[T]he degree of confirmation assigned to any given hypothesis is sensitive to properties of the entire belief system … simplicity, plausibility, and … - Jerry Fodor

FACULTY PSYCHOLOGY is getting to be respectable again after centuries of hanging around with phrenologists and other dubious types. By I mean, roughly , the view that many fundamentally different kinds of psychological mechanisms must be postulated in order to explain the facts of mental life . Faculty psychology takes seriously the apparent heterogeneity of the mental and is impressed by such prima facie differences as between, say, sensation and perception, volition and cognition, learning and remembering, or language and thought.

From the point of view of semantics, errors must be accidents: if in the extension of "horse" there are no cows, then it cannot be required for the meaning of "horse" that cows be called horses. On the other hand, if "horse" did not mean that which it means, and if it were an error for horses, it would never be possible for a cow to be called "horse." Putting the two things together, it can be seen that the possibility of falsely saying "this is a horse" presupposes the existence of a semantic basis for saying it truly, but not vice versa. If we put this in terms of the crude causal theory, the fact that cows cause one to say "horse" depends on the fact that horses cause one to say "horse"; but the fact that horses cause one to say "horse" does not depend on the fact that cows cause one to say "horse"...

When taken as a way of modeling cognitive architecture, really does represent an approach that is quite different from that of the classical cognitive science that it seeks to replace. Classical models of the mind were derived from the structure of Turing and Von Neumann machines. They are not, of course, committed to the details of these machines as exemplified in Turing's original formulation or in typical commercial computers—only to the basic idea that the kind of computing that is relevant to understanding cognition involves operations on symbols.. In contrast, connectionists propose to design systems that can exhibit intelligent behavior without storing, retrieving, or otherwise operating on structured symbolic expressions. The style of processing carried out in such models is thus strikingly unlike what goes on when conventional machines are computing some function.