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. 2016 Apr 17;41(3):315–328. doi: 10.1093/jmp/jhw008

The Brain Dead Patient Is Still Sentient: A Further Reply to Patrick Lee and Germain Grisez

Nicanor Pier Giorgio Austriaco OP 1,*
PMCID: PMC4889819  PMID: 27089894

Abstract

Patrick Lee and Germain Grisez have argued that the total brain dead patient is still dead because the integrated entity that remains is not even an animal, not only because he is not sentient but also, and more importantly, because he has lost the radical capacity for sentience. In this essay, written from within and as a contribution to the Catholic philosophical tradition, I respond to Lee and Grisez’s argument by proposing that the brain dead patient is still sentient because an animal with an intact but severed spinal cord can still perceive and respond to external stimuli. The brain dead patient is an unconscious sentient organism.

Keywords: brain death, bodily integration, neurological criteria, sentience

I. INTRODUCTION

Traditionally, the presence or absence of bodily integration has been used to definitively discern the presence or absence of human life where decomposition of the body is the surest sign of death. The cessation of heart and lung function anticipated this bodily disintegration. This is the criterion endorsed both by Pope St. John Paul II when he taught that the “death of the person is a single event, consisting in the total disintegration of that unitary and integrated whole that is the personal self. … This is then considered the sign that the individual organism has lost its integrative capacity” (John Paul II, 2001, 91), and by the United States President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research when it concluded that “death is that moment at which the body’s physiological system ceases to constitute an integrated whole” (President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, 1981, 91).

For the Catholic philosophical tradition, this criterion for the loss of bodily integration at death emerges from the philosophical claim that death results from the separation of the soul, which is the principle of the organism’s integrity and unity, from its matter. 1 In contrast, for the secular philosophical tradition represented in the work of the President’s Commission, this criterion for death is linked to the claim that death involves the loss of homeostasis, defined as the property of living organisms to maintain a stable internal environment through energy-consuming processes that maintain integrated functioning. 2 Proponents have used this criterion to argue for the validity of the total-brain death (TBD) definition for death, which proposes that the human being is dead when there is complete and irreversible cessation of functioning of all parts of his brain: Since the brain is the integrating organ of the human body, loss of the brain inevitably leads to loss of bodily integrity and thus to death. 3

In recent years, however, there has been increasing evidence—primarily from the work of D. Alan Shewmon 4 —that the TBD patient is able to continue to live and to maintain some integrated functions, albeit with the necessary assistance of mechanical ventilation. 5 The medical evidence was compelling enough for the President’s Council on Bioethics to conclude:

If being alive as a biological organism requires being a whole that is more than the mere sum of its parts, then it would be difficult to deny that the body of a patient with total brain failure [the Council’s preferred description for a brain dead patient] can still be alive, at least in some cases. (President’s Council on Bioethics, 2008, 57)

The evidence for integration has also prompted two prominent secular bioethicists, Robert D. Truog and Franklin G. Miller, to propose that the phenomenon of brain death should be acknowledged for what it truly is, a social construct that involves declaring a patient legally but not biologically dead. 6

In contrast to Truog and Miller who have affirmed that the integrated TBD patient is still alive, Catholic bioethicists Patrick Lee and Germain Grisez have responded to the evidence for the integration of the TBD patient by arguing that he is still dead because the integrated entity that remains is not even an animal, not only because he is not sentient but also, and more importantly, because he has lost the radical capacity for sentience. 7 In their view, if the TBD patient is not even an animal, he certainly cannot be the human organism that he was before total brain failure. He must therefore be dead. This is an argument that is particularly pertinent to Catholic bioethicists, given the Catholic philosophical tradition’s reliance on an Aristotelian account of the human being as a rational animal.

The Lee and Grisez argument is also of interest to a non-Catholic audience because it remains one of only two arguments proposed from within the Catholic philosophical tradition in defense of the total brain criterion for death today. 8 As is becoming increasingly clear among Catholic bioethicists, there is a crisis of confidence in the received justification for the legitimacy of the total brain death criteria. If Lee and Grisez’s argument is flawed, then that would be one less reason to affirm that the TBD criteria truly demonstrate the death of the body as the Catholic philosophical tradition properly understands death. This would contribute further to the ongoing erosion of societal support for the neurological criterion for death. One only has to imagine the negative impact of a papal encyclical rejecting the legitimacy of the brain death criterion on worldwide organ donation rates to appreciate the import of this debate within the Catholic tradition to scholars outside the tradition.

