The semantic evaluation of a mental state is typically relational (e.g., whether beliefs about water are true depends on how things stand with water in the world).
The issue comes down to one concerning the individuation of mental states. How do we determine what is and is not the “same” belief? Fodor begins by introducing the constraint that he calls “methodological individualism,” viz., “the doctrine that psychological states are individuated with respect to their causal powers” (1987, 42). This implies, among other things, that if one psychological state is incapable of causing anything different to happen than some other psychological state, then the t