Abstract

In this dissertation, I attempt to understand Joseph Priestley's scientific beliefs. I describe his scientific practices, for the purpose of showing how they shed light on two key issues in philosophy of science: scientific explanation and hypothesis confirmation. I discuss these matters in the historical context of the eighteenth-century Chemical Revolution. ;In the first chapter, I discuss Priestley's view of causation and reconstruct his account of explanation as a species of what is now called 'contrastive' explanation. A contrastive explanation attempts to answer a why-question of the kind Why E rather than E$\sp\prime$? ;In the second chapter, I show that although the eighteenth-century chemists provided a remarkably coherent account of three chemical concepts viz. chemical element, chemical property, and chemical operation, they failed to offer any non-question-begging criterion which could be employed to distinguish these concepts from the corresponding mechanical concepts. ;In the third chapter, I argue that Priestley's chemical beliefs were similar to that of Antoine Lavoisier. Both were Stahlian chemists. Both accepted the identification of chemical properties with chemical reactivities, as a way to distinguish chemical substances from one another. However, I argue, Priestley's theory of matter was different from that of Lavoisier. This led him to reject Lavoisier's employment of the Principle of Conservation of Mass in establishing the chemical simplicity of certain substances. ;In the fourth chapter, I analyze Lavoisier's argument for the claim that water is a chemical compound and Priestley's refutation of it. I show the complex nature of these arguments and point out how each argument draws on various resources which might appear far removed from the answers to the local question involving the nature of water. ;In the last chapter, I first develop what I construe to be a distinction between evidence and data. I then show Priestley's inferential practices to be a species of Inference to the Best Causal Explanation. I propose some ways to evaluate the adequacies of competing causal explanations. I also consider the inadequacies of hypothetico-deductive and Bayesian accounts of hypothesis confirmation