In this brief essay, written from within and as a contribution to the Catholic philosophical tradition, I respond again to Lee and Grisez’s argument—in my first response to this argument, I had called it the radical capacity for sentience (RCS) argument 9 —by proposing that the brain dead patient is still sentient because an animal with an intact but severed spinal cord can still perceive and respond to external stimuli. 10 Or to put it another way, the brain dead patient is an unconscious sentient organism. 11

II. THE RCS ARGUMENT: THE BRAIN DEAD PATIENT IS NOT CAPABLE OF SENTIENCE

In brief, Patrick Lee and Germain Grisez’s argument for the nonsentience of the TBD patient is as follows. They begin by proposing a gedanken experiment: Suppose a human being named John is decapitated so that both his head and his decapitated body are kept alive as two separate entities. Is the decapitated body a human organism? They then ask: How about a living entity consisting of all but only the organs and tissues from the waist down of a youthful accident victim? Is that a human organism as well? In response, Lee and Grisez say no, because in their view, the brain-dead patient, the decapitated person, and the waist-down biological unit are not even animals:

But the decapitated body and the totally brain dead individual are similar to the waist-down unit rather than to the individual who has lost everything below the heart and lungs, because the headless body and the brain-dead individual are no longer sentient organisms. Neither of them is an animal, and so neither can be a human being. (Lee and Grisez, 2012, 277)

At the heart of their argument, Lee and Grisez hold to a definition of an animal that has a distinctively Aristotelian provenance: An animal as a living organism that has a radical capacity for sentience or the capacity to develop a capacity for sentience where, all things being equal, sentience is the capacity to perceive and to respond to one’s external environment. 12 An animal is a living organism that has the radical capacity to see, to hear, to feel pain and pressure, and so forth. Since Lee and Grisez argue that the human brain is required for sentience—they claim that “there … is common agreement that no mammal can sense without brain functioning—a mammal’s sentience requires either a brain capable of functioning or the capacity to develop a brain” (Lee and Grisez, 2012, 279)—the loss of the brain, in their view, inevitably leads to the loss, not only of the capacity for, but also the radical capacity to develop a capacity for, sentience.

As such, according to Lee and Grisez, a brain-dead patient is not an animal. And if the TBD patient is not an animal, a fortiori he cannot be a rational animal, that is, a human being. Therefore, they argue, the human organism who was the TBD patient has ceased to be even an animal. He is dead. Or as Lee and Grisez put it: “An individual such as TK [a patient who had undergone total brain death who is often discussed in the primary literature], therefore, that has undergone total brain death is not an animal and so not a rational animal, a human being” (Lee and Grisez, 2012, 279). Using Aristotelian terminology, loss of the total brain, and therefore, the loss not only of the radical capacity for sentience but also of the capacity to develop (or recover) the capacity for sentience, according to this RCS argument, necessarily involves a substantial change that transforms a human being into something that is not even an animal.

Finally, I want to emphasize that Lee and Grisez affirm that the TBD patient still has bodily integrity. However, although they acknowledge that “Shewmon has disproved that assumption [that nothing more than an aggregate of disintegrating organs and tissues survives total brain failure] by showing that TK and similar individuals are living individuals” (Lee and Grisez, 2012, 276), they conclude nonetheless that the living organism that remains, because it is not even an animal, is akin to a plant. For Lee and Grisez, the total brain dead patient is a non-sentient organism comparable to a tomato or a pumpkin or a head of lettuce.

III. RESPONSE: THE BRAIN DEAD PATIENT IS STILL SENTIENT

In response to Lee and Grisez, I would like to begin by clarifying my understanding of what constitutes animal sentience. Often when a philosopher or a theologian thinks about animals, he or she thinks about gorillas, dogs, and cats. However, as a biologist, I would also like to point out that fruit flies, bees, and earthworms are animals, too. 13 These critters are sentient because, all things being equal, they too can perceive and respond to their environment, even though some of them—earthworms have neither eyes nor ears—cannot see or hear. They can also move from one place to another. Strikingly, fruit flies and earthworms are able to learn if they are put through a classical conditioning test (Ratner and Miller, 1959; Berry et al., 2012). All things being equal, that is, when all of an organism’s bodily systems are functioning normally, sentience is the ability to respond to one’s environment in a nonreflexive manner.

