The introduction of the “brain death” criterion constitutes a significant paradigm shift in the determination of death. The perception of the public at large is that the Catholic Church has formally endorsed this neurological standard. However, a critical reading of the only magisterial document on this subject, Pope John Paul II’s 2000 address, shows that the pope’s acceptance of the neurological criterion is conditional in that it entails a twofold requirement. It requires that certain medical presuppositions of the neurological standard are fulfilled, and that its philosophical premise coheres with the Church’s teaching on the body-soul union. This article demonstrates that the medical presuppositions are not fulfilled, and that the doctrine of the brain as the central somatic integrator of the body does not cohere either with the current holistic understanding of the human organism or with the Church’s Thomistic doctrine of the soul as the form of the body. Summary:The concept of “brain death” (the neurological basis for legally declaring a person dead) has caused much controversy since its inception. In this regard, it has been generally perceived that the Catholic Church has officially affirmed the “brain death” criterion. The address of Pope John Paul II in 2000 shows, however, that he only gave it a conditional acceptance, one which requires that several medical and philosophical presuppositions of the “brain death” standard be fulfilled. This article demonstrates, taking into consideration both the empirical evidence and the Church’s Thomistic anthropology, that the presuppositions have not been fulfilled. [ABSTRACT FROM AUTHOR]