Thought experiments play an important epistemic, rhetorical and didactic function in Galileo’s dialogues. In some cases, Salviati, Sagredo and Simplicio agree about what would happen in an imaginary scenario and try to understand whether the predicted outcome is compatible with their respective theoretical assumptions. There are, however, also situations in which the predictions of the three interlocutors turn out to be theory-laden. Salviati, Sagredo and Simplicio not only disagree about what would happen, but they reject each other’s solutions as question-begging (...) and somtimes even dismiss each other’s thought experiments as misleading or nonsensical. (shrink)