 The compatibility of functionalism and representationalism is not evident on its face, though a number of prominent contemporary philosophers appear to embrace both positions (e.g., Fodor 1968, 1975, 1981, 1990; Armstrong 1973; Harman 1973; Lycan 1981a, 1981b; Stalnaker 1984; Lewis 1994). As Millikan (1984), Papineau (1984), and others have suggested, it seems one thing to say that to believe is to be in a state that fills a particular causal role, and it seems quite another to say that beliefs are essentially states that represent how things stand in the world. How can something represent the world outside simply by virtue of playing a certain causal role in a cognitive system? Suppose, for example, that a state represents by virtue of having an indicator function of the sort described at the end of §1.1 above. The indicator function of an internal state or system would seem, at least sometimes and in part, to depend constitutively on the evolutionary history of that state or system, or its learning history, and not simply on the causal relationships it is currently disposed to enter. Despite the word “function” in “functionalism”, it’s not clear that standard functionalist accounts, limited as they are to appeal to a state’s actual, potential, or typical causal roles, can incorporate facts about a system’s evolutionary history or learning history: Conceivably, for example, two states in different individuals may have exactly analogous causal roles, yet differ in their (as Millikan says) “proper function” because of differences in the evolutionary or learning history of those systems.