CPR forced doctors to rethink the moment of death
For most of history, a person was dead when breathing and heartbeat stopped. Then cardiopulmonary resuscitation and prompt defibrillation showed that both could sometimes be restarted, turning a seemingly final state into a reversible one. Defining exactly when life ends has been surprisingly slippery ever since, for doctors, lawyers and philosophers alike.
Biologically, death is the irreversible end of the functions that keep an organism alive, after which it usually begins to decompose. The trouble lies in the word irreversible. The old standard, now called clinical death, can sometimes be undone. Critics of the circulatory definition point out that a loss may be permanent in practice yet not truly irreversible if resuscitation starts fast enough, so the whole debate comes down to what those two words mean.
Many physicians therefore focus on the brain, and brain death sometimes serves as the legal definition. Even that splits opinion: some insist every brain function must stop, while others argue that once personality and identity are irretrievably lost, the person has died even if the brainstem still works. Organ systems also shut down at different times, so there is rarely a single clean moment. Defining death through the loss of consciousness runs into its own snags, since many living organisms are probably not conscious and consciousness itself resists definition.
Across nature, most organisms that avoid predators, starvation and disease eventually die of old age, but a few, such as the immortal jellyfish, are biologically immortal, though they can still die from other causes. When every member of a lineage has gone, it is extinct. Among humans, about 56 million people die each year, and by 2022 an estimated almost 110 billion people had died, roughly 94 percent of everyone who has ever lived.
Awareness of death is universal to human culture and has shaped religion, ethics and law. Many traditions teach survival in an afterlife, as spirits or through reincarnation, while materialist views treat death as the end of personal identity. Communities honour the dead through funerals, cremation or sky burial, and some cultures see dying as a gradual passage rather than one event. The scientific study of death is called thanatology.
Source: Death
