic or deterministic fashion. Causality as Regular Association versus Causal Mechanisms When we speak of a causal relationship between X and Y, what is the nature of causality in the relationship? Social science takes two main ontological positions on the nature of causal relations.1 First, the skeptical, neo-Humean understanding of causality as patterns of regular empirical association has traditionally been the most prevalent in social science (Brady 2008; Kurki 2008). David Hume, in a reaction to the then-prevalent theory that saw causality as a necessary connection in the form of a “hook” or “force” between X and Y, contended that we cannot measure the “secret connection” that links causes and effects. We can observe that an object falls to the ground, but we cannot observe the gravitational forces that caused the object to fall. Given this inability to empirically verify that X caused Y, Hume argued that we should define causes merely in terms of constant conjunction (correlations ) between factors; any theorization of “undetectable” mechanisms would quickly, in his opinion, degenerate into metaphysics (Brady 2008; Hume 1975). Causation is therefore taken to mean nothing but the regular association between X and Y, controlled for other relevant possible causes (Chalmers 1999: 214; Marini and Singer 1988). [3.138.138.144] Project MUSE (2024-04-17 15:24 GMT) What Are Causal Mechanisms? 25 Causation in the regularity approach is therefore understood in terms of regular patterns of X:Y association, and the actual causal process whereby X produces Y is black-boxed. Regularity can be analyzed by examining patterns of correlation between X and Y. For causality to be established, Hume argued that three criteria for the relationship between X and Y need to be fulfilled: (1) X and...