Persons, Identities, and Medical Ethics

In Human Identity and Bioethics, David DeGrazia eloquently lays down the philosophical foundations of, and major debates within, what has become known as the "identity problem." This term comprises a number of distinct yet interrelated issues. What exactly is it that makes me a single human person persisting through time with a single identity? Is it my body—that I am and have been a single biological creature? Or is it is my mind—that my psychological states interconnect into a single continuum? At what point does one begin to be a person, and can a fetus or severely demented individual really be described as one? And finally, if I truly have a single identity that persists through time, how does the narrative of my life fit into the picture?

DeGrazia discusses a number of leading theories that address these main questions of the identity problem. He then seeks to explore the bioethical implications of such theories by applying them to current clinical and legal issues in medicine. Although philosophers have debated human nature for centuries, John Locke is credited with being the father of personal identity theory. He began exploring this area because he was concerned about the legal—and hence practical—implications of his theoretical work. One may say that by employing examples based on clinical cases, DeGrazia is returning to the practically applicable side of identity theory.

Adopting a biology-based approach to the identity problem, DeGrazia asserts that one persists through time as a single human individual due to the singularity of one's human body. He renames the persistence problem the problem of "numerical identity" in order to differentiate his position from those of psychology-based theorists, which concentrate instead on singularity of mind, requiring that an individual's psychological states be continuous—or at least connected—for her to be the same person over a period of time. According to some psychologically inclined theories, one can even exist as a human being yet be a "nonperson," as might be the case when one lacks complex conscious awareness. DeGrazia rejects this psychology-based approach, which he refers to as "personalism" due to its focus on one's identity as a person rather than as a human. Instead, he asserts that, even if an individual may be said to be a different person (or, for that matter, a non-person) over time, one's numerical, biological identity as a single human being is what truly matters.

Unlike most other identity theorists, DeGrazia employs examples from clinical medicine and bioethics to illustrate his position. For example, he presents the reader with the case of a man who, together with his doctor, writes an advance directive. Later on, the man is afflicted with severe dementia, and the doctor, who had known him well, is not sure he should honor the directive. De-Grazia uses this case as a platform to launch a discussion of identity from a number of different perspectives, which he constantly relates to the issue at hand. He concludes by advocating the authority of advance directives.

A novel element of DeGrazia's argument is that he attempts to incorporate narrative theories of identity into his biology-based conceptual framework. Narrative identity theory holds that a person's identity is comprised of and molded by the stories she tells herself and others about who she is. Unlike numerical identity theory, narrative theory focuses on character traits, values, and goals, rather than on the problem of persisting though time as a single individual. While DeGrazia's attempt to account for and synthesize both narrative and biological theories of identity is innovative, narrative theory is a better fit with traditional psychology-based theories of personal identity. The narratives we create of our lives depend on a highly complex form of conscious awareness and psychological functioning, so to couple narrative and psychology seems intuitively appropriate. DeGrazia sets himself a difficult task by attempting to divorce them, and whether he is successful at that is debatable.

Nevertheless, by applying philosophical theory to clinical practice, DeGrazia is able to employ his philosophical conclusions about the identity problem as solutions to real-world dilemmas...