Koszenie Kosiarza:
Czy mozna odwrocic proces starzenia sie i czy nalezy to uczynic ?

Czy mozemy to zrobic?

W

ydaje sie, ze istnieje pewna kontrowersja na temat, czy ostatnie odkrycia dotyczace telomerow sa poprawne naukowo, jednak pytania powstaly przede wszystkim jesli chodzi o ich znaczenie. Czy rzeczywiscie oznaczaja one, ze mozemy manipulowac proces starzenia jako calosc? Wielu uwaza, ze na starzenie wplywaja inne czynniki, i ze skracanie sie telomerow to tylko element - byc moze nawet nie najwiekszy. Hayflick powiedzial podczas swej wizyty w Science Friday, ze "... starzenie sie jest, w materiale biologicznym, bardzo podobne do tego co zachodzi w urzadzeniach mechanicznych lub pojazdach, rzeczach tego rodzaju..." W tym samym programie inny gosc przedstawil swe badania nad ograniczeniem kalorii - jedzenie nie mniej by spowolnic proces starzenia - mowiac, ze jego wyniki badan wspieraja teorie, ze wolne radykaly sa mocno zaangazowane w prozesie starzenia, i ze redukcja wolnych radykalow moze byc waznym sposobem pozwalajacym na osiagniecie korzysci z ograniczen kalorycznych.

Uwagi powyzsze sa przykladami na to, co powszechnie okresla sie mianem teorii "zuzycia", z wolnymi radykalami jako najpopularniejszymi z proponowanych przyczyn takiego zuzycia. Na pierwszy rzut oka teorie te wydaja mi sie byc patentowanym absurdem i mam problemy ze zrozumieniem jak to mozliwe, ze poswiecili sie im powazni badacze. Ostatecznie, jezeli wszystko sprowadza sie do teorii zuzycia, to powstaje oczywiste pytanie: dlaczego niemowleta nie rodza sie jako stare? Faktycznie, jak przebiega w ogole zycie, jezeli wszelka ozywiona materia ulega degradacji w przeciagu kilku dziesiecioleci? Brakuje rowniez przekonujacego wyjasnienia, dlaczego rozmaite gatunki charakteryzuja sie tak gruntownie rozna dlugoscia zycia. Mozna powiedziec, ze slonie dysponuja lepszymi molekularnymi mechanizmami obronnymi przeciw degradacji spowodowanej przez wolne radykaly niz myszy, ale dlaczego tak jest? Jesli dodac do tego wszystkiego przyklady egzotycznych organizmow z ksiazki Fossel’a, ktore potrafia dowolnie wlaczac i wylaczac swoj proces starzenia, a nawet ponownie odmladzac sie po zaprogramowanym okresie starzenia sie, to pojawia sie oczywiste pytanie: czy wyjasnienia bazujace na teorii zuzycia maja ostatecznie w ogole jakis sens?

W pewien sposob stopniowa akumulacja nienaprawianych szkod moze miec znaczenie dla starzenia sie. Rozwazyc trzeba dowolny rodzaj zranienia zwiazany z uszkodzeniem tkanki - na przyklad rana cieta. Wedlug powszechnego doswiadczenia proces gojenia sie nie jest nigdy doskonaly. Po zakonczeniu procesu gojenia sie pozostaje zawsze niewielka tkanka blizny. Mozna to przedluzyc nieco dalej i powiedziec, ze zranienia maja miejsce bez przerwy, a na wiele przyczyn nie mamy wplywu. Na przyklad Ziemia jest bez przerwy bombardowana promieniami kosmicznymi. Ich znaczna czesc jest przechwytywana przez pole magnetyczne Ziemi, a inne zatrzymywane sa przez gorna atmosfere. Niektore jednak docieraja do powierzchni Ziemi. Te najbardziej naladowane energia to, za wyjatkiem kliku raczej rzadkich przypadkow, jadra zelaza, wynik ostatniego stadium reakcji nuklearnej w supernova (ekspolodujace gwiazdy). Jadro zelaza to cios wprost z bram piekla. Nie tylko uszkadza ono fragment DNA lecz jest wstanie zniszczyc kilka tuzinow komorek na raz. A jesli ma to miejsce, to komorki, ktore sie dziela i zastepuja komorki martwe, moga nigdy nie pasowac doskonale do swych sasiadow.

