In the past, death has often been defined with a few confident words. For example, the first edition of Encyclopaedia Britannica informed its readership that "DEATH is generally considered as the separation of the soul and body; in which sense it stands opposed to life, which consists in the union thereof" (1768, v. 2, p. 309). The confidence and concision had dissolved by the time the fifteenth edition appeared in 1973. The entry on death had expanded to more than thirty times the original length. The earlier definition was not mentioned, and the alternative that death is simply the absence of life was dismissed as an empty negative. Readers seeking a clear and accurate definition were met instead with the admission that death "can only be conjectured" and is "the supreme puzzle of poets" (1973, v. 5, p. 526).
This shift from confidence to admission of ignorance is extraordinary not only because death is such a familiar term, but also because so much new scientific knowledge has been acquired since the eighteenth century. Actually, the advances in biomedical knowledge and technology have contributed greatly to the complexity that surrounds the concept and therefore the definition of death in the twenty-first century. Furthermore, the definition of death has become a crucial element in family, ethical, religious, legal, economic, and policy-making decisions.
It would be convenient to offer a firm definition of death at this point—but it would also be premature. An imposed definition would have little value before alternative definitions have been considered within their socio-medical contexts. Nevertheless, several general elements are likely to be associated with any definition that has a reasonable prospect for general acceptance in the early years of the twenty-first century. Such a definition would probably include the elements of a complete loss or absence of function that is permanent, not reversible, and useful to society.
These specifications include the cautious differentiation of "permanent" from "not reversible" because they take into account the argument that a death condition might persist under ordinary circumstances, but that life might be restored by extraordinary circumstances. Despite this caution there are other and more serious difficulties with even the basic elements that have been sketched above. That a definition of death must also be "useful to society" is a specification that might appear to be wildly inappropriate. The relevance of this specification is evident, however, in a pattern of events that emerged in the second half of the twentieth century and that continues to remain significant (e.g., persistent vegetative state and organ transplantation). Competing definitions of death are regarded with respect to their societal implications as well as their biomedical credibility.
Attention is given first to some of the ways in which common usage of words has often led to ambiguity in the definition of death. The historical dimension is briefly considered, followed by a more substantial examination of the biomedical approach and its implications.
The word death is used in at least three primary and numerous secondary ways. The context indicates the intended meaning in some instances, but it is not unusual for ambiguity or a shift in meanings to occur in the midst of a discussion. People may talk or write past each other when the specific usage of "death" is not clearly shared. The three primary usages are: death as an event; death as a condition; and death as a state of existence or nonexistence.
Death as an event. In this usage, death is something that happens. As an event, death occurs at a particular time and place and in a particular way. In this sense of the term, death is a phenomenon that stays within the bounds of mainstream conception and observation. Time, place, and cause can be recorded on a death certificate (theoretically, in all instances although, in practice, the information may be incomplete or imprecise). This usage does not concern itself with mysteries or explanations: Death is an event that cuts off a life.
Death as a condition. This is the crucial area in biomedical and bioethical controversy. Death is the nonreversible condition in which an organism is incapable of carrying out the vital functions of life. It is related to but not identical with death as an event because the focus here is on the specific signs that establish the cessation of life. These signs or determinants are often obvious to all observers. Sometimes, though, even experts can disagree.
Death as a state of existence or nonexistence. In this sense, it can almost be said that death is what becomes of a person after death. It refers not to the event that ended life nor the condition of the body at that time, but rather to whatever form of existence might be thought to prevail when a temporal life has come to its end.
Miscommunications and unnecessary disagreements can occur when people are not using the term death in the same way. For example, while grieving family members might already be concerned with finding someone to stay in contact with a loved one who will soon be "in death," the physicians are more likely to focus on criteria for determining the cessation of life. In such situations the same word death is receiving functionally different definitions.
