Personale Identität und intrazerebrale Stammzelltransplantationen

Abstract

Perhaps no field of medical or biotechnological research had a more profound impact on the medical science at the beginning of the 21st century than stem cell technology and the neurosciences. An intersection between both disciplines lies in the attempt to utilize stem cells for the treatment of chronic neurological diseases. Through intracerebral transplantation of cells or tissues, researchers hope to develop new therapeutic strategies for diseases such as stroke and Parkinson"s disease. However, these new therapies have raised a number of ethical concerns. Thus, it has been argued that the direct manipulation of the brain could necessarily alter the patient"s personality and his personal identity, thereby risking his future survival. The main aims of this thesis were to evaluate the possible consequences of intracerebral stem cell transplantations for the identity and survival of the patient and to propose normative implications for their future use and research. It argues that based on Derek Parfit"s theory of personal identity, changes of the patient"s identity are only possible if there are severe psychological changes in a short amount of time, thus disrupting psychological continuity. It is likely that only extensive interventions in those brain areas that are crucial to personality are capable of causing such changes. The thesis also argues that stem cell transplantations should be regarded as examples of what Parfit calls "partial survival". In such cases, it is up to the patient to evaluate the psychological changes. Because this evaluation process will necessarily depend on the subjective views of the individual, it is hardly possible to define acceptable and unacceptable changes. Therefore, there is no reason to suppose that intracerebral stem cell transplants will necessarily lead to ethically objectionable changes of psychology or identity. Stem cell transplantations can thus be an ethically adequate tool for the treatment of patients.