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Frequently Asked Questions on the Ethics of Lifespan and Healthspan Extension

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longevitytreeBy Ilia Stambler



The mission of healthy life extension, or healthy longevity promotion, raises a broad variety of questions and tasks, relating to science and technology, individual and communal ethics, and public policy, especially health and science policy. Despite the wide variety, the related questions may be classified into three groups. The first group of questions concerns the feasibility of the accomplishment of life extension. Is it theoretically and technologically possible? What are our grounds for optimism? What are the means to ensure that the life extension will be healthy life extension? The second group concerns the desirability of the accomplishment of life extension for the individual and the society, provided it will become some day possible through scientific intervention. How will then life extension affect the perception of personhood? How will it affect the availability of resources for the population? Yet, the third and final group can be termed normative. What actions should we take? Assuming that life extension is scientifically possible and socially desirable, and that its implications are either demonstrably positive or, in case of a negative forecast, they are amenable – what practical implications should these determinations have for public policy, in particular health policy and research policy, in a democratic society? Should we pursue the goal of life extension? If yes, then how? How can we make it an individual and social priority? Given the rapid population aging and the increasing incidence and burden of age-related diseases, on the pessimistic side, and the rapid development of medical technologies, on the optimistic side, these become vital questions of social responsibility. And indeed, these questions are often asked by almost any person thinking about the possibility of human life extension, its meaning for oneself, for the people in one’s close circle, for the entire global community. Many of these questions are rather standard, and the answers to them are also often quite standard. Below some of those frequently asked questions and frequently given answers are given, with specific reference to the possibility and desirability of healthy human life extension, and the normative actions that can be undertaken, by the individual and the society, to achieve this goal.

Q: Is human life extension possible? Why do you think so?

A: Is it possible for people to achieve a significant life extension? In other words, is it possible to achieve either a substantial increase in the average human life expectancy or an increase in the maximum (or record) lifespan specific for the human species? The wide-spread belief in the impossibility of significant human life extension often relies on the notion of a “limit” to the human lifespan. Yet, it should be noted that, even when proposing a “limit” to the lifespan, it is often realized by the proponents that this “limit” is quite flexible and theoretically not very limiting. It is theoretically possible to overcome this “limit” by changes in inner biological structure and/or environmental conditions, including improvements in biomedical technology.[1] But of course, there are currently clear practical limits and constraints in our ability to greatly increase the human lifespan with the current medical technological means. And these practical constraints and limits have been realized even by the most ardent advocates of human life extension. They just do not reconcile with those limits, they desire and strive to overcome them by improving biomedical technology.

However, on the basic theoretical level, there is no law in nature that sets a strict insurmountable limit to the lifespan of any organism. As stated by the Nobel Prize winning physicist Richard Phillips Feynman, “there is nothing in biology yet found that indicates the inevitability of death.”[2] This is demonstrated by the existence of non-aging, slowly aging, and even “potentially immortal” life-forms and the constant evolutionary adaptations of the lifespan even for the humans, according to particular changing environmental and genetic conditions.[3] There may be contingent limitations due to the inner biological structure and environment, but these are not “limits” in the principal physical sense (like “nothing can travel faster than the speed of light”). The existing practical limits to the human lifespan, due to internal disorder, adverse environment and imperfect medical capabilities, are “rules that can be broken”.

Indeed the seemingly well-established “rules” and “limitations” of human longevity have been overcome continuously. There has been a persistent increase in life expectancy around the world. It is estimated that during the past 150 years especially, the average life expectancy at birth increased by several decades globally.[4] The rise in life expectancy continues, though currently the increases in the “developing world” are much faster and larger than in the “developed world.”[5] There is no ceiling yet seen or foreseen for this increase. An ever growing proportion of the life expectancy rise is attributable to advances of biomedical technology, rather than mere hygiene.[6] Still, closing the gaps in life expectancy and in access to medical technologies, within particular societies and between societies, remains a grand challenge.[7] The rise in human life expectancy is not a “law of nature” either, it is not inevitable or to be taken for granted, it also can be negatively affected by inner disorder, adverse external environment or bad medicine. The things that can be fixed can also be broken, and vice versa. Yet, the possibility of a significant, even radical, rise in life expectancy appears to be proven beyond any doubt.

