The Impact of Underdetermination on the Deliverances of Imagination and Intuition

What follows is an excerpt from the introduction of my master’s thesis in the History and Philosophy of Science, written in 2015. If you’re interested in the complete text, you can download the PDF here.

Introduction

The method of cases is a philosophical tool with a long history, dating back at least to the works of Plato. It allows to test a philosophical theory by conducting an experiment in thought alone. Let’s say you have a working theory of the philosophical concept of knowledge: what it means to know something is to have a justified, true belief. Now you test that theory by stipulating a scenario like the story of Smith and Jones from the original Gettier case, which fulfills all the requirements of the traditional theory of knowledge, but where most people still want to say that the subject S does not know that p. These judgments are what we would call intuitive, and much philosophical writing assumes that they are not just a trivial consequence of your background theory, but rather hold some evidential weight of their own. As such, our intuitive judgment in the stipulated case serves as counterevidence against the tested theory.

This method has been used for thousands of years, and very heavily so. We find examples in classic antiquity, like Plato’s description of Gyges’ ring; we find them throughout medieval scholastic philosophy, like Aquinas’ use of cannibals to get clear on the concept of resurrection; we find them in early modern philosophy, as with the Cartesian Demon; and of course we find examples abound in contemporary philosophy, such as the Gettier cases, stories of brains in vats and philosophical zombies. It is easy to see that the method of cases is at the heart of a lot of philosophical theorizing.

For a method so central to the practice of philosophy, one would expect its epistemological grounding to be well understood. Surprisingly, though, for the longest time its reliability was blindly taken for granted. Only recently, beginning in the late 1980s, the faculty of intuition, which is part of the method of cases has come under serious attack. Studies from what now falls under the rubric of ‘experimental philosophy’ have shown systematic variation in peoples’ intuitions, a result that very much threatens the reliability and objectivity of the faculty of intuition and by extension also the method of cases. What followed was a lively debate about the epistemology of intuition, which thrives to this day and deals with questions like: Are intuitions beliefs, or are they mental states sui generis? Are they evidence for deeper philosophical truths, or are they no more than individual psychological states without epistemic import? Is there a wholly rational and – so as not to beg the question – non-intuitive explanation for them having evidential weight and if not, how much of a problem is that? These are some of the issues that are central to the ongoing intuitions-debate.

In my thesis, I want to put the spotlight on another serious shortcoming of thought experiments: the inherent fact that each and every thought experiment can only provide a partial description of a possible world. What I hope to show is that this underdetermination of every thought experimental scenario opens up the method of cases to various objections. My strategy will be to analyze the debates revolving around two highly influential thought experiments and then demonstrate how each debate can be used to illuminate a different methodological problem. The common thread of these problems is that they are a direct consequence of the thought experiment giving only a partial description of a possible world.

None of these objections are entirely new. However, while some have been wrongfully ignored in the past, others have not been properly recognized for their implications for the method of cases. What my thesis would have to offer, then, is to connect these objections to the array of already existing issues facing the faculty of intuition and the method of cases.

Considering the central role of the method of cases in philosophical practice and the seriousness of the objections, I believe that my thesis offers fresh insights into a truly pressing methodological problem.