I agree that the brain is the basis of all the things that we have described as behavior in this class. Some things, however, can be accounted for by the brain more easily than others--such as physical actions, as opposed to non-observable behavior. Electrical stimulation of a certain region of the brain may result in the twitch of a certain muscle. But how is one to observe how abstract things like feelings/emotion are produced if it can only be acknowledged by the individual having those feelings? I guess if the person were conscious during experimentation, he or she would be able to articulate whatever thoughts or emotions were experienced at whatever probings, but emotions (as well as the meanings that are attached to words that describe them) are so subjective; I think it would be hard to reproduce the results of such an experiment, using different individuals. The act of believing is another thing that I think might be hard to account for.
Nice issue, and very important one: can one study things which are "subjective"?, i.e. things where what is to be accounted for is something which can be known only from the verbal report of a person? Hope we'll get a chance to talk about that in the course, since it comes up in a variety of important contexts. PG