Abstract

Up until the time of John Locke, who founded the empiricist tradition, many philosophers adhered to the Aristotelian notion that causes produce their effects in virtue of their power or efficacy to do so. Causal couplings between things were said to be the manifestation of particular kinds of efficacy . Efficacy qua power was viewed as either a particular kind of primitive thing mysteriously associated with physical objects or as a unique, irreducible property had by physical objects. In either case, efficacy was supposed to be the ultimate source of physical change; the efficacy associated with an object--the so-called "efficient" cause--was said to manifest itself in the changing of another object. ;With the rise of empiricism, philosophers became more and more concerned about this notion of efficacy. For it is not at all evident that we can derive it from sensory experience. This skepticism culminated in the publication of David Hume's A Treatise of Human Nature, where it was proposed that the concept of efficacy be purged from our notions about causation. ;In part I of this dissertation, I first establish that the reasons Hume gives for expunging the notions of efficacy, and causal necessity, from our talk about causation are not nearly as compelling as Humeans have frequently said that they are. Then I argue that Hume's account falls miserably short in living up to its promise of properly classifying our preanalytic notions about causation and attempts to improve upon Hume's account have been singularly unsuccessful. While other philosophers have pointed many of these problems out before, one still frequently hears neo-Humean philosophers referring to Hume's "proofs" that there is no efficacy or causal necessity. Indeed, these so-called proofs are most often advanced as rebuttals to non-Humean accounts of causation. Similarly, one still hears about the success of various neo-Humean theories. ;In part II, I argue that Hume's treatment of causation reflects a particular view of the metaphysical possibilities for accounting for causal efficacy. More specifically, all the evidence presented by Hume against the perceivability of efficacy appears to rest upon an underlying ontological assumption to the effect that efficacy must, if it exists, be a kind of nonrelational attribute had by particular material things. It is my contention that Hume was wrong about the metaphysical possibilities for accounting for the notion of efficacy. ;Accordingly, in part II, I develop a metaphysical account of the nature of efficacy which does not construe it as a property had separately by individual material things. Rather I argue that efficacy, or power, is correctly viewed as a physically real, irreducible, relational attribute shared jointly by material things. To make a long story short, on my account, causal occurrences are produced by the joint having by material things of a special kind of attribute, viz., a productive relation. The attribute is, by its very nature, a causal link between material things; it can only be exemplified by more than one thing and, in exemplifying it, materials things simply are causally connected