The glass vase on my desk is fragile. It should be handled with care because it it is likely to shatter or crack if it is knocked, dropped, or otherwise treated roughly. The vase has certain dispositions, for example the disposition to shatter when dropped. But what is this disposition? It seems on the one hand to be a perfectly real property, a genuine respect of similarity common to glass vases, china cups, ancient manuscripts, and anything else fragile. Yet on (...) the other hand my vase's disposition seems mysterious, "ethereal" (as Nelson Goodman (1954) put it) in a way that, say, its size and shape properties are not. For my vase's disposition, it seems, has to do only with its possibly shattering in certain conditions, conditions which I hope will never be realized. In general, it seems that nothing about the actual behavior of an object is ever necessary for it to have the dispositions it has. Many objects differ from each other with respect to their dispositions in virtue of their merely possible behavior, and this is a mysterious way for objects to differ. (shrink)

Many recently released Hollywood films feature superheroes like Superman, Ironman, the Hulk, Optimus Prime, and so on who possess amazing superpower and defeat supervillains with unassailable commitment to moral justice. Interestingly, different superheroes possess and exercise their superpower in very different fashions. What is more, this aspect of their difference is intimately related to an issue that is lately in intense debate among metaphysicians of powers and dispositions, the issue of the possibility of intrinsic interferers with dispositions. This paper will (...) argue that a strong case can be made against this possibility when we give due weight to the commonsensical understanding of superheroes and their superpower. Whilst other arguments have been raised against the possibility of intrinsic interferers with dispositions in the latest literature, this will present further difficulties for those who accept it. (shrink)