Perhaps the greatest source of hope is the rapid development of therapeutic means for life extension. The primary proofs of feasibility are based on the successful cases of life extension experimentally achieved in animal models and the development of new intervention techniques, based on the ever better elucidation of the mechanisms of aging. For example, there were proposed several arrays of presumed major determinants of aging and pathways toward their counteraction, based on empirical evidence in cell, tissue and animal models, and even some initial human indications. Some examples of such arrays include the SENS program (Strategies for Engineered Negligible Senescence),[8] the NIH Geroscience priority research areas,[9] and the “hallmarks of aging.”[10] Notably, these sets of major aging determinants and countermeasures tend to focus on research and intervention at the cellular and molecular levels, with relatively little attention paid to the systemic regulatory level of aging. Addressing the regulatory mechanisms may perhaps be the next big frontier of life extension research and development.[11] That is to say, having created the necessary technological tools to tackle the basic molecular mechanisms of aging, it may then become necessary to learn to coordinate, dose and calibrate the use of those tools. Nonetheless, despite the challenges, there are now clear proofs of practical technological feasibility of intervention into aging processes and lifespan modification.

These feasibility proofs for aging modification and lifespan intervention are a part of the more general and very encouraging trend of the rapid development of biomedical technologies. This rapid general progress of biomedical science and technology gives hope, but also breeds concerns, mainly the concerns over safety, efficacy and availability of potential interventions. Hopefully the potential drawbacks can be avoided, while the benefits can be brought to fruition and enjoyed to the fullest by the largest possible number of people. But in any case, the fact of progress in scientific, technological and medical capabilities is difficult to deny. For example, consider the amount of progress made since the positing of the cellular theory of immunity by the founder of gerontology Elie Metchnikoff in the late nineteenth century (slightly more than 100 years ago) until the beginning of synthesis of the first prototypes of artificial immune cells recently.[12] Aging and longevity research has always been an integral part of this progress, and moreover, several important biomedical technologies and therapies, such as probiotic diets, hormone replacement therapy and cell therapy, were born out of aging and longevity research.[13] There are grounds to hope for a continuation of this tendency, for its reinforcement, rather than its cancellation or reversal.

In fact, the recent progress in technology (including biomedical technology) has been so vast and rapid that some authors spoke of “exponential acceleration” of technological development, due to technologies’ convergence and cross-fertilization, improved communication and computational capabilities.[14] Yet, even with less optimistic and uncertain forecasts, assuming the speed of technological development to continue at least as fast as it was for the last century and a half, and at least for a comparable time in the future – we may expect dramatic improvements in biomedical technological capabilities and their distribution. Of course, reaching truly effective, safe and widely available anti-aging and life-extending capabilities may still be a long way off. Their actual achievement, as well as their safety, efficacy and affordability, especially at the initial stages of application, may remain some of the main potential problems to be overcome. Still, the principal feasibility of a significant human life expectancy and lifespan extension by scientific and technological means appears to be evident. But do we want this extension, if it were possible? Is it generally desirable? In other words, is life extension “a good thing”? What would we use it for and who would use it? The scientific and technological feasibility assessment opens the door for the ethical desirability assessment.

Q: Is healthy life extension a good thing?

A: Quite surprisingly (at least for the proponents of healthy longevity), for decades and centuries, there has been expressed strong opposition to the very idea of life extension. The opposition has been frequent among philosophers, and even among physicians and researchers of aging. There has been a strong tendency among well-established physicians and scholars to consider aging as inexorable and therefore “normal,” and to see the lifespan as fixed and immutable. Accordingly, any attempts to “meddle” with the aging process or to significantly extend longevity would be considered foolish, futile and even somehow unethical.[15] A host of ethical and societal problems contingent on life extension were hypothesized by the doubters of this pursuit. Their arguments have often substituted the terms, opposing “immortality” or “indefinite life extension” as a way to imply the undesirability of any significant longevity extension, even healthy longevity. This implied the general undesirability of the development of medical technologies for longevity extension. Of course, it is necessary to note that the contrary view, namely that the pursuit of life extension is possible and desirable, has also been a persistent and highly respectable ethical and medical tradition. It was upheld, among others, by a founder of modern hygiene – Christoph Wilhelm Hufeland (1762-1836), the founder of therapeutic endocrinology – Charles-Édouard Brown-Séquard (1817-1894), the founder of geriatrics – Ignatz Leo Nascher (1863-1944), the founder of gerontology – Elie Metchnikoff (1845-1916) and many more.[16] Yet, so far the intellectual stream purporting to oppose the possibility and desirability of a significant life extension has been by far the more dominant. The apparent weight of authority of the critics and skeptics, and the wide popularity of the skeptical views, may again emphasize the question: “Is increasing longevity, especially healthy longevity, really desirable, for the individual or the society?”