It is important to acknowledge that the fruitfly and the earthworm are sentient animals because it is clear that the TBD patient is not sentient in the way that a crying infant or a roaring lion is sentient. But is the TBD patient sentient in the way that a fruitfly or an earthworm is sentient? Is the TBD patient able to perceive and to respond to his environment in the way that these other animals perceive and respond to their environments? I will argue that he is able to do so.

Lee and Grisez grounded their argument in a comparison between the TBD patient and a decapitated body. I would like to ground mine in a comparison between the TBD patient and a patient who has suffered a complete spinal cord transection. Here, the spinal cord is unable to communicate with the brain. What do these patients and animal models for complete spinal cord transection tell us about the spinal cord and how it functions after it has been severed from the brain?

Recent and not-so-recent works with animals with spinal cord transections have shown that the severed spinal cord can mediate numerous specific responses to stimuli that extend beyond mere reflex (Field-Fote, 2000; Knikou, 2010). For example, turtles with severed spinal cords are still able to perform coordinated limb movements that resemble the form of scratching that turtles with intact spinal cords generate in the performance of other rhythmic behaviors such as swimming and walking (Field and Stein, 1997). Fascinatingly, it appears that the severed spinal cord of the turtle is able to generate and to coordinate two different forms of scratching in response to external stimuli (Field and Stein, 1997). There are also data from cats that suggest that the spinal cord can learn how to step after being severed from the brain (Cote, Menard, and Gossard, 2003). Indeed, the gait of these decerebrate cats will adjust itself to the speed of the treadmill upon which the animals are suspended. (Note that there are YouTube videos available online that show decerebrate cats walking and running on a treadmill. 14 ) Moreover, cats with transected spinal cords that received 12 weeks of postural training stood with full weight bearing on the hind limbs five times longer than the maximum duration of standing in the nontrained cats (de Leon et al., 1998). These studies have been extended to other animal models, and together they suggest that simple hind-limb motor responses to cutaneous or electrical stimulation can be enhanced in animals with completely transected spinal cords via classical conditioning (Shurrager and Culler, 1940). In other words, a cat’s severed spinal cord is able to learn, and to do so without a brain!

Finally, though studies with human patients with transected spinal cords are few, there is robust evidence that suggests that the human spinal cord too has the central pattern generators (CPGs) responsible for generating the basic motor patterns that are foundational for the specific responses seen in spinally transected turtles, cats, and dogs (Guertin, 2014). Most strikingly, spinal cord injury patients with a completely transected spinal cord who participated in the locomotor training of the Christopher and Dana Reeve Foundation NeuroRecovery Network were able to recover voluntary motor function—including assisted walking! —when their CPGs were electrically stimulated, years after their paralyzing accidents. 15 In toto, these findings suggest that the animal spinal cord, including the human spinal cord, is capable of acquiring the ability to perform complex motor tasks, such as stepping and standing, following the elimination of descending input from the brain. The spinal cord is not simply a conduit for signals from the brain to the body! In the absence of the brain, it can assume a primitive brain-like function that involves coordinated behaviors in response to external stimuli. 16 It can even learn! In sum, it has radical capacity for sentience, which can be actualized in the absence of a brain.

In light of the evidence from patients and animal models with complete spinal cord transections, I propose that the TBD patient is still an animal because his severed spinal cord retains the capacity for sentience, defined here as the capacity to perceive and to respond to his environment, in the absence of a brain. Given the evidence that humans have central pattern generators like cats do, it is likely that TBD patients, like patients with transected spinal cords, given time and electrical stimulation of their spinal cords, could respond to moving treadmills as decerebrate cats respond to them. These movements would not be mere reflexes but would be coordinated responses to stimuli from the environment that are integrated by the spinal cord. They would be the responses of a disabled sentient animal mediated by a severed spinal cord that had actualized its capacity for sentience.

