- Old age is a shipwreck … Charles De Gaulle
- But think of the alternative … Maurice Chevalier
- Death, thou shalt die! … John Donne
- Except for the religiously inclined, like Donne, it seems fatuous to talk of conquering death. Death is not the last disease mankind will have to overcome. It is what follows when the organism finally succumbs to disease or injury, the absence of life where there was life before. One does not, after everything else has happened, catch death too: if that were the case people would sometimes recover from death; but in this world, at least, they never do.
- Does that mean men must die? This cannot be a logical "must." The familiar premiss "All men are mortal" is hardly analytic, since children who understand they are human are sometimes surprised to learn they will die. The statement must be empirical, an inductive generalisation of some sort. What evidence do we have for its truth? Just that all men we have known have died except those now living. Could anyone know it is true? I do not see how. The last man alive could know he is dying, but never that he had died.
- However, this point cuts both ways. There seems no way a man could know he is not mortal, either. If Zeus or a voice from the heavens proclaimed to me that I had been given the gift of immortality, accompanied by suitable displays of miraculous powers, I might have good psychological reasons for expecting an open-ended personal future. But no amount of assurances could make this a necessary truth. There never could be a time when, having survived so long, I could be sure of living on still another day.
- But then what shall we say about the notion of conquering death? If it does not convey immortality because nothing can logically guarantee this, is it an empty phrase? I shall take it to mean just the indefinite prolongation of life. And since as I argued nothing in our logical conventions or even our conceptual scheme rules this out, it is a meaningful concept.
- But is it theoretically as well as logically possible? Here the analogy with disease may not be entirely misleading. For we do speak of, and understand, the "conquest" of diseases like malaria and cholera where we do not mean they have been wholly eradicated, but that in some parts of the world at least they have been brought under medical control to a degree that few people ever have fatal encounters with them. Similarly, the notion of conquering death can be pared down to this: the idea that we might some day be able so to prolong life that few of us would die over very long time-spans, and then only by bizarre accidents. Is this conceivable? Could death itself become as rare as, say, death by tetanus or influenza is today? And would that be desirable?
- I want to discuss this possibility at length, but first we have to get clear what the death of a human being amounts to.
THE PHYSIOLOGY OF DEATH
- Looked at biologically, a human being like any organism above unicellular level is an integrated four-dimensional clone of cells. Obviously if all the cells constituting a human being die, he is dead too. But this cannot be our criterion of death, since some cells (e.g. cartilage cells) go on living for hours after a man's death; and no one would say we are burying him alive because part of, say, his left knee is living as we lower him into the grave. For the same reason we do not say a man is dead when a peripheral part of his body has died, e.g. a foot after severe frostbite. In both cases there has not been involvement of the central integrating organs, the life or death of which determines our judgment of the individual's continued survival.
- What are these organs? First, there are the major supporting organs that keep the brain alive and conscious: heart and lungs. Second, the brain itself. Normally these function so interdependently that there is little point in distinguishing them with regard to the death of a man. Lung failure or heart failure or both together prevent oxygen-carrying blood from reaching the brain; hypoxia in the brain causes rapid destruction of tissue; and when the reticular core of the brainstem is damaged, there can be no recovery of consciousness. However, it must not be thought that these organs have a rough parity of importance to human life. Strictly speaking, it is not true that men die of heart attacks or drowning or lung cancer. Rather, these events cause paralysis or destruction of respiratory and cardiac functions, which causes anoxia in the brain; and it is this which in turn causes death of the brain and person. The point can be made this way: a bullet through the heart kills within minutes, but a bullet through the upper brainstem kills instantaneously. Admittedly, the distinction will seem picayune to someone facing a firing squad; but as we shall now see, it can have great importance in some controversial medical contexts.
- In 1968 the Ad Hoc Committee of the Harvard Medical School issued a report intended to provide a definition of irreversible coma1. The authors were no doubt aware they were doing more than that: in effect the report sets out criteria of brain death2 which, if accepted, allow the physician to pronounce a terminal patient dead while his body, or the rest of it, is still living. The connection of this with the problem of justifying organ transplantation3 is too obvious to require discussion. Briefly summarized, these are the criteria:
- 1. Total lack of receptivity or responsiveness to externally applied stimuli, even what would be most painful stimuli, in the form of speaking or groaning, withdrawing a limb or quickening of respiration.