The answer that may be given by the proponents of life extension is very simple: “YES. People want to live longer and to liver healthier.” Or to put it even more bluntly, “it is better to be healthy, wealthy, wise and long-lived, than otherwise.” And that may conclude the discussion. Yet, some explanations and arguments are still required. Usually, the arguments against extending longevity are standard and are refutable in standard ways. Some of these “golden standards” are briefly presented below. These arguments have been adduced and countered in the relevant ethical literature.[17] Indeed, almost any person, anywhere in the world, reflecting for a short time on the possibilities of human life extension, comes up with most of these concerns, and if reflecting or debating a little longer arrives at most of the refutations. The questions and answers below may provide a short summary of such debates.

Q: Would extending longevity enhance human suffering, or conversely, is death a solution against suffering?

A: No. Death is not a solution against suffering. Suffering is not inevitable. Human beings have the ability to actively influence their fate and relieve suffering. And essentially, the desire to extend life does not imply a desire to prolong suffering, but a desire to prolong health (increase the healthspan).

Q: Would extending longevity lead to extending boredom?

A: Arguably no, as extended life also implies extended ability to learn and change. The sense of boredom does not necessarily depend on the period, and often comes and goes periodically. And generally, the feeling of boredom does not seem to be a sufficient reason to abandon the pursuit of life. And if it is (for some people) – their choices are in their hands, and should not diminish the choices and chances of others.

Q: Would extending longevity make human life meaningless?

A: Arguably no, as life may carry a meaning of its own, independent of death. It is difficult or even impossible to place a temporal limit on the meaning, love and enjoyment of life. Human beings are entitled to choose a prolonged existence, and that choice and pursuit alone may give their life meaning.

Q: Would not extending longevity stop progress, make individuals and societies stagnant?

A: Rather to the contrary, the potential for learning will be increased by longer life-spans, and such a prolonged “cultural adaptation” may be sufficient and necessary for the survival of the society. Moreover, rationally controlled development and care for the survival of the weak may be more advantageous for progress than blind and cruel Darwinian selection.

Q: Are not aging and death from aging natural and inevitable? Does not their acceptance as natural and inevitable give comfort in facing them?

A: Concerning the inexorable “natural” limit to the human life, however comforting a reconciliation with death may be, it should not replace an active quest for life preservation. Almost never is a particular cause of death completely “inevitable,” but is always due to some identifiable material agent, and thus subject to prevention or amelioration. There is no limit “set in stone” to either the lifespan or the healthspan.

Q: Would not there be a problem of “identity” when extending life? In other words, would the incessant transformations of the body and mind permit us to speak of a long-term preservation of identity?

A: During a prolonged life history, there may be a continuity of human existence. Or else, some “core” personal pattern may be preserved, while various extensions and additions to it may develop in time.[18]

Q: Would not the life-extending means be made available only for the rich and powerful, or some other select groups? How can we prevent this injustice?

A: Indeed, perhaps the most frequent type of worry relates to the future availability of resources due to life extension. The common assumption is that ‘there will never be enough for everybody’. This assumption has taken the form of two major related concerns: ‘longevity will only be available for the rich’ and ‘overpopulation will happen due to extending longevity’. Referring to the availability of resources, a very strong and persistent apprehension has been about the potentially unequal and selective access to life-extending technologies. Of all the possible concerns and challenges of human life extension, this is probably one of the most likely and disturbing, seeing the present inequalities in the access to health care.[19] Would then the extension of life only be made accessible for the rich and powerful? Would such preferential access for select groups be justifiable or inevitable? Would not such a fundamental disparity in the ability to survive threaten the very fabric of social coherence, when the society will be filled with constant resentment and struggle? It has been asserted that the inability to provide a good to all people should not prevent providing it to some people.[20] Yet, such assertions may offer little consolation to people doomed to an early death by their social status. The inequality of access to medical means and technologies, and hence the unequal possibilities for lifespan and healthspan extension, appears to be a real danger. This danger is already here, manifesting in the present unequal access to health care, and is not necessarily reserved to future technologies. This danger needs to be recognized and a wide and equitable sharing of medical technologies, both the present and emerging ones, needs to become a primary social objective.

