What Is Death?

This chapter discusses how the line between life and death has been blurred by advances in science and technology. For much of human history, determining death was a straightforward process. When illness or injury caused the irreversible loss of heart, lung, or brain function, their mutual interdependence meant that the other vital functions would inevitably cease within a matter of minutes. A physician could declare a patient dead simply by showing the absence of a heartbeat, breathing, or reaction of the eye to light. The introduction of new medical procedures in the 1950s, including mechanical ventilation and cardiopulmonary resuscitation (CPR), meant that a person whose heart had stopped beating, or lungs had stopped breathing, could be kept alive. These patients presented a problem for the traditional understanding of death because they had irreversibly lost some vital functions, but not others. To understand the nature of human death, one must begin by defining the concept: what is it for any living thing to die? Having answered this metaphysical question, one can move to an epistemological one: what is the appropriate standard for judging that something has met the definition of death? Finally, one requires criteria and tests to affirm that the epistemological standard has been met: when can we confidently say that someone is dead?