The on-going redefinition of death is the result of the technological deconstruction of dying. Instead of a relatively instantaneous, binary process, death is now more like a “syndrome,” a cluster of related attributes, with a probabilistic diagnosis.[5] This disaggregation requires that we decide how many of these attributes are required before we begin treating someone as “dead,” just as physicians must decide how many psychiatric traits are required before making a diagnosis of "schizophrenia." Electroencephalograms can only determine if there is a cessation of electrical activity on the surface of the brain, not in the deeper structures, and cannot determine if the electrically quiescent brain tissue is irrecoverable. Many of those who are diagnosed as brain dead in fact have clear evidence of functioning midbrains and brainstems, and are not necessarily irreversible.[6] A key argument in favor of whole brain death criteria over neo-cortical death, that the brain provides integrative functions that the body needs to survive, has also been shown to be fallacious since patients meeting the current clinical criteria for whole brain death have survived for years.
Below I review some of the emergent technologies which will allow us to not only keep “brain dead” patients alive, but also repair their brain damage, requiring a re-specification of death from the whole-brain standard to the neo-cortical standard and beyond. The development of these life support and neuroremediation technologies will force us to finally accept a personhood-based “neo-cortical” position on brain death. But instead of legitimating the simple termination of life support for PVS patients, diagnostic protocols used to determine permanent vegetative state and brain death will have to be supplemented by therapeutic trials of neuroremediation, and predictions about the results of such trials. The legal identity of the reconstituted personalities resulting from these therapies will be contested, and oblige the clarification of the legal status of discontinuous personalities in the law.
Ultimately, the nanotechnological neuro-prosthetics that we develop to remediate brain injuries will also lend themselves to the sharing and backing up of memories, thoughts and personalities. That point may be recognized as the “death of death.”
2. STEM CELLS, NEUROGENESIS and NEUROTROPHICS
Research is proceeding rapidly in the repair of brain damage with stem cell transplants and neurotrophics to stimulate neurogenesis.[7] Research has demonstrated that there are stem cells in the adult brain, and that they can locate and differentiate to repair damage in the brain, restoring function. Jeffrey Gray has repaired ischemic brain damage in rats with injections of rat stem cells.[8] Macklis and his team at Harvard have successfully induced neural stem cells present in adult brains of mice to differentiate and repair sections of damaged mouse brain.[9] Research is also rapidly progressing on gene therapy on neurons in the brain, to increase dopamine production in Parkinsons and boost nerve growth factors.[10],[11]
In the near future, with combinations of stem cells, neurotrophic drugs and gene therapies, we will be able to remediate damage to brains that would meet current clinical criteria for brain death. Brain repairs might reconnect undamaged parts of the brain which still encode memories, skills and personality traits.
3. Neural-Computer Prostheses
Methods to stimulate neurogenesis not only offer means of regenerating brain tissue for those who have suffered severe brain injuries or brain death, but also to facilitate the integration of brain prostheses. Many centers around the world are perfecting direct two-way communication between the brain and neuro-computing prostheses.[12],[13],[14]
The first step has been direct brain control of external computing and prostheses. For instance Mojarradi et al. at NASA have designed microarrays for the motor cortex to wirelessly control arm or leg prostheses.[15] Krishna Shenoy’s lab at Stanford[16] is working on implanted electrodes which drive external computing. Roy Bakay and Phil Kennedy at Emory University have put computer chips into the motor control regions of the brains of patients in the locked-in state. The patients’ neurons grow into contact with the chip permitting two-way communication, and when the patients think about moving various muscles they send a radio signal to an external computer. Slowly the patterns of neuronal firing against the chips’ electrodes allow the patients to control computer cursors by thought alone.[17] Totally paralyzed people are now surfing the web, sending email and controlling their environment by thought alone.
The next step is to implant computing media in the brain able to act as prosthetic replacements for damaged brain structures. Berger and his lab at the University of Southern California have successfully modeled the neuronal inputs and outputs of the hippocampus, and are conducting trials of computerized prosthetic hippocampi.[18] Rapid advances in neural network software and the reverse engineering of the brain’s neuronal interactions will allow these prosthetics to be adaptive and record new memories and pathways.[19] Eventually brain prostheses will replace the parts of a severely damaged brain which cannot be repaired or regrown using stem cells and neurogenesis.
