-Frida F. Simonstein, MSc., PhD. Research Centre for Social Ethics and Policy, School of Law, University of Manchester. Address for correspondence: Moshav Maor, 38830, Israel. Email: firstname.lastname@example.org
Religions preach resignation to the fact that we must die someday, however finding ways of curing diseases and, actually curing the sick are, and have been for long, a central element of their concerns and imperatives. And yet, finding cures and curing mean interventions that impede dying and this is quite paradoxical. Until now, these interventions have done nothing but postponed the time we die. But what should we do if curative interventions have the 'side effect' of postponing dying indefinitely?
Stem cells since their discovery in 1998, have been one of the hottest scientific issues because they can be coaxed to differentiate into any type of cell in the body. Consequently, they are opening up new possibilities, such as lab-grown tissues or even replacement organs to treat a variety of human ills, from diabetes to Alzheimer's.
However, if "aging is neither inevitable nor necessary" as Tom Kirkwood remarks then we should start to work out afresh the huge challenges these prospects pose to society under this new scientific perspective.
This paper notes that stem cell therapies may prolong life indefinitely and discusses the forces that are hastening the search for such therapies. Consequently it analyses notions of unrestricted longevity when dictated by 'normal' life span perspectives. Questions regarding timeless people and their possible boredom, the novelty of fresh people and new generations, brain capacity, identity and global justice are addressed. Finally it asks the question whether we should we make people to live longer along with 'normal' people when knowing how to do so.
Contrasting with previous knowledge regarding cell differentiation, stem cells can be found also in adults. Evidence is showing that those cells can become brain cells, liver cell precursors, or all three kinds of muscles, heart, and skeleton. Support for this 'unorthodox' view affecting the genetic 'fate' of already differentiated cells is found also in the demonstration that DNA in the nucleus of a fully differentiated cell from an adult animal, when transferred into a primitive, enucleated egg cell can be reprogrammed to encode an entire organism. The genetic expression is obviously affected by signals derived from its surroundings and this means also permitting the generation of stem cells from the same individual. 
One of the main forces behind stem cell research is the fact that over 100 millions Americans suffer from illnesses that might be alleviated by cell transplantation technologies that use these cells. What makes stem cells so valuable is that they can restore bone marrow, replace cells for Parkinson's for spinal cord injury for new cartilages in arthritis patients, fix damaged tendons to name a few at work already.
20 years ahead in the US alone, the population over age 65 is expected to double and the number of Americans over age 85 is projected to quadruple. Age- related disease costs billions of dollars and burdens millions physically and financially. The additional costs in medical and long term care that are incurred annually in the US because of loss of functional independence are calculated at $26 billion.
Not surprisingly then, human stem cells have become one of the hottest areas in biotechnology as several private companies have jumped in to try to exploit them commercially. They have produced already cardiac muscle cells and three types of nerve cells from the stem cells. They have had also a partial success in introducing new genes into stem cells to control their differentiation into specialized cells identifying genes that either initiate, or help maintain, the development of specific cell types.
ES may provide an unlimited source of replacement tissues for treating terrible human diseases. Although the way forward will not be easy, and failures in treatment would probably occur more than once, appears clearly that there is a unique congruence of desires arriving from three angles: sick people hoping to be cured, researchers, and the biotechnology industry.
Opinions may vary widely about whether the potential benefits outweigh the ethical costs of using life-extending technologies. Even though medical researchers are already doing life extension research as they seek ways to prevent and treat heart disease, cancer and the other major killers whose incidence increases so steeply as people get older.
The question that follows is, what should we do when we finally find indefinitely prolonged lives. Questions regarding timeless people and their possible boredom, the novelty of fresh people, the necessity of new generations, brain capacity and identity, and finally global justice should be addressed.
"You have been given only a limited period of time, and if you do not use it for blowing away the clouds of your mind, it will pass away and you will go with it, never to return" 
But what if the time we have been given or have created for ourselves turns to be unlimited? Heidegger, addresses time as "the phenomenal aspect of temporality which is closest to us". And he adds that out of it arises the ordinary everyday understanding of time, which evolves, into the traditional conception of time. However it is more likely that the notion of time had its beginnings in the temporality of the sun disappearing every day and rising again the day after and the measure of time evolved by the reoccurring of the seasons. The concept of time has not emerged necessarily by our own temporality.