Uszkodzenie tkanki mozna rozpatrywac jako zdarzenie probablistyczne: kiedykolwiek komorki musza zostac zastapione w matrycy tkanki istnieje skonczone prawdopodobienstwo, ze cos nie powiedzie sie w komunikacji miedzy nowymi komorkami a ich sasiadami i zaistnieje pewien, chocby nawet tylko mikroskopijny, stopien uszkodzenia. Przywrocenie komorkom zdolnosci dzielenia sie niekoniecznie zapewni calkowite usuniecie uszkodzen. Uszkodzenia tkanki stwarzaja wowczas mozliwosc stopniowego akumulowania szkod - rodzaj starzenia sie. Nie wydaje sie obecnie prawdopodobnym, ze jest to najwazniejsza przyczyna starzenia sie takiego jakim je znamy. Jezeli jednak cos usunie najwazniejsza przyczyne, wowczas pozostale przyczyny, ktore moglyby miec znaczenie jedynie w przeciagu setek lat, moga nabrac znaczenia najwazniejszej przyczyny. Tak, ze moze byc przedwczesnym zupelne zarzucenie teorii zuzycia, szczegolnie, ze dalecy jestesmy od zupelnego zrozumienia wszystkich przyczyn kumulujacych sie uszkodzen.

Istnieje wszakze kontrargumet do tego kontrargumentu: to, ze tkanki zostaja uszkodzone niekoniecznie oznacza, ze witalne informacje sa niepowetowanie stracone, bez zadnej mozliwosci odzyskania. Ostatecznie, zaplodnione jajeczko "wie" jakos, jak urosc do doroslej istoty ludzkiej. Pozostawia to otwarta mozliwosc, ze nawet skumulowane uszkodzenia tkanki moga zostac zreperowane nawet na mikroskopijnym poziomie. Jezeli wiec Michael Fossel radzi nam by dbac o nasz zab madrosci, poniewaz nawet przy pomocy terapii telomerowej nie bedziemy w stanie uzyskac nowego kompletu, to sadze, ze jest on jednak wlasciwie calkiem konservatywny. Nowe zeby, tak jak i glowny "zegar" starzenia sie, moga byc mozliwe szybciej niz sadzi wiekszosc ludzi.

Druga z najwazniejszych teoria stazrenia sie - teoria Hormonu Smierci, ktora takze przybiera rozne formy - wydaje sie byc trudniejsza do podwazenia. Powiada ona, ze rownowagi hormonalne w organizmie zmieniaja sie w przeciagu calego zycia, i ze starzenie sie jest po prostu innym ich przejawem, podobnie jak menopauza (wyzwalana przez wyczerpanie sie kobiecej produkcji jajeczek) oraz meskie wzory lysienia, wywolane przez skumulowana ekspozycja korzonkow wlosow na testosteron. Najwazniejsza slaboscia tej teorii jest to, ze starzenie wydaje sie byc ogolnym procesem, ktory dotyczy prawie kazdego organu i tkanki ciala, a hormony sa w tendecji calkiem selektywne w swych skutkach, kierujac sie ku konkretym organom dla wywolania konkretnych zmian. Tak, ze jesli pewien zestaw "hormonow smierci" bylby najwazniejsza przyczyna starzenia sie, to nalezaloby oczekiwac, ze degeneracja skupi sie w pewnych miejscach; zamiast tego, choc nie wszystkie organy dotkniete sa starzeniem jednakowo, dotkniete sa prawie wszystkie, wlacznie z ich wszystkimi tkankami.