4. CRYONIC SUSPENSION
Another technology that may eventually challenge our death concept is cryonic suspension, the freezing of heads or whole bodies for eventual reanimation.[20] All diagnostic protocols for the determination of brain death call for hypothermia to be ruled out when patients appear to be dead. But what if the patient is thoroughly frozen, and can’t be safely thawed for many decades? If future nanomedical devices could repair the cellular damage caused by freezing, the ontological status of the frozen patient would be the same as the current hypothermically dead or the future, remediable brain dead patient: missing and probably dead, but possibly retrievable.
Unfortunately those who wish to be cryonically preserved must be legally dead first, else those who assist their freezing are considered accessories to suicide or murder. Cryonicists believe that future reanimation would be more successful if they could initiate the freezing before somatic failure, and certainly before cerebral death. Cryonics firms have already been accused (and acquitted) of murder for having failed to have a physician pronounce death before they began the suspension procedure. In 1993, the California Supreme Court ruled that a man with a terminal brain tumor could not have his head removed and frozen before he died.
Clearly the frozen do not meet a consciousness-based definition of life based on continuous, waking sentience, much less self-aware personhood. On the other hand, if such a standard is applied too rigidly, people who are in deep sleep, who are hypothermically suspended[21] but revivable, or who have been placed in temporary therapeutic states of arrest, would also be dead. The key question for the status of the cryonically preserved is the assessment of the likelihood that they can be revived. We have a very high likelihood that the sleeping will awake as their former selves, and at least we know of cases when hypothermic patients have fully recovered. Since we have never seen a reconstituted frozen mammal, the possibility of cryonic recovery is harder to accept. But the rapidly developing field of nanotechnology is creating an expectation that we will be able to repair and revive frozen bodies in this century.
5. NANONEUROLOGICAL REPAIR AND PROSTHESES
Cryonicists acknowledge that the freezing process results in the rupture of many cellular membranes, and that micro-cellular repair will be the principal challenge of future reanimators. Cryonicists have therefore enthusiastically embraced the new field of nanotechnology which promises to eventually create molecular-scale, self-replicating robots capable of moving through frozen tissue without further disrupting cell walls, identifying damaged tissue and repairing it. Cryonicists expect this level of nanotechnology to be available within the next forty to hundred years.
The rapid advance of nanomedicine certainly gives reason for such optimism. The August 30 2003 issue of the Lancet editorializes “Nanomedicine is a discipline whose time has come.”[22] Similarly in 2002 the US National Science Foundation (NSF) convened a large project to examine the consequences of the convergence of nanotechnology, biotechnology, information technology and cognitive science (NBIC) for “improving human performance.” The project drew together more than a hundred experts on science and technology from government, academia and business. The enormous 2002 report of the NBIC project includes detailed plans for nanotechnology to be intimately woven into the body and brain in the very near future, including a variety of projections of brain prostheses that the converging technologies will make possible in the coming decades. Computer scientist Ray Kurzweil projects that by 2030 the accelerating, converging and shrinking technologies will make possible a complete intracranial network of nanorobots, communicating with each neuron, and permitting immersive virtual reality, parallel processing, and backing up of memories and thoughts.[23] The introduction of such a nano-neuro network would have obvious therapeutic potential for the reconstruction of personality, skills and memory in a damaged brain.
6. THE MISSING AND THE DEAD
As our technologies for brain repair and prosthetic support of brain functions improve, so also do the odds that significant personhood can be recovered from a “dead” brain. In some sense, although we know the whereabouts of their body, the brain damaged person is a missing person. They are in a condition from which they may or may not return. There is the possibility that they have suffered information loss beyond the ability of technology to restore, or they may not. We have to decide whether to mount a search on the basis of our assessment of the likelihood that they are still alive.
Our ability to predict the likelihood of recovering some semblance of the original person will be important for families who are considering attempting reanimation. If recovery is unlikely, the person’s advance directives or surrogate decision-makers should specify whether reanimation should be attempted when the likely result is a new person. Once the person is revived, they will need to be assessed for whether they are in fact sufficiently identical to the prior person. If the reanimated person is a substantially new person there will be a strong case for them to be considered a successor or relative of the deceased.
The prognostic prediction is then a part of the determination of the deadness of the patient, just as it is in the determination of the permanence of the “permanently vegetative state” (PVS). American practice toward PVS is based on the recommendations of the Multi-Society Task Force on the Permanent Vegetative State that patients should be considered permanently unconscious if they are unaware for three months after non-traumatic injury (such as chemical overdose) or 12 months after a traumatic brain injury. Once classified as permanently vegetative, caregivers and physicians are given much more latitude for conservative treatment, often in effect allowing death to “take its course.”
