The duality of the brain and the multiplicity of minds: can you have it both ways?

Abstract

Multiple Personality Disorder (MPD), now known as Dissociative Identity Disorder (DID), has been of great interest to the public for over a century. Case histories of MPD can be found in the literature as far back as the eighteenth century; nevertheless, publications from the latter part of the nineteenth century best describe this disorder as we know it today. This paper traces the case history literature of DID (MPD) from the earliest period to the present. This is done in such a way as to illuminate the basic theoretical and epistemological issues that are necessary to understand the process of dissociation (both normal and abnormal aspects) and the role of hypnosis and its relationship to organic and 'hysterical epilepsy.' The theories of Janet, Prince and Sidis are the major authorities discussed. The paper concludes with a discussion of the danger inherent in fostering a deterministic or reductionistic theory of consciousness.