The secondary usages are mostly figurative. Death serves as a dramatic intensifier of meaning; for example, the historian's judgment that the rise of commerce contributed to the death of feudalism, or the poet's complaint that life has become death since being spurned by a lover. There are also extended uses that can be considered either literal or figurative, as when the destruction of the universe is contemplated: The issue open to speculation is whether the universe is fundamentally inanimate or a mega-life form.
Biomedical approaches to the definition of death have become increasingly complex and influential since the middle of the twentieth century. Throughout most of human history, however, death was defined through a combination of everyday observations and religious beliefs. The definition offered in the 1768 edition of Encyclopaedia Britannica is faithful to the ancient tradition that death should be understood as the separation of soul (or spirit) from the body. The philosophical foundation for this belief is known as dualism: Reality consists of two forms or essences, one of which is material and certain to decay, the other of which has a more subtle essence that can depart from its embodied host. Dualistic thinking is inherent in major world religions and was also evident in widespread belief systems at the dawn of known history.
Definitions of death in very early human societies have been inferred from physical evidence, a limited though valuable source of information. Cro-Magnon burials, for example, hint at a belief in death as separation of some essence of the person from the flesh. The remains were painted with red ochre, consistently placed in a north-south orientation, and provided with items in the grave that would be useful in the journey to the next life. Anthropologists discovered similar practices among tribal people in the nineteenth and early twentieth centuries. The fact that corpses were painted red in so many cultures throughout the world has led to the speculation that this tinting was intended as a symbolic representation of blood. People throughout the world have long recognized that the loss of blood can lead to death, and that the cold pallor of the dead suggests that they have lost the physical essence of life (conceived as blood), as well as the spiritual (conceived as breath). A religious practice such as symbolically replacing or renewing blood through red-tinting would therefore have its origin in observations of the changes that occur when a living person becomes a corpse.
A significant element in traditional definitions of death is the belief that death does not happen all at once. Observers may clearly recognize signs of physical cessation; for example, lack of respiration and responsiveness as well as pallor and stiffening. Nevertheless, the death is not complete until the spirit has liberated itself from the body. This consideration has been taken into account in deathbed and mourning rituals that are intended to assist the soul to abandon the body and proceed on its afterlife journey. It was not unusual to wait until only the bones remain prior to burial because that would indicate that the spirit has separated, the death completed, and the living emancipated to go on with their lives.
Definitions of death as an event or condition have usually been based on the assumption that life is instantly transformed into death. (This view has been modified to some extent through biomedical research and clinical observation.) Historical tradition, though, has often conceived death as a process that takes some time and is subject to irregularities. This process view has characterized belief systems throughout much of the world and remains influential in the twenty-first century. Islamic doctrine, for example, holds that death is the separation of the soul from the body, and that death is not complete as long as the spirit continues to reside in any part of the body. This perspective is of particular interest because medical sophistication has long been part of Islamic culture and has therefore created a perpetual dialogue between religious insights and biomedical advances. The question of reconciling traditional with contemporary approaches to the definition of death requires attention to recent and current developments.
For many years physicians depended on a few basic observations in determining death. Life had passed into death if the heart did not beat and air did not flow into and out of the lungs. Simple tests could be added if necessary; for example, finding no response when the skin is pinched or pricked nor adjustive movements when the body is moved to a different position. In the great majority of instances it was sufficient to define death operationally as the absence of cardiac activity, respiration, and responsiveness. There were enough exceptions, however, to prove disturbing. Trauma, illness, and even "fainting spells" occasionally reduced people to a condition that could be mistaken for death. The fortunate ones recovered, thereby prompting the realization that a person could look somewhat dead yet still be viable. The unfortunate ones were buried—and the most unfortunate stayed buried. There were enough seeming recoveries from the funeral process that fears of live burial circulated widely, especially from the late eighteenth century into the early years of the twentieth century.