Another cognate situation is the missing person. When someone goes missing on the high seas, or doesn’t return from war, common law has long held that these missing persons be declared dead for practical reasons. If the circumstance of the missing person’s death is uncertain, and there is some possibility they have been shipwrecked, taken hostage, or hiding, the court imposes a waiting period of some years before death may be declared. The Uniform Probate Code, adopted by 18 states and more or less in effect in the rest, declares death to have occurred after a five year waiting period. If there continues to be strong evidence that the missing person may be living, judges may put off declaring death even after this waiting period. Once the absentee is declared dead, most states protect the heirs and those who declared the person dead from liability for wrongly distributing their property, and otherwise harming their interests.
The deadness of the missing person is also partly determined by our decision to mount a search mission or not, which is also true with the therapeutic situation of the “do not resuscitate” order. The person in arrest with a DNR is much deader than the person in arrest subject to resuscitation. The non-heart-beating donor controversy has also made explicit what was implicit with DNRs; the intention to resuscitate a heart/breathing-arrested person partly determines when in the dying process a person is declared dead.
Similarly the intention to treat the brain dead as alive determines their status under New Jersey’s brain death law. New Jersey permits Orthodox Jews to define and treat their brain dead relatives as alive. Also the U.S. approach to the fetus can show a similar social determination, as in the proposed US laws which would punish as a murderer someone whose assault leads to the miscarriage of a desired fetus, but would still permit a mother to have an abortion of an undesired fetus.
So the intention not to attempt identity recovery is itself part of the determination of death. As technology erodes the brain death standard, the future operational definition of “dead enough” will become something like: “The patient cannot be revived to self-awareness, with continuity of previous memories and personality, because they have irretrievably lost that information, or we are unable to recover them, or the patient or their surrogate decision-makers do not wish them to be revived.”
7. THE STATUS OF RECONSTRUCTED PERSONALITIES
The beneficiaries of these therapies will probably continue to be disabled in many ways, and have lost much of their memory, skills and personality. The neurogenesis required to restore self-awareness may actually destroy identity-critical memories, as is suggested by Tsien et al.[24] The question these technologies will raise is how much of one's personality and memories one can lose for the new person grown in one’s brain to be considered a new legal person. At the extreme McMahan asserts that the complete replacement of the cerebral tissues would clearly constitute a new person:
Replacement of the (cerebral) tissues through the transplantation of new hemispheres might make consciousness possible, but this would not count as receiving the same mind, even if the new hemispheres were perfect duplicates of those destroyed. There would be a new and different mind.[25]
But what of a new person who had forgotten everything of their former self except their taste in food or music? Would the family, society and the law consider this a successful recovery of the original person?
I believe there are three steps we should take to address the legal and identity ambiguities of personalities reconstituted from destroyed brains. First, we should develop a set of criteria to distinguish the legal personhood of the prior person and any future person who occupies their body but lacks sufficient psychological continuity to be the same person. The prior person should be declared dead, all their obligations and contracts should cease, and the subsequent person should become an heir of the prior person. The prior person’s property should automatically be ceded to a trust to pay off debts and disburse to beneficiaries of the will, but funds should be reserved to provide for the subsequent person’s welfare. The patient’s family should have custody of the new person until they are returned to full autonomy.
Second we need to develop a thorough predictive model of the destruction of personality and memory in the patient’s brain, and the likely results of remediation, before initiating therapy. This model will allow the family and other surrogate decision-makers to decide if there will likely be enough of their loved one left to allow continuity of personal identity. Above a certain threshold of prognostic certainty and level of identity recovery the family and physicians will be obliged to attempt the recovery. If the likelihood that the person will be recovered falls below a certain threshold the patient’s advance directives and surrogate decision-makers will be allowed to determine whether there should be a trial of neuroremediation. If the person is sufficiently recovered, they would assume their former identity, but if they are judged a different person, they would be an heir.
Third, advance directives will need to be amended to elicit patients’ wishes about reconstituting partial selves. Some may fear the prospect of a partially reconstituted self, while others may welcome any continuity, even if it is just physical continuity with a new person inheriting their body.
Some will certainly argue that legal personhood is identical to body continuity, and that any reconstituted personality would be identical to the prior person. Others may limit identity to those who recover identity-critical information and self-awareness without becoming significantly dependent on non-biological prostheses. For instance Youngner and Bartlett addressed the possibility of future mechanical remediation of brain injuries, and accepted that such remediation would be unproblematic for brainstem functions. But they go to great lengths to reject the possibility of mechanically-mediated cognition.