- 2. No spontaneous movements or breathing when the mechanical respirator is turned off for three minutes (long enough to see if the brainstem is functioning but not long enough to cause brain damage by anoxia).
- 3. No reflexes: pupil fixed and dilated, unresponsive to bright light; no ocular movements, postural activity, swallowing, yawning, tendon or muscular reflexes.
- 4. Flat electroencephalogram during ten minutes of recording, and no EEG response to noise or to pinching.
- 5. All of the above tests to be repeated twenty-four hours later with negative results.
- 6. Provided conditions of hypothermia (below 32° C.) and pharmacological depression (such as barbiturates) have been excluded, these indications of irreversible cerebral damage are conclusive.
- Now, it is interesting that within the medical profession itself, and among others concerned with bioethical problems, there has been considerable disagreement about whether irreversible cerebral damage is itself tantamount to death of the person. In one sense, of course, it is not, because the person's body when on a heart and lung machine is still living, albeit artificially. But these days no one but a primitive Aristotelian would suppose the heart is the seat of consciousness; if it is agreed the brain is dead then we know the patient's conscious life has ended forever. Why should there be any difficulty here? So far as I can see, what has disturbed some people is just the fact that in a few, fortunately very rare, cases one can have neocortical death without brainstem death4. When this happens the patient, though permanently unconscious, is able to breathe spontaneously and exhibit reflex actions, thus passing the Harvard test for being alive, for as long as six months. One concerned group has said: "While an isoelectric EEG may be grounds for interrupting all forms of treatment and allowing these patients to die, it cannot itself be the basis for declaring dead someone who is still spontaneously breathing and who still has intact cerebral reflexes. It is inconceivable that society or the medical profession would allow the preparation of such persons for burial5." All I can say to this is that it is not inconceivable to me. When reasonably assured of a loved one's neocortical death, it would not have the slightest interest for me that this person was still breathing when prepared for burial, however grisly it might seem to those who have to do that. And I should hope those close to me would feel the same way in my own case. If someone suggested to me that my body might survive death of the neocortex for several months or years, provided it were fed and cleaned properly, etc., that would have no greater appeal to me than preservation of my appendix in a bottle of formaldehyde. For in the sense in which life has value for human beings, I would have been dead all that time. What we are talking about is not a living person but a breathing corpse. And if the notion of burying a breathing corpse is repulsive, then I suggest we simply stop it from breathing.
- These morbid reflections do, however, provide us with some gain in physiological specificity. While a functioning reticular formation in the upper brainstem is necessary to consciousness accompanying neocortical functions, without the neocortex such paleocortical structures can maintain only the crudest sort of wakefulness6, and nothing like conscious human life. So at a bare minimum the conquest of death must mean indefinite prolongation of neocortical function—sustained and altered, normally, by those lower brain centres.
THE LOGIC OF SENESCENCE
- All things get older; only living things age. A bacterium may live indefinitely under the right conditions, but more complex organisms cannot. If they manage to survive long enough, they all deteriorate and then die. They do not die of age; no one, really, succumbs to the burden of his years. But beyond maturity there always lies decline, greater and greater vulnerability to stress, injury, disease. It is interesting that in industrialised societies with high standards of medical care the number of people who achieve old age increases constantly, but the life span of men does not. It has been estimated that if cancer were extirpated this would add only 1.5 years to the allotted human span; even today only 1 in 100 of us will reach 90 years of age, and 1 in 1000 age 100. As of 1963 the oldest known man whose birth was fully authenticated died at 113 years 100 days, and that was back in 18147.