W rzeczy samej jest interesujacym, ze nieliczne czesci ciala, ktore z wiekiem nie ulegaja znacznej degeneracji, to dokladnie te same, ktore prognozowalaby hipoteza telomerow. Jednym z takich miejsc jest tkanka wykladajaca jelito cienkie, w ktorym natura dziwnym trafem wyposazyla komorki w pewna ograniczona zdolnosc telomerazy, poniewaz musza sie one dzielic o wiele intensywniej w przeciagu zycia zwierzecia. (To tyle o tym, ze zuzycie mialoby miec z tym cokolwiek wspolnego; najwyrazniej natura potrafi zapewnic odmladzanie rzeczy, jesli rzeczywiscie tego chce.) Innym jest miesien serca. Komorki miesni, podobnie jak komorki nerwowe, nie dziela sie u doroslych ludzi. A same komorki miesni nie podlegaja znacznej degeneracji w przeciagu zycia. Serce, ktore jest po prostu duzym miesniem specjalnego rodzaju, daje rade utrzymac swa pelna wydolnosc nawet na przestrzeni maksymalnego okresu trwania zycia, zakladajac, ze nic nie ograniczy mu doplywu krwi lub w inny sposob nie uszkodzi z zewnatrz.

But, as with the “wear and tear“ theories, the Death Hormone hypothesis cannot yet be dismissed in its entirety. The chief reason for hanging onto it, or something like it, is this observation: Life is not static. Throughout life, the human body changes; even after maturity is reached, changes occur that cannot be regarded as simply deterioration due to cells no longer being able to divide, or accumulated damage. Ovaries empty; hair follicles get their fill of testosterone and shrivel up; the prostate swells, again apparently in response to testosterone. Bones and cartilages, notably in the nose, gradually change shape in response to gravity. And certainly the brain changes, in myriad physical ways, as it interacts with its surroundings and accumulates experience. What will happen if we keep our cells youthful, and these other processes continue? Not having seen such a thing happen, we really cannot be sure what this combination would be like.

All right, some may object: So let’s say that aging is totally, or at least mainly, genetically based. How do we know that the telomeres account for all of that programming? How do we know that there aren’t a whole bunch of aging-related genes, unrelated to telomeres, that will have to be figured out before we can really affect the aging process very much? The best explanation to this would have to be highly technical; it would be a good question to ask Dr. Fossel. But I do feel confident in venturing this observation: Suppose that there are ten entirely different, genetic causes other than telomeres that are critically involved in aging; and suppose that we have to control all of them together to get any significant change in maximum lifespan. Our knowledge of the human genome is increasing on an exponential trajectory, and if you ask yourself how much longer it would take to achieve another tenfold increase in our knowledge of this genetic system, the likely answer is: a few years. Just a few years. So if Fossel is wrong, and telomeres are not the dominant mechanism, but ten other equally important and totally independent genetic mechanisms have to be deciphered, maybe we won’t see results for twenty-five years instead of twenty. That difference will, in fact, be critical for millions of individuals. But it won’t change the basic shape of the change that is about to happen.

Actually, this objection is one which Hayflick suggests in his Scientific American book review of Fossel’s book, saying: “Most biogerontologists agree not only that cells must contain multiple biological event counters…” (emphasis mine). Hayflick, in many of his statements, seems to have the view that aging is an inscrutable process that will only be understood when we thoroughly understand all major aspects of life itself. He says, “If you think understanding cancer is difficult, try aging.” Fossel, on the other hand, would almost certainly say that cancer and aging are actually two sides of the same coin, a view that he discusses at many points in his book. Fossel is of the opinion that aging is not an unsolvable mystery, and that we know this, in part, because nature is able to turn it on and off easily when it sees fit to do so.

Hayflick also doubts that the riddle of aging will be solved soon because little money is being expended on it. He says that the 1993 budget of the National Institute on Aging was only US$401 million, and that most of that was spent on studying aging-related diseases such as Alzheimer’s, and other effects of aging, rather than on understanding the basic process itself. Dr. Fossel did not directly tackle this question in his book, but I will, and my response is simply this: There is much more going on that affects our knowledge of aging than just what the NIA spends on it. For one thing, there’s the Human Genome Project, itself a US$3 billion endeavor, and other related projects, in government, academia, and industry, not only in the U. S. but around the world. But beyond that, there is a whole scientific and technological infrastructure which is improving in a more-or-less exponential fashion. Our investigations of genetics are just one part of a much larger picture: Our ability to observe, and to manipulate, very small objects. That ability is improving so fast that most of the sequences in the human genome will probably be worked out in just the last couple of years of the project. Then what will happen? Will the accumulation of knowledge slow down? Not likely: It will almost certainly continue to accelerate. By the time Fossel’s predicted twenty years are up, there is virtually no telling what we may know that we don’t know now.

