Abstract

The aim of this work is to identify and characterize the fundamental causal/explanatory entities in nature. Chapter One criticizes the methodology of much of the recent work on laws of nature, which consists of analyzing our concept of a law with thought-experiments. This procedure faces two objections. Firstly, such thought-experiments beg the questions they are intended to answer, due to the weakness of our grip on the concept of a law. Secondly, the conceptual approach to laws is misconceived: the concept of a law plays no significant role in science, and if it plays a role in philosophy, that is an accident of history that lacks rational justification. Chapter two considers symmetry as a possible surrogate for laws of nature and, specifically, clarifies the role of symmetry in, or its relation to, conservation laws, Curie's principle, the historical development of theories in high-energy physics, and gauge theories. The over-all conclusion is that, contrary to many physicists, symmetries are not the fundamental explanatory facts. Chapter Three begins with a clean slate and argues that the explanation of any event is to be found in the dispositional properties of the entities that participate in it. Firstly it is shown that much of scientific methodology is naturally understood as the study of dispositions, and that the characteristic results of scientific inquiry---its "laws"---can be understood as making claims about objects' essential dispositions. Secondly, I argue against empiricist analyses that dispositions must be understood realistically as relatively stable properties. Chapter Four criticizes law-based theories of explanation for assuming a determinate and empirically meaningful notion of laws, and outlines instead a theory of dispositional explanation, describing some of the varieties of dispositional explanation and showing how dispositions themselves are explained: the dispositions of compound objects are explained by reference to the dispositions of their constituent parts, but we cannot explain the dispositions of simple entities except to attribute them to the essential natures of such objects