What the classical aphasia categories can't do for us, and why.

A good deal of activity in contemporary aphasia research goes under the label "neurolinguistics." What characterizes this enterprise is, among other things, its goal of identifying neurally realized computational subsystems that support language processing. In this essay the thesis is put forward that this goal will not be served by the continued exploitation of the classical (Wernicke-Lichtheim) taxonomic categories. These categories, it is argued, cannot by virtue of their "polytypic" structure support the relevant neurolinguistic generalizations.