Brain Death and Human Organismal Integration: A Symposium on the Definition of Death

Abstract

Does the ability of some brain dead bodies to maintain homeostasis with the help of artificial life support actually imply that those bodies are living human organisms? Or might it be possible that a brain dead body on life support is a mere collection of still-living cells, organs and tissues which can coordinate with one another, but which lack the genuine integration that is the hallmark of a unified human organism as a whole? To foster further study of these difficult and timely questions, a Symposium on the Definition of Death was held at The Catholic University of America in June 2014. The Symposium brought together scholars from a variety of disciplines—law, medicine, biology, philosophy and theology—who all share a commitment to the dead donor rule and to a biological definition of death, but who have differing opinions regarding the validity of neurological criteria for human death. The papers found in this special issue are among the fruits of this Symposium.

Does brain death, understood as the irreversible loss of brain function, truly mark the death of a human being? Since its first formulation by the 1968 Harvard Ad Hoc Committee, the concept of brain death has been a matter of significant controversy. ¹ New evidence and highly publicized recent cases—like that of Jahi McMath and Marlise Muñoz—have intensified that controversy not only among scholars and medical professionals but also among the general public. Particularly influential in this regard has been the research of pediatric neurologist D. Alan Shewmon, showing that some patients diagnosed as brain dead can “survive” ² weeks, months, or even years if maintained on a ventilator, defying the claim that cessation of heart and lung function follows inexorably and imminently (usually within a few days) upon the cessation of brain function, even when ventilator support is provided (Shewmon 1998; 2001; 2010). Shewmon’s evidence seems to call into question the standard rationale for the claim that total brain death marks the death of a human being—namely, that a functioning brain is necessary for integration of the body. ³ Indeed, it was largely due to this evidence that the 2008 President’s Council on Bioethics abandoned this standard rationale and argued instead that brain death marks the death of a human being because the brain is required for the organism to perform its “fundamental work” (The President’s Council on Bioethics, 2008).

By reaffirming the validity of neurological criteria for the determination of death despite the apparent collapse of the traditional rationale, the Council’s conclusion allows for continuation of the practice of removing vital organs from patients who are dead according to neurological (but not cardiopulmonary) criteria, without thereby violating the rule that requires organ donors to be dead before harvesting their organs. Some see the President’s Council’s conclusion as untenable, a mere rationalization to avoid admitting that the current practice of organ donation after brain death does indeed violate the dead-donor rule in some cases (Miller and Truog, 2009). ⁴ Bioethicists such as Robert Truog, Franklin Miller, and Scott Halpern suggest that it would be more honest simply to abandon the dead-donor rule, allowing patients whose death is imminent “to die in the process of helping others to live”—that is, to die as a result of the removal of their vital organs for donation—if they so choose (Truog, Miller, and Halpern, 2013, 1289). Others, such as Robert Veatch, propose distinguishing between, on the one hand, death in the moral and social sense as indicating a loss of full moral and legal standing, and, on the other hand, death in the traditional biological sense (Veatch, 2015). ⁵ On this view, while those who are brain dead may not necessarily be biologically dead, they are morally, socially and legally dead, and can be treated as such.

Yet, regardless of what one thinks of these controversial proposals, the factual conclusion that partially motivates them—that is, that whole-brain death does not mark the loss of genuine somatic integration—seems premature. It is undeniable that, if maintained on a ventilator and given appropriate pharmacological support, brain dead bodies will not always undergo an imminent and rapid decline toward complete disintegration and deterioration. Yet does the ability of some brain dead bodies to maintain homeostasis with the help of artificial life support actually imply that those bodies are living human organisms? Or might it be possible that a brain dead body on life support is a mere collection of still-living cells, organs, and tissues, which can coordinate with one another, but which lack the genuine integration that is the hallmark of a unified human organism as a whole?

To foster further study of these difficult and timely questions, a Symposium on the Definition of Death was held at The Catholic University of America in June 2014. The Symposium brought together scholars from a variety of disciplines—law, medicine, biology, philosophy, and theology—who all share a commitment to the dead-donor rule and to a biological definition of death, but who have differing opinions regarding the validity of neurological criteria for human death. Among the fruits of this Symposium are the papers and Summary Statement—signed by almost all participants—found in this special issue.