When addressing this concern, the upper class life-extensionists often reassure that the life-extending treatments will eventually be made cheaper as the technologies develop, and they will ‘trickle down’ to the poor from the rich. Moreover, the rich may allow such treatments to the poor as they are interested to maintain ‘active and healthy workforce.’ Hence, in this type of social agreement, for the poor, a chance to obtain the treatments may only be contingent on their utility as ‘workforce’, and if they have no such utility (for example, if the labor needs are already fulfilled, also from robotics), there are absolutely no incentives and no obligations to provide them with the life-extending treatments. Hence, at least for the initial stages of therapy development, the following options may be available for people of lesser means: 1) Wait patiently until the therapies will ‘become cheaper’ and/or ‘trickle down’ from the rich; 2) Fight for the right of access (perhaps also violently); 3) Advocate for universal public research, development and distribution programs for life-extending and health-extending therapies, that will also give the public strong entitlement to such therapies. The third option appears preferable. Yet, in any case, the inequality of access does not seem to be a reason to hinder the emergence of new medical technologies, but only to intensify their development. The sooner they emerge, the faster they will likely become available for the people, hopefully for all.

Q: Would not extending longevity lead to shortage of resources for the society, or “overpopulation”?

A: It has been a persistent fear that extending longevity would lead to a shortage of resources for the global population as a whole due to its unsustainable increase. This scenario is also commonly known as ‘the problem of overpopulation due to life extension’. Yet, it must be argued that the term “overpopulation” does not simply relate to the number of people on a certain territory. Rather, it indicates the degree of availability of resources, especially food, for people at that territory. And, based on the available evidence and trends of development, scarcity of resources should not be anticipated as a result of increasing longevity. It was calculated already in the 1960s by the Agricultural Economics Research Institute, Oxford, that the agricultural productivity, even at that time, would be more than sufficient to feed 45 billion people globally.[21] Since that time the agricultural capabilities in the developed countries increased dramatically, way ahead of increases in life expectancy or population.[22] The technological capabilities are here to feed the world. Then, why are there still famines? It often happens because of mismanagement or because the right technologies are not applied.[23] But technologies generally, or life-extending technologies in particular, should not be considered a cause of overpopulation or shortage of resources. On the contrary, in wealthy, technologically advanced countries, with high life expectancy, there are hardly any signs of “overpopulation” or shortage of resources. “Overpopulation” is often the problem of poorer, “developing” countries that overcompensate for high mortality (low life expectancy) with high birth rates, and that have limited access to medical and technological means to provide for the population increase. Hence, also in those countries, the way to combat overpopulation may be by increasing life expectancy, and the concomitant quality of life, medical and technological capabilities, not by decreasing them. Indeed, longevity (life expectancy) is an indispensable part of the Human Development Index, and it correlates with and synergistically reinforces its other parts, such as education and quality of life.[24] One may argue that even at diminishing resources, the prolongation of human life may be valuable and desirable. Yet, the most likely concomitant of extended longevity is rather abundance and not scarcity, as the same types of technologies that improve agricultural, technological and medical capabilities, are also instrumental for increasing the lifespan and healthspan.

Q: Would not increasing life quantity mean decreasing life quality? In other words, wouldn’t we have “too many old sick people”?

A: Arguably, the perception of the life of the elderly person as a “liability” to the person or to the society is ethically questionable, and the preservation of life may be desirable even at some loss of life quality. Yet, it must be emphasized that the improvement in life quantity is commonly (though not always) inseparable from the improvement in life quality. A robust organism (similar to a robust machine) as a rule both operates efficiently and for longer periods of time. The same mechanisms that improve health, also improve longevity. A good example is centenarians, who enjoy both exceptional longevity as well as quality of life, preserved mental and physical ability, almost to the end of their lives.[25] This is a model worth attempting to imitate or even improve on. Still, there is an evidently increasing incidence of aging-related diseases, following increasing life expectancy. Yet, this increasing incidence is not a reason to stop biomedical research and development, especially for the amelioration of aging-related degeneration – the main cause of disease and disability in the aged, but to intensify this research and development. The advancement of this research and development is perhaps the only practical way to alleviate the aging-related suffering and improve healthy and productive longevity for the elderly population. Essentially, it is the extension of the human healthspan (healthy and productive lifespan) and not just of the lifespan that is pursued in the research and development of new medical means and technologies.

