Biological Approaches to Mental Representation 555can see the important intentional generalizations.
On this view, neuroscience is a non-intentional science. We often see this view
expressed in philosophy of mind. Consider, for example, Stephan Schiffer’s puzzle
over Ava, who is about to cross the street when she sees a car coming and steps
back to the curb. As Schiffer remarks, there was within Ava an unbroken chain
of neural events, beginning with the stimulation of receptor cells in her eyes by
light reflected from the oncoming car and ending with her stepping back. Each of
these neural events was a cause of the one following it and so of her stepping back.
This, Schiffer says, conforms to certain laws:
As these laws are laws of neurophysiology, laws that pertain to the elec-
trochemical properties of the neural events they subsume, this premise
implies that there is a sufficient explanation of Ava’s stepping back
wholly within the language of physical science. [Schiffer, 1987, 146–7]What need is there, Schiffer goes on to ask, for an explanation in intentional terms?
What explanatory role can representational properties play? Note that Schiffer
is not questioning the need for neurophysiological explanations in the face of the
in-principle sufficiency of more basic physical explanations, he is questioning the
need for intentional explanations, in the face of the sufficiency of neurophysiologi-
cal explanations, on the assumption that neurophysiological explanations are not
intentional.
The same assumption crops up in early arguments for eliminative materialism by
Paul Churchland. Churchland [1981], for example, argues that folk psychology is
a moribund research program and suggests that it might ultimately be replaced by
mature neuroscience. Folk psychology is the psychology we learn in the schoolyard
rather than in the schoolroom; it is our ordinary everyday understanding of minds,
commonsensical rather than scientific. Churchland argues that there is much about
the mind on which folk psychology is silent. It cannot explain mental illness, the
function of dreams, pre-linguistic learning, or the formation of a 3D visual image
from a 2D retinal array.
He argues that it is, in the terms of Imre Lakatos, a barren and stagnant research
project, one that has made no progress for thousands of years. Folk psychological
terms, such as “belief”, “desire”, “judgment” and “knowledge” are, he maintains,
defined by their role in the predictive and explanatory laws of folk psychology
— the laws, such as they are, that are used “in the market place” to explain and
predict human behavior. Since this body of laws could prove to be radically wrong,
the categories defined in terms of them could turn out to have no home in mature
scientific psychology.
This is considered a central argument for eliminative materialism, and more
specifically for the claim that talk of intentional mental states might be eliminated
from science. However, this is only an argument for eliminative materialism on
the assumption that neuroscience itself is non-intentional. If it were intentional,
then the ascendance of neuroscience would be a vindication of intentional realism.