Imaginary Exceptions : On the Powers and Limits of Thought Experiment

Thought experiment is one of the most widely-used and least understood techniques in philosophy. A thought experiment is a process of reasoning carried out within the context of a well-articulated imaginary scenario in order to answer a specific question about a non-imaginary situation. The aim of my dissertation is to show that both the powers and the limits of this methodology can be traced to the fact that when the contemplation of an imaginary scenario brings us to new knowledge, it does so by forcing us to make sense of exceptional cases. The dissertation has five chapters: an introduction, three case studies and a conclusion. My main contention is that certain patterns of features which coincide only fortuitously may nonetheless play a central role in the organization of our concepts, and that to the extent that imaginary scenarios involve disruptions of these patterns, our first-order judgments about them are often distorted or even inverted. In the introduction and conclusion, I discuss the role of imaginary exceptions in the acquisition of new knowledge. I argue that appeal to imaginary cases is unavoidable because the world is neither maximally replete nor effortlessly navigable, and that appeal to exceptional cases is indispensable if we wish to avoid mistaking accidental regularities for regularities that reflect deeper truths about the world. In the first case study, I discuss a famous thought experiment of Galileo’s, and I try to show that the guided contemplation of an imaginary scenario can provide us with new scientific knowledge in a way that argument alone cannot. In the second