|1. The methodological thesis: psychology should not make use of hypotheses about inner mental events. (Rejection of "mentalism," the idea that psychology should be the study of inner mental states.) This thesis is what Sober calls the negative thesis of methodological behaviorism.|
|first argument for the methodological thesis:
1. we must be able to conclusively verify any scientific hypothesis;
2. we can't conclusively verify hypotheses about inner states;
3. hypotheses about inner states are not scientific (and so shouldn't be the subject of a scientific psychology)
|Premise 1 is false. we don't conclusively verify scientific hypotheses; we employ "inference to the best explanation," i.e. abduction. (Notice that if conclusive verification were required, science couldn't make any claims about things we can't directly observe, including things like electrons and force fields.)|
|second argument for the methodological
mental states just mediate between stimulus and response;
we can ignore them and predict responses directly on the basis of stimuli
|Compare: a computer's program just mediates between input and output, so we can predict output directly on the basis of input. The antecedent is true, in a sense, but the consequent doesn't follow.|
|2. The linguistic thesis: mental terms refer to behaviors (or in more sophisticated versions, to dispositions to behave). This thesis is what Sober calls the positive thesis of "logical behaviorism."|
|argument for the linguistic thesis:
1. when we learn words, including words for mental states, we learn to associate them with observable phenomena (behavior, in the case of terms for mental states);
2. words refer to what we learn to associate them with; therefore,
3. words refer to observable phenomena (behavior, in the case of terms for mental states).
|we need to distinguish between (a) truth conditions and (b) verification conditions. Our evidence for most scientific phenomena is not directly the phenomenon itself, but rather other things that are caused by the phenomenon in question. (For example, our evidence for the existence of dinosaurs is dinosaur fossils, but it would be a mistake to infer that dinosaurs are nothing more than their fossils! It is a similar mistake to think that mental states are nothing more than behavior.) To relate this back to the argument at the left, premise 1 may be true but premise 2 is false. Words do not refer to whatever we learn to associate them with, because in many cases we learn to associate them with verification conditions, not truth conditions.|
|3. The metaphysical thesis: mental states are identical
with behaviors (or at least with sets of behaviors, or dispositions to behave, or
The linguistic thesis, if correct, would provide an argument for the metaphysical thesis: if words for mental states refer to behaviors or dispositions to behave, then mental states themselves are behaviors or dispositions to behave.
|Two kinds of objections:
(1) it seems possible to exhibit the behavior associated with a mental state without actually being in that state (consider very good actors);
(2) it seems possible to have a mental state without exhibiting any of the behavior associated with that state (consider Dennett's example about using curare plus an amnestic drug during surgery).