Persistence through time is like extension through space. A road has spatial parts in the subregions of the region of space it occupies; likewise, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies. This view — known variously as four dimensionalism, the doctrine of temporal parts, and the theory that objects “perdure” — is opposed to “three dimensionalism”, the doctrine that things “endure”, or are “wholly present”.1 I will (...) attempt to resolve this dispute in favor of four dimensionalism by means of a novel argument based on considerations of vagueness. But before argument in this area can be productive, I believe we must become much clearer than is customary about exactly what the dispute is, for the usual ways of formulating the dispute are flawed, especially where three dimensionalism is concerned. (shrink)

Precis of my book by this title, for a symposium.

Marya Schechtman takes issue with analytic philosophy's emphasis on the first sort of question to the exclusion of the second.

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)

Marya Schechtman offers a new theory of personal identity, which captures the importance of being able to reidentify people in our daily lives. She sees persons as loci of practical interaction, and defines the unity of such a locus in terms of biological, psychological, and social functions, mediated through social and cultural infrastructure.

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)

The Human Animal is an extended defense of what its author calls the Biological Approach to personal identity: that you and I are human animals, and that the identity conditions under which we endure are those which apply to us as biological organisms. The somewhat surprising corollary of this view is that no sort of psychological continuity is either necessary or sufficient for a human animal—and thus for us—to persist through time. In challenging the hegemony of Psychological Approaches to personal (...) identity, Olson offers a number of inventive and original arguments which are certain to evoke discussion and debate. (shrink)

Many philosophers have taken there to be an important relation between personal identity and several of our practical concerns (among them moral responsibility, compensation, and self-concern). I articulate four natural methodological assumptions made by those wanting to construct a theory of the relation between identity and practical concerns, and I point out powerful objections to each assumption, objections constituting serious methodological obstacles to the overall project. I then attempt to offer replies to each general objection in a way that leaves (...) the project intact, albeit significantly changed. Perhaps the most important change stems from the recognition that the practical concerns motivating investigation into personal identity turn out to be not univocal, as is typically thought, such that each of the different practical concerns may actually be related to personal identity in very different ways. (shrink)

Many people believe that for someone to now be responsible for some past action, the agent of that action and the responsible agent now must be one and the same person. In other words, many people that moral responsibility presupposes numerical personal identity. In this paper, I show why this platitude is false. I then suggest an account of what actual metaphysical relationship moral responsibility presupposes instead.

It has long been thought that certain key bioethical views depend heavily on work in personal identity theory, regarding questions of either our essence or the conditions of our numerical identity across time. In this paper I argue to the contrary, that personal identity is actually not significant at all in this arena. Specifically, I explore three topics where considerations of identity are thought to be essential – abortion, definition of death, and advance directives – and I show in each (...) case that the significant work is being done by a relation other than identity. (shrink)

Traditionally, it has been assumed that metaphysical and practical questions about personhood and personal identity are inherently linked. Neo-Lockean views that draw such a link have been problematic, leading to an opposing view that metaphysical and ethical questions about persons should be sharply distinguished. This paper argues that consideration of this issue suffers from an overly narrow conception of the practical concerns associated with persons that focuses on higher-order capacities and fails to appreciate basic practical concerns more directly connected to (...) our animality. A more inclusive alternative is proposed. (shrink)

This paper discusses two features of the "morally responsible self." The first has to do with the preconditions of personal identity assumed to inhere in a morally responsible self. The paper argues that it is not a requirement of moral responsibility that the self held responsible for some action is one and the same individual as the self that performed it. the second feature involves what's known as the "deep self" theory of responsibility. The paper discusses the history of the (...) theory, as well as some critical contemporary exchanges about it. (shrink)