IV. RESPONDING TO TWO POTENTIAL OBJECTIONS

Two objections could be made to my claim that the walking behavior of decerebrate cats demonstrates that TBD patients retain a spinal-cord-based radical capacity for sentience, and as such, are still sentient animals. The first involves a dispute over whether or not simple neuronal circuits can undergird sentient behavior, and the second—which is more important—involves a dispute over whether or not consciousness is a prerequisite for sentient behavior.

First, an objector could argue that the sensing and responding observed in these decerebrate animals is not sentient behavior properly so called. He could point out that the walking behavior of decerebrate cats is mediated by a relatively simple neuronal circuit that involves only a few sensory inputs and simple motor outputs. Sentient behavior, in the objector’s view, presupposes more complex neuronal circuitry. As such, it is not sentient behavior but is a mere reflex action. Therefore, decerebrate cats cannot be used as a paradigm for TBD patients.

In response, a recent scientific study has shown that the rapid avoidance behavior of a fruit fly—clearly a behavior that qualifies as sentient, as anyone who has missed an evasive fly with a fly swatter will attest to—is mediated by a simple neuronal circuit involving a handful of giant fiber neurons (von Reyn et al., 2014). This indicates that the structural basis for a behavior, whether it is mediated by a complex or a simple neuronal circuit, cannot be used to distinguish sentient behavior from mere reflex activity. As such, there is no reason to think that the walking behavior of the decerebrate cat is not sentient behavior simply because it is mediated by a simple neuronal circuit. In fact, I think that most people would affirm from their own experience that walking behavior, especially walking behavior that can be altered by altering the speed of a treadmill, is sentient behavior properly so called. This common everyday intuition is supported by the experiments from the Christopher and Dana Reeve Foundation NeuroRecovery Network that show that the spinal cord is able to integrate and to process environmental stimuli even when it is disconnected from the brain. 17 As such, determining the complexity of the underlying neuronal circuit that mediates a particular behavior or the absence of complexity cannot be used to distinguish sensation from reflex.

Second, an objector could argue that the walking behavior of a decerebrate cat is not sentient behavior properly so called because it is behavior that is not associated with consciousness. The decerebrate cat does not “know” that it is suspended above and is walking on the treadmill. As such, the objector could argue that the walking behavior of decerebrate cats is not sentient behavior since sentient behavior, especially the sentient behavior associated with mammals, presupposes that the organism is aware of its performing that behavior. As such, the walking behavior of the decerebrate cat, once again, is but a mere reflex action. Again, decerebrate cats cannot be used as a paradigm for TBD patients.

In response, I begin by noting that this objection equates sentience with consciousness. If one cannot be sentient without consciousness, then sentience is a type of consciousness. As such with this objection, my interlocutor has reduced the RCS argument to a radical capacity for consciousness (RCC) argument. However, as I noted in my earlier response to the RCS argument (Austriaco, 2009, 6–8), it is troubling that Lee and Grisez have proposed that the loss of one’s radical capacity for consciousness or one’s radical capacity to develop the capacity for consciousness, understood as the loss of that minimal part of the brain that is necessary, though not necessarily sufficient for consciousness, is death:

Our position that the complete loss of specifically human capacities is the human being’s passing away does not entail that everyone who is unconscious and will never regain consciousness is already dead. Many unconscious people who will never regain consciousness would regain it if they were given appropriate care. Our position only entails that the loss of the capacity for consciousness is death. (Lee and Grisez, 2012, 283)

I find this argument troubling because it is not unreasonable to think that the neuroscientists in the future will be able to identify smaller and smaller regions of the brain that make consciousness permanently irretrievable when this or that region of the brain is destroyed, no matter how much appropriate care a patient without this region of the brain goes on to receive. 18 This would be a small region of the brain that is necessary but not sufficient for consciousness. To put it another way, this would be a small part of the brain without which consciousness—which in itself as a complex phenomenon could involve widespread neuronal networks spanning multiple and large areas of the brain—would not be possible. Does this mean that we will eventually have a brain-region-specific definition for death: No small region of the brain, no radical capacity to develop the capacity for consciousness, therefore, no human personal life? If Lee and Grisez’s argument were true, it would certainly mean this. Recall that their position “only entails that the loss of the capacity for consciousness is death” (Lee and Grisez, 2012, 283). Patients without this small region of the brain would have permanently lost their capacity for consciousness, because they would have permanently lost a brain region that is necessary but not sufficient for consciousness.