Heidegger argues also that Being-in-the-world is being already been delivered over to death, that there is a lack of totality, in Being, which finds an end with death. He adds that death is a way to be. He reflexes that in fact, as soon as man comes to life, "he is at one old enough to die" and adds that death "is a phenomenon of life" and "a well known event occurring within the world" .
That "there is a certainty of death" was certainly true when he wrote this. However he suggests also the temporality of our notions when he says, "so far as one knows, all man 'die'." Interestingly, the most relevant idea to a possible near future in Heidegger's 'being-towards-death' is found in the notion that along with the certainty of death "goes the indefiniteness of its 'when'."
"The term evolution itself already reveals the creative role of individual finitude, which has decreed that whatever lives, must also die. For what else is natural selection with its survival premium, this main engine of evolution than the use of death for the promotion of novelty, for the favoring of diversity, and for the singling out of higher form of lives with the blossoming forth of subjectivity?" 
Jonas however seems to ignore the fact that humans have interfered and stopped evolution by their own doing. Vaccines, antibiotics, surgeries and in general better hygiene and better health care prevent natural selection with its supposed 'survival premium' for almost everyone is surviving well passed the reproductive age, at least in developed countries. Death or 'finitude of the individual' is already not necessarily required for the promotion of novelty.
Reaching ripe old age and dying from mere attrition of the body is, as a common phenomenon, very much an artifact as Jonas rightly puts it. But is Jonas proposing to return to ancient times? Jonas provides a fairly answer to this question when he argues that the 'blessing ' of death for the individual person is true only after a completed life, "in the fullness of time" yet what the word 'fullness' does mean? And what means "exhorting from nature more than its original allowance to our species" ?
Man's life span down the ages has changed radically. The Neanderthal man lived for only 20 years. In medieval England life span was 33 years, in early 20th century in Europe life span reached the age of 50. And today life expectancy in developed countries has gone up to 80 years. If what Jonas proposes as 'original allowance to our species' is to be followed, then in Sierra Leone where life expectance of humans is 26 years, people there are exhorting from nature 'more than they should' already, at least by prehistoric standards.
It could be argued however that Neanderthals were probably another species. But then a quick look at classical Greece and classical Rome shows a life span of 28 years in both, a third of current 'normal' life spans!  However if this was all they had, this was obviously the 'fullness of time' belonging to the human species then.
Interestingly the discourse of a being-towards-his-death by Heidegger leads him finally to Nietzsche's idea "against one becoming too old for its victories'. The anticipation of one's own death he says, "lies in giving itself up, and thus shatters all one's tenaciousness to whatever existence one has reachedc it guards from falling back behind oneself, or behind the potentiality-for-Being which it has understood."
But if this is so, if the anticipation of death means giving up, then we would have never been able to reach the life span we meet today. At which age we should give up, before which surgery, which transplant, which cure? Having a surgery to remove cataract at the age of 85 that will permit a man to continue reading the newspaper until the age of 88, or until he eventually dies, does mean being too old for such 'victory'?
But then, how many of such victories could we afford for there are others awaiting to be born?
"[I]t is one thing to contemplate our own 'immortality', quite another to contemplate a world in which increasing numbers of people live indefinitely, and which future children have to compete with previous generations for jobs, space, and everything else." 
Dying of the old Jonas argues makes place for the young. This rule becomes more stringent he says "as our numbers push or already exceed the limits of environmental tolerance". Yet although the numbers count, nobody is preventing from families to have as many children as they want. This is the case in developing countries in which the number of children dying from diseases is high. But this is the case also in religious orthodox groups that are not using contraceptives because it goes against their faith, in developed countries [where the rate of mortality of children is almost non-existent ].
In any case apart from China, nobody interferes with natality rates even if those are raising the specter of population as well. On the other hand-developed societies are making fewer children, owing to the fact that the life lottery has almost disappeared and a couple can have less children without fearing their premature death. And yet who could have known at the beginning of the 20th century that the average number of children per family at the end of the same century would drop from eight children to less than two?
"Natality cis as essential an attribute of the human condition as is mortalityc. It denotes the fact that we all have been born, which means that each of us has a beginning when others already had long been there, and this ensures that there will always be such that see the world for the first time, see things with new eyes, wonder where others are dulled by habit, start out from where they are arrivedc 
This is certainly true, but at what cost? The huge investment put on each child from its very beginning is enormous. Each child grows inside his mother's womb at her expense, lowering her immune system, changing her body, and using her nutrients. A baby would be born with normal rate of hemoglobin while his mother could have at the same time half the normal rate! Biologically, the embryo is a perfect parasite.