Q: Would the new life-extending technologies be safe and effective?

A: This is a critically important scientific question. The responsible and active research and development will help answer it. It is quite possible that the emerging anti-aging and life-extending therapies may not be as effective as anticipated or may be even unsafe, at least at their initial stages of development and application. The efficacy and safety of any new medical treatment are essential scientific and public concerns and they need to be addressed through rigorous study, through the development of and adherence to strict scientific criteria for efficacy and safety. Compliant with such criteria, new anti-aging and life-extending therapies may be highly desirable and beneficial commodities.

Q: What should be done to extend one’s life? What should be done to develop the means to achieve healthy life extension?

A: Given the feasibility and desirability of the pursuit of healthy life extension, we enter the realm of normative suggestions and actions. What is it exactly that we need to do to achieve something that we desire and may have a chance to achieve, if not for ourselves then for our loved ones? What should we do to facilitate the emergence and availability of life-extending therapies? These are critical questions of public policy, in particular healthcare and science policy, and they need to be raised in the public arena. Clearly, particular regulatory, organizational and policy frameworks will yet need to be developed for the efforts to achieve healthy life extension for the population. It may be yet too early to provide detailed regulatory and policy recommendations toward this achievement. Yet, some preliminary suggestions may be offered. These may include increased funding, incentives and institutional support for research and development deliberately directed toward alleviation of the degenerative aging process and for healthy life extension.[26] More specific policies should be elaborated thanks to increased public and academic involvement and debate.[27] However, these are also questions of personal responsibility, and each person should study, think and decide for oneself and make personally feasible plans to facilitate the achievement of these goals.

Q: What are the main obstacles slowing down progress in the development of anti-aging and life-extending therapies? What would be the best way to overcome them?

A: The main obstacle is perhaps the immense scientific difficulty of the problem itself. Aging is an extremely complex process, with many uncertainties. Hence, any potential attempts at intervention will yet require a vast amount of careful thought and effort. This does not mean that such attempts should be abandoned. On the contrary – we need to tackle the problem, “not because it is easy, but because it is hard.” The payoff from its solution would be too great to abandon. But we need to admit that the problem is difficult and therefore its solution will require strong efforts. People would need to make such efforts, and they are not always willing or ready to make them. Hence one of the major bottlenecks is perhaps the general deficit in the ability or willingness of many people to invest time, effort, money and thought for the development of healthspan and lifespan extending therapies and technologies. Clearly, the more people become supportive and involved for their development, the more resources are intelligently and productively invested in it, the faster the technologies will arrive and the wider will be their availability.

There may be many reasons why such massive involvement and support have not been happening as strongly as the healthy longevity enthusiasts would hope for. One reason may be a common mental or emotional block against such therapies – many people simply do not believe that ameliorating degenerative aging and healthy life extension are possible or even beneficial, and hence they are unwilling to get involved in the impossible and undesirable tasks. It is the duty of healthy longevity advocates to convince people that these tasks are scientifically feasible and humanely desirable – and they have all the necessary arguments and data to prove it. Yet, more worrying may be the people who already admit that the combat of aging and healthy life extension are feasible, but they still do not invest any (or any significant) intellectual or material resources to achieve these goals. The main reasons for this inaction may be that they do not see immediate or fast benefits or profits for themselves, or are preoccupied with making a living (why pursue some distant goals, when one and one’s family need to survive tomorrow?) or are generally apathetic. Hence a major bottleneck is this transition from a theoretical “belief” or “understanding” into a practical action and support. Presumably, this transition can be facilitated by creating tangible incentives for people to get involved, such as jobs and grants for researchers, advocates and educators in the field, and improved institutional and social status for the field. These are largely issues of state-level public health and research policy, and they may be advanced by more political involvement. But these are also issues of individual persuasion, a person after a person. Even if it may be difficult or even impossible to convince most people to make longevity research and advocacy their main priority, without appropriate immediate material and social benefits and incentives, hopefully many could be convinced to dedicate at least a tiny bit of their time, effort, thought and money to this worthy long-term goal.