At that point, and probably long before, however, end-stage Alzheimer’s and some PVS (Persistent Vegetative State) and coma patients would be considered dead according to Lee and Grisez’s RCS argument. They would have lost that small region of the brain that is necessary but not sufficient for consciousness and as such would have permanently lost their radical capacity for consciousness: They would have undergone a substantial change becoming something other than human beings because they have lost that characteristic capacity for consciousness that makes their matter apt to be informed by a rational soul. These disabled patients too could be killed to harvest their organs. Again, for those who still embrace a dead donor rule that acknowledges that end-stage Alzheimer’s patients are biologically alive—and I acknowledge that there are scholars, especially non-Catholic bioethicists, who would have no problem with the claim that end-stage Alzheimer’s and other severely disabled patients should be declared dead and as such would have no problem with Lee and Grisez’s argument—this would be deeply troubling, and for those working within the Catholic philosophical tradition, this would be contrary to the magisterial teaching of the Catholic Church. 19

Instead, I propose that we do not have to go down this path towards a brain region definition for death that would imperil the lives of Alzheimer’s and terminally comatose patients. In fact, I argue that the whole reductionist approach of identifying that “critical” part of the brain that is necessary for the radical capacity for consciousness by identifying that part, which when lost, renders the individual permanently unconscious—a clinical task presupposed by Lee and Grisez’s RCS/RCC argument—is conceptually flawed and wrongheaded. It will not and cannot work, because we will never be able to determine if the TBD patient has truly lost his radical capacity for consciousness. Therefore, I propose that it is reasonable and prudent to assume that the TBD patient retains his radical capacity for consciousness and as such is still a rational animal, even if he is permanently unconscious. Let me explain.

Lee and Grisez are looking for diagnostic criteria that will correctly identify the patient who has permanently lost his capacity for consciousness. He would then be dead. Recall their statement: “Our position only entails that the loss of the capacity for consciousness is death” (Lee and Grisez, 2012, 283). Lee and Grisez contrast this with the patient who has only temporarily lost her capacity for consciousness, which she would regain if she were given appropriate care. She would still be alive. Using classical terminology, Lee and Grisez are looking for diagnostic criteria that would distinguish patients with an active potential for consciousness from those that do not. An active potential is actualized wholly from within. It is indicative of an entity’s nature—its ontological status. For example, an acorn has an active potential to become an oak tree, even if it needs soil and water in order to realize this potential. By definition, a human being has an active potential for consciousness. Note that this active potential could be blocked by sleep, by disease, or by bodily dysfunction. However, if the unconscious individual is awakened or is cared for in an appropriate manner, the brain could heal itself so that this active potential could be actualized again. Thus, Pope St. John Paul II (2004) explained, “A man, even if seriously ill or disabled in the exercise of his highest functions, is and always will be a man, and he will never become a ‘vegetable’ or an ‘animal.’” Clearly, it is crucial for the legitimacy of Lee and Grisez’s proposed RCS/RCC definition for death that we be able to identify clinical criteria that we can use to distinguish a blocked active potential from an absent one so that we do not mistakenly reduce a human person either to an animal or to a vegetable.