Finally, there is one aspect of aging that is likely to pose the most fundamental difficulties of all. There is one organ that we are more concerned about the aging of than any other; that organ is, of course, the brain. It turns out that the 100 billion or so neurons in the brain do not age at all in the “Hayflick sense”. They never hit their Hayflick limits, or even come close, because they never divide. So telomere theory will not directly do anything to prevent the gradual loss of neurons with age. It may help in one sense: The glial cells—the cells that surround all our neurons, nourishing and protecting them—do divide and age, and if we can keep them youthful and vigorous it should greatly aid in slowing neuron loss. There is reason for hope in the fact that healthy hearts, as we have seen, do not seem to lose capacity with age; and heart cells, of course, are another kind of non-dividing cell.

Still, given enough time, neurons die. How fast that will happen in an otherwise non-aging individual cannot be known in advance. Most of all, we don’t know what will happen to the mind as neurons die and the rest of the body is kept young. It probably won’t be all that long, in fact, before it will be possible to induce new neurons to grow in the brain and take the place of lost ones. But what if that happens? What if you lose 99 per cent of the neurons in your cerebrum, and they are replaced with fresh ones? Will that brain still contain you? Answering such a question requires understanding the nature of human consciousness itself—possibly the most difficult riddle in all of nature, and maybe not even answerable at all by anything we would recognize as science.

In view of all the preceding, my own predictions are: (a.) Reversing human aging, and radically altering the human lifespan, will probably happen just about as fast as Fossel is predicting; (b.) In the short run—perhaps for a few decades after that—age reversal will still be an imperfect process, because of a few things such as cumulative tissue damage; (c.) There is absolutely no way to tell right now what the ultimate effect of neuron loss will be when the Hayflick limit is removed; and (d.) Somewhat farther in the future—but measured in decades, not centuries—Fossel’s predictions will actually look very conservative: If we acquire the ability to fix telomeres in twenty years then, in two hundred years—probably much less—it will be possible to acquire abilities and characteristics which we can scarcely imagine at present. And just what will life be like then?

That last remark is a good place to segue into discussing the next major question:

In his book, How and Why We Age, Leonard Hayflick voices serious concern about a variety of consequences of any major change in the maximum human lifespan, saying:

It is not yet possible for us to perturb the aging phenomenon in humans or to increase our life span. In my view, those who believe that it is possible or about to happen have an obligation to initiate a public dialogue on the question now.

1. We’ll have a world full of people who will act like teenagers, but have the powers of adults.

   In its original form, this is easily dismissed as a ridiculous worry. The things we think of as the wisdom that comes with age will surely not be lost just because of restored biological vigor. Experience will not be forgotten; in fact, improved health and vigor will surely help in remembering the wealth of life’s experiences.

   On the other hand, I have wondered how much of what we think of as “growing up” is really just a matter of adopting a reduced set of expectations, and accepting a reality that is less and less pleasant as aging progresses. Others, notably Thoreau, have voiced similar sentiments about the “counsel of defeat” associated with old age. With more time available, and with an improved ability to make use of it, some attributes we associate with age may be seen less. But that is a long way from saying that people will develop immature, narcissistic personalities because they will be “younger”.

   There is a more credible variant of this argument, though, and it goes like this: If people have immature attitudes to begin with—and immature attitudes include, notably, selfishness and insensitivity to the problems of others—then an extended, vigorous lifespan will allow these people to do much more harm. I’ll speak to this as a separate question later.

2. We’ll have a world full of people who will be physically young, but mentally old and set in their ways.

   If people remain biologically young, but accumulate a lot of experience—perhaps hundreds of years’ worth—will they become “dead wood”, unable to adapt to changes in the world around them? I don’t think that there is any way to truly know the answer to this in advance. All we really know about now is people who accumulate experience at the same time as they are getting physically aged. We simple have no experience with the type of organism we are about to see.

   As you become more experienced in anything, does that make you less adaptable to further change because you have developed existing habits that interfere with laying down new ones—or more able to learn new things because of already having a frame of reference to which they can be referred? We can expect to see both phenomena at work, but which of the two will predominate in a 200-year-old person is a question that is likely to keep a lot of geronto-psychologists busy for a long time to come.

