Defining death is one thing; providing criteria by which it can bereadily detected or verified is another. A definition is an account ofwhat deathis; when, and only when its definition is met, death hasnecessarily occurred. The definition offered above was that acreature is dead just when the vital processes by which it issustained have irreversibly ceased. A criterion for death, bycontrast, lays out conditions by which all and only actualdeaths may be readily identified. Such a criterion falls short of adefinition, but plays a practical role. For example, it would helpphysicians and jurists determine when death has occurred.