Children dependency does not end with birth, as we all know. The effort put into rearing a child to become a full human being - from birth to high school - is a model of parents and teachers in deepest slavery for new generations. "Procreation, and the pleasures of having and rearing children" could well be 'out of date' for immortal humans. Especially if they had to choose between giving up their own lives to have a child. For children are happiness as the song goes, but surely they are a great deal of trouble as well.
Moreover do 'fresh people' always have 'fresh ideas' as Harris and Jonas presuppose? Although all children 'see the world for first' not everyone really wonder. Children also are easily malleable and as such they are prone to continuity rather than changes. History shows that this is mostly the case. One good example is Galen's concepts on medicine in general and on the structure of the body in particular, which survived him for fourteen centuries!
A quick and very basic calculus gives the astonishing number of, at least, 56 generations of lots of 'fresh people' that nevertheless sustained very outdated, and wrong, ideas. Appears to be that 'fresh ideas' need more than 'fresh people' and that is an open mind, courage, and, at least some, experience. Moreover, Galen's long-lasting theories show that 'fresh people' are not always a guarantee of 'fresh minds'.
On the other hand, what a waist of efforts and investment is to lose a well-trained mind. As Dworkin puts it, though in a different context,
"It is a waste of the natural and human creative investments that make up the story of a normal life when this normal progression is frustrated by premature death or in other ways. But how bad it is-how great the frustration-depends on the stage of life in which it occurs, because the frustration is grater if it takes place after than before the person has made a significant personal investment in his own lifec"
This sound quite convincing as a justification for increasing life spans, for the more investment we make, the less we would like to lose it by dying. For should we throw away the investment we have put in trained minds if we have the possibility of keeping them young for longer? If people were neither "old, nor frail, nor necessarily retired" we could use Dworkin's idea of the investment already made on a life from a new perspective, in order to justify its indefinite prolongation, and in good shape.
For some however, the prolongation of life means boredom, an existence that is worse than death. Bernard Williams  refers to this in 'The Makropulos case', based in the imaginary story of Elina Makropulos [EM] who has been living to the age of 342 due to a magic elixir her father, a physician, prepared for her long ago and she has been drinking it for 300 years, every year, making her immortal.
Williams tells us that for EM unending life has come to such a state of "boredom, indifference and coldness that singing or silence have become for her the same." So she refuses to take her elixir again and consequently she dies. The reason for her refusal is that she has been 42 years old for 300 years and so Williams argues, this is enough time to get so bored as to prefer being dead. Although he thinks that if one had to spend eternity at any age, that age seems an admirable age to spend it at, her problem he argues, lies in having been at it for too long. "Her trouble was, it seems, boredom: a boredom connected with the fact that everything that could happen and make sense to one particular human being of 42 had already happened to her."
Yet, Williams is over simplifying the issue, for nobody that lives 342 years remains 42 years old for 300 years. She might look 42, but where exactly is it written that what person does at 42 he cannot do at 64? Or not have done it when 24? Or never try it again at 240? Looking like somebody that is 42 does not oblige her to behave like a 42 years old forever, whatever this behavior might signify. A person evolves through her life as she wishes.
If for Williams immortality is defined as either "inconceivable or terrible" he can well speak only for himself. Glover for example discussing the EM case argues that boredom depends on one's character and that with the right company he would be quite happy to have the chance "to sample a few million years and see how it went." Kirkwood goes farther, not only referring to continuity as Glover does. When he refers to a world of immortals he adds the idea of never-ending personal development of pleasure and skills.
Well-trained minds may wonder, when doing new things. And longevity may well combine the investment of education with experience in life for further development and skills. There are people that have understood this already: a physician, Head of Department, is starting law studies at the age of 52. She wants now to become a judge. At the beginning of the previous century however, she would have been most probably death already. So obviously 'premature' death depends on which era we are living.
And yet could we go on and develop our skills endless?
Jonas argues that because we are finite beings, even if our vital functions continued unimpaired, there are limits to what our brains can store and keep adding to. 
