I investigate Thomas Aquinas's metaphysical account of human death, which is defined in terms of a rational soul separating from its material body. The question at hand concerns what criterion best determines when this separation occurs. Aquinas argues that a body has a rational soul only insofar as it is properly organised to support the soul's vegetative, sensitive, and rational capacities. According to the ‘higher‐brain’ concept of death, when a body can no longer provide the biological foundation necessary for the (...) operation of conscious rational thought and volition, a substantial change occurs in which the rational soul departs and the body left behind is a ‘humanoid animal’ or a mere ‘vegetable.’I argue that the separation of soul and body does not occur until the body ceases to function as a unified, integrated organism. A rational soul is not only the seat of a human being's rational capacities; it is also the principle of the body's sensitive and vegetative capacities. Since Aquinas defines a human being as a composite of soul and body, and not with merely the exercise of rational capacities, the determination of death requires incontrovertible evidence that the body has ceased all the operations that correspond to the soul's proper capacities. The evidence of this is the body's loss of its integrative organic unity and the criterion for determining when this loss occurs is the irreversible cessation of whole‐brain functioning. (shrink)

Patrick Lee and Germain Grisez have argued that the total brain dead patient is still dead because the integrated entity that remains is not even an animal, not only because he is not sentient but also, and more importantly, because he has lost the radical capacity for sentience. In this essay, written from within and as a contribution to the Catholic philosophical tradition, I respond to Lee and Grisez’s argument by proposing that the brain dead patient is still sentient because (...) an animal with an intact but severed spinal cord can still perceive and respond to external stimuli. The brain dead patient is an unconscious sentient organism. (shrink)