A related development served as a foreshad-owing of complexities and perplexities yet to come. Scientifically minded citizens of late-eighteenth-century London believed they could rescue and resuscitate victims of drowning; they could and they did. Not all victims could be saved, but there were carefully authenticated cases in which an apparent corpse had been returned to life. Some of the resuscitation techniques they pioneered have entered the repertoire of emergency responders around the world. They also tried (with occasional success) the futuristic technique of galvanic (electrical) stimulation. The impact of these experiments in resuscitation far exceeded the small number of cases involved. The fictional Dr. Frankenstein would reanimate the dead by capturing a flash of lightning—and nonfictional physicians would later employ electric paddles and other devices and techniques for much the same purpose. The wonder at seeing an apparently dead person return to life was accompanied by a growing sense of uneasiness regarding the definition of death. It would not be until the middle of the twentieth century, though, that new developments in technology would pose questions about the definition of death that could no longer be shunted aside.
The accepted legal definition of death in the middle of the twentieth century appeared simple and firm on the surface. Death was the cessation of life as indicated by the absence of blood circulation, respiration, pulse, and other vital functions. The development of new biomedical techniques, however, soon raised questions about the adequacy of this definition. Cardiopulmonary resuscitation (CPR) had resuscitated some people whose condition seemed to meet the criteria for death. Furthermore, life support systems had been devised to prolong respiration and other vital functions in people whose bodies could no longer maintain themselves. In the past these people would have died in short order. The concept of a persistent vegetative state became salient and a disturbing question had to be faced: Were these unfortunate people alive, dead, or somewhere in between? This question had practical as well as theoretical implications. It was expensive to keep people on extended life support and also occupied hospital resources that might have more therapeutic uses. It was also hard on family members who saw their loved ones in that dependent and nonresponsive condition and who were not able to enter fully into the grieving process because the lost person was still there physically.
Still another source of tension quickly entered the situation. Advances were being made in transplanting cadaver organs to restore health and preserve the life of other people. If the person who was being maintained in a persistent vegetative state could be regarded as dead, then there was a chance for an organ transplantation procedure that might save another person's life. Existing definitions and rules, however, were still based on the determination of death as the absence of vital functions, and these functions were still operational, even though mediated by life support systems.
Pressure built up to work through both the conceptual issues and the practical problems by altering the definition of death. The term clinical death had some value. Usually this term referred to the cessation of cardiac function, as might occur during a medical procedure or a heart attack. A physician could make this determination quickly and then try CPR or other techniques in an effort to restore cardiac function. "Clinical death" was therefore a useful term because it acknowledged that one of the basic criteria for determining death applied to the situation, yet it did not stand in the way of resuscitation efforts. This concept had its drawbacks, though. Many health care professionals as well as members of the general public were not ready to accept the idea of a temporary death, which seemed like a contradiction in terms. Furthermore, clinical death had no firm standing in legal tradition or legislative action. Nevertheless, this term opened the way for more vigorous attempts to take the definition of death apart and put it back together again.
Meanwhile, another approach was becoming of increasing interest within the realm of experimental biology. Some researchers were focusing on the development and death of small biological units, especially the individual cell within a larger organism. The relationship between the fate of the cell and that of the larger organism was of particular interest. Soon it became clear that death as well as development is programmed into the cell. Furthermore, programmed cell death proved to be regulated by signals from other cells. Although much still remains to be understood, it had become apparent that a comprehensive definition of death would have to include basic processes of living and dying that are inherent in cells, tissues, and organs as well as the larger organism. It has also provided further illumination of the lower-level life processes that continue after the larger organism has died. The person may be dead, but not all life has ceased. The cellular approach has still not drawn much attention from physicians and policy makers, but it has added to the difficulty of arriving at a new consensual definition of death. How many and what kind of life processes can continue to exist and still make it credible to say that death has occurred? This question has not been firmly answered as such, but was raised to a new level with the successful introduction of still another concept: brain death.
Technological advances in monitoring the electrical activity of the brain made it possible to propose brain death as a credible concept, and it quickly found employment in attempting to limit the number and duration of persistent vegetative states while improving the opportunities for organ transplantation. The electrical activity of the brain would quickly become a crucial element in the emerging redefinition of death.