This might be so, but even if it is, we are using currently a minimal fraction of our brain and much of its functions, are still unknown. We have not worked out even how memory functions. What we do know is that the capability of new storage declines while aging because brain cells die. We also know that the brain shrinks with age owing to cell mortality. But if we could avoid brain cell death or replace death cells with new ones would it be necessary periodically to clear the mind -like computer memory- of its old contents "to make place for the new" ? The answer is that we certainly do not know. However it seems that our memory has a zip-unzip capacity and we do not remember everything anyway, as our brain cleans memory [or zips it?] all the time. I do not remember clearly what I did at the age of 18 until 28, bored while changing diapers to babies. However the huge amounts of photographs I have with my children in those days clearly show that I was there. Where have disappeared my memories then? Could it be that because I was storing memories in photographs my mind could spare them? If this is so then our mind erases memories spontaneously. Also we seem to remember only exciting, pleasurable or traumatic events. Our mind loses anyway recollection of events, unimportant or boring, and skills we don't use. However, not remembering 10 years of my life does not mean that my entity changed. Nor does it mean that remembering my past looking at photographs makes me a different person.
"It is a duty of civilization to combat premature death among human kind worldwide and in all its causes - hunger, diseases, war, and so on." 
Although I certainly agree that this should be the ultimate goal, it is not quite clear what 'premature' should be. Although Jonas believes that the question of immortality is rather academic "for no serious prospect is in sight for breaking the existing barrier" he recognizes also that "the dream is taking form" although he refers to it as a result of a "technological intoxication". But is not this technology that has been able to extend life spans of people and also to widen the range of people that reach old age in the developed world during the last century? Also it is technology - mostly - which will prevent people from dying in the third world.
Jonas however refers to global justice. Yet the question is whether should we avoid saving the life of a man aged 80 in Japan in order to prevent from dying a man who is 27 in Sierra Leone? But in the name of global justice we should be asking the same question regarding people who need life saving therapies in their forties, or their sixties. In fact by this line of reasoning we should be prevented from getting any form of therapy after the age of 27! And yet, not preventing a person from dying at any age if this could be prevented means killing him. And if the same man chooses not to undertake a life saving therapy, he would be committing suicide. Obviously people do not volunteer to give up their life at any age in order to save people in Sierra Leone, nor it seems to be justified by any reasonable concept of justice for them to do this.
Giving up one's own life will not help the people in Sierra Leone anyway, for global justice is a matter of global policy, which should be aiming to improve health care everywhere, for everybody by other means. Killing people by preventing from them life saving therapies at the age of 80 will not prevent from people in Sierra Leone from dying at the age of 27 as it didn't when people in the first world had life spans of 50.
What remains is to understand how mortal people could live along with 'immortals' and who should be given prolonging life therapies and for how long? The first question seems to be easy to answer. Although not yet 'immortals' we have different life spans anyway. Some die young because we cannot cure them and yet we do not avoid curing somebody in her forties because her brother died from cancer when he was 32.
The second question is more complicated because it has to do with balance between society and personal choice. After all if the person who becomes 'immortal' chooses also to reproduce as much as he can then we would be in a difficult situation. This will be for one person getting the best of both worlds.
Harris suggests that society could offer people life-prolonging therapies only on condition that they did not reproduce, "except perhaps posthumously". However, cancer for example, is a disease that is mostly age related and most of the remaining plagues of the last century, in the developed world are also related to late onset genes. This mean that people needing such therapies today would already have procreated. The other possibility is that they agree that if they did reproduce then they have disqualified themselves from subsequent therapies. Yet, such a possibility does mean again that nobody will get these therapies in these days because everybody has reproduced already. Some people then will start avoiding having children in the first place, to get the chance of having a prolonged future.
Kirkwood pictures a world where every person is given the right to have two children during their lives. Yet, deciding to complete one's reproduction quota signifies one's self-imposed death sentence. Such a world has reached the kind of "generational cleansing" by voluntary euthanasia Harris refers to as a future possibility. This sounds better than a collective decision of what a fair innings of a 'full life-span' should be, because at least, the decision is autonomous and the choice is made individually. However it is not clear which scheme of current morality would be behind it. Although there is no sufficient reason to prevent people from prolonging their lives indefinitely, schemes of morality addressing the needs and the limitations of 'immortal' people should be discussed and renewed afresh under this new perspective.
Stem cells, by their ability to replace damaged tissues and organs are opening new horizons for therapies related to aging. What is more, the forces driving currently the research on aging are enormous: curing on one hand and making money on the other. These conclusions merge together producing one factual frame that means prolonging life, perhaps indefinitely, in the future.
