Is a human alive who has only his vegetative functions and no consciousness of his being? Is not a patient virtually dead who has no brain activity whatsoever? And if he is in irreversible coma, can his organs be removed for transplantation into a conscious body? These questions and even more vexing ones have recently raised a host of legal, ethical, moral, and religious considerations that require resolution. Ideas about what constitutes death vary with different cultures and in different epochs. In Western societies, death has traditionally ....