Brain death: mind over matter
Understanding the basis of an alternative form of death determination.
Written By Anna Baker
The introduction of death by neurological criteria – brain death – altered the boundaries of physiological death when it was defined in the 1960s. It showed that our existence as a person – not just derivative biological life – is contingent on the continued functioning of the brain and brainstem. As brain function is what underlies the existence of the mind and personhood, it is critical to evaluate brain death from a philosophical perspective.
“Medical thought is fully engaged in the philosophical status of man” – Foucault, The Birth of the Clinic, 1976
Motivations for creating an alternative criterion of death determination
Life support, which enabled doctors to extend life in critically and terminally ill patients, began to significantly advance in the mid-1940s to 1960s. This included positive pressure invasive ventilators that enabled mechanical ventilation of patients, electroencephalography (EEG) to identify clinical signs of consciousness, and extracorporeal membrane oxygenation (ECMO) machines, which continuously remove a patient’s blood, reoxygenate it, then return it into their body.
Patients with significant neurological injury would have died within minutes without this technology, which is why cardiorespiratory criteria has been the only criteria of death for most of history. Therefore, medical professionals of the 1960s were faced with a new dilemma of death determination as they began to analyse the consequences of indefinitely sustaining the physiological function of irreversibly comatose patients via use of life support machines. Determination of death at this time incorporated only cardiorespiratory criteria, requiring “a total stoppage of circulation of the blood, and a cessation of animal and vital function consequent thereupon, such as respiration, pulsation, etc.”. This did not encompass the new ability to maintain the vital functions of a human body with no brain function – a body without a mind or sense of self that would cease all functioning if not for its connection to numerous machines and therapeutics. Brain and brainstem function became the most important factor for death determination in such cases.
A philosophical examination of how death can be declared on the basis of irreversible loss of neurological function is essential to better understand this alternative criterion of death.
Two substances or concepts of life, and therefore death: the person and the organism
Demarcating the functionalities that distinguish the person versus the organism is essential in the philosophical conceptualisation of brain death. McMahan’s 1995 paper The Metaphysics of Brain Death delves into this concept, which will be outlined in this article. This is further developed by considering the notion of the “organism as a whole” (the integrated brain and body), and whether its disintegration after irreversible loss of brain function equates to death. This demands a clear definition of the criteria of life, which will be explored via the 2009 paper Philosophical considerations on brain death and the concept of the organism as a whole by Bonelli et al.
Death of the person versus death of the organism
McMahan argues that “the person or self is one thing and the human organism is another. We require a separate account of death for each”. Death of the organism involves the irreversible loss of integrated functioning of the human body. Death of the brain does not equate to the death of the organism because the brain is just one component, one organ of the body. Nor does it coincide with the death of the organism because the brain-dead patient is on multi-organ support machines. But as the vital functions of the organism rely on brain and brainstem function, once life support is removed, the death of the organism swiftly follows. Therefore, brain death is death despite the artificial emulation of vital functions by mechanical organ support; the biologically alive organism is a necessary but insufficient condition to consider a person as living. This is reflected in brain death legislation, such as the significant Uniform Determination of Death Act passed in the United States in 1981 which clarified that death can be determined by the traditional cardiorespiratory criteria of death or by neurological criteria. Death of the organism relates to the irreversible cessation of circulatory and respiratory functions (inevitably followed by loss of brain function, and therefore death of the person) whilst death of the person relates to the irreversible cessation of all functions of the entire brain and brainstem – brain death.
