Abstract

1. Reflecting on possible cases can be very valuable in differing ways. Sometimes it makes clear a consequence of a theory, a consequence that then plays an important role in debates about the theory. Utilitarians who favour maximising average happiness confront utilitarians who favour maximising total happiness with possible cases where there are enormously many sentient beings whose lives are barely worth living. Sometimes reflecting on possible cases serves to clarify a doctrine. Classical versions of consequentialism value equity for its good results; they don't value it per se. What this means is that in cases where we have two actions alike in the value of their consequences but differing in that one delivers a more equitable distribution, classical consequentialism treats the two actions as morally equivalent. Sometimes reflections on possible cases reveal relationships that are not immediately obvious. Take Galileo's famous thought experiment directed against the view that the heavier a body is the faster it falls in a vacuum. He describes a possible case where the only way to retain the view requires embracing independently implausible views about how various ways two bodies are connected to each other make a big difference to how fast the joined bodies fall. The thought experiment reveals a connection that might otherwise escape notice.This reminds us that we should not expect a uniform answer to the question, What role do thought experiments play? However, it is conventional wisdom that very often their role is to make trouble for one or another proffered conceptual analysis. Take two thought experiments that have been found especially compelling by the analytical philosophical community: Edmund Gettier's examples of true, justified belief, where the beliefs are true by some kind of fluke, and Ned Block's example of a being that makes ‘intelligent’ responses to the challenges the …