Thought experiments rethought - and reperceived

Contemplating imaginary scenarios that evoke certain sorts of quasi-sensory intuitions may bring us to new beliefs about contingent features of the natural world. These beliefs may be produced quasi-observation ally; the presence of a mental image may play a crucial cognitive role in the formation of the belief in question. And this albeit fallible quasi-observational belief-forming mechanism may, in certain contexts, be sufficiently reliable to count as a source of justification. This sheds light on the central puzzle surrounding scientific thought experiment, which is how contemplation of an imaginary scenario can lead to new knowledge about contingent features of the natural world.