A survey was conducted of patients who showed no electrical activity in their brains as measured by electroencephalograms. Only three of the 1,665 patients recovered cerebral function— and all three had been in a drug-induced coma. This finding led researchers to recommend that electrocerebral inactivity should be regarded as a state of nonreversible coma. Researchers suggested that this core determinant should also be supported by other types of observations, including inability to maintain circulation without external support and complete unresponsiveness. Researchers would later recommend that a distinction should be made between "coma" and "brain death." There are several levels of coma and a variety of possible causes; brain death refers to a state of such severe and irreparable damage that no mental functioning exists or can return.
The breakthrough for the new concept occurred in 1968 when an Ad Hoc Committee of the Harvard Medical School proposed that the nonreversible loss of brain should be the reigning definition of death. More traditional signs were still included. The person was dead if unresponsive, even to ordinarily painful stimuli, showed no movements and no breathing, as well as none of the reflexes that are usually included in a neurological examination. There were two new criteria, however, that were not measured in the past: a flat reading on the electroencephalogram (EEG) and lack of blood circulation in the brain. "The Harvard criteria," as they were known, soon became the dominant approach to defining death.
Subsequent studies have generally supported the reliability of the criteria proposed by the Harvard Medical School committee. The new definition of death won acceptance by the American Medical Association, the American Bar Association, and other influential organizations. A 1981 president's commission took the support to an even higher level, incorporating the concept into a new Uniform Determination of Death Act with nationwide application. The basic Harvard Committee recommendations were accepted. However, some important specifications and cautions were emphasized. It was noted that errors in certification of death are possible if the patient has undergone hypothermia (extreme cold), drug or metabolic intoxication, or circulatory shock—conditions that can occur during some medical procedures and could result in a suspension of life processes that is not necessarily permanent. Furthermore, the status of children under the age of five years, especially the very young, requires special attention. (Task forces focusing on reliable examination of young children were established a few years later and introduced guidelines for that purpose.)
The most significant position advanced by the president's commission dealt with a question that as of 2002 is still the subject of controversy: whole-brain versus cerebral death. In the early 1980s there was already intense argument about the type and extent of brain damage that should be the basis for definition of death. The commission endorsed the more conservative position: The person is not dead until all brain functioning has ceased. This position takes into account the fact that some vital functions might still be present or potentially capable of restoration even when the higher centers of the brain (known as cerebral or cortical) have been destroyed. Death therefore should not be ruled unless there has been nonreversible destruction in the brain stem (responsible for respiration, homeostasis and other basic functions) as well as the higher centers. Others make the argument that the person is lost permanently when cerebral functions have ceased. There might still be electrical activity in the brain stem, but intellect, memory, and personality have perished. The death of the person should be the primary consideration and it would be pointless, therefore, to maintain a persistent vegetative state in a life support system.
The process of redefining death is not likely to come to a complete halt within the foreseeable future. Innovations in technology contributed much to the ongoing discussion. The EEG made it possible to monitor electrical activity in comatose patients and its application opened the way for the concept of brain death. Advances in life support systems made it possible to maintain the vital functions of people with severely impaired or absent mental functioning—raising questions about the ethics and desirability of such interventions. Organ transplantation became a high visibility enterprise that is often accompanied by tension and frustration in the effort to match demand with supply.
Further advances in technology and treatment modalities and changes in socioeconomic forces can be expected to incite continuing efforts to redefine death. More powerful and refined techniques, for example, may provide significant new ways of monitoring severely impaired patients and this, in turn, might suggest concepts that go beyond current ideas of brain death. A simpler and less expensive method of providing life support could also reshape working definitions of death because it would lessen the economic pressure. Organ transplantation might be replaced by materials developed through gene technology, thereby reducing the pressure to employ a definition of death that allows for an earlier access to organs. Changes in religious belief and feeling might also continue to influence the definition of death. For example, the current biomedical control over death might face a challenge from widespread and intensified belief that all other considerations are secondary to the separation of soul from body. Cybernetic fantasies about virtual life and death might remain fantasies—but it could also be that the most remarkable redefinitions are yet to come.
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