The organism as a whole: criteria for life
To better understand this delineation of death of the person versus organism, defining the core criteria for life of the “organism as a whole” – a phrase used by Bonelli et al. in their 2009 paper - is essential. They proposed four criteria for life: integration, coordination, dynamics, and immanency. But they argued that to be an “organism as a whole” also requires completion, indivisibility, autofinality, and identity. Bonelli et al. argued that if one of the latter characteristics is absent there is no longer a living being, only “derivative life”. From the first set of criteria, the brain-dead patient lacks immanency, which refers to integration, coordination, and dynamics in the sense that they must autonomously “spring” from the living body. Furthermore, the physiological function produced by organ-supportive intervention does not meet the four latter criteria as it is not coupled with any higher cortical function or brainstem function. Therefore, the brain-dead patient is not an “organism as a whole”. Ultimately, only a functioning brain – the provider of central regulation, coordination, and integration – can complete a person. Otherwise “a living being is imitated at best”. Such considerations are essential when understanding how physiological maintenance of vital organs, respiration, circulation, and neuroendocrine functions via life-sustaining machines and therapeutics is compatible with a determination of death by brain death criteria.
The significance of brain function, mind, and body in defining life and death
A person is not their body but their mind, the source of their identity. As the irreversible loss of the mind is central to brain death, one can begin by considering a conception of the mind that rival schools of thought agree on: “the mind is either generated by or identical with the states and operations of the brain”. This relates to eliminative materialism, a brain-reductive stance of neurophilosophy that reduces consciousness to the brain’s neuronal activity and is the basis of today’s conception of brain death. In brain-dead patients, whilst the brain ceases to function, the substance of the brain still exists. Therefore, the mind cannot be equated to the brain. But as it is in the functioning physical substance of the brain that the mind is realised, the mind can be reduced to the neurological functioning of the brain. Therefore, cessation of function of the entire brain is sufficient for the cessation of existence of the mind and, therefore, the self. Hence, this comprises the death of the person, allowing the declaration of brain death. Upon the removal of life support machines, death of the organism by cardiorespiratory criteria then ensues.
However, opponents to the current brain death criteria, such as Seifert (Is “brain death” really death?, 1993), argue that if the body is “kept from disintegrating” and retains signs of life (i.e. kept on life support indefinitely), it is wrong to declare irreversibly comatose patients dead. However, the “signs of life” to which they refer are not immanent – they are a result of external machines. The body is unable to autonomously function once life support is removed. Hence, brain death – death of the person – is followed by death of the organism. Therefore, brain death is a valid and necessary criterion for death. This leads to a consideration of the interaction of life-sustaining technologies and brain-dead patients.
The machine-human hybrid
Progression to brain death only occurs due to the decision to connect a person with catastrophic brain injury to life-sustaining machines. Brain dead patients reside in ambiguity between people and cadavers. In her 2002 book Twice Dead, medical anthropologist Margaret Lock employs the term “living cadaver” to conceptualise the state of existence of the brain-dead patient that is created by the hybridisation of life support machines and a brain-dead human. It is the ambiguity of this hybrid that incites moral disputes around whether the living cadaver is assigned to life or death.
From a moral and economic standpoint, Lock argues, the physiological function of a brain-dead patient’s body should not be prolonged unnecessarily via life-sustaining technologies just because modern medicine has the capability to do so. Prolonging life support of a brain-dead patient should only occur if they are an organ donor, as this requires that organ function and circulation is maintained until removal of the organs. It follows that medical professionals attend to such patients in some respects as if they were living. But it must be remembered (and, essentially, communicated to family members) that a body sustained by machines but irreversibly lacking its central integrator and seat of the mind is not a living person. Rather, derivative biological life (a body lacking completion, indivisibility, autofinality, and identity) is being sustained.
Conclusion
Understanding and explaining brain death from only a reductive medical perspective is insufficient. This approach neglects consideration of the liminal space between life and death that the brain-dead patient occupies, which requires a philosophical evaluation alongside its scientific explanation, as well as - beyond the remit of this article - consideration of the cultural values and beliefs which have long enabled humans to transcend the transitory existence of the human body and the finality of death. Understanding the boundary between a person (deceased) versus an organism (a body on life support) and of the criteria of life that demarcate brain-dead patients’ state of being from that of the “organism as a whole” is, therefore, of great utility for understanding brain death as an alternative criterion of death.
This article explores themes from Anna’s dissertation, “The re-conception of end of life: evaluating brain death and the medicalisation of death”. This, and further reading, is available at the QR code below.