- The notion of a relatively fixed life-span in almost all forms of life above unicellular level suggests that we are somehow genetically programmed to age and die. However, there is no empirical evidence to support this idea, and upon reflection one sees it is superfluous. Darwinian principles apply to species, not to individuals; if the evolutionary rationale of individual decline and death is to avoid overpopulation and to assure dominance of new generations, who, by random mutation, will be better adapted to changing environmental circumstances, it is sufficient that members of the species not be programmed to go on sustaining size, strength, and physiological efficiency beyond maturity and reproductive activity. Bidder puts the point well:
- If primitive man at 18 begat a son, the species had no more need of him by 37, when his son could hunt for food for the grandchildren. Therefore the dwindling of cartilage, muscle and nerve cell, which we call senescence, did not affect the survival of the species; the checking of growth had secured that by ensuring a perfect physique between 20 and 40. Effects of continued negative growth after 37 were of indifference to the race; probably no man ever reached 60 years old until language attained such importance in the equipment of the species that long experience became valuable in man who could neither fight nor hunt8.
- If this is a substantially correct account of the logic of senescence, then the human situation is deplorable in two respects. First, the rising life expectancy of individuals in medically privileged societies, coupled with a fairly fixed total life-span for the species as a whole, means we are condemned to spending more and more of our lives in progressively debilitating bodily condition. Whereas primitive and even medieval European man probably lived less than 1/5 of his life in senescence, we are approaching a curve in which most of us will pass 1/2 of our lives that way. A study made some years ago with 400 males shows what we can expect9. Between the ages of 30 and 75 a man loses, on the average, the following: brain weight, 44%; blood flow to the brain, 20%; cardiac output, 30%; kidney plasma flow, 50%; the number of nerve trunk fibres, 37%; nerve conduction velocity, 10%; the number of taste buds, 64%; the maximum oxygen uptake during exercise, 60%; the maximum voluntary breathing capacity, 57%; strength of hand grip, 45%; basic metabolic rate, 16%; and total body weight, 12%. Since all these changes are gradual over 45 years, the ageing person does not feel suddenly deprived; if, however, they took place very quickly, one would have no hesitation describing this as a catastrophic loss.
- Secondly, and perhaps more important, the complete waste of human ability and experience that accompanies the termination of senescence is a constant, recurring loss to all of society. Imagine a digital computer with 1010 units which builds up an extremely sophisticated programme for solving equations over several years, constantly improving the programme as it goes along, adding to its memory store, etc., until one day it breaks down, destroying within minutes all its circuitry and memory banks and simply disintegrating into metallic scrap. But something not entirely unlike that occurs every time a trained or educated human being dies. We spend the first two decades of our lives growing up, learning the language, acquiring basic knowledge and skills. Then we spend two more decades developing whatever special abilities we have to full productive potential. It is precisely at this point, the beginning of the plateau of maximum service to society, when incipient bodily deterioration becomes noticeable10. From here on the continued refinement of our skills and growth of our knowledge and judgment proceed side by side with physical decline for two or three decades, until we are forced into retirement, waiting quietly for the end. This pattern, whereby the occupational and intellectual worth of the individual continues to increase in inverse proportion to the ability of the organism to sustain this physically, is the price we pay for our evolutionary origins.
- Given these unpalatable facts, it is not surprising that men have always sought some magical way of staving off senescence and death, though usually from individual concerns rather than social ones. King David, among others, was counselled to lie between two young girls; according to Marsilio Ficino (1498), the old man should drink milk from the breast of a young girl11. No doubt these are pleasant enough remedies, though probably too stressful for the elderly. Pope Innocent VIII (1432-1492), showing perhaps a different predilection, had the blood of young men transfused into his veins; since nothing was then known of incompatible blood-types, he promptly died. Voronoff (1866-1951) attempted grafting monkey testicles onto his aged male clients; Metchnikoff (1845-1916) recommended yogurt and removal of the large intestine. Even today the search goes on. In Bucharest, one can get injections of H-3 and KH-3; and in Switzerland, injections of living cells, usually from a lamb embryo12. Unfortunately it is unclear how any of these measures would add to the genotype what is not there, i.e. instructions to the body's cells to sustain their functions indefinitely when this is unnecessary to species survival.
- Perhaps aware of the fundamental problem, many people these days are opting for an entirely different kind of solution, what might be called the Great Postponement. Here the idea is that what we cannot do today will certainly be possible tomorrow, or the day after, or the day after that. All we individuals need concern ourselves with is being around when the currently impossible becomes possible, i.e. in some indefinite future state of scientific and technological progress. And the way to do that, they say, is by getting yourself frozen. But there are two, in some ways opposed, schools of thought on the subject, and in fairness they must be separated.
