Thought experiments and mental simulations

Thought experiments have a mysterious way of informing us about the world, apparently without examining it, yet with a great degree of certainty. It is tempting to try to explain this capacity by making use of the idea that in thought experiments, the mind somehow simulates the processes about which it reaches conclusions. Here, I test this idea. I argue that when they predict the outcomes of hypothetical physical situations, thought experiments cannot simulate physical processes. They use mental models, which should not be confused with process-driven simulations. A convincing case can be made that thought experiments about hypothetical mental processes are mental simulations. Concerning moral thought experiments, I argue that construing them as simulations of mental processes favours certain moral theories over others. The scope of mental simulation in thought experiments is primarily limited by the constraint of relevant similarity on source and target processes: on one hand, this constraint disqualifies thought from simulating external natural processes; on the other hand, it is a source of epistemic bias in moral thought experiments. In view of these results, I conclude that thought experiments and mental simulations cannot be assimilated as means of acquiring knowledge.