The metaphysics of dementia: The intersection of personal identity and clinical ethics

An advance directive is a legally binding contract which an individual of sound mind creates in order to direct care when she is no longer able to communicate her desires. The moral authority of a directive is derived from the values and autonomy of the individual who drafts this document. The purpose of the document is to extend the patient's autonomy into a possible future in which the patient lacks decision-making capacity. Such precedent autonomy, however, faces a significant metaphysical challenge from personal identity theorists: If the person who drafted the advance directive no longer exists, then the directive should not be binding.;Several authors have in fact asserted that the original person no longer exists; thereby concluding that advance directives in at least some cases of dementia ought not to bind the "later person" her medical providers. The personal identity attack on advance directives thereby has the potential to significantly alter current clinical practice in end-of-life care.;This dissertation attempts to rescue the moral authority of the advance directive, grounding it in precedent autonomy and developing a solution to the metaphysical quandaries presented by authors such as Brock, Buchanan, Dresser, McMahan, and Parfit. In particular, two such quandaries are considered: the problem of too many thinkers and the slavery problem.;The dissertation argues that the preferred solution to the puzzles is a narrative theory of constitutional concern grounded in the Constitution View of Lynne Rudder Baker. The constitutional approach is contrasted and compared with animalism and with psychological continuity views of personal identity. Animalism, the dissertation argues, suffers from an inability to explain the transplant intuition. The psychological view accepts the transplant intuition, but has traditionally been unable to explain the sameness relation in cases of diachronic identity. Baker's Constitution View -- supplemented with insights by Harold Noonan's pronoun revisionism and Marya Schechtman's narrative theory of identity -- is able to explain the sameness relation. I call this revised constitutional account the Theory of Constitutional Concern and defend it against possible objections. It is a sui generis relation of ethical concern to supplement Baker's own sui generis formulation of personal identity.