NORMAL INABILITY VERSUS PATHOLOGICAL DISABILITY - WHY OSSORIOS DEFINITION OF MENTAL DISORDER IS NOT SUFFICIENT

Ossorio's proposed definition of mental disorder as ''inability to eng age in deliberate action'' is evaluated and compared to Wakefield's an alysis of mental disorder as ''harmful dysfunction.'' Ossorio's defini tion is found to be neither necessary nor sufficient for disorder. The most severe problem is its extreme overinclusiveness; normal mental f unctioning includes many restrictions on deliberate action, and entire nonpathological domains, such as ignorance and lack of skill, are enc ompassed within Ossorio's definition. Bergner's attempt to defend Osso rio's definition through various construals of its clauses is found to be ad hoc and unsuccessful. It is argued that the harmful dysfunction analysis adequately explains the shared classificatory judgments abou t disorder and nondisorder that Ossorio's definition fails to explain, and that Bergner's ''epistemological'' objection to the harmful dysfu nction analysis is invalid.