- The first and more radical school is the "Freeze Dead" school, which pins its faith on eventual thawing out and reanimation13. For about $10,000 you can arrange to have your corpse perfused with glycerol or DMSO and cryogenically interred in a liquid nitrogen environment; robot surgeons of the future will obligingly "reconstruct" the damaged brain so that you will live again, perhaps unendingly14. Certainly this proposal will do no harm, if you can afford $10,000 and particularly like the idea of permanent embalmment: the advantage of believing in any kind of resurrection is that you will never find out you were wrong. However, there can be no serious expectation of surgeons' "restoring" thousands of millions of destroyed and missing neurons with all the precise interconnections they had before you died so that you, an individual person, would live again; how could they, since the pattern of neocortical connections disappeared before you were frozen?
- The second school, recognising this fact, is more modest. It urges research in cryogenics so that some day suspended animation15 may be achieved in mammals, eventually in men, without the present-day hazards of ventricular fibrillation, cellular destruction by formation of ice crystals, and other problems. It is, in other words, the "Freeze Alive" school of thought. But it, too, banks on one's being reawakened centuries later when, in one author's words, "All disease and aging are cured—relegated to history16.” Here, of course, there is an explicit assumption that genetic engineering will allow us to change the genotype itself. Without this being achieved, "hybernauts" of the future will not gain greater longevity by suspended animation17; seventy or so years of conscious life is still no more than seventy years if you live half of it in the twentieth century and half in the twenty-second.
- Can the genotype be changed? Sir Macfarlane Burnet, discussing the publicity accompanying Kornberg's successful synthesis of DNA in 1967, has this to say:
What they [Kornberg and Tatum] were envisaging in principle was that in due course it could become possible to extract from normal human cells the sequence of DNA that was missing from or wrongly made in the patient. Once isolated these could be used as the pattern, the template, for the synthesis by bacterial enzymes of numerous replicas of itself. This is acceptable as a possibility of the foreseeable future. The next step would be the crucial and probably impossible one: to incorporate the gene into the genetic mechanism of a suitable virus vehicle in such a fashion that the virus in its turn will transfer the gene it is carrying to cells throughout the body and in the process precisely replace the faulty gene with the right one. I should be willing to state in any company that the chance of doing this will remain infinitely small to the last syllable of recorded time18.But Sir Macfarlane was talking only of one faulty gene responsible, say, for a specific hereditary defect like harelip. If senescence and hence greater vulnerability to fatal injury or disease is due to most of the human body's organs' not being programmed to sustain optimum efficiency beyond maturity, then to "cure" ageing would involve altering a vast number of genes such that all these organs never falter or wear out. I conclude, always tentatively, that as long as we have bodies we shall grow old and die, and that no amount of scientific optimism will change this.
- But must we have bodies? I said earlier that conscious human life—the only sort worth having—is rooted in neocortical function, sustained and alerted to consciousness by the reticular formation in the brainstem and associated structures. It follows that an intact human brain kept in vitro but nourished by a properly oxygenated and glucose-supplied blood flow mechanically pumped into it through the severed arteries could support conscious life; indeed there is partial support for this claim in the fact that monkey brains have been kept alive for several days in vitro: the EEG recordings indicated periods of consciousness20.
- However, an isolated human brain, devoid of neural inputs and unable to affect anything with its motor commands, would have an unenviable life. It would see nothing, hear nothing, feel nothing. When conscious it could only feed on its memories of an embodied past and, eerily, talk to itself, an endless silent monologue. (Theologians will recognise in this description the physiological analogue of continued existence as a disembodied21 soul.) It would appear that to live a genuinely human life, a body is necessary after all.
