Death is irreversible, but our understanding of it keeps improving. At one point, pulmonary arrest was considered death. Then, cardiac arrest. Now, we use th

Death is irreversible, but our understanding of it keeps improving. At one point, pulmonary arrest was considered death. Then, cardiac arrest. Now, we use the cessation of brain activity as an approximation, but there have been plenty of cases of patients with zero brain activity making full recoveries. The best definition of death is probably information-theoretic death. But that's not something we know how to measure (yet), so the organ harvests continue: https://en.wikipedia.org/wiki/Information-theoretic_death https://en.wikipedia.org/wiki/Information-theoretic_death