3. We’ll have a world full of people who will be old, weak and frail, but will stay around for a long time, creating a severe burden for a society that will have to take care of them.

   In the mid-1980s, then-Governor Richard Lamm of Colorado caused an uproar by saying that old people had a duty to “get out of the way” and not be a burden on society by continuing to live as helpless invalids. Much has been made of the notion that the U. S. Social Security fund—and its counterpart in other countries—may be bankrupted in the next few decades, as a huge bolus of Baby Boomers propagates through the “age pyramid”. But, as I explain in Bogeymen, a separate page of this site, this is an overstated problem to begin with, partly because the passage of one generation into retirement is a temporary phenomenon, occurring over a couple of decades.

   The more serious concern, though, is that an aging population will be more frail and less healthy. This is one of Hayflick’s chief concerns. As the ultimate nightmare scenario, he points to the Struldbrugs, in Johnathan Swift’s Gulliver’s Travels,

   …who grew older and older and more and more frail but never died, even when the functional capacity of their aging organs eventually dropped below the point necessary to sustain a minimum quality of life. The Struldbrugs longed for the blessing of death, but it never came. They suffered immortality as a curse as the aging process continued interminably.

   Hayflick says elsewhere,

   I am apprehensive about extending average life expectation beyond age one hundred once the leading killers are resolved because the result would be disease-free but still functionally weaker, still inexorably aging people…Old people will simply become older, condemned to the viscissitudes of a continuing aging process…

   This is a curious thing for Hayflick to say because, earlier in his book, he talks about the folly of refining palliative measures (a “state-of-the-art heart-lung machine”) while ignoring the more basic problems of systemic breakdown caused by the overall aging process. Yet he speaks of old age often being the happiest part of people’s lives. It is clear that he would like to see a situation in which, more and more, we “square the curve”, by preventing or curing the diseases of old age, while not extending the maximum human lifespan. Ideally, everyone would live to some maximum age—say, 120—without any serious diseases, then simply go to bed one night and not wake up again.

   In my view, this ideal is both unattainable and undesirable. While it is true that most old people are not truly in bad health, in that they do not have clear manifestations of life-threatening or crippling illnesses, they are weaker than younger people, and less able to enjoy the full range of activities of life. The more we succeed in dealing with the diseases of age, the more really old people we will have. On balance, this is probably progress: Most people would probably opt for a prolonged old age, without serious disease, albeit in a weakened state, instead of dying at an earlier age. But one is almost driven to wonder if a person living to 100 in an increasingly frail condition really suffers much less, in totality, than someone who drops dead of a massive coronary at age 35. The more I consider the future Hayflick advocates, the less attractive it sounds.

   The fact is that we are already on the horns of a dilemma, whether we like it or not. We are already creating huge numbers of people with resemblances to the Struldbrugs, and there are only two ways out of the jam. Either we go back to reducing the average life span, so that aging is a relatively rare condition—in effect, turning back the clock to an earlier time, and abandoning the benefits of civilization—or we find a way to prevent the gradual decline into an aged condition that is well under way after only a few decades. In the end, to picture the vast majority of people having long and healthy old ages up to about 100 or 110 years of age, then politely dropping dead, without having incurred a lot of medical expenses, takes a lot more imagination and optimism than it takes to envision a true reversal of aging.

   A final note on this question of the aged being a burden to society: There is an analogous situation to this, on a smaller scale, in the treatment of people with disabilities. Since becoming paralyzed, Christopher Reeve has continually argued that, given the billions of dollars spent every year to keep alive people with crippling injuries, increased funding for research that has a real prospect of actually eliminating those disabilities would be a bargain. To me, the situation with aging is fundamentally similar, except that the period of full function that can be restored is much longer, the affected population is vastly larger, and the problems to be solved by research are much more difficult. Nevertheless, the reasoning involved seems essentially the same. Worried about Social Security going broke? Eliminate the need for it!

   Twenty years ago, Reeve’s reasoning would not have been taken seriously, because the ability to repair serious spinal cord injuries such as his was far off in the future, at a distance that was completely unpredictable. Now, although we don’t have the solution, we can see it from here. The same is likely to be true for aging.