- But need it be a human body, hence vulnerable to ageing and death? Need it even be a living body? I do not see why. After all, the body is just the means by which our brains interact with the extrabodily environment. In principle, though it is technologically very far-fetched, we could someday build prosthetic bodies housing portable, miniaturised heart-and-lung machines that keep the brain—comfortably installed in the head cavity—well-nourished with blood and glucose, etc. Descending neural pathways from the brain would end at, say, the medulla oblongata, where the electrical charges they emit could activate a miniaturised digital computer to perform limb movements. Conversely, receptors in the prosthetic body would send messages up to the computer, which could in turn fire the proper sequence of ascending nerve fibres that transform these into proprioceptive, kinesthetic, somesthetic, and tactile sensations in the brain. It is important to note that these sensations would be qualitatively indistinguishable from those we now experience. A touch or caress upon the surface of the prosthetic body would be felt by the person whose brain it is as his bodily sensation: One must not think one would be sacrificing all the pleasures of having a body by exchanging the one he now has for an inanimate replica body. And indeed for aesthetic and psychological reasons, as well as satisfying third-person criteria of personal identity, this prosthetic body should be modeled on his own: he might, however, introduce one or two long-desired cosmetic changes.
- What I have just described is technically outrageous, but it does not require overriding any physiological realities22. Even vision and hearing could be achieved with a prosthetic body of sufficient sophistication, by having mechanical sensors fire the appropriate neurons in the visual and auditory cortices directly, thus bypassing the normal optic and auditory nerve pathways: indeed in the case of vision that would only be an extension of present research23. But I shall leave further details to the imagination. I am not sure, for example, whether it would be worthwhile to develop mechanical digestive and excretory systems, just in order not to forgo the pleasures of the table; or whether one should sacrifice some surface sensitivity in the prosthetic body to avoid risk of activating pain mechanisms in the brain. These are complications we can afford to neglect.
AGEING IN CYBORG24 MAN
- The idea of escaping the evolutionary limitations of our present bodies by having our brains transplanted25 at postmaturity into bodies which, being inorganic, do not age or deteriorate, has a prima facie attractiveness about it. If I am correct that death amounts to destruction of the neocortex, then the most common causes of this—failure of supportive organs due to conditions like heart disease or lung cancer—would not kill cyborg26 man. Indeed a great number of widely held theories about the mechanisms of senescence in higher animals would have no application to him. These include those which emphasise the increase of collagen, a fibrous protein, in the body27; the theory that capillary breakdown due to circulatory deficiency is the culprit28; the decline-in-endocrine-gland approach; that version of the waste product theory which blames faulty metabolism and the increase of toxic substances in the blood29; and the theory that failing autoimmunological surveillance related to a diminishing thymus is responsible30. Even such general restrictions on longevity as the "Hayflick Limitation," which limits the number of times an embryonic human cell can divide in tissue culture (about fifty31), seems irrelevant to the postmitotic cells of the brain. Radiation, of course, can destroy the chromosomal integrity of any cell, including those of the human brain, but at less than cytoxic levels it does not seem to have any effect on ageing32.
- The greatest challenge to any hope of vastly prolonging human life by corporeal prosthesis is found in Abnutzungstheorie, the "wear and tear" view of ageing. For if this is right the brain of cyborg33 man would, just like any bodily organ, wear out in time. And certainly the large (statistically established) loss of brain weight between ages thirty and seventy-five mentioned earlier supports this pessimism. However, it is far from clear how, if at all, this loss contributes to death. For one thing, cellular fallout appears to begin at puberty rather than middle age, while both physical strength and intellectual growth are still increasing. What is more, it seems to taper off in the last decade of a normal life-span. A recent study by Tomlinson suggests that there is no significant difference in the proportionate brain weight of intellectually unimpaired people who die at sixty-five and those who die at seventy-five. Speaking of twenty-eight cases, he says: "As a group, loss of brain weight and the degree of cerebral atrophy was relatively slight, and the lateral ventricles were only slightly larger than those of normal young adults. Indeed all the brain weights fell within the normal limits for young adults and many brains showed no apparent cortical atrophy or significant ventricular dilation34."
