Just after a fourteen-year-old boy named Nicholas Breach learned that a tumor on his brain stem would be fatal, he told his parents, Rick and Kim Breach, that he wanted to be an organ donor. They respected his decision, and so did the boy’s medical team at the Children’s Hospital of Philadelphia. Bernadette Foley, Nick’s social worker there, said that the decision reflected a “maturity and sensitivity” and a wish to help others—something Nick had shown throughout his eight-year battle with recurrent tumors. “I’ve never been to a meeting like this one,” Foley said. “The peace that came over the family and Nick was remarkable, and once it was out that this was the end, and the decision was made about organ donation, Nick said he was happy. They all seemed to be happy.” The decision was redemptive, she said. “In a way, it gave some meaning to his life.”

By the time I met Nick, he was confined to a hospital bed that had been set up in the living room of the Breaches’ house, a brick bungalow outside Harrisburg. It was difficult for him to speak, and we chatted only briefly—about his dog, Sarah; his brother, Nathan; and his hope that his heart, lungs, liver, kidneys, and pancreas might enable other people to live—and then he dozed off.

As Nick slept, his parents told me that, amid their other worries, they had run into unexpected problems with the donation. Nick had wanted to die at home, with only palliative care, but organ donation is a high-tech affair. In most cases, the donor is someone with brain damage so severe that he requires a respirator to breathe, even though his heart continues to work on its own. A neurologist determines that the patient’s brain has been irreversibly and totally destroyed, and on this basis pronounces him dead. This condition is known as brain death. If the patient’s family has consented to donation, he is left on the respirator, which, along with his still-beating heart, keeps his organs viable for transplant until they can be harvested. The Breaches accepted that Nick would now have to be hospitalized at the very end, but their insurance company balked at the change in plan—and the added expense—reminding them that they had already elected basic hospice care. Only after the family’s state legislator and the regional organ-procurement organization got involved did the insurance company agree to pay. A plan was devised to keep Nick at home until the last possible moment and then to transport him to a hospital, where an informal protocol had been set up to help him become an organ donor.

Even with the logistical and financial arrangements in place, there was no guarantee that Nick would meet the criteria for brain death. Because the tumor was on his brain stem, which controls core physiological processes like breathing and body temperature, it was very likely that Nick’s higher brain—the thinking part—would remain active until he died from respiratory or organ failure. (His oncologist told me, “In his condition, what happens is the body goes. He’s a consciousness trapped inside.”) This would probably rule him out as a donor.

When I spoke to Nick’s parents, they still had trouble with the notion that, to become a donor, it was not enough for their son to die with his body more or less intact. He would have to have the right kind of death, with the systems in his body shutting down in a particular order. “I’m so confused about this part of it,” his mother said. “I don’t understand why, if his heart stops beating, they can’t put him back on a respirator.” Rick, too, was confused about the moment at which “the plug will be pulled.” In reality, there is no moment when the plug is pulled; to keep the organs viable, the respirator is left operating—and the heart keeps beating—until the surgeon removes the organs.

Confusion about the concept of brain death is not unusual, even among the transplant professionals, surgeons, neurologists, and bioethicists who grapple with it regularly. Brain death is confusing because it’s an artificial distinction constructed, more than thirty years ago, on a conceptual foundation that is unsound. Recently, some physicians have begun to suggest that brain-dead patients aren’t really dead at all—that the concept is just the medical profession’s way of dodging ethical questions about a practice that saves more than fifteen thousand lives a year.

From the beginning, transplant practice has been governed by a simple, unwritten rule: no matter how extreme the circumstances, no matter how ill or injured the potential donor, he must die of some other cause before his vital organs can be removed; it would never be acceptable to kill someone for his organs. But, ideally, a donor would be alive at the time his organs were harvested, because as soon as the flow of oxygenated blood stops, a process called warm ischemia quickly begins to ruin them. By the nineteen-sixties, as doctors began to perfect techniques for transplanting livers and hearts, the medical establishment faced a paradox: the need for both a living body and a dead donor.

The profession was also struggling with questions posed by another new technology: respirators. These machines had become a fixture in hospitals in the nineteen-fifties, and at first their main purpose was to help children with polio breathe until they regained their strength. Doctors began to use them for patients with devastating brain injuries—the kind brought on by severe trauma or loss of oxygen as a result of stroke or cardiac arrest. Some of these people recovered sufficiently to be removed from the machines, but others lingered, unable to breathe on their own, inert and unresponsive even to the most noxious stimulus, and without any detectable electrical brain activity, until their hearts gave out—often a matter of hours, but sometimes of days or even weeks.