To clarify the legal and social context within which the debates over brain death are taking place, Bioethics Defense Fund Attorneys Nikas, Bordlee, and Moreira (2016) present a survey of the current US laws enacted in the various states across the nation related to brain death and organ donation, highlighting the ways in which recent controversies have shaken the public’s faith in the reliability of neurological criteria for the determination of death particularly in relation to organ donation. The authors conclude that “clarity in law and policy based on medical ethics that reject the utilitarian use of human beings are necessary to bridge the gap between the medical community and an increasingly wary public in order to rebuild trust in regard to ethical criteria for both the determination of death and standards for organ procurement” (Nikas, Bordlee, and Moreira, 2016, 238–9).

The remainder of the papers present and defend a variety of positions regarding the ontological status of brain dead bodies. Condic (2016) and Moschella (2016) both defend the view that death of the whole brain (including the brain stem) does indeed mark the death of the human organism as a whole. Approaching the issue as a neurobiologist, Condic presents evidence that calls into question the claim that brain dead bodies on life support are genuinely integrated. Rather, she argues that while the cells and tissues that once formed a part of an integrated human body may maintain the appearance of continued integration, their functions after brain death can all be explained as the result of local coordination between cells, the sort of coordination that can also be found in cells and tissues ex vivo. According to Condic, in post-natal human beings the brain is necessary for genuine integration because only the brain is capable of “[compiling] information from diverse structures and systems to generate a response that (1) is multifaceted, (2) is context dependent, (3) takes into account the condition of the whole, and (4) regulates the activity of systems throughout the body for the sake of the continued health and function of the whole” (2016, 271). Condic goes on to consider hard cases, like that of severe upper cervical spinal cord injury (SCI) patients whose brains are largely disconnected from the rest of the body and who thus lack the global, autonomous self-integration that is the mark of a unified organism as a whole. How can such individuals still count as living human beings on her view, despite their inability to function as self-sustaining organisms? To answer this question, Condic relies on Aristotle’s definition of human beings as rational animals. Because human beings are rational animals, argues Condic, either the persistence of mental function (the basis for the exercise of rationality) or the persistence of global, autonomous organismal integration (the basis for animality) is sufficient evidence that a human being is still alive. Mental function clearly persists in SCI patients, and they are therefore alive according to Condic’s criteria. However, since whole brain death marks the irreversible loss of both the basis for rationality and the basis for animality, brain death is death.

My own paper complements Condic’s by offering a deeper analysis of the underlying metaphysical issues. Beginning with a critique of Shewmon’s analogy between brain dead bodies and SCI patients, I argue that, pace Shewmon, the standard rationale for brain death need not imply that an SCI patient is a conscious non-organism. Rather, on my view, an SCI patient is indeed an organism, even though that organism is severely disabled and, strictly speaking, has been reduced to the head alone insofar as the brain is no longer able to regulate the body below the site of the transection. I then go on to show that, more generally, Shewmon’s criticisms of neurological criteria for death rest on a failure to interpret correctly the metaphysical significance of biological facts, particularly facts regarding the biological capacities of brain dead bodies. Drawing on Aristotelian-Thomistic hylomorphism, I claim that the soul (or Aristotelian form) is the formal principle of all of an organism’s capacities, including its capacity for self-integration. To be an organism, therefore, an entity must possess “the root capacity for self-integration (of which the soul is the principle).” Yet how do we know when an organism has lost this capacity, and thus has died? I develop and defend the view that the presence of the root capacity for self-integration, and thus of the soul, “is evidenced by (1) possession of the material basis of the capacity self-integration—i.e., the capacity for control of respiration and circulation—or (2) possession of the material basis of the capacity for sentience” (Moschella, 2016, 289). Since the material basis for the ability to breathe spontaneously and for sentience (understood as conscious perception) lies in the brain, brain death implies loss of the body’s root capacity for self-integration (or at least absence of any evidence for the continued presence of that capacity). Brain death, therefore, implies the death of the human organism.

Patrick Lee (2016) offers an alternative defense of the validity of neurological criteria for human death, one which attempts to bypass the question of whether or not it is possible for genuine integration to persist in a body after brain death. Lee argues that “even if some brain-dead bodies are organisms, or complex entities of some sort, they are not human organisms: They lack the radical capacity for conscious sentience—a prerequisite for rationality in a human being—and so are not rational animals” (Lee, 2016, 301). After developing this “radical capacity for sentience” argument and defending it from a number of objections—including the objections raised in Nicanor Austriaco’s (2016) paper in this issue—Lee clarifies that, while his view may seem to be a radical departure from the standard rationale for considering brain death to be death, it should in fact be interpreted as a specification of that rationale. The concept of integration, claims Lee, applies analogously to different types of entities. While brain dead bodies may exhibit a certain level of integration, on Lee’s account they lack the “integration required of a human being” because they lack “the structure necessary for the radical capacity for conscious sensation”—that is, the brain or the capacity to develop a brain—and have thus undergone a substantial change (Lee, 2016, 312).