- Dayan has made a thorough review of evidence for pathological change in the ageing human brain and it is surprising how difficult it is to say in what these changes consist. Atrophy clearly occurs, but the nature of the loss is unknown since suggested anatomical sites for the loss have been disproven at almost every place where exact counts have been made. Argyrophilic plaques appear in the cortex in the sixth or seventh decade of life, and neurofibrillary tangles at about the same time: these are independent idiopathic degenerative processes, but they do not appear to affect the most important neuronal processes. Neuroaxonal dystrophy is another invariable finding, but of very limited functional significance; and the same appears to be true of amyloid deposits around small blood vessels in the cortex and of intra-neuronal inclusions35 Other types of brain lesions associated with ageing are too variable to be significant. It is true that lipofucins build up in brain cells (and in heart muscle cells) with age; another version of the waste product theory holds this to be responsible for senescence. However, artificially induced concentrations of these substances in rats did not alter their life-span36, and there is some evidence this pigment can be decreased by chemical treatment37.26
- But even if cellular fallout and cortical atrophy are not themselves clearly fatal, it is true that with age our brains become more and more susceptible to disorders of cerebral blood flow that can cause fatal brain trauma such as atheroma of the arteries, thrombosis, embolisms, aneurysms, sclerosis, etc. However, it is not known to what degree circulatory deficiencies reflect degenerative changes in the ageing brain, or are due primarily to failing cardiac/respiratory support systems in an ageing body38. If the latter is the case, cyborg39 man's brain might very well retain efficient blood circulation indefinitely, because of superior artificial (and easily replaceable) support systems. Even if, as now appears the case40, cerebrovascular insufficiency in the elderly is due to malfunctioning central ganglion cells, leading to decreased oxygen and glucose uptake, it has been shown that brain metabolism is responsive to pharmaceutical treatment41 In cyborg42 man autoregulatory mechanisms of the brain could be monitored by computer and appropriate chemicals injected into the blood stream when needed. About all one can say in our present state of knowledge is that we just do not know whether, under these idealised conditions, the human brain could survive the ageing process for an indefinite period of time.
THE INTELLECT OF CYBORG43 MAN
- Senility is so often associated with senescence in our experience of elderly people that one might legitimately wonder if, even if cyborg44 man's brain did not die with age, it would not become so intellectually deteriorated that the whole exercise would be futile. What is the point of keeping a man alive and conscious in a youthful-looking prosthetic body if he becomes doddering, absent-minded, amnesic, cranky, etc., anyway?
- Bromley45 and Welford46 have independently shown that there is a decline in intellectual ability with normal ageing, which they attribute to deterioration in the central processing functions of cognition. However, this relates to intelligence testing of a large number of individuals from all walks of life. One would expect that in the creative professions the gain from experience, learning, and refinement of judgment outweighs this mild decline in general capacity. After all, the value to us of a playwright or paleontologist or painter is not measured by his performance on the WAIS over the years, but on the quality and quantity of his output. Even if this also declines between, say, ages fifty and sixty-five, that may not be disconnected from the fact that he is then becoming but two-thirds or so of the man he was in terms of organic, physiological efficiency. Cyborg47 man would not show physiological deterioration like this; it remains to be proved that he would nevertheless decline intellectually. Even Bromley admits that effects of ageing appear to be less conspicuous in the brain than some other systems of the body48.32 Without deleterious changes in the body at all, why should the brain begin to fail?
- And indeed if not, if cyborg49 man's brain neither died nor deteriorated with age, think of what this could mean to society. Imagine that we had been able to do hundreds of years ago what I am suggesting we may be able to do hundreds of years from now. Who can say that the geniuses of the seventeenth century would not have done two, three, any number of times as much great work had they lived on in good health to age 200, 300, or more years? Shakespeare might not have gone into voluntary retirement; Newton's life might have overlapped with Einstein's; and Beethoven might be with us still. True, even cyborg50 man could perish in the accidents of life. A hard enough blow to the prosthetic head would dispatch him as easily as it does us. He could still drown or get run over or have an irate husband shoot him. But once the principal causes of human mortality are eliminated, the genius has as good an opportunity to live half a millennium as to live half a hundred years.
IS DEATH DESIRABLE?
- Leon Kass has said that death is "not only inevitable, but also biologically, psychologically, and spiritually desirable51." I hope I have said enough to show that one may rationally doubt whether it is inevitable. Dr. Kass offers no argument for the rest of his statement. That death should be biologically desirable suggests Weismann's old argument that "Worn-out individuals are not only valueless to the species, but they are even harmful, for they take the place of those which are sound52." Alex Comfort's rejoinder to this is worth quoting: "This argument both assumes what it sets out to explain, that the survival of an individual decreases with increasing age, and denies its own premiss, by suggesting that worn-out individuals threaten the existence of the young53." However, Kass may only have meant that in most species overpopulation would result from this. That is true; but the difficulty and expense of creating cyborg54 men are such that either (1) only few individuals of great promise would be preserved this way, somewhat like the system of academic tenure today, or (2) in a society which could afford to give every mature male and female this option, overpopulation would have been solved by birth control, planetary and stellar migration, etc., long before.
