This book is not written for posterity. It is meant to constitute part
of my contribution to a continuing debate at the intersection of the
philosophy of mind, the philosophy of language, epistemology, and the
philosophy of cognitive science. The debate is over how mental states
are individuated. Many philosophers, call them externalists (or anti-
individualists), believe that the individuation of mental states
requires appeal to an individual's social and/ or physical environment.
I am not among them; I am an internalist ( or individualist). This book
attempts to show that the leading proponents of externalism make a lot
of mistakes in defending their view. This is either because the view is
false, so any defense of it is bound to make some mistake or another, or
it is because the people defending externalism have not been very
careful, or both. I have included some introductory material so that
those not already familiar with the issues involved might nevertheless
gain entry into the debate. The intended audience, however, consists in
those professional philosophers and students of philosophy who are
already familiar with and interested in the question of how mental
states are individuated. I do not spend much time trying to motivate an
interest in this issue. Like all philosophy, it is interesting and
worthwhile if one is blessed (or cursed) with the appropriate kind of
intellectual curiosity. Those who do not meet this requirement proceed
at their own risk.