Although there is a need for a global policy scheme, which should improve health care everywhere for everybody, global justice could not require people of developed societies to give up their lives if a cure for their diseases is found. We also could not prevent from people to live longer lives as a side effect of a possible cure as much as we do not prevent from people cures while other die because there is not cure available for them. However a scheme of morality, which underlies the needs, and limitations of immortal people should be worked out afresh under this new perspective.
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Jonas, H. (1992). The Burden and Blessing of Mortality, Hastings Center Report, 22, 34-40.
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Kirkwood, T. 2001, 'The end of age'. The Reith lectures 2001, BBC.
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Times 2 Analysis, The Times, April 19 (2000) 8
Fetal Cell Transplants. Special report'. (2001) New scientist. March, 24. Maariv newpaper, February 22 (2000) 17.
 Kirkwood, T. eThe end of age'. The Reith lectures 2001, BBC.
 Vogel, G. (2000) eCan old Cells Learn New Tricks? Stem Cells Branch Out'. Science 287 1418-1419.
 Moore, M. (1999) gTurning Brain into Bloodh ? Clinical Applications of Stem-Cell Research in Neurology and Hematology'. The New England Journal of Medicine 34 605-607. Another source for ES cells is found in the umbilical cord and a new trend is developing. Parents aware of the possibilities are storing their children's umbilical cord blood, taken simultaneously with birth, in blood banks, for future life saving therapies that could use their own stem cells . Wolf, S. (1999) eStoring Lifeblood: Cord Blood Stem Cell Banking'. American Journal of Nursing 99, 64-66.
 Perry, D. (2000) ePatients' Voices: The Powerful Sound in the Stem Cell Debate'. Science 287, 1425.
 Barinaga, M. (2000) eFetal Neuron Grafts Pave the Way for Stem Cell Therapies'. Science 287 1421-1422.
 Mehler, M., Kessler, J. (1999) eProgenitor Cell Biology: Implications for Neural Regeneration.' Arch Neurol. 56 780-784.
 Marshal, E. (2000) eThe Business of Stem Cells'. Science 287 1419-1420.
 Perry, D. (2000) Patients' Voices: The Powerful Sound in the Stem Cell Debate. Science 287 1425.
 Marshal, E. op. cit.
 There is a recent report of failures and side effects in the treatment of Parkinson's with fetal tissue. eFetal Cell Transplants. Special report'. (2001) New scientist. March, 24.
 Kirkwood, T. op cit, 21
 Cited in Times 2 Analysis, April 19 (2000) 8 .Extracted from Forester, M. (1999) The Spiritual Teachings of Marcus Aurelius. Hodder & Stoughton, London.
 Heidegger, M., op cit. 278.
 Ibid, 278.
 Ibid. 289.
 Ibid. 291.
 Ibid. 297
 Ibid. 301. My italics.
 Ibid. 302. My italics.
 Jonas, H. (1992). The Burden and Blessing of Mortality, Hastings Center Report, 22, 34-40.
 Kirkwood, T. eThe end of age'. The Reith lectures 2001, BBC.
 Heidegger, M. op. Cit.
 Ibid. 308.
 Harris, J. (2000) eIntimations of immortality'. Science 288 59.
 Jonas, H. Op. Cit.
 Guyer, B., Freedman, MA. Strobino, DM. And Sondik, EJ. (2000) eAnnual summary of vital statistics: trends in the health of Americans during the 20th century'. Pediatrics, 106, 1307-1317.
 Jonas, H. Op. cit.
 Harris, J. Op. Cit.
 Galenus from Pergamon, the Greek physician who lived in the 2nd century AC took care of wounded gladiators in ancient Egypt and became prestigious in Rome. His writings were considered the only authority in medicine until the 17th century AC. Poynter, F. N. and Keele K.D. (1961) A short history of medicine. Scientific Book Club - (Science in society). London
 Dworkin, R. (1993) Life's Dominion. Harper Collins. London
 Ibid. 88.
 Harris, J. Op. Cit.
 Williams, B. (1973) Problems of the Self. Cambridge University Press. Cambridge.
 Ibid. 90.
 Ibid. 90.
 Glover, J. (1977) Causing death and saving lives, Penguin books. London.
 Ibid. 57
 Kirkwood, T. (1999) Time of our lives. Weidenfeld & Nicolson. London..
 Maariv newpaper, February 22 (2000) 17.
 Jonas, H. Op. Cit..
 I would call people who have got stem cell therapy eimmortal' for language convenience. This does not mean that they could not die by other means, accidents for example.
 Harris, J. op.cit.