 The second component of the answer echoes one of the answers given to Heal: for a Simulation Theorist who conceives of ST as a theory in cognitive science, intuitions have a limited value in assessing a definition of “mental simulation of”. In fact, the main aim of this definition is not that of capturing folk intuitions, but rather that of offering a clear enough picture of the relation of mental simulation on the basis of which an adequate theory of mindreading can be built. So, if the proposed definition fails, say, to help distinguishing ST from TT, or is of limited use in theory-building, or is contradicted by certain important results from cognitive science, then one has a good reason to abandon it. On the contrary, it should not be a cause for concern if  RES+REU  does not match the folk concept MENTAL SIMULATION OF. The notion “mental simulation of” is a term of art—like, say, the notions of I-Language or of Curved Space. These notions do poorly match the folk concepts of language and space, but linguists and physicists do not take this to be a problem. The same applies to the notion of mental simulation.