Defining death may seem like an academic exercise, but the number of organs available for transplant depends on a standard definition of the exact moment when a donor has died. In its latest report the President's Council on Bioethics has basically backed current practice against its critics, but it offers a new philosophical explanation of how to recognise death. It calls this “engagement with the world”.

With thousands of people on waiting lists for organs in every country, much is at stake in the debate over brain death. At the moment, doctors transplant vital organs from donors whose brain and brain stem no longer function, even though machines keep their lungs breathing and their hearts pumping. This “brain death” standard has come under attack from two directions.

First, some doctors, notably an American paediatric neurologist, Alan Shewmon, argue that “brain-dead” people still perform some functions that we attribute to living persons. Their wounds can heal, they can regulate temperature, women can sustain a healthy pregnancy, and children can become sexually mature. If this notion were accepted, the number of transplants would plummet, as many donors would be deemed to be alive.

On the other hand, some doctors contest the “dead donor rule”, that vital organs can only be taken from people who are dead. Nearly dead is dead enough, they say, and if even if a patient with irreversible brain damage can breathe on his own, doctors should be able to harvest organs.

The President's Council on Bioethics has rejected both of these arguments, but acknowledges in a long and thoughtful discussion that they do raise unsettling questions. But it justifies the total brain failure standard by contending that an organism is dead when it no longer responds to and interacts with the environment.

“Determining whether an organism remains a whole depends on recognizing the persistence or cessation of the fundamental vital work of a living organism—the work of self-preservation, achieved through the organism’s need- driven commerce with the surrounding world. When there is good reason to believe that an injury has irreversibly destroyed an organism’s ability to perform its fundamental vital work, then the conclusion that the organism as a whole has died is warranted. “

This does not mean that a person has to be conscious. Simply experiencing the need to breathe is evidence that he is interacting with the environment. So the Council's approach does not mean that brain-damaged people like Terri Schiavo would be deemed death.

"People are getting nervous that we're pushing the standard of death in order to get organs. The public is afraid that surgeons in search of organs for transplant will bend the definition of death to get them," bioethicst Arthur Caplan told Wired. "This report keeps that bright line in place."

And Council member Gilbert Meilaender commented: "There are people who want to argue that we should define death in terms of higher brain capacities — that if you lose the capacity for consciousness, we should regard you as dead, though you're breathing without assistance. But suppose we have a body like that. I wouldn't bury it. It's lost some human capacities, but it's not ceased to be a living being." ~ Wired, Jan 13