# 3.3.4: Functionalism

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Belief is the spring of action. We explain people’s actions in terms of their mental states. People do what they do because of what they believe, desire, fear, hope for, and so forth. The behaviorists were on to something in thinking about mental states in terms of dispositions. But recall that the behaviorists were looking for a way to analyze talk about mental states entirely in terms of observable things like behavior. They wanted to avoid positing unobservable things going on in the head. Talk of dispositions for the behaviorists was not talk of underlying and possibly unobservable brain states that give rise to behavior. Rather it was merely talk of tendencies that might allow us to understand mental state terms as synonymous with complex “if. . . then. . .” conditional statements. The behaviorists sought a way to avoid understand mental terms as referring to unobservable things going on in the head. To many, taking the mental out of the head seemed a problematic feature of behaviorism. But this is just what behaviorists set out to do, understand talk of the mental in public, observable terms.

The functionalists would understand talk of mental dispositions differently. To have a mental disposition is not, by definition, just to satisfy a certain “if . . ., then. . .” claim. Rather, to be in a mental state is to be in some underlying state, perhaps unobservable, that fulfills a certain functional role. The molecular structure that makes the spring flexible might not be observable to us. But for the spring to be flexible, for it to have this disposition, is for it to be in some underlying state that makes the spring such that if we exert a force on it, it will bend and absorb that energy. We can call that underlying state that accounts for something having a disposition the causal basis of the disposition. With this idea in hand, we can mark a difference in how a behaviorist and a functionalist would understand the idea of a disposition. For the behaviorist, talking of mental states as dispositions does not involve the attribution of any causal basis, it only gives us a way of translating talk of the mental into talk of observable behavior by means of complicated “if . . ., then . . .” statements. For functionalism, on the other hand, talking of mental states as dispositions does involve attributing underlying causal base properties. To be in a mental state is to have some underlying causal basis for behaving in this way if these conditions are met, or behaving in that way if those conditions are met, etc.

Given this differing treatment of talk of mental dispositions, the functionalist avoids a problem we raised for behaviorism. We seem to understand what it means to believe that Obama was president in 2002. But if this mental state attribution is really just a shorthand way of expressing a complex behavioral disposition, then we ought to be able to fill in the associated “if . . then . . .” claim. But we can’t. So talk of mental states can’t simply be regarded as synonymous with talk of behavioral dispositions. Unlike the behaviorist, the functionalist is not trying to define away talk of the mental in terms of talk of observable behavior. The functionalist is happy to leave the mental in the head. Talk of behavioral dispositions don’t define mental terms for the functionalist, they rather provide a means for specifying what it is for an underlying brain state to realize, or be a causal basis for, a mental state type.

We were lead to functionalism by the idea that a given mental state might be realized by various different states in different brains. This suggests a physicalist interpretation of functionalism, a view that insists that mental states are realized by physical states. But note that functionalism needn’t be restricted in this way. Any state, physical or otherwise, can realize a mental state so long as it fulfills the appropriate role. Being guided by spirits in the appropriate way might, in principle, be the causal basis for having a certain mental disposition. So, strictly speaking, unlike the brain state identity theory, functionalism is not committed to physicalism, the view that the mental is ultimately physical. One could be a functionalist about mental states and a Cartesian dualist.