Abstract

Persons: what are they? What do they do? Almost everyone who has been confronted with these sorts of questions is quick to offer a reply. With very little or no reflection, we learn that persons have a unique and privileged status, and that they are the kind of entity that is most readily identified as human. As with most quick and ready replies, these claims should be greeted with caution. In my dissertation, I argue that persons are entities that satisfy certain functionally-specifiable traits. This, in turn, raises a number of philosophically interesting issues. For example, given current neurophysiological data, I argue that each hemisphere of a normal human brain possesses the requisite criteria for personhood, and consequently, that normal humans are two-personed. I defend this counterintuitive conclusion against various objections. Although the view I defend is disturbing in many respects, compelling reasons for a two-personed human emerge. I also explore the implications that this conclusion might have for theories of personal identity. Some have suggested that the neurological data I cite forces us to reject personal identity altogether. Contrary to this suggestion, I argue that personal identity need not be rejected. Though the findings of split brain research may require that we reject the view that we survive as single persons, this does not force us to dismiss personal identity. Rather, we should view our survival in much the same way that twins view their survival. Considered as a pair of persons, we, like twins, survive only if both members of the pair survive. Finally, I consider the normative consequences of my proposals. If it is reasonable to maintain that persons are "owed" certain kinds of treatment, it follows that each hemisphere-based person should be treated in a manner appropriate to any other given person. Hemisphere-based persons should be treated with respect, fairly, and in any other way that corresponds with their unique status. Though the consequent practical difficulties may appear to be overwhelming, I argue that they do not necessitate a radical revision of our social, legal and moral institutions. Though an increased sensitivity may be required in certain rare circumstances, most of our ordinary normative policies will remain untouched