 On the other hand, some functionalists—here, too, both a priori and empirical—consider realizer functionalism to be in a better position than role functionalism to explain the causal efficacy of the mental. If I stub my toe and wince, we believe that my toe stubbing causes my pain, which in turn causes my wincing. But, some have argued (Malcolm 1968; Kim 1989, 1998), if pain is realized in me by some neural event-type, then insofar as there are purely physical law-like generalizations linking events of that type with wincings, one can give a complete causal explanation of my wincing by citing the occurrence of that neural event (and the properties by virtue of which it figures in those laws). And thus it seems that the higher-level role properties of that event are causally irrelevant. This is known as the “causal exclusion problem”, which is claimed to arise not just for functional role properties, but for dispositional properties in general (Prior, Pargetter, and Jackson 1982)—and indeed for any sort of mental states or properties not type-identical to those invoked in physical laws. This problem will be discussed further in Section 5.2.