In the opening pages of ‘Sensations and Brain Processes’, Smart discusses four very different views about what one is doing when one says things like “I have a yellowish-orange after image”:
Ultimately, Smart finds each of the first three options wanting. He rejects the idea that sensations are irreducibly psychical on grounds of parsimony, and because they would be ‘nomological danglers’. He rejects the behaviorist view on the grounds that after-image sensations, unlike (perhaps) pain sensations are not associated with a stable class of behavioral dispositions. He rejects the expressivist view on the grounds that when we report after-images we are genuinely reporting something.
This leaves the view that we are reporting a brain process as the only view standing. Our next step is to understand what that view involves.
Smart describes his view of sensations as follows:
“Let me first try to state more accurately the thesis that sensations are brain processes. It is not the thesis that, for example, ‘after-image’ or ‘ache’ means the same as ‘brain process of sort X’ ...It is that, in so far as ‘after-image’ or ‘ache’ is a report of a process, it is a report of a process which happens to be a brain process. ...All it claims is that in so far as a sensation statement is a report of something, that something is in fact a brain process. Sensations are nothing over and above brain processes ...
When I say that a sensation is a brain process or that lightning is an electric discharge, I am using ‘is’ in the sense of strict identity. ...When I say that a sensation is a brain process or that lightning is an electric discharge I do not mean just that the sensation is somehow spatially or temporally continuous with the brain process or that lightning is just spatially or temporally continuous with the discharge.” (144-5)
After presenting the theory, Smart turns to a series of replies to what he takes to be the most pressing objections to the theory. We will discuss the following objections: