The Uses of Borrowed Knowledge: Chaos Theory and Antidepressants

Keywords
chaos, metaphor, rhetoric, values

Ever since the popularization of chaos the-ory in the 1980s, there has been an explo-sion of interest in work in nonlinear dynamics generally and the study of strange attractors in particular. From law to economics to theology, researchers in the social sciences and the humanities have sought to make use of the concepts, methods, and results of chaos theory. Previous generations have seen similar attempts to explore the consequences of relativity theory or quantum mechanics for their own areas of inquiry. In examining the implications of chaos for the treatment of mental illness, Douglas Heinrichs provides an example of this phenomenon, which I call "borrowed knowledge." Lacking expertise in the areas of psychotherapy or psychopharmacology, I view his suggestions as a case study in the ways that knowledge gets used across disciplinary boundaries. In these remarks, I examine some of the different functions that borrowed knowledge can serve in order to argue that although cross-disciplinary borrowing can be a fruitful source of new insights, it is not without its dangers. I look at the persuasive function that borrowed knowledge can serve in making one's ideas plausible candidates for further exploration, as well as in motivating methodological change. I look at the conceptual work performed by metaphors, paying special attention to the question of how we can judge whether or not a nonliteral use of knowledge from the natural sciences is fruitful. And finally, I look at the ways in which borrowed knowledge can be used to address evaluative questions—in this case, questions about autonomy and appropriate therapeutic practice. I do not mean for these various functions to be thought of as exclusive categories. Instead, they overlap, interact, and combine in various ways.

Rhetorical Functions, Disciplinary Prestige, and Methodologic Change

In examining the persuasive uses of chaos theory, I should make it clear that by "persuasive" I do not mean illegitimate or deceptive. When Heinrichs points out that what he calls the traditional model of brain function is used to present and explain the use of antidepressants (ADs) to clinicians and the general public, it becomes clear that he believes an alternative model can be useful for explicating and justifying the use of ADs for clinicians and patients. This descriptive function of the metaphorical appeal to a chaotic "attractor landscape" shows up where Heinrichs discusses the use of the chaotic model for patient education and the "rationale for pharmacotherapy," giving patients "appropriate expectations."

But the rhetorical functions of chaos theory also come into play with audiences other than patients; they apply to the audience for the scholarly article itself, perhaps attracting attention because of the novelty or promise of a new field of research, but also harnessing the considerable disciplinary prestige that the natural sciences wield in our culture. All of these functions are useful in directing attention to the author's suggestions for further research, especially where he suggests that it would provide the clinician with guidance in working with an individual patient. Here I take it that Heinrichs has made fruitful use of the work of Thelen and others on the variability of individual developmental trajectories. This proposal for methodological change suggests that focusing on the dynamics of system and its evolution through time may be important in addition to focusing on equilibrium states. The disciplinary prestige of the natural sciences can provide a valuable and legitimate resource for the persuasive task of encouraging one's colleagues to explore a new methodological approach.

A further rhetorical use is found in the appeal to the unpredictability of chaotic systems to account for the variability of results in the application of ADs. We see this where Heinrichs says, "a meaningful science of persons is possible even in the face of their ultimate unpredictability" (2005, 221). The disciplinary prestige of the natural sciences, which in studying chaotic systems are able to achieve genuinely "scientific" status without being able...