For decades, physicians, philosophers, theologians, lawyers, and the public considered brain death a settled issue. However, a series of recent cases in which individuals were declared brain dead yet physiologically maintained for prolonged periods of time has challenged the status quo. This signals a need for deeper reflection and reexamination of the underlying philosophical, scientific, and clinical issues at stake in defining death. In this paper, I consider four levels of philosophical inquiry regarding death: the ontological basis, actual states of (...) affairs, epistemological standards, and clinical criteria for brain death. I outline several candidates for the states of affairs that may constitute death, arguing that we should strive for a single, unified ontological definition of death as a loss of integrated functioning as a unified organism, while acknowledging that two states of affairs may satisfy this concept. I argue that the clinical criteria for determining whole-brain death should be bolstered to meet the epistemic demand of sufficient certainty in defining death by adding indicators of cerebro-somatic dis-integration to the traditional triad of loss of consciousness, loss of brainstem function, and absence of confounding explanations. (shrink)