4. People will be unwilling to take risks, since they face the risk of losing, not just a few decades of life, but a potentially limitless life span.

   This is a concern that I have never heard anyone else discuss, but I take it with some seriousness. If you have the chance to continue living almost indefinitely, why blow it by getting out and doing dangerous things? If most of the remaining danger to life is from accidents, why take chances?

   The perception that accidents and other violent events are the main threat to life will surely affect people and societies. It will still be necessary for people to get out and expose themselves to various degrees of danger in order to secure their livelihoods, and to pursue pleasures that make life worth living. This will be balanced against the greater consequences if something should go wrong. I expect certain readjustments in attitudes to occur: For one thing, in employment, people would be increasingly rewarded based on their willingness to expose themselves to physical risk—and, in a less direct way, to economic risk, since this can translate into physical risk. They will be rewarded less for the value of their time, since this will be a less precious commodity. In this way, the system will ensure that enough people assume enough risk to keep society functioning.

   At the same time, I don’t think that this is likely to pose some sort of ultimate crisis to society, where people would be unwilling to leave home for fear that they could possibly be killed. Most of the time, we do not give a great deal of thought to the danger of sudden, violent death, unless a particular threat begins to loom very large. In any case, sudden, violent death somehow seems much more dignified than slow, prolonged decline. It may be less painful as well. Given a medical technology with enough proficiency in repairing all kinds of damage—as we’re likely to have in our lifetimes—it may be that most deaths that do occur will be from causes so overwhelmingly sudden and violent that their victims suffer little or no pain or anxiety. That, to me, seems an infinitely more sporting proposition than what we have now.

5. For people to assume the power to prevent aging is an incredible act of hubris that is a direct affront to the natural order of things, and to God himself.

   This is a deliberately pointed rendition of a general sentiment that, surely, most people who have thought about this issue have considered at one time or another. I think it lies at the core of the objections that a number of influential thinkers—among them, Ivan Illich, Christopher Lasch, and Theodore Roszak—have voiced about modern medicine in general. Roszak, in particular, has mentioned nightmare scenarios about people being trapped for long periods of time in bodies that are beyond repair, still possessing at least some consciousness, and unable to do anything to escape their suffering, even through death. In this view, death is the Merciful Reaper, who eventually releases everyone from even the most horrible forms of suffering. Death is the ultimate dead-man switch, placing bounds on the degree of suffering that bodily life can inflict on the spirit.

   The responses to this are two. First, tomorrow is promised to no one, and never will be. It will take a lot more than genetics to change that. That central fact of life will seem all the more constant as the length of time you have left to live becomes indefinite, rather than clearly bounded as it is now.

   Second, indefinite suffering in an intolerable situation, in an ageless body, would only be one more in a series of horrors that technology has made possible in this century. Concerns like this make it clear that, in deciding whether increasing the quantity of life is a good thing, we have to include the quality of life in our calculations. This goes as well for other concerns I will examine shortly, such as the “population question” and the “inequality question”.

6. The means for prolonging life would be available only to the well-off.

   If this actually did happen, it would admittedly be a truly terrible thing. I can hardly think of anything more odious, more intolerably oppressive, than a privileged group of people who had managed to arrogate unto themselves the means for prolonging life indefinitely. But I also have trouble seeing how this could actually happen. The means of controlling the aging process will not involve the possession of some special substance that can only be found in a special place, or anything of the sort. It will involve information—the very thing that, in the late twentieth century, seems the most difficult to keep bottled up. Moreover, the information does not consist of one particular secret, but of literally billions of pieces of information—so much, in fact, that managing all that information will require respectable amounts of computer resources. By the time the puzzle is worked out, its essential principles will be well-known to much of the world’s population.

7. Without aging, the problem of overpopulation will get even worse.

   Ever since we crawled out of the ocean
   And stood upright on land
   There are some things
   That we just don’t understand:
   Relieve all pain and suffering
   And life us out of the dark
   Turn us all into Methuselah—
   But where are we gonna park?
   —Don Henley
   

   Overpopulation is one of the chief reasons that Hayflick cites for thinking that a longer lifespan would not be a good thing. What should be done about the growth in human population is a matter beyond the scope of this discussion, but a couple of things should be pointed out. First, the present growth rate of the human population, already down somewhat from its percentage peak a couple of decades ago, is roughly twice the death rate. So if people stopped dying at all, the population would grow about twice as fast as it does now. If aging suddenly stopped and reversed for all people, but people stopped having children at the same age as they do at present, the population would grow faster, but at some rate substantially less than double the current rate. This immediately puts an upper bound on the size of the problem.

