Dissertation: The Emergence of Causation


The understanding of the world's causal structure provided by fundamental physics stands in stark contrast to the understanding provided by the special sciences. At the level of fundamental physics, causal influence appears to be relatively undiscriminating---it appears that most past fundamental physical events causally influence most future fundamental physical events. In contrast, the special sciences appear tell us that many past high-level events are causally irrelevant to many future high-level events---_e.g._, China's one child policy did not cause Zimbabwe's hyperinflation. In part, the dissertation focuses on what this disparity can teach us about the nature of causality. There is a popular thesis according to which high-level events are causally related whenever their low-level, fundamental physical realizers are causally related. I contrast this with a thesis I call _causal emergentism_, according to which, though there is high-level causation, what it is for high-level events to be causally related isn't just for their low-level realizers to be causally related. I argue for causal emergentism on the grounds that it provides the only adequate means of squaring the apparent plenitude of low-level causation with the apparent scarcity of high-level causation. I additionally provide a theory of causation which is capable of explaining how and why the world's causal structure varies across different levels of description. According to this theory, causation requires the presence of what I call _structural determination relations_ between different properties of the world. Following authors like Halpern, Hitchcock, Pearl, Woodward, Spirtes, Glymour, and Scheines, I represent these properties of the world with variables, and represent structural determination relations as equations relating the values of those variables. Most of these authors have interpreted structural determination relations as encoding <em>counterfactual</em> information. I show that, if structural determination relations are understood in this way, then they will not be guaranteed to be independently manipulable---a property these relations must possess if they are to be used to provide an account of causation along the lines many of these authors propose. In contrast, I propose an account according to which one variable is structurally determined by upon others if and only if, roughly, the values of the latter variables are sufficient for the value of the former throughout a certain nearby region of modal space. Given either definition, however, there need not be a relations of structural determination between two high-level properties of the world simply because there is a relations of structural determination between the low-level properties which realize them. After articulating this account of structural determination, I formulate an account of causal counterfactuals and singular causation in terms of networks of structural determination. On this account, structural determination relations provide the pathways along which causal influence propagates; and causation is, roughly, counterfactual dependence within a network of structural determination relations. A few extra bells-and-whistles are necessary. However, once causal counterfactual conditionals have been properly grounded in networks of structural determination, the standard objections to counterfactual accounts of causation dissolve.

The University of Michigan