I contend, however, that this task of identifying Lee and Grisez’s needed diagnostic criteria to distinguish patients with a blocked active potential for consciousness from those who have permanently lost it will be difficult—if not impossible—to accomplish. Human beings have a natural capacity to regenerate neuronal tissue in their brain. However, this capacity is limited. Thus, it is widely accepted today that we cannot regenerate an extensively damaged neocortex. But what if we discover drugs that could hyperstimulate the brain’s natural healing process so that it could once again regenerate a complete neocortex where it could not do so today? During embryogenesis, the human body was once able to grow and to organize a whole brain from rudimentary cellular tissue. Therefore, I do not think that it is unreasonable to think that the scientists of the future will discover a way to reactivate this silenced molecular program in damaged adult brain cells to enhance the brain’s inherent ability to regenerate new tissue. Already today, we have discovered ways to regenerate nerve cells from non-nerve cells in the damaged or Alzheimer’s brain simply by expressing the NeuroD1 protein in vivo (Guo et al., 2014). Given the real possibility of developing drugs that enhance the brain’s regeneration potential tomorrow—say by reactivating a brain cell’s endogenous NeuroD1—can we definitively and confidently conclude that the unconscious patient with a damaged neocortex or whole brain today has truly and permanently lost his active potential, that is, his radical capacity, for consciousness? I think not. 20 Since we can never determine if the TBD patient has truly and permanently lost his active potential for consciousness, and since the human patient has an inherent dignity that has to be respected, I propose that it is reasonable and prudent to assume that he retains it. He is still a sentient animal, even if he is permanently unconscious.

V. CONCLUSION

In this brief essay, I have proposed that the scientific evidence obtained from investigating animals that have suffered a complete spinal cord transection falsifies a critical presupposition in Lee and Grisez’s argument, that is, that no mammal can sense without a functioning brain. In fact, a severed spinal cord is still able to mediate and to coordinate responses to external stimuli, and as such has the capacity for sentience in the absence of a brain. It is analogous to the primitive brains found in fruit flies and in earthworms. I have argued, therefore, that TBD patients are still sentient organisms, that is, they are animals, because their severed spinal cords retain the capacity to develop a capacity for sentience. He is still a living patient, though a severely disabled one.

ACKNOWLEDGMENTS

I thank the following colleagues for their helpful comments on earlier drafts of this paper: Basil Cole, OP, David Albert Jones, and Nicholas Tonti-Filippini. This paper was written while I was a Visiting Research Fellow at the Anscombe Centre for Bioethics and at Blackfriars Hall, both at the University of Oxford. I wholeheartedly thank Professor David Albert Jones and the Dominican community at Blackfriars for their welcome and generous hospitality.

NOTES

1.

See Catechism of the Catholic Church, no. 997: “In death, the separation of the soul from the body, the human body decays and the soul goes to meet God, while awaiting its reunion with its glorified body.”

2.

For an instance of this justification of the loss of integration criterion for death, see Truog and Miller (2014a).

3.

This is the basic argument made by the President’s Commission (1981). Also see the analysis in the seminal paper, “On the definition and criterion of death” (Bernat, Culver, and Gert, 1981); and more recently, in “Whither Brain Death?” (Bernat, 2014).

4.

For Shewmon’s seminal papers, see the following: Shewmon (1997; 2001; 2010).

5.

For descriptions of these integrated functions, as well as references to the primary literature, see Shewmon (2012).

6.

For example, see Truog and Miller (2014a; 2014b).

7.

See Lee and Grisez (2012). It is striking that Shewmon made a similar argument justifying the TBD criteria—an argument that he eventually repudiated (see Shewmon, 1985).

8.

Whereas Lee and Grisez argue that the TBD patient is dead because he has lost his humanity while retaining his bodily integration, other Catholic scholars, including Nicholas Tonti-Filippini, Maureen Condic, and Melissa Moschella, propose that the TBD patient is dead because he has lost the bodily integration that is characteristic of the human organism. These are the only two arguments used by Catholic proponents to defend their advocacy of the TBD criteria today.

9.

For my first response to the RCS argument, see Austriaco (2009). For an earlier exposition of my view on brain death, see Austriaco (2003).

10.

I am aware that there are other areas of recent scholarship that bear on the question of the legitimacy of the total brain death criteria, including relevant discussions surrounding the ontological constitution of the human being as an organism. However, engaging that work is not the main focus of this work, which attempts rather to deal specifically with a single argument in favor of the TBD criteria in the Catholic philosophical tradition.

11.

Elsewhere, I also argue that TK’s autopsy report—TK was a famous TBD patient who was maintained on life support in Nebraska for twenty years—demonstrates that the TBD patient retains his organismal integration because he retains several physiological functions linked with the intact organism. For example, TK was able, among other things, to maintain a robust immune response many years after experiencing total brain failure. Though there are bioethicists who tend to conflate the two debates, in my view, the debate over whether or not the TBD patient is a sentient organism is a distinct one from the debate over whether or not the TBD patient is an integrated organism. See Austriaco (forthcoming).