Responding to an earlier version of the “radical capacity for sentience” argument articulated by Grisez and Lee (2012), Austriaco makes the case that brain dead bodies may indeed possess the capacity for sentience. Although he readily admits that “the TBD [totally brain dead] patient is not sentient in the way that a crying infant or a roaring lion is sentient,” he reminds the reader that fruit flies and earthworms are also animals, and claims that a TBD patient may be able “to perceive and to respond to his environment in the way that these other animals perceive and respond to their environments” (Austriaco, 2016, 319). Austriaco supports this claim with evidence indicating that, even when severed from the brain, the “spinal cord can mediate numerous specific responses to stimuli that extend beyond mere reflex” (Austriaco, 2016, 319). Recognizing that Lee and Grisez would be likely to respond by clarifying that the sort of sentience required of a human animal (or of any mammal) is conscious sentience, Austriaco goes on to criticize this revised formulation of their argument, which he calls the “radical capacity for consciousness” argument. Austriaco considers this argument deeply troubling, claiming that it could lead to a “brain-region-specific definition for death” according to which “end-stage Alzheimer’s and some PVS and coma patients would be considered dead” (Austriaco, 2016, 322). Although Lee claims that his position would not in fact have this implication, Austriaco believes that—particularly given the difficulty or perhaps even impossibility of distinguishing “patients with a blocked active potential for consciousness from those who have permanently lost it”—it is “more reasonable and prudent” to assume that a TBD patient “is still a sentient animal, even if he is permanently unconscious” (Austriaco, 2016, 324).

Unlike Condic, Moschella, Lee, and Austriaco, Christian Brugger does not directly argue for or against the claim that total brain death marks the death of a human being. Rather, Brugger’s essay focuses on the presence of persistent doubt regarding the ontological status of brain dead bodies, arguing that, in the presence of such doubt, we should err on the side caution, treating brain dead bodies as living human beings unless we are morally certain that they are not. After outlining the evidence presented by Alan Shewmon in support of the claim that integrated functioning can persist in brain dead bodies on life support, Brugger shows how that evidence has led to a widespread loss of confidence in the standard “brain-as-regulator-of-holistic-integration” rationale for the neurological definition of death. Brugger believes that “reasonable doubt against the conclusion that a body has lost the capacity [to self-organize] exists when the body appears to express it and no evidence to the contrary is sufficient to rule out the conclusion that the apparent expression is a true expression” (Brugger, 2016, 336). Does such “evidence to the contrary” exist? To answer this question, Brugger engages at length with Condic’s argument in defense of the validity of neurological criteria for human death, concluding that while it “is sufficient to exclude moral certitude that BD individuals are alive,” it is not sufficient to “yield certitude that they are dead” (Brugger, 2016, 339). Brugger also engages with Lee and Grisez’s “radical capacity for sentience” argument, but finds it unpersuasive. Brugger concludes that the burden of proof on this matter falls on those who defend the validity of neurological criteria for human death, and that this burden has not yet been met.

Although the Symposium’s participants were all approaching the issue of brain death from within the Catholic philosophical and theological tradition, the papers published here, including the Summary Statement outlining the Symposium’s conclusions, are of broad relevance. As the foregoing summaries show, none of the papers in this issue is premised upon the truth of any theological claim. While the authors’ discussions are all consistent with Catholic teachings regarding the definition of death and the nature of the human person, the positions presented are philosophical. Thinkers within the Catholic tradition—including James Bernat, who is perhaps the most prominent defender of the standard rationale for considering brain death to be death, and Alan Shewmon, who has strongly criticized that rationale—have been highly influential in debates about brain death from the very beginning. Further, the development of a consistent position on the topic that is in line with Catholic teaching is of particular practical importance given the Catholic Church’s widespread role in the provision of healthcare. My hope is that the papers in this issue will provide new insights that can help to deepen and clarify the ongoing scholarly and public debates on this important topic.