 The advantages proffered by this approach contributed to its widespread social acceptance and legal adoption in the last few decades of the 20th century. As mentioned, every American state has legally adopted the whole-brain standard alongside the cardiopulmonary standard as in the UDDA. It is worth noting, however, that a close cousin to the whole-brain standard, the brainstem standard, was adopted by the United Kingdom and various other nations. According to the brainstem standard—which has the practical advantage of requiring fewer clinical tests—human death occurs at the irreversible cessation of brainstem function. One might wonder whether a person's cerebrum could function—enabling consciousness—while this standard is met, but the answer is no. Since the brainstem includes the reticular activating system, the on/off switch that makes consciousness possible (without affecting its contents), brainstem death entails irreversible loss not only of unassisted respiration and circulation but also of the capacity for consciousness. Importantly, outside the English-speaking world, many or most nations, including virtually all developed countries, have legally adopted either whole-brain or brainstem criteria for the determination of death (Wijdicks 2002). Moreover, most of the public, to the extent that it is aware of the relevant laws, appears to accept such criteria for death (ibid). Opponents commonly fall within one of two main groups. One group consists of religious conservatives—and, recently, a growing number of secular academics—who favor the cardiopulmonary standard, according to which one can be brain-dead yet alive if (assisted) cardiopulmonary function persists. The other group consists of those liberal intellectuals who favor the higher-brain standard (to be discussed), which, notably, has not been adopted by any jurisdiction.