Before beginning any discussion on this topic, it is worth noting the obvious: Jewish law is made up of timeless principles and timely applications of these principles. Discussions of the interaction between timeless principles and timely applications frequently are disconcerting to Orthodox Jews because they wish for halacha to generate answers that are always timeless. In areas where the scientific and medical data is still evolving, this is virtually impossible. Hence, the word “tentative” is in the title. New data will certainly generate different answers.
“Brain death” is a misnomer. Nearly everyone agrees that as a matter of Jewish law (as well as common sense), were full cellular death to take place in the brain, such a person would be dead. Indeed, the common functions associated with human existence would cease after this event ““ which we can refer to as “physiological decapitation” ““ and human life would then cease.
But this type of complete brain death ““ what ought to happen after total cessation of any blood flow to the brain, or what happens after actual decapitation ““ is either very rare or non-existent. Study after study confirms that patients are declared brain dead under criteria far short of total and complete cessation of all blood flow to the brain, and microscopic examination of brain cells post mortem clearly shows that cellular life continues in the brain. This is why the President’s Council on Bioethics in its important January 2009 report sought to introduce a change in terminology from “brain death” to “total brain failure” without the word “death” or the even better classification of “irreversible apneic coma.” The current state of medical literature makes it clear that “brain death” is now being used to describe a state in which the brain fails to provide direction and instruction to (among others things) the lungs to function, and thus natural respiration ceases. However, this diagnosis is not useful in cases such as hypothermia, drug intoxication or a stroke where equivalent symptoms exist due to these reversible conditions. Even when these criteria are met, the President’s Commission insists that the patient must additionally be in a “completely unresponsive coma,” demonstrate no “brainstem reflexes” and not have a “drive to breathe” during the apnea test.
What we commonly call “brain death” is now generally defended in medical, scientific and Jewish literature as a form of “respiratory death” in contrast to “cardiac death,” which is when the heart stops beating.
Whether this definition of death ““ the combination of permanent brain stem dysfunction and respiratory death (even when a ventilator is used), but not full brain death nor cardiac death ““ is sufficient as a matter of law, ethics and philosophy remains hotly disputed, both within and outside the Jewish tradition.
Indeed, the President’s Council on Bioethics clearly states:
In this chapter, we set forth and explore two positions on this philosophical question. One position rejects the widely accepted consensus that the current neurological standard is an ethically valid one for determining death. The other position defends the consensus, taking the challenges posed in recent years as opportunities to strengthen the philosophical rationale for the neurological standard.
This debate exists in the Jewish tradition as well, focusing both on the technical Talmudic and post-Talmudic sources, as well as the larger set of issues. Like the medical and scientific literature, it is detailed and complex. Indeed, a firm resolution of this matter with concrete Talmudic or logical proofs is difficult.
Given that reality of uncertainty, what is one supposed to do as a matter of normative practice?
Three options strike me as possible as a matter of halacha. The first, attributed to the contemporary sage Rabbi Aharon Lichtenstein, is to tell people that one is uncertain but to validate as reasonable other views alternatives, thus effectively permitting people who want to donate organs to rely on those authorities who permit such activity.
A second approach is the one adopted by Rabbi Hershel Schachter, who also considers the matter to be uncertain as a matter of halacha. He rules that since the matter touches on the prohibition of murder, one must be strict for all views here and prohibit as a matter of functional Jewish law anything that causes death.
My own intuition is unlike both of these great rabbis ““ poskim far more learned than myself. I’m more inclined to the view of the late Rabbi Shlomo Zalman Auerbach, which is that a person who is brain stem dead and on a ventilator must be considered as if he is alive as a matter of Jewish law, but, as a matter of end-of-life care:
…if a patient is diagnosed as brain dead by routine criteria, it is permissible to disconnect the respirator even though the patient has not been absolutely proven to be brain dead as required by halacha. If the heart stops for thirty seconds in a clinically diagnosed brain dead patient, the patient is dead according to halacha.
As Rabbi Yitzchak Breitowitz notes:
R. Shlomo Zalman [Auerbach] does permit under these circumstances (a definitive diagnosis of brain stem death) shutting off the respirator. If no respiration or heartbeat is detected for a period of thirty seconds, the patient may then be halachically declared dead and his organs harvested…. In essence, R. Auerbach’s psak paves the way for the legitimization of heart and liver transplants even according to those views that do not accept brain stem death as definitive halachic death.
Even this might not be entirely correct, as the presence of some hypothalamus function seems to have caused Rabbi Auerbach to step back from this ruling as a matter of medical fact. But the basic insight central to his approach works in fact as a matter of halacha. This attempt to bridge the gap as a matter of halacha and medical science seems to me to be the best approach to this area.
What this means practically is that brain dead patients may be harvested for organs but not according to the standard protocol generally in place. The patient’s family, obviously emotional and distressed, must involve their rabbi who will advise doctors on the protocol appropriate for their faith, so that this urgent mitzvah can be performed in a religiously sensitive manner.
As with all matters of halacha and medicine, as the facts change, the reality needs to be reexamined.
 Even Rabbi Bleich ““ a fierce opponent of brain death ““ notes that this view has “a measure of cogency.” See his Time of Death and Jewish Law at page 131 (but see his note 4).
 See http://bioethics.georgetown.edu/pcbe/reports/death/chapter3.html
 http://bioethics.georgetown.edu/pcbe/reports/death/chapter4.html. . Let me add a fact that weighs on my calculus in this area and adds to my personal uncertainty. Nearly every person I respect as a Torah scholar of substance who is also well trained in the sciences supports the view that Jewish law ought to accept brain stem death when combined with respiratory failure, notwithstanding the opposition to this view by many eminent poskim. This compounds my uncertainty as to what the halacha really is.
 For an excellent review of the literature, see the fine review article by Rabbi Irving Breitowitz, with a short reply by Rabbi Moshe Tendler, and a further reply by Rabbi Breitowitz, initially published in the Orthodox Union’s magazine, Jewish Action. This can be found at: http://www.hods.org/pdf/Breitowitz%20Brain%20Death%20Controversy.pdf
 Listen to the nuance presented in the name of Rav Aharon:
Rav Lichtenstein recognizes, as does the RCA, that this is a complex issue in which there are differing views. His personal opinion is that he remains in doubt concerning the matter, and he does not rule that brain stem death is halachically death. However, when confronted with a situation of a family in great distress who were disposed to authorize the donation of the organs of their loved one – and who were relying on the position of an eminent authority such as Rav Shapira, who accepted the validity of brain stem death – Rav Lichtenstein affirmed their right to rely on this opinion. Further, he stated that if one accepts the opinion of Rav Shapira it is in fact a great mitzvah to donate organs.
 BeIkvei HaTzon, chapters 36 and 37.
 Dr. Avraham Steinberg, http://www.thefoundationstone.org/en/beitmidrash/general/3025-medical-halachic-decisions-of-rabbi-shlomo-zalman-auerbach.html
 See http://www.hods.org/pdf/Breitowitz%20Brain%20Death%20Controversy.pdf on the last page (pages are not numbered in sequence)
 See Nishmat Avraham (Hebrew) Volume 5 page 99 where a letter from Rabbi Auerbach is printed to that effect.