the principle is learned, we
will know that the kind of
brain event we should expect to
find to explain the shadow
effect will be one encompassing
the storage of a learned
principle. If we finally do find
the neural correlate of this
effect, we would still retain the
principle as part of the
explanation. If we discarded
the principle, the brain event,
couched solely in the language
of neural discharge, would
have little meaning.

    I believe that only in rare
instances do we have an
inkling of the physiological
brain event underlying
perception. In the chapters
that follow, therefore, I will
not be talking very much about
brain mechanisms but instead
will explore explanations of
perception couched in
functional terms—–namely,
what kind of process can be
occurring that would explain
the type of perception in
question.