12.

For Aristotle, perception is the capacity of soul that distinguishes animals from plants. Every animal has at least the capacity to perceive through touch, though many animals have other sensory modalities that allow them to interact with their environments (see De Sensu 1, 436b10-12; De Anima ii 2 413b-4–7).

13.

Aristotle considered earthworms, imperfect animals. For discussion, see Rota (2011).

14.

Decerebrate cat walks and exhibits multiple gait patterns, Youtube [On-line]. Available: https://www.youtube.com/watch?v=wPiLLplofYw (accessed March 2, 2016).

15.

For discussion and details, see the following studies: Harkema et al. (2011); Angeli et al. (2014); and Vasudeva, Abd-El-Barr, and Chi (2014). The Lancet provides a fascinating podcast that describes how the spinal cord is able to receive, to integrate environmental cues, and to learn. See The Lancet [On-line]. Available: http://download.thelancet.com/flatcontentassets/audio/lancet/2011/20may.mp3 (accessed April 11, 2016).

16.

There is evidence that the mammalian spinal cord is capable of integrating the autonomic nervous system, including cardiovascular responsiveness to peripheral stimulation. See the following papers: Laskey, Schondorf, and Polosa (1979); and Mathias (2006). For Shewmon’s analysis that the human spinal cord is a primitive organ of integration, see Shewmon (1999).

17.

For discussion, see the scientific references and online resources listed in footnotes 15 and 16.

18.

It is already clear that adult patients who have irreversibly lost their neocortex have permanently lost their capacity for and their capacity to develop the capacity for consciousness because the neocortex is necessary, though it is not sufficient, for consciousness in adults. Thus, despite Lee and Grisez’s protestations to the contrary, their RCS/RCC argument could be used to justify a cortical definition for death that posits that adult patients who have permanently lost their once-functioning neocortex are dead. In my view, Lee and Grisez’s argument is flawed because it does not properly account for the difference between those neurological structures that are necessary for consciousness and those that are necessary and sufficient for the same in the adult human being. An adult does not need to lose the whole brain to lose one’s radical capacity for consciousness or for the radical capacity for developing the capacity for consciousness. All one needs to lose this capacity permanently is to irreversibly lose a neurological structure that is just necessary for consciousness. A small part of the brain can easily fulfill this criterion, even if consciousness as a whole could involve widespread neuronal networks spanning multiple and large areas of the brain. Consider an analog wall clock. The function of the wall clock involves all of its gears and springs. However, the loss of all the gears or of a single critical gear can permanently cripple the clock. In the same way, I propose that loss of the whole brain or of a single critical region of the brain can permanently deprive the person of consciousness.

19.

For instance, the Congregation for the Doctrine of the Faith (2007) has taught that “a patient in a ‘permanent vegetative state’ is a person with fundamental human dignity and must, therefore, receive ordinary and proportionate care which includes, in principle, the administration of water and food even by artificial means.”

20.

Now some may counter this argument by suggesting that with these drugs of the future, we are simply activating a passive potential for consciousness in the brain with the damaged neocortex. (In contrast to an active potential, a passive potential is actualized from without. It requires the active causal intervention of an external agent in order to be realized. Thus, an acorn only has a passive potential to become a violin because it would need the agency of a master craftsman in order to realize this end. Passive potentials are not indicative of the inherent nature of a thing.) If this view were correct, treating a comatose patient with these drugs of the future to regenerate his neocortex would literally involve bringing a new human organism into existence, different from the one who had lost his neocortex in the first place. This would be bizarre, but it would certainly be a plausible explanation for the medical procedure of regenerating a neocortex. Nonetheless, I propose that it is inherently difficult to distinguish “hyperstimulating” a pre-existing capacity of regeneration from “creating” a nonexisting capacity of regeneration. The former would involve unblocking an active potential, whereas the latter would entail transforming a passive to an active potential. As such, we cannot and should not base a definition of death on imprecise criteria that are incapable of truly distinguishing those patients with a blocked active capacity for consciousness from those who have permanently lost it.

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