- That death is spiritually desirable is incomprehensible to me since in many of the great living religions, at least, it is the (other-worldly) conquest of death which gives them much of their attraction and rationale. But of course in another sense what Kass says is true: for some religions it is terribly important that you experience complete physical death before, with luck and merit, you are allowed to live again. But since I am not concerned in this essay with spiritual matters, I shall let that pass.
- That death is psychologically desirable is a more interesting suggestion. On the surface it has a certain appeal. There are certainly moments when, peering vaguely ahead into our lives, Marcus Aurelius' plaintive question "Quousque tandem?" takes on real meaning. Death appears as the darkness at the end of a cone of diminishing light, and it is not unwelcome. It equals perfect rest, the end of tribulations. But apart from those unfortunates whose continued lives have become circled in pain or stress, we show a remarkable reluctance to step into the shadows. We cling on, and scream against the dying light. Perhaps that is just selfishness; but how many of us, in good health and with undiminished intellectual powers, would really say: "Well, tomorrow is all right with me"? Surely on the morrow we would want to say the same. It is only because the cone stretches far ahead that the shadows seem welcome.
- But I do not like to think of death just in my own case. We must all have had friends, or at least one friend, who was personally so valuable to us that his decline and death seems an irreparable loss to ourselves and everyone who knew him. Such a person, bright and warm and enriching to the end, was in fact based in a well-functioning neocortex being slowly more threatened with death from an ageing supportive body system. We need only ask ourselves this question: If I could have him, or her, sitting here with me in my study tonight, joking and commenting on the latest news or theory or what have you, would it matter greatly that he or she was there in a prosthetic body? And if he or she could have been installed in such a body when he or she was thirty-five or forty, would that be worse than the cruel image Shakespeare etched in our racial memory with these words?
... and his big manly voice
Turning again toward childish treble, pipes
And whistles in his sound. Last scene of all,
That ends this strange eventful history,
Is second childishness and mere oblivion-
Sans teeth, sans eyes, sans taste, sans everything.
… As You Like It
Footnote 1: Journal of the American Medical Association, 205 (1968), 337-40.
Footnote 4: J. B. Brierly et al., "Neocortical Death After Cardiac Arrest," Lancet, 2 (1971) , 560-65. Neuropathological examination confirmed death of the neocortices in these patients.
Footnote 5: Task Force on Death and Dying, The Institute of Society, Ethics, and the Life Sciences, "Refinements in Criteria for the Determination of Death: An Appraisal," Journal of the American Medical Association, 221 (1972), 48-53.
Footnote 6: P. Bard and M. B. Macht, "The Behaviour of Chronically Decerebrate Cats," Neurological Basis of Behaviour (London: Churchill, 1958), pp. 55-75.
Footnote 7: Alex Comfort, Ageing: The Biology of Senescence (London: Routledge & Kegan Paul, 1964), fig. 72 p. 272, pp. 275, 88.
Footnote 8: G. P. Bidder, "Senescence," British Medical Journal, 11 (1932), 5831; see also Comfort, Ageing, Ch. 8.
Footnote 9: Nathan W. Shock, "The Physiology of Aging," Scientific American (January 1962), 100-10.
Footnote 10: It is true that the maximum work rate drops 30% between ages 30 and 75, and the maximum work rate for short bursts as much as 60% (Shock, 101) . But that is physical work. My remarks obviously do not apply to unskilled manual labour, or to professional sports.
Footnote 11: Comfort, Ageing, p. 183.
Footnote 12: Theory and Therapeutics of Aging, ed. Ewald W. Busse (New York: Medcom Press, 1973), Chap. 1.
Footnote 14: R. C. W. Ettinger, The Prospect of Immortality (New York: Doubleday, 1964), pp. 29-30.
Footnote 16: Robert W. Prehoda, Suspended Animation (Philadelphia: Chilton, 1969), p. 126.
