- Evidence-Based Medicine and Evaluativism
Philosophy, psychiatry, values, causal
The rise of evidence-based medicine (EBM) in psychiatry has brought, in its train, a concentration on the validity of psychiatric taxonomy to augment the previous focus on reliability (in the medical sense of inter-subject agreement). This is not surprising. If EBM is to be a trustworthy guide to future events, such as patient recovery, it must be based on projectible predicates (Goodman 1983). Not all the predicates that apparently fit past observations would produce true predictions for the future. Furthermore, there is reason to think that employing projectible predicates goes a long way to satisfy the (widespread if contested) aim of being based on a nomological science (Papineau 1986). Thus, the successful implementation of EBM within psychiatry requires the successful articulation of a valid psychiatric taxonomy.
This connection helps to explain why fears about the application of EBM to psychiatry often turn on fears about the application of the criteriological model of diagnosis to individuals. In her commentary in this issue, Gloria Ayob has examined some of the arguments concerning the application of EBM to individuals. In this brief commentary, I examine a different potential source of disquiet focused on the underlying nature of psychiatric taxonomy.
Dimensions for Psychiatric Taxonomy
In their recent paper, Peter Zachar and Kenneth Kendler suggest a number of different dimensions according to which rival conceptions of psychiatric taxonomy can be mapped. These include (1) causalism–descriptivism, (2) essentialism– nominalism, (3) objectivism–evaluativism, (4) internalism–externalism, (5) entities–agents, and (6) categories–continua (2007, 557). At the heart of the objectivism-evaluativism dimension is the question:
Is deciding whether or not something is a psychiatric disorder a simple factual matterY (objectivism), or does it inevitably involve a value-laden judgment (evaluativism)?(Zachar and Kendler 2007, 558)
Objectivists argue that the concept of disorder is a simple or plain factual matter by contrast with an evaluation. The apparently evaluative connotations of disorder, they argue, can either be reduced to, or explained away in, more basic terms, which are not themselves essentially evaluative. Thus, for example, the attempt to explain disorder in statistical terms is a form of objectivism. The more plausible attempt to explain disorder through the idea of a biological or proper function is also usually presented as a form of objectivism. (The most famous proponent of a biological approach, however, Jerome Wakefield, adds to an objectivist-aspiring core an explicit value in the form of harm [End Page 175] [Wakefield 1999].) Whether or not it can be successful as a form of objectivism, in addition to whether an analysis in biological terms is possible, depends on whether the account of function can fully discharge any initial evaluative or normative assumptions.
There seems to be good evidence that current psychiatric taxonomy, at least, contains values. John Sadler, for example, makes a powerful case for this in his substantial work Values and Psychiatric Diagnosis (2005). Sadler, furthermore, addresses in some detail a further set of questions concerning the kinds and nature of the values involved. I outline just one further question about the nature of values involved.
Zachar and Kendler contrast the presence of values with objectivism. Objectivity has at least two relevant senses reflecting contrasts with two senses of subjectivity. It—objectivity—might mean requiring no special subject for the conception and framing of relevant judgments. (This mirrors primary, by contrast with secondary qualities, and Williams' idea of an absolute conception [Williams 1978]). Or, it might mean disciplining and providing a contrast between correctness and incorrectness, or truth and falsity, for the relevant judgments. This contrasts with subjective whimsy.
Although it seems relatively straight forward that the conception and framing of value judgments requires that subjects have a particular kind of mind, that still leaves open the other issue. Are value judgments disciplined by anything or does the "truth" of a value judgment collapse back into its being sincerely made?
Evaluativism in Psychiatric Taxonomy and EBM
This question relates to the application of EBM to psychiatry in this way. On a disciplined account, psychiatric taxonomy can aim to get right the mixture or, better, the compound of simple facts and values...