Function, Dysfunction, and the Concept of Mental Disorder

Naturalistic accounts of mental disorder aim to identify an objective basis for attributions of mental disorder. This goal is important for demarcating genuine mental disorders (e.g., schizophrenia, bipolar disorder) from artificial or socially constructed disorders (e.g., Drapetomania, homosexuality). The articulation of a demarcation criterion provides a means for assuring that attributions of 'mental disorder' are not merely pathologizing different forms of social deviance (or normal behavior). The most influential naturalistic and hybrid definitions of mental disorder (Boorse, 1976; Wakefield, 1992) identify biological dysfunction as the objective (i.e., factual) basis of mental disorders: genuine mental disorders are (necessarily) caused by biological dysfunction. There is disagreement regarding how to conceptualize the proper (or 'normal') mental functions that are disrupted in mental disorders.

In a rich and provocative article, Anne-Marie Gagné-Julien (2021) argues that the causal role (CR) account of function defended by Robert Cummins (1975, 1983) can provide an objective foundation for the concept of mental disorder. Compared to Boorse's and Wakefield's (allegedly) value-free accounts of function, Gagné-Julien's account is explicitly value-laden insofar as it acknowledges the values and interests involved in ascriptions of function. She argues that this normative account of function can provide an objective basis for judgments of dysfunction (and hence, mental disorder) if it satisfies the social rules of objectivity articulated by Anna Alexandrova (2017, 2018). Gagné-Julien's article is a welcome contribution to the literature on defining mental disorder, especially in its rejection of the anachronistic ideal of objectivity as value-freedom and application of an alternative social account. However, her resulting account of 'objective function' fails to yield the concrete kind of criterion required to address the demarcation problem.

The social objectivity that Gagné-Julien suggests normative accounts of function can achieve fails to directly address the problem of demarcating genuine mental disorders. Theorists who define mental disorder in terms of biological dysfunction aim to provide a clear and concrete criterion that distinguishes functional from dysfunctional mental traits. Gagné-Julien's analysis fails to present such a criterion. In particular, her CR account of function fails to specify a clear standard of 'proper function,' which is needed to distinguish functional from dysfunctional mental capacities. Gagné-Julien endorses the CR account defended by Cummins (1975), which conceptualizes functions as causal contributions of a component part to a capacity of a larger system. Taken in its generic form, a problem with Cummins's CR account is that—without specifying the higher goals of a system—it cannot identify the 'proper' (or 'normal') functions of systems and generates numerous pseudo-functions (Griffiths, 1993; Millikan, 1989; Neander, 1991). This difficulty arises because CR functions are interest-relative insofar as scientists choose to analyze capacities that are relevant to their fields of study (Amundson & Lauder, 1994). Because Gagné-Julien is interested in functions relevant for mental health, she needs to indicate what the higher goals of proper ('healthy') mental functions are (i.e., mental capacities for what?). As a point of contrast, Boorse (1977) endorses a CR account that assumes that—relative to the interests of medicine—survival and reproduction are the highest goals of human organisms (pp. 555–556).¹ Accordingly, the proper (or 'natural') function of a biological part is its statistically typical ('normal') causal contribution to an organism's (current) capacity to survive or reproduce. Regardless of whether this is the right account of function relevant for health, it offers a concrete criterion that can distinguish functional mental capacities (i.e., causal contributions to biological fitness) from dysfunctional mental capacities (i.e., internal states that disturb these functions). The social account of objectivity that Gagné-Julien presents as constraining her favored CR account does not yield a concrete criterion of this sort. Rather, Alexandrova's analysis suggests that an objective theory of mental capacities should satisfy certain social conditions that ensure that the value presuppositions of the theory are subjected to critical scrutiny.

These considerations highlight the fact that Gagné-Julien's analysis and Boorse and Wakefield's analyses assume incommensurable ideals of objectivity, which are suitable for different philosophical...