In Chapter 3 we present the first main part of our case for Causal Mechanism, by discussing in detail apoptosis, a central biological mechanism. We examine how John Kerr and his co-workers first introduced apoptosis in 1972. We then present the most important stages in scientific research regarding apoptosis during the last decades that led to its identification as a central biological mechanism, explaining the shift from morphological descriptions to biochemical descriptions of the mechanism. We generalise the molecular definition of a pathway to arrive at a more general notion of a causal pathway. We also show that several distinctions used by biologists in order to differentiate between causal pathways and identify the genuine biological mechanisms (active vs passive, programmed vs non-programmed, physiological vs accidental) do not correspond to internal features of causal pathways, but concern an external feature, that is, the role those processes play within the organism.

In Chapter 9 we present and defend a causal account of multilevel mechanistic explanation by examining various case studies from biology. We argue that two key consequences of Causal Mechanism are (1) that levels and mechanisms are distinct notions and (2) that levels of multilevel explanations are levels of composition. This view is in stark contrast to Craver’s account, according to which levels in multilevel explanations are levels of mechanisms and multilevel explanations are instances of constitutive explanations. A key claim of the chapter is that whatever contributes to the phenomenon is part of the same pathway; but causal pathways can contain entities from multiple levels of composition. In order to motivate and illustrate our view, we use various examples from biology and medicine. We criticise some common views associated with the picture of a hierarchy of mechanistic levels and argue that our view allows for causation at higher levels.

This chapter applies the theory to India. I first describe the colonial history of how the British annexed certain Indian states into direct rule and signed treaties with other Indian princes as indirect rule. I then develop a theory of different types of indirect rule within India—a formal type of indirect rule through princely states and an informal type of indirect rule through zamindars/landlords. These different types of colonial indirect rule created different causal pathways of structural inequalities and low state capacity, which persisted through path dependent mechanisms into the postcolonial period to result in Maoist insurgency in the 1980s. The zamindari landlord tenure system created one causal pathway of land/caste inequality and lower bureaucratic penetration in the northern epicenter of insurgency in Bihar/Bengal, while the princely states in central-eastern India created a second causal pathway of exploitation of land and natural resources in tribal areas in Andhra Pradesh and Chhattisgarh. I also theorize the role of rebel agency in the form of Maoist leaders and organizations and analyze how the interaction of rebel agency with the structural conditions created by indirect rule creates conjunctural causation for Maoist insurgency.