Folk Psychology and Neurophilosophy
The Churchlands started working upward from neuroscience to a unified theory of the mind in the 1970s—a time when physicalists discussed how mental states could be brain states or how subjective experience could be accounted for—but as the Churchlands saw it, without adequate reference to computational neuroscience.
Think of the brain in terms of neurally coded information vectors—nothing resembling folk-psychological statements. Perception is a matter of vector processing; what moves through the brain’s perceptual processing streams is vector- encoded information. The language of the brain is not a language of thought with propositions that resemble our folk-psychological propositions; it is a language of mathematics. We are to take Galileo’s statement that the book of nature is written in mathematics seriously, and we are to apply it to neuroscience and the philosophy of mind.
Folk Psychology and Unity of Science
One view of science is that we ought to strive for a single unifying theory. In this view, biology can be reduced to chemistry, which can be reduced to physics. A similar story can be told for other branches of scientific inquiry: they all reduce to physics. But where does folk psychology fit into this picture? Any attempt to integrate it—any attempt to reduce it to physics—seems to fail. But that folk psychology discords with our modern scientific world picture is unsurprising. Isn’t that the case with all folk theories? So far, no folk theories have turned out to be true. According to the Churchlands, folk psychology is likely to be false as well. Folk sciences are, sooner or later, replaced by real science, as we have seen in the cases of folk chemistry, folk physics, and folk astronomy.
Folk psychology will be replaced by neuroscientific theory. If folk psychology is right—the eliminative materialist argues—then it should be reducible to neuroscience, just like biology is reducible to chemistry and chemistry is reducible to physics.