Abstract

How can an experiment which occurs only in thought lead to new and accurate conclusions about the world beyond thought? What makes thought experiments relevant to the domains they are designed to explore? ;One answer is that successful thought experiments are grounded. Explaining the nature of this grounding relationship, especially as it applies to ethics, is the main task of this dissertation. ;A thought experiment is an experiment that occurs in thought. The "thought" label distinguishes it from an ordinary physical experiment, while the "experiment" label distinguishes it from other types of merely analogical, conjectural, or hypothetical reasoning. Many of the components that are necessary for a successful physical experiment are also necessary for a successful thought experiment. A thought experiment, like a physical experiment, must isolate and vary variables in order to answer a question within a given theoretical context. The result of the experiment has repercussions for its theoretical context. ;The grounding relationship holds between the components of the thought experiment and the theoretical context of the thought experiment. In order for the thought experiment to be successful, both the experimental set-up and our responses to it need to be grounded in the thought experiment's theoretical context. ;An experimental set-up will be grounded whenever it meets the following conditions. The concepts used must be defined normally, dependent and independent variables must be isolated and relevantly related, and the propositions of the thought experiment must be relevantly related to the given theoretical context and the question under examination. ;Grounding responses to thought experiments will then be largely a matter of anticipating and disarming distorting influences. Factors influencing responses include the individual's knowledge of the theoretical context, the state of development of that context, the nature of the presentation of the thought experiment, and subjective filters. ;It is sometimes difficult to ascertain whether a thought experiment in ethics is grounded. This is largely due to the nature of the theoretical context of thought experiments in ethics. In order to assess the relationship of thought experiments in ethics to their theoretical context, I advocate employing a contextualist methodology involving the process of wide reflective equilibrium. While contextualists use this approach to arrive at considered judgements relating to specific ethical problems, I show that wide reflective equilibrium can also be used to examine the grounding of thought experiments. ;I conclude the dissertation with an examination of the relationship of thought experiments to computer simulations, a study of various common thought experiment distortions, and some tests and methods designed to aid constructing successful thought experiments