Do we know what death is? For centuries, death was diagnosed when the heartbeat ceased, but heart machines now mean that a patient can survive even after their heart stops. The focus then shifted to brain-death, yet brain-dead patients’ bodies can continue to function – a brain-dead female can even carry a pregnancy to term. So brain-death is not the death of the human organism. Lukas J. Meier argues that this suggests we should stop thinking of death as biological, and instead see it as psychological: what really matters is not the death of the organism, but the death of the psyche.

Imagine a situation that we all dread: one day you receive a call, informing you that a friend has had a severe car accident. You rush to the hospital. The doctors explain to you that your friend suffered catastrophic head injuries and has just been declared brain dead. As most of his body is still intact, preparations for the explanation of organs are now underway. Your friend had indeed expressed his wish to serve as an organ donor in the event of an early death.

While you are still digesting the shocking news, you take a closer look at your friend’s body. His eyes are closed and he is unable to breathe on his own. A ventilator provides oxygen. But when you touch his arm, you notice that his body is warm rather than cold and stiff. You feel his pulse. His heart is beating normally. Compared with other patients in intensive care, who – so the doctors assure you – are alive, you cannot discern any difference: many of them are connected to ventilators, too. Just like your friend, they appear to be profoundly asleep. Yet everyone insists that these patients are alive, whereas your friend has died. You begin to wonder what is going on. What is the rationale behind this verdict?

For many centuries, death had been diagnosed when heartbeat and breathing had permanently ceased. In the middle of the twentieth century, a technological innovation called into question this practice: heart-lung machines were now able to temporarily replace these vital functions by mechanically perfusing the body with oxygenated blood. A heart that was not beating for several minutes no longer indicated that the patient had died. Consequently, a new criterion was required for the diagnosis of death in the presence of external life support.

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A growing number of authors to believe that the destruction of a single organ – the brain – does not necessarily correspond to the ceasing to exist of the organism as a whole.

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With the ability to bypass heart and lungs mechanically, focus shifted to another organ: the brain. The brain is the body’s central control mechanism. Consequently, so the rationale went, the destruction of this organ must be equivalent to the dissolution of somatic unity of the whole organism. Devoid of the brain’s coordinating influence, the body’s organs – although they may remain functional for a while – no longer work in concert, and the organism is to be regarded as dead. Brain death, as this novel criterion was termed, has become accepted as a legal indicator of death in many jurisdictions. It is also an important pillar of organ-transplantation programmes as it means that organs may be taken also from brain-dead individuals, thus increasing the pool of potential donors.

However, ever since the introduction of brain death there have been doubts as to whether the loss of function of the brain alone is indeed biological death. With the help of external life support, brain-dead bodies can maintain homeostasis, energy balance, and temperature regulation. They eliminate cellular wastes, heal wounds, and fight infections. They show sexual maturation and proportional growth and, if female, can carry a fetus to term. Most of these functions require a high level of internal coordination, which appears to contradict the hypothesis that the destruction of the brain marks the end of all meaningful functional integration. The preservation of these mutually interdependent functions has led a growing number of authors to believe that the destruction of a single organ – the brain – does not necessarily correspond to the ceasing to exist of the organism as a whole.

If this view is correct, brain-dead patients are declared dead prematurely. While this is a problem in and of itself, the consequences for organ donation are particularly severe. The cornerstone of all transplantation programmes is the so-called dead-donor rule: patients must be dead before their organs are explanted. There are good reasons for this strict requirement – ethical and practical. Only militant consequentialists would consider killing a patient in order to save the lives of other individuals morally appropriate. And from a purely practical standpoint, very few people would sign up to become potential organ donors if there was a remote chance that they might not yet be dead when their organs are taken.

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Does this mean that we must abandon the practice of organ donation following brain death? Since hundreds of thousands of patients are waiting for a transplant, the consequences of such a step would be catastrophic. Luckily, there is still a way out.

While the friend in our hypothetical situation may look just like many other patients in intensive care, and while, as we have established, some integrated processes are still continuing in his body (albeit with the help of extensive external support), there is also an important difference between him and everyone else in intensive care: the friend is irreversibly comatose. He is never going to regain consciousness, to have any perceptions and emotions, or even to dream. Why can we be so sure about this?

Consciousness is a product of two elements: wakefulness and awareness. Wakefulness is generated by a system in the brainstem – the part of the brain that is closest to the spinal cord. Awareness is predominantly a function of complex interactions between several areas in the upper brain. A patient is only conscious when he or she is both awake and aware of something – for example, of a sound or a thought. Even dreaming requires that there is some degree of wakefulness and awareness.

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We could, thus, move brain death to the psychological domain rather than understanding it as a strictly biological phenomenon.

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Some patients whose upper brains are severely injured while the lower parts of their brains remain intact may still exhibit sleep-wake cycles. They open their eyes periodically although – to the best of our current knowledge – they do not have any conscious experiences. This syndrome is called persistent vegetative state. In brain-dead patients even this residual periodical wakefulness is absent. This is because in most jurisdictions the diagnosis of brain death necessitates the irreversible loss of function in all parts of the brain. In extinguishing the prerequisites not only of awareness but also of wakefulness, brain death is therefore an overdetermined, and thus extremely reliable, criterion of the irreversible absence of consciousness and any other mental activity. The patient is in the deepest possible coma because he or she lacks the anatomical structures required for wakefulness; yet even if these were intact, he or she could not be aware of anything.

Identifying brain death with the irreversible loss of consciousness is therefore entirely uncontroversial – unlike equating it with organismic death. Limiting the definition to the former would permit us to keep the neurological criterion – the destruction of the entire brain – while simultaneously providing a different justification for why this state is the end of our existence: even if brain death may not be the death of an organism in all circumstances, it is undoubtedly the moment after which no psychological subject – no person – will be associated with the respective body. We could, thus, move brain death to the psychological domain rather than understanding it as a strictly biological phenomenon.

Upon the total destruction of his brain, the friend in our example was gone in a meaningful sense; the psychological person that he had been, the conscious mental entity, is no longer there. And as a result of the efficiency of modern life-support systems that keep the body functional at a basic level, this state can be reached without his organism ceasing to function at the same time. Brain death is therefore still death; it is just the death of a different subject.

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The destruction of the brain no longer marks the ceasing to exist of the organism as a whole.

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Is this a sensible proposal? Death per definitionem is an irreversible state. However, advancements in life-supporting technology have created a situation in which the loss of central control that occurs in brain death can be compensated for with increasing precision. This tendency is going to continue, so that biological justifications of brain death, according to which an organism devoid of a functional brain has ceased to exist, will become increasingly implausible as more and more functions can actually be maintained with external help.

One of the few domains that is still withstanding advancements in the external provision of organismic functions is the mental. To escape the dilemma posed by ever-improving technology, and in order to put into place a definition that is both conceptually sound and physiologically accurate, we should therefore indeed consider shifting the justification of brain death from the vegetative to the mental realm. Paradoxical as it may seem, it is our lack of success in replacing functions of the latter kind that is the prerequisite of guaranteeing the irreversibility that any definition of death must have at its core.

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Given the great sophistication of life-support systems, the destruction of the brain no longer marks the ceasing to exist of the organism as a whole – just as the cessation of cardiopulmonary function lost this status with the advent of heart-lung machines. But brain death is still the event that seals the fate of the person, and our current practice of organ procurement may continue on the basis of this psychological rationale while simultaneously honouring the dead-donor rule.

Lukas J. Meier’s research can be accessed at https://lukasjmeier.com/