Two ways of imagining Galileo's experiment

Thought experiments provide a conspicuous case study for epistemologists of the imagination. Galileo’s famous thought experiment about falling stones is a central example in the debate about how thought experiments in science work. According to a standard interpretation, the thought experiment poses a challenge to an Aristotelian principle about falling bodies that conceives of bodies in an extremely liberal way. This chapter argues that this interpretation is implausible and then shows how the thought experiment might present a challenge to a principle that conceives of bodies in a less permissive, more plausible way. The new interpretation of the thought experiment relies on a distinction between two ways of imagining Galileo’s experiment, one of which requires Aristotelians to temporarily ignore their belief in the principle under challenge. It is suggested that the distinction tracks an increasingly familiar distinction among dual-process theories in psychology: ‘intuitive’ and ‘reflective’ imagination. In order for Aristotelians to appreciate the thought experiment’s challenge to their theory, they are expected to use their intuitive imagination and not just their reflective imagination.