   In all discussions of the population question, a critical question is: What will the eventual birth rate be, once conditions stabilize? Recent experience strongly suggests that, when living conditions improve and life expectancy increases, birth rates decline, and the population stabilizes. This is, in fact, what separates Malthusians such as Paul Ehrlich from their critics: Both groups agree that, when some factor improves the living conditions of a population, the population eventually stabilizes at a new level, and living conditions also stabilize at a new level. The Malthusians believe that the new living conditions are no better than the old ones—or even worse. Those on the other side of the argument believe that the new conditions are better than the old, so that it makes sense to try to improve living conditions; and that, in fact, more improvements will cause the “demographic transition”—to affluence, lower birth rates, and stable population—to happen faster.

   In a population without aging, what we have to ask is: What would happen to birth rates? The worst thing would be for people to continue being fertile and having children at their usual rates, indefinitely into advanced age, made possible by their lack of aging, along with some as-yet-unknown way of preventing menopause. What we would hope would happen, instead, for the sake of stable population, is that people would have fewer children, and that population would stabilize with very low birth rates and very low death rates.

   What we do not know, and cannot know until these changes actually occur, is just how people will behave in those conditions. Clearly, as long as humans remain limited to this planet as a home, there is a limited capacity for additional population growth, with doubts about how long even the present population can be supported decently. But global population is already changing fast enough that any effects from a change in maximum life span, even if they happened right now, would only alter the timetable to a limited degree. Whatever problems will be caused by overpopulation will be upon us before we can expect anti-aging therapies to have much effect; and at the same time, with or without elimination of aging, and with or without other changes in the quality of life for the world’s people, eventually birth rates must fall to match death rates, because of the earth’s finite carrying capacity.

8. An end to aging would allow some people to gain unlimited power.

   Hayflick expresses concern about long lifespans being available to the less desirable elements of society:

   It might also be argued that aging and natural death are the only humane ways of ridding us of the tyrants, serial killers and other undesirables who would otherwise continue to threaten or harm us…Few of us would welcome increased longevity for those who bring misery to others.

   I, for one, would not want to see a thousand people sacrifice their longevity in order to ensure that one serial killer has a limited lifespan. There has to be a better way; whatever reservations I may have about the death penalty are minor compared to how I feel about relying on nature to eliminate such persons. But Hayflick’s comment hints at something that I do think is worth a closer look: People who place a lot of value on getting power and retaining it may be able to accumulate power, and hold onto it, in ways they could not dream of if their lifespans were limited to the usual length. I think Hayflick’s concern would be more appropriately directed toward the more respectable evildoers in society—the ones who steal with a briefcase instead of a gun.

   Older people are often thought of as being “set in their ways”, and resistant to change. Much of this may come from the fact that people nearing the ends of their careers, or the ends of their lives, perceive correctly that they have only a short amount of time in which to benefit from adopting new ways. There is also neurological evidence to support the idea that older people have a harder time forming new memories, even though they can reason clearly, and can remember quite well what they have already learned. But all this pertains to people who are subjected to the normal processes of aging. Someone who is freed from those constraints can continue to accumulate experience, connections, wealth, and power, without having to slow down and eventually fade from the scene. The eventual consequences for society are a big unknown.

   Even now, we see signs of increasing inequality in our society as a result of an economy where education and experience are increasingly necessary conditions for success. At the moment, these changes seem to benefit people in their earlier adulthood more than they benefit those in their fifties or sixties. Experience and physical deterioration tend to increase together under the current régime, putting a natural check on the accumulation of wealth and power. But an indefinite lifespan could change all that. Like old-growth trees choking out new saplings as well as shorter species, these young-old people could institute a new form of tyranny, much more far-reaching and entrenched than any seen before in history.

