Multiple Personality and Personal Identity

Abstract

I Bizarre situations often help us to discover the range of a concept; by pushing it to or beyond its limits, they thereby display more clearly where those limits lie. In particular, investigations into the concept of a person use this technique regularly-one need only think of Locke's fiction of the prince and the cobbler swapping bodies, or of our contemporary fantasies of brain and hemisphere transplants, of robots virtually indistinguishable from people, and so forth. Occasionally, too, we can resort to science fact rather than science fantasy; consider the spate of recent work on commissurotomy patients (Nagel [I97I], Puccetti [1973], Wilkes [1978], Marks [1980], Puccetti [1981i]), where some, notably Puccetti, have argued that we have unearthed two persons in each body. The phenomenon of multiple personality has received little explicit attention from philosophers, although it sometimes rates a mention in parentheses or footnotes. One reason for this neglect is that it is something of a scientific embarrassment, seeming to offer an unfortunate illustration of how nature may follow art. Certainly in the late-nineteenth century, when multiple personality was taken as a genuine diagnostic category and philosophers and scientists were fascinated by it, there was a wave of reported cases; then the increasing scepticism of the mid-twentieth century seemed virtually to abolish the condition. (Of 63 patients admitted to Bellevue hospital in 1933-4 suffering from loss of identity, not one was declared to be a case of multiple personality; schizophrenia, manic depression, psychosis, aphasia, amnesia, cerebral arteriosclerosis, presenile dementia, cerebral trauma, epilepsy and carbon monoxide poisoning sufficed as diagnostic tools (Sutcliffe and Jones [1962]).) Second, there are sound methodological reasons for dropping or at least suspending belief in multiple personality as a discrete and identifiable phenomenon: the condition is an unusual and an intriguing one, so doctors greet potential cases with keen interest and attention--thereby providing strong positive reinforcement to the patient to develop distinct and distinguishable alternate personalities. It is highly likely that role playing, whether conscious or unconscious, is an essential element in the aetiology of the condition (see Taylor and Martin [1944], Orzech, McGuire and Longnecker [1958], and Congdon, Haig and Stevenson [1961]). Finally, contemporary psychiatry has largely abandoned the almost automatic resort