It is…easy to imagine a patient's integrated vegetative functions being fully assumed by complex machines or well-trained health professionals. Any problems in such a takeover would be of a purely technical nature. In contrast, conceptual problems surround the replacement of a patient's consciousness and cognition. We believe it is impossible for a person's thoughts and feelings to be replaced by a mechanical device and still retain their essential nature. If the replacement is successful, the thoughts and feelings would no longer be those of a human; if they remained essentially unchanged, the replacement was not successful. This point shows the essential, conceptual connection between higher brain functions and the continued life of the person. No comparable problem arises with the replacement of vegetative operations...If a living person is to exist, the thoughts and conscious processes must be those of a human, not a machine.[26]
Youngner’s distinction between continuity of personhood maintained by organic therapy and continuity maintained by non-organic prostheses has no ethical justification. Nor is such prejudice likely to persist as people with powerful brain prostheses become increasingly common.
8. BEYOND PERSONAL IDENTITY
Despite our every instinct to the contrary, there is one thing that consciousness is not: some entity deep inside the brain that corresponds to the ‘self,’ some kernel of awareness that runs the show, as the ‘man behind the curtain’ manipulated the illusion...in The Wizard of Oz. After more than a century of looking for it, brain researchers have long since concluded that there is no conceivable place for such a self to be located in the physical brain, and that it simply doesn’t exist. [27]
Just as technology drives us to clarify that we value continuous, discrete self-aware persons more than the biological platforms they come on, so it will also force us to acknowledge that continuous, discrete personhood is a fiction. Neuroremediation technology and brain-computer interfaces will erode the apparent boundaries and continuity of the self, and the autonomy of the individual and her decisions.
Threats to the self will develop in many areas. Our control over the brain will slowly make clear that cognition, memory and personal identity are actually many processes that can be disaggregated. We will have increasing control over our own personalities and memories. Full nanorobotic replication of the mental process opens the possibility of identity cloning, distributing one’s identity over multiple platforms, sharing of mental components with others, and the merging of several individuals into one identity.
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Technological Threats to Liberal Individualistic Assumptions about Continuous Discrete Personhood
- Identity Malleability: Parental, social and personal control of memory, identity and personality
- Posthuman Persons: Radically enhanced minds
- Identity Sharing: Sale or sharing of memories, thoughts and skills,
- Identity Cloning: Persons multiply copied into new biological or computing media
- Distributed Identity: Distinct persons distributed over, or sharing, a set of bodies and machines
- Group Identity: Multiple bodies and machines integrated into a collective identity, without clear personal identity, e.g. hive minds, the Borg
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When we get to the point where neurological functions can be controlled, designed, cloned, shared, sold, and turned on and off, the fact that the continuous, autonomous self is an illusion will become more obvious. This will also pose a fundamental challenge to liberal democracy as noted by the futurist thinker Alexander Chislenko: “When one can easily modify, borrow, or drop, merge with others, and separate, any of their external and internal features … there won't be distinct lines between individuals anymore.” [28]
Once we are forced to drop this fundamental predicate of Enlightenment ethics, the discrete, continuous, autonomous individual, we are beyond the ethical frameworks of liberal democratic law and bioethics. Perhaps we will also then be beyond death, since it will be possible to backup and preserve all aspects of personal identity and experience, either as discrete individuals, or in distributed parts.
9. CONCLUSIONS
The current definition of death, worked out twenty years ago to address the technology of the respirator, is falling apart. Some suggest we dispense with “death” as a unitary marker of human status, while others are pushing for the recognition of a neocortical standard. This century will begin to see a shift toward consciousness and personhood-centered ethics as a means of dealing not only with brain death, but also with extra-uterine feti, intelligent chimeras, human-machine cyborgs, and the other new forms of life that we will create with technology. The status of these forms of life will be one important element of the struggle between the “transhumanists,” advocates of non-anthropocentric personhood and post-human technological possibilities, and their opponents the “biofundamentalists” or “bioLuddites.” Each proposal to extend human capabilities beyond our “natural” and “God-given” limitations, or to blur the boundaries of humanness with brain prostheses, will be fought politically and in the courts. Prominent bioethicist George Annas suggests for instance that brain implants and human-machine cyborgs, among many other technologies, be made “crimes against humanity” by international treaty.[29]
Nonetheless I believe we will soon need to scrap the brain death standard in favor of a much more tentative, probabilistic, information-theoretic understanding of death, as the loss of identity-critical information. The preservation of identity-critical information, regardless of whether on an organic or inorganic platform, will be considered continuity of legal personhood. Then, we will, eventually, face the challenge of a society in which death becomes completely meaningless and individual identity itself begins to unravel.
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