WHEN did Shalom Ouanounou die? A court in Ontario must decide. The 25-year-old Canadian’s doctors say September, at which point they assessed that Ouanounou was brain dead after a severe asthma attack, and incapable of breathing without the assistance of a ventilator. His family, though, say he died five months later, in March, when his heart and breathing stopped. Such cases are among several that challenge laws governing when someone has died. So how should countries go about dealing with death?

What it means to be dead was long considered simple. A lack of pulse and breath was the standard sign. That changed in the 1950s and 60s with advances in modern medicine. Machines could, for the first time, keep pumping blood through a person’s arteries and veins, and keep aerating their lungs, after they lost the ability to do so themselves. In 1968 a committee at Harvard Medical School recommended that brain death should be the standard definition. Today most Western nations consider as dead someone who is brain dead. Brain death can be confirmed either by the end of breathing and the pulse (since someone who lacks either cannot have a functioning brain), or by a doctor’s assessment that the brain has irreversiblly and permanently lost its functions. There are three reasons why policymakers and most doctors have focused on the brain. One is that Western societies emphasise the importance of the mind, for which the brain is used as a proxy. The second is the cost of keeping a person on life support. The final reason is to facilitate organ transplants, since more organs can be usefully removed from someone who still has oxygen circulating in his body. 

Today several cases are challenging the idea that the brain’s vitality should be the key arbiter of death. Some people see practical concerns: they dispute that the brain can be called dead if some functions that it regulates, such as menstruation, remain; or they worry that people will be prematurely declared dead in order to secure organs. But the main challenges tackle the very definition itself. In many cases, this is down to religious belief. Jews from Orthodox sects, from which Mr Ouanounou hails, only consider someone dead when his heart and breathing cease. Some Muslims hold similar beliefs. Another case in Canada turns in part on the Christian beliefs of Taquisha McKitty, who was declared dead last year after a drug overdose. Her family say that she believed that the soul is present so long as her heart beats—and she is breathing, even if only because of medical equipment. In other cases, it is from personal or communal conviction. Japan is reluctant to see the brain-dead as gone, partly because the whole body is given prominence in Japan, rather than merely the mental part, as in the West. 

A few jurisdictions have found ways to adjust to these challenges. The American state of New Jersey bans doctors from declaring someone dead on the basis of irreversible brain damage if they have reason to believe it would contravene the patient’s religious convictions. In 2008 Israel introduced a brain-death standard but still allows some scope for the patient to choose (if indeed her wishes are known) between that definition and a cardio-respiratory one. New York state directs doctors to show “reasonable accommodation” not only for religious protests against the brain-death standard, but also for moral ones. Facing a severe shortage of organs, Japan in 1997 enacted a law allowing those who clearly express their wishes to be a donor to be declared dead when their brains shut down. Few dispute that, for society to function, death must be clearly defined. But challenges like Mr Ouanounou’s suggest that countries should consider allowing people to opt out of their national definition—within limits—by making their wishes known in advance. Places that do this already, such as New York, have not caused any special problems as a result, suggest it may be feasible for other jurisdictions.

Dig deeper:When death is not the end