   Let me be clear about this: My concern is not about society being deprived of “new blood”. These would be vigorous, healthy people, biologically young. Nor am I concerned about these wealthy, powerful young-old people acting like teenagers. They may be far, far worse. They may have the experience of old people, with bodies like teenagers; and that, in this advanced industrial society, may be a deadlier combination than an adult with the mind of a teenager. When you consider that these individuals will tend to reshape society in directions that suit their interests—a winner-take-all paradigm, like the direction in which we seem to be heading already—the potential consequences become scary. If rewards accrue strictly on the basis of performance; if performance depends critically on experience, as it increasingly does; and if experience can be accumulated without limit, it may be possible for a new breed of ageless taipans to put a lock on most of the wealth of the world—one that will be nearly impossible to break.

   Of all the objections raised about changing the maximum human lifespan, this is the one I take the most seriously. But even this is not, in principle, too much different from some of the others already mentioned, such as overpopulation or hubris. Long lifespans can only be a desirable thing in the right kind of world—one where people are not allowed to accumulate power and use it to oppress others, one in which people are not tortured indefinitely, where criminals are not allowed to perpetrate their crimes indefinitely, where people everywhere can look forward to living long enough for aging to be a concern, and above all where life is pleasant enough that living a long time is a desirable thing. Quality of life is an issue inseparable from the length of it.

Hayflick seems, in fact, confused at times about what altering the aging process would mean. In his book, he offers this especially puzzling passage:

…Regardless of the age at which you chose to arrest the clock, there would always be the possibility that life satisfaction might have been greater at a later time. The particular age you chose probably would depend in part on the ages chosen by important people in your life, especially your family and friends. This freedom of choice could create any number of social, biological, economic, and political problems and a bizarre asynchrony of ages. An example: You stop the aging process at age forty-five, but your older brother or sister chose thirty-five and your parents chose twenty-five. Your children may choose other ages or choose not to arrest their aging process at all. How will you relate to parents who are younger than you, children who are older than you, or siblings aging at a different rate? …

Hayflick seems to have maturity and deterioration thoroughly confused. This is not the end of it. A half-page later, he says:

…Many older people find they have never been happier than in their later years. Why, then, if you are still young and have not yet had the opportunity to experience a happy old age, risk not experiencing what might be the best years of your life?

My conclusions are: that human aging, as we know it now, will soon be eliminated; that it will be readily available and widely desired; and that its ultimate effect on society, for good or ill, is inseparably related to other major concerns that we confront as we near the end of this century. I, for one, have heard all the bad news as well as the good, and remain hopeful—even confident—that this new development can, should, and will occur.

It does seem that many things in human affairs have a way of occurring when, and only when, the time is right. Modern industry, with its fossil fuels and its freons, caused ozone depletion, global warming, and acid rain, but not much before we developed ways of studying and remedying the problem. Modern air travel brought us AIDS, but not before we had already started to unravel the genetics of viruses. Nuclear physics gave us weapons capable of destroying the world, but not long before we had satellites capable of detecting their deployment anywhere on the face of the earth. Things seem to have a way of happening only when the time is appropriate for them, and not too much before. And so I think it will be with aging. Had this ability somehow been available to mankind two centuries ago, without anything else being different in society, it’s hard to picture how it would have been ultimately beneficial. But now I think we can handle its problems, and that the benefits to society—through individuals with unprecedented combinations of experience and physical vigor—will far outweigh the negatives.

There is one remaining possibility that is even more speculative, but is worth thinking about: Will there be some sort of Event that will upstage even as profound a change as assuming control over aging? And if so, will the control of aging, and the biological revolution of which it is a part, somehow contribute to that larger development, or will that Other Thing somehow render it all irrelevant? How you answer that depends, of course, on what you think that Other Thing might be—nuclear war, cometary impact, divine intervention, contact with extraterrestrials, time travel (as Terence McKenna thinks may happen by 2012), or perhaps the transition from biologically-based intelligence into artificial intelligence. There are enough such possibilities for us to scare ourselves, comfort ourselves, or simply amuse ourselves with, that thinking how these might relate to the relatively modest change of being able to alter cellular genetics is an interesting exercise in itself.

Of course, you can dismiss all these arguments and predictions as the selfish desires of a Boomer who does not want to acknowledge the inevitable advancing of The Clock. And that they may well be. But they may also be correct.