When philosophers address personal identity, they usually explore numerical identity: what are the criteria for a person's continuing existence? When non-philosophers address personal identity, they often have in mind narrative identity: Which characteristics of a particular person are salient to her self-conception? This book develops accounts of both senses of identity, arguing that both are normatively important, and is unique in its exploration of a range of issues in bioethics through the lens of identity. Defending a biological view of our (...) numerical identity and a framework for understanding narrative identity, DeGrazia investigates various issues for which considerations of identity prove critical: the definition of death; the authority of advance directives in cases of severe dementia; the use of enhancement technologies; prenatal genetic interventions; and certain types of reproductive choices. He demonstrates the power of personal identity theory to illuminate issues in bioethics as they bring philosophical theory to life. (shrink)

In this paper I argue that a Naturalist conception of personhood, such as the one defended by Derek Parfit, implies that there are degrees of personhood, i.e., that it makes sense to say one individual has a greater degree of personhood than another. I describe both criteria of general personhood, which distinguish between persons and non-persons, and criteria of particular personhood, which distinguish between one person and another. I examine some of the consequences for ethics, including the rights to life, (...) self-determination, and treatment. There may be circumstances in medicine where we have to judge the value of a patient's life in order to decide what medical treatment, if any, to provide, and although it may be emotionally difficult and politically dangerous, one relevant factor is what degree of personhood that individual has. (shrink)

Personhood is a foundational concept in ethics, yet defining criteria have been elusive. In this article we summarize attempts to define personhood in psychological and neurological terms and conclude that none manage to be both specific and non-arbitrary. We propose that this is because the concept does not correspond to any real category of objects in the world. Rather, it is the product of an evolved brain system that develops innately and projects itself automatically and irrepressibly onto the world whenever (...) triggered by stimulus features such as a human-like face, body, or contingent patterns of behavior. We review the evidence for the existence of an autonomous person network in the brain and discuss its implications for the field of ethics and for the implicit morality of everyday behavior. (shrink)

Challenging, with several powerful arguments, some of our deepest beliefs about rationality, morality, and personal identity, Parfit claims that we have a false view about our own nature. It is often rational to act against our own best interersts, he argues, and most of us have moral views that are self-defeating. We often act wrongly, although we know there will be no one with serious grounds for complaint, and when we consider future generations it is very hard to avoid conclusions (...) that most of us will find very disturbing. (shrink)

Can we understand what makes someone the same person without understanding what it is to be a person? Prereflectively we might not think so, but philosophers often accord these questions separate treatments, with personal-identity theorists claiming the first question and free-will theorists the second. Yet much of what is of interest to a person—the possibility of survival over time, compensation for past hardships, concern for future projects, or moral responsibility—is not obviously intelligible from the perspective of either question alone. Marya (...) Schechtman encourages us to adopt a more unified perspective. (shrink)

Using a philosophical framework that is informed by neuroscience as well as contemporary legal cases such as Terri Schiavo, this text offers readers an introduction to this topic. It looks at the ethical implications of our knowledge of the brain and medical treatments for neurological diseases.