Philosophy, Psychiatry, & Psychology

In 1960 Szasz argued that the concept of mental illness lacked literal meaning, that there was no such objective entity as mental illness and that the use of the concept (a use which could only be seen as metaphorical) had serious bad practical consequences (Szasz 1960). A key assumption made by Szasz, and one shared by several writers, was that the meaning of the concept of physical illness is transparent. In recent work Fulford has rightly challenged this assumption, arguing that in fact the meaning of this concept is no clearer than that of mental illness. In developing his own position, Fulford has argued that evaluation is central to both concepts, and that attention to this point reveals that the concept of mental illness constitutes a better starting point for getting clear on the notion of illness as a whole insofar as it contains a more overt evaluative element. From this perspective he is then able to consider whether illness should be seen as a failure of function, a much discussed issue. Here Fulford’s suggestion is that we should distinguish disease, which is naturally analyzed in terms of failure of function (in line with the conventional medical model), from illness, which is naturally analyzed in terms of failure of action (Fulford 1989; 1992; 1995).

Szasz seems to have had two serious practical concerns motivating his view that the concept of mental illness lacks literal meaning. These concerns were the abuse of psychiatric powers and the misuse of drug therapy. This paper has two main aims. One is to show that it is possible to provide an analysis of the concept of mental illness [End Page 187] which can accommodate Szasz’s concerns. The second is to argue, against Fulford and others, that the concept is best analyzed in terms of failure of function. Thus while Fulford’s approach is a significant advance on that of Boorse, Kendell, and Szasz, it has still conceded too much in analyzing the distinction between illness and disease as a distinction between failure in function, on the one hand, and failure in action on the other (Boorse 1975; Kendell 1975; Szasz 1960); this in turn leads to an unduly sharp distinction between the concept of physical illness and that of mental illness. By contrast, it will be argued that the claim that the concept of mental illness contains a more overt evaluative element than that of physical illness is misleading, and while it is broadly correct to locate mental illness as related to failure in intentional action, such a failure can itself be understood as a failure of function.

In developing these points, it is argued in the paper that the concept of mental illness can be satisfactorily clarified if, and only if, the concept is related it to an Aristotelian conception of human nature. Doing this explains the way that mental illness (like physical illness) is fundamentally a failure of function, and in what sense both the concept of illness and that of function are evaluative. (The importance of this clarification is clear since Szasz moves from the observation that mental illness is an evaluative...