Experimental Philosophical Bioethics of Personal Identity

The question of what makes someone the same person through time and change has long been a preoccupation of philosophers. In recent years, the question of what makes ordinary or lay people judge that someone is—or isn’t—the same person has caught the interest of experimental psychologists. These latter, empirically oriented researchers have sought to understand the cognitive processes and eliciting factors that shape ordinary people’s judgments about personal identity and the self. Still more recently, practitioners within an emerging discipline, experimental philosophical bioethics or “bioxphi”—the focus of this chapter—have adopted a similar aim and employed similar methodologies, but with two distinctive features: (a) a special concern for enhanced ecological validity in the examples and populations studied; and (b) an interest in contributing to substantive normative debates within the wider field of bioethics. Our aim in this chapter is to sample illustrative work on personal identity in bioxphi, explore how it relates to studies in psychology covering similar terrain, and draw out the implications of this work for matters of bioethical concern. In pursuing these issues, we highlight recent work in bioxphi that includes the perceived validity of advance directives following neurodegeneration, the right of psychologically altered study participants to withdraw from research, how drug addiction may cause one to be regarded by others as “a completely different person,” the effect of deep-brain stimulation on perceptions of the self, and the potential influence of moral enhancement interventions on intuitive impressions of a person’s character.