ABSTRACT
A little over half a century ago, medical science gained the ability to keep patients alive in a state of permanent unconsciousness: a state where the mind seems to be gone, but the body is alive. This raised questions about how to define death, and which criterion of death is correct. A criterion of death is some physiological state of affairs found in all and only those patients who are dead according to whatever definition of death matches that criterion. A criterion is correct if it matches the correct definition of death. However, previous discussions of death have not always clearly distinguished criteria of death from definitions of death, and as a result, the arguments for and against various definitions have not always been clearly developed.