Physicians wondered what to do with these patients, whether removing the machines would be murder or mercy killing or simply a matter of letting nature take its course. At the same time, some noticed that the patients were perfect sources of viable organs for transplant, at least as long as their hearts kept beating. And then, in 1967, a Harvard anesthesiologist named Henry K. Beecher asked the dean of the medical school to form a committee to explore the issues of artificial life support and organ donation, which he believed were related. The Harvard committee, which Beecher chaired, included ten physicians, a lawyer, and a historian, and its report was published the following year in the Journal of the American Medical Association. “Responsible medical opinion,” it announced, “is ready to adopt new criteria for pronouncing death to have occurred in an individual sustaining irreversible coma as a result of permanent brain damage.” Heartbeat or no, the committee declared, patients whose brains no longer functioned and who had no prospect of recovering were not lingering but were already dead—brain dead.

This physician-assisted redefinition of death meant that removing life-support machinery from these patients was no longer ethically suspect. And, by creating a class of dead people whose hearts were still beating, the Harvard committee gave transplant surgeons a new potential supply of organs. In the nineteen-seventies, however, only twenty-seven states adopted brain death as a legal definition of death. Theoretically, this meant that someone who had been declared dead in North Carolina could be resurrected by transferring him to a hospital in South Carolina. Practically, it meant that a doctor procuring organs from a brain-dead person was not equally protected in all jurisdictions from the charge that he was killing his patient.

In 1980, a commission appointed by President Carter began to look at medical ethical questions, which included finding a definition of death that could serve as a model for state laws. The commission recommended that doctors be given the power to declare people dead based on the neurological criteria suggested by the Harvard committee. Eventually, this recommendation was accepted in all fifty states.

The commission also wanted to convince the public that brain death was not just a legal fiction but the description of a biological truth. Two rationales were considered. In one, called the “higher-brain” formulation, a brain-dead person is alleged to be dead because his neocortex, the seat of consciousness, has been destroyed. He has thus lost the ability to think and feel—the capacity for personhood—that makes us who we are, and our lives worth living. But such “quality of life” criteria, the commission noted, raised uncomfortable ethical and political questions about the treatment of senile patients and how society valued the lives of the mentally impaired.

Instead, the commission chose to rely on what it called the “whole-brain” formulation. The brain, it was argued, directed and gave order and purpose to the different mechanical functions of our bodies. If both the neocortex and the brain stem (which regulates core physiological processes, such as breathing) stopped working, a person could be pronounced dead—not just because consciousness has disappeared but because, without the brain, nothing connects: there is no internal harmony, and the body no longer exists as an integrated whole.

When Nick Breach decided to become a donor, one of his first questions was whether he would be dead when his organs were taken. His parents told him that he would be, and, in a way, they saw this as one of the few things they could be sure about. Rick and Kim were more troubled by their son’s next concern, that he might be taken from them prematurely. They began a vigil that took on a strange dual nature: keeping Nick company, making him comfortable, spending as much time as possible with him, and, at the same time, monitoring him for the signs—whatever they might be—that death had come so close that it was time to get him to the hospital so that he could become an organ donor.

The organ-procurement agency that worked with the Breaches during those months was called Gift of Life. In 2000, Gift of Life, which is based in Philadelphia and has a staff of a hundred, helped manage more than eight hundred organ donations at a hundred and sixty-two member hospitals in Pennsylvania, New Jersey, and Delaware—five per cent of the total organs removed in the country.

The agency’s mission is to “positively predispose all members of the community to organ and tissue donation so that donation is viewed as a fundamental human responsibility.” Public-service ads, a pamphlet featuring Michael Jordan, and bumper stickers that say “Don’t take your organs to Heaven—Heaven knows we need them here” are all promoting an attitude about how, as Howard M. Nathan, the bearded, energetic forty-seven-year-old who heads Gift of Life, put it, “society should feel about this subject.” Because of the drama and human interest of Nick Breach’s case, the agency was naturally eager to publicize it: “Here’s a young man who is awake and aware, contemplating his death, and he becomes a donor,” Kevin Sparkman, the agency’s director of community relations, explained. “What a great example of what we want families to do!”

