Recent philosophical discussions of our capacity to attribute mental states to other human beings, and to produce accurate predictions and informative explanations of their behavior which make reference to the content of those states have focused on two apparently contrasting ways in which we might hope to account for these abilities. The first is that of regarding our competence as being under-girded by our grasp of a tacit psychological theory. The second builds on the idea that in trying to get (...) a grip on the mental lives of others we might be able to draw on the fact that we are ourselves subjects of mental states in order to simulate their mental processes. Call these the theory view and the simulation view. In this paper I wish to discuss an argument—which I shall call Collapse—to the effect that if our capacities can be explained in the way that the simulationist supposes then they can also be explained along lines that the advocate of the theory view favours. I am not the first person with simulationist sympathies to have addressed this argument. However, my response is somewhat less concessive than others in the literature: while they attempt to soften its force by attempting to reformulate the simulationist view in a way that evades the conclusion of the argument, I attempt to meet it head on and to show that it does not even succeed in refuting the version of simulationism which it takes as its target. (shrink)