The Mind-Body Problem

To the Editor: Eliminative materialism is a philosophical theory developed by Paul M. Churchland (1) that argues that neuroscience has restricted, and will eventually eliminate, any need for psychology. In his article, Dr. Kendler addressed whether it is appropriate for psychiatrists to accept the theory that “The sufficient cause for all material events is other material events” (p. 992). In opposition to eliminative materialism, Dr. Kendler presented conventional arguments that focus on ordinary (folk) psychology, which explains nonpathological human action by means of propositional attitudes, e.g., beliefs and desires. He also alluded to arguments against eliminative materialism, based on irreducibility of subjective states (“qualia”), multiple realizability of mental states, and human autonomy. These arguments, which presume normal action and absence of brain disease, have flaws that Churchland has addressed (2). The gist of Churchland’s response was that even if neuroscience cannot yet eliminate folk psychology or qualia, future advances will make this possible and desirable.

The preceding arguments are not very effective because eliminative materialism seems farfetched in dealing with actions of individuals without brain dysfunction but plausible in those with brain diseases that may causally explain their deviant behaviors. Churchland (1) recognized that mental illness associated with brain disease provides the strongest argument for eliminative materialism. “So long as one sticks to normal brains,” he wrote, “the poverty of folk psychology is perhaps not strikingly evident.” But he noted that the poverty of psychological explanation, and the rationale for eliminative materialism, becomes clear “as soon as one examines the many perplexing behavioral and cognitive deficits suffered by people with damaged brains” (1).

A fair and effective critique of eliminative materialism should occur in a domain in which the theory is plausible and strong. Thus, rather than examining normal patients, we should examine ones marked by neurological dysfunction. If psychological explanations are useful, even for disorders associated with well-defined and causally relevant brain dysfunction, then eliminative materialism would be undermined where it seems most plausible. Implicitly, then, it would also be undermined in ordinary behavior. If eliminative materialism could be weakened where it is strongest (i.e., in neuropsychiatric illness), then the general case against it would be bolstered as well.

This theoretical argument is developed and supported by case material in an article in which I reviewed the relationship between causal, neuroscientific explanation and meaningful, psychological explanation in psychiatry (3). There is growing evidence that psychiatric disorders have many causes spanning the biopsychosocial spectrum and thus necessitating multifactorial explanatory models (4, 5). Such empirical findings support arguments against eliminative materialism, which are based not on folk psychology, in which Churchland’s theory is already weak, but on clinical neuropsychiatry, in which biological dysfunction is causal; so his theory seems plausible. While Dr. Kendler accurately depicted traditional philosophical arguments against eliminative materialism, alternative arguments make a stronger case for an ongoing need for psychology and multifactorial explanations in contemporary psychiatry.