The author challenges brain-based diagnoses of death by re-examining the concept of death, its definition, the anatomical criterion, and the clinical signs or tests. Dr. Shewmon challenges the fundamental assumptions underlying brain death: (1) that the brain is the body's "critical system"; and (2) that the body even has a localized "critical system." He does not redefine death, but shifts the anatomical criterion from a single focus (the brain) to the entire body. The clinical tests correspondingly shift from those implying loss of brain function to those implying thermodynamically supracritical microstructural damage diffusely throughout the body. He concludes that the notion of "brain death" as bodily death is logically and physiologically incoherent, and that its replacement by something scientifically more credible would promote not only the sanctity of life, but ironically even transplantation as well.