When a person is identified as a potential organ donor—generally, when he is about to be pronounced brain dead—Gift of Life dispatches a transplant coördinator to the hospital to try to obtain the family’s consent. (An organ-donor card is merely an indication of a patient’s wishes; the family has the final word.) “The first thing we do is insure that the family understands and acknowledges that their loved one is dead,” Linda Herzog, a senior hospital-services coördinator, told me.

Consent rates are tied directly to knowledge of brain death: families who think that donation is actually going to kill the patient refuse more often than families who believe that their relative is already dead. This is not as straightforward as it may seem, largely because of the lifelike appearance of the brain dead, whose skin is still warm to the touch and who are known within the industry as “heart-beating cadavers.” Gift of Life has developed a program that trains hospital staffs to explain the phenomenon to families. I watched in a darkened conference room as Herzog reviewed the program for two transplant coördinators, who were scheduled to present it later that afternoon in a Philadelphia hospital.

Using slides, Herzog ran through the process by which brain death is established. A neurologist performs a series of tests at the bedside—checking for such things as pupillary reflexes, response to pain, and the ability to breathe spontaneously. (If the patient is entirely unresponsive during two such examinations, the doctor concludes that his whole brain—cortex and brain stem—has been destroyed.) This is not a terribly sophisticated procedure, but it’s far more complicated than, say, ascertaining that a person has no pulse, and far less self-evident. Even when the tests are conducted or reënacted in front of family members, they often rely on their intuitions and insist that the patient is still alive. This failure to accept the truth is a function of denial, Herzog said, and she went on to note, with some dismay, that even highly trained professionals who fully accept the concept sometimes talk to brain-dead patients.

”It took us years to get the public to understand what brain death was,” Nathan said. “We had to train people in how to talk about it. Not that they’re brain dead, but they’re dead: ‘What you see is the machine artificially keeping the body alive . . .’ “ He stopped and pointed to my notebook. “No, don’t even use that. Say ‘keeping the organs functioning.’ “

Virtually every expert I spoke with about brain death was tripped up by its semantic trickiness. “Even I get this wrong,” said one physician and bioethicist who has written extensively on the subject, after making a similar slip. Stuart Youngner, the director of the Center for Biomedical Ethics at Case Western Reserve University, thinks that the need for linguistic vigilance indicates a problem with the concept itself. “The organ-procurement people and transplant activists say you’ve got to stop saying things like that because that promulgates the idea that the patients are not really dead. The language is a symptom not of stupidity but of how people experience these ‘dead’ people—as not exactly dead.”

Last year, I went to Havana for the Third International Symposium on Coma and Death, a conference held every four years and attended primarily by neurologists and bioethicists, joined by lawyers, anthropologists, and members of the clergy. At one session, I watched as a videotape of a recumbent adolescent boy, his feet toward the camera, his legs bowed, almost froglike, played on a television monitor in a corner of the room. He wore shorts, and there were two tubes entering his body, one in his abdomen, the other in his throat. The boy’s chest rose and fell to the whir and click of the respirator, but otherwise he was perfectly still.

On the tape, a trim, balding man named Alan Shewmon, a pediatric neurologist at U.C.L.A., stood near the bed and conducted a medical examination. He looked into the boy’s eyes, shook maracas next to his head, inserted a swab in a nostril, dropped cold water into the ears and lemon on the tongue, pinched and palpated and inspected. None of these actions drew a response from the boy, whom I will call Matthew.

Shewmon was also standing next to the monitor in Havana, offering additional commentary. He has been thinking about death for most of his career. A practicing Catholic, he has made contesting the concept of brain death a specialty, and has served on a Pontifical Academy of Sciences task force on the subject. Shewmon’s inquiry has led him from the higher-brain rationale through the whole-brain rationale to his current position: a strong conviction that brain death, while a severe disability, even severe enough to warrant discontinuing life support, is not truly death.

Although Matthew didn’t seem dead, it was hard to think of him as alive. On the monitor, a nurse removed the upper tube, suctioned the small hole in the boy’s throat, noted that he did not cough, and continued the routine of the exam. Then something different happened: some ice water trickled onto the boy’s shoulder, and it twitched. And though the screen was too small to see this, Shewmon told us that Matthew sprouted goose bumps, that his flesh was mottling and flushing with the stress of the exam. He was showing signs, that is, of precisely the kind of systemic functioning that the brain dead would generally be expected to lack.