Footnote 18: Macfarlane Burnet, Genes, Dreams and Realities (New York: Penguin, 1973), p. 81.
Footnote 20: Robert J. White, Maurice S. Albin, and Javier Verdura, "Preservation of Viability in the Isolated Monkey Brain Utilizing a Mechanical Extracorporeal Circulation," Nature, 202 (1964), 1082-83.
Footnote 22: A special problem, however, would be finding a way to prevent degeneration of the severed nerve endings in the lower brainstem above the break: in higher vertebrates this always occurs. Some technique of artificial nerve regeneration is the major requirement here.
Footnote 23: G. S. Brindley and W. S. Lewin, "The Sensations Produced by Electrical Stimulation of the Visual Cortex," Journal of Physiology, 196 (1968), 479-93.
Footnote 27: T. Verzar, "Aging of Connective Tissue," Gerontologia, 1 (1957), 363-78.
Footnote 28: N. Seyle and P. Prioreschi, "Stress Theory of Aging," Aging: Some Social and Biological Aspects, ed. N. W. Shock (Washington: American Association for the Advancement of Science, 1960), pp. 261-72.
Footnote 29: A. Carrell and A. H. Ebeling, "Antagonistic Growth Activity and Growth Inhibiting Principles in Serum," Journal of Experimental Medicine, 37 (1923), 653-59.
Footnote 30: R. W. Walford, "Auto-immunity and Aging," Journal of Gerontology, 17 (1962),281-85.
Footnote 31: T. Hayflick, "The Limited in vitro Lifetime of Human Diploid Cell Strains," Experimental Cellular Research, 37 (1965), 614-36.
Footnote 32: P. Alexander, "Is There a Relationship Between Aging, the Shortening of Life Span by Radiation and the Induction of Somatic Mutations?" in Perspectives in Experimental Gerontology, ed. N. W. Shock (Springfield: Thomas, 1966), Chap. 20.
Footnote 34: B. E. Tomlinson, "Morphological Brain Changes in Non-Demented Old People," Ageing of the Central Nervous System, edd. H. M. van Praag and A. T. Kalverboer (Haarlem: Bohn, 1972), p. 51.
Footnote 35: A. D. Dayan, "The Brain and Theories of Ageing," ibid., pp. 64-66.
Footnote 36: N. M. Sulkin and P. Srevanij, "The Experimental Production of Senile Pigments in the Nerve Cells of Young Rats," Journal of Gerontology, 15 (1960), 2-9.
Footnote 37: K. Nandy and G. H. Bourne, "Effect of Centropheonoxine on the Lipofucin Pigments in the Neurons of Senile Guinea-pigs," Nature, 210 (1972), 313ff.
Footnote 38: Lord Brain and J. N. Walton, Brain's Diseases of the Nervous System (7th ed.; London: Oxford University Press, 1969), Chap. 4.
Footnote 40: M. Ditch et al., "An Ergot Preparation (Hydergine) in the Treatment of Cerebrovascular Disorders in the Geriatric Patient: Double-Blind Study," Journal of the American Geriatrics Society, 19 (1971), 208.
Footnote 41: D. B. Rao and J. R. Norris, "A Double-Blind Investigation of Hydergine in the Treatment of Cerebrovascular Insufficiency in the Elderly," Johns Hopkins Medical Journal, 130 No. 5 (1972), 317-24.
Footnote 45: D. B. Bromley, "Some Effects of Age on the Quality of Intellectual Output," Journal of Gerontology, 12 (1957), 318-23; id., "Age Difference in Conceptual Abilities," Processes of Aging, edd. R. H. Williams, C. Tibbits, and W. Donahue (New York: Atherton, 1963), Vol. 1.
Footnote 46: A. T. Welford, Ageing and Human Skill (London: Oxford University Press, 1958).
Footnote 48: D. B. Bromley, "Intellectual Changes in Adult Life and Old Age," Ageing (n. 23), pp. 76-100.
Footnote 51: In his "Death as an Event: A Commentary on Robert Morison," Science, 173 (1970), 701-12 n. 10.
Footnote 52: A. Weismann, Uber die Dauer des Lebens (Jena, 1882).
Footnote 53: Comfort, Ageing, p. 11.
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