Mild Cognitive Impairment: Which Kind Is It?

There is much stimulating material in the Graham and Ritchie's paper (2006), concerning not just disease-classification but also the ethics of diagnosis. My concern is with the way in which they adduce Ian Hacking's views in the philosophy of science in support of their own. The authors quote with approval his "dynamic nominalism" and its influence on Zachar's concept of "practical kinds." Hacking's view, as the authors quote it, is that "People classified in a certain way tend to conform to or grow into the ways that they are described; but they also evolve in their own ways, so that the classifications and descriptions have to be constantly revised" (1995, 21). The act of classifying changes both the classifier and the subject of classification, resulting in facts and categories that are both socially created and real. Hacking calls this "the looping effect of human kinds," and comments that "Multiple personality [disorder] is an almost too perfect illustration of this feedback effect" (1995, 21). The authors comment that Zachar (2000) builds on Hacking's position, discarding essentialist notions of classification that are limited to inherent biological properties, and turning instead to "practical kinds—nonarbitrary cultural artifacts intended to meet pragmatic needs (e.g. therapeutic, predictive prognostic, labeling effects, and physiology)" (Graham and Ritchie 2006, 36). Practical kinds, they believe, offer a way out of the clinical approach focused on mild cognitive impairment (MCI) as a precursor to, or mild form of, Alzheimer's disease. The inclination of the authors, as I read them, is to treat MCI as a practical or human kind, and not, like Alzheimer's disease, as a natural kind.

My concern is whether the "looping effect of human kinds" can be transferred to the case of MCI from Hacking's original case study in Rewriting the Soul, multiple personality disorder (MPD). Hacking wished there to undermine the traditional debate over whether MPD is a "social or psychiatric artifact." He claims, correctly I think, that the presupposition behind the question "Is MPD a real disorder as opposed to a product of social circumstances?" should be rejected. The fact that a disorder is a product of social circumstances does not make it less real (1995, 12). On the looping of human kinds, Hacking comments that "The concept of child abuse [implicated in MPD] may itself be so made and molded by attempts at knowledge and intervention, and social reaction to these studies, that there is no stable object, child abuse, to have knowledge about." This is a "no fact of the matter" response, and it is based on the recognition of conceptual change. He later adds that child abuse "is a real evil, and it was so before the concept was constructed. It was nevertheless constructed. Neither reality nor construction should be in question" (1995, 61, 68). However, Hacking's conclusions about the reality of MPD express only a muted skepticism. Utilitarian skeptics approach this question by asking, "What is the most effective treatment?" Hacking writes that "in their hearts [such skeptics] suspect that the outcome of multiple therapy [therapy that condones or even encourages the development of multiples in the patient] is a type of false consciousness" (1995, 267). The skeptics about MPD are making a moral judgment, he believes; but on whether that moral judgment is correct, he is silent, although the suspicion must be that he agrees with it.

How do these considerations apply to the case of MCI? Graham and Ritchie rightly note that classifying a subject as suffering from MCI, and informing them of the diagnosis, will affect them adversely—it will cause suffering not least because there is at present no cure. However, it must surely be conceded that any disease at all—physical or mental—is a social entity insofar as it involves behavioral ascriptions to the subject concerning their incapacity. The authors also note the vested interests—especially from the pharmaceutical industry—in developing a diagnostic category of MCI. These interests are present in the development of any significant diagnostic...