Q: What suggestions should be made to people who want to get involved in longevity research and advocacy, but don’t know where to start?

A: The main advice for people who want to get involved in longevity research and advocacy is just: “Start getting involved” – pick yourself up and start studying, thinking and working for the cause. This may sound trivial, but this is exactly the problem of transition from theoretical “understanding” and “wishes” to practical action. Many people remain in the theoretical “wishing” stage. But if there is a sincere heart-felt “wish” – there can be many practical “ways” that can be quickly found and pursued. First of all, the person should become better acquainted with the field, study it, even at the popular level. There is now plenty of online resources. If there is sufficient motivation, one may consider an academic study course or professional carrier in the area or related areas, depending on the possibilities at hand. But for the first “acquaintance” stage, just getting some familiarity with longevity science can initiate a person into the field. Such increased interest and knowledge, combined from many people, may raise the demand for therapies that may in turn improve the offer.

Another basic way to start is to band with others. There are now extensive possibilities to join others with a similar interest, ranging from discussions with friends to more formal live and online study groups to joining networks and public associations of supporters of longevity science. Communication with like-minded people can catalyze joint focus groups, research or outreach projects. The most tangible products of such communication could be individual and joint publications (online or in print) and meetings (online or live), or even concrete research and technological outcomes – which may in turn instigate further waves of interest and involvement. There are now expanding possibilities to participate, volunteer and assist in research, donate to or join existing academic and public organizations involved in longevity research and advocacy. There are now also increasing possibilities to participate in “crowd-sourcing” and “crowd-funding” campaigns and projects. If there are no such possibilities yet in one’s area or country, one may consider creating such organizations, campaigns and projects themselves, even in a small scale.

And of course, anyone could endeavor to research and practice a healthy, life-prolonging life-style (such as moderate exercise, moderate and balanced nutrition, and sufficient rest and sleep), to improve one’s chances to benefit from effective, safe and accessible life-extending technologies whenever they may arrive. This may also sound trivial, but this could also be an attractive way of initiation, with immediate practical benefits, yet with an eye for the future.

These pieces of advice may not seem very specific. It seems yet impossible to more specifically state: Do this regimen, study this text, join this organization, vote to advance this legislation, or support this project – and your and everybody else’s healthy longevity is guaranteed! It is unlikely that anyone can be that specific, given the current imperfect state of knowledge, and the diversity of situations and approaches. Yet anyone and everybody should be encouraged to become more interested, knowledgeable, communicative and active in the field, according to their personal wishes and possibilities. From our cumulative actions, not necessarily coordinated, we may have a better chance to create the necessary “gradient” toward our common goal of extending healthy longevity.



References and notes

[1]. Various historical perceptions of the lifespan limit are discussed in Ilia Stambler, A History of Life-Extensionism in the Twentieth Century (2014), in particular in Chapter 4, in the sections “Theories of Aging” and “Rectifying ‘Discord’ and conserving ‘Vital Capital’” and passim throughout the book (Ilia Stambler, A History of Life-Extensionism in the Twentieth Century, Longevity History, 2014,

Below are some of the notable works in the relatively recent history of these debates. Interestingly, even when positing a limit to a species-specific, particularly human, maximum lifespan (under particular internal biological organization and external environmental conditions), the authors do acknowledge that these internal and environmental parameters can be modified, especially through biomedical interventions into fundamental aging processes. See:

Nathan Keyfitz, “What difference would it make if cancer were eradicated? An examination of the Taeuber Paradox,” Demography, 14 (4), 411-418, 1977;

Nathan Keyfitz, “Improving life expectancy: An uphill road ahead,” American Journal of Public Health, 68, 954-956, 1978;

Arthur Schatzkin, “How long can we live? A more optimistic view of potential gains in life expectancy,” American Journal of Public Health, 70, 1199-1200, 1980;

James F. Fries, Lawrence M. Crapo, Vitality and Aging. Implications of the Rectangular Curve, W.H. Freeman and Co., New York, 1981;

James F. Fries, “Aging, Natural Death, and the Compression of Morbidity,” The New England Journal of Medicine, 303, 130-135, 1980;

Edward L. Schneider, Jacob A. Brody, “Aging, natural death and the compression of morbidity: Another view,” The New England Journal of Medicine, 309, 854-856, 1983;

Michael McGinnis, “The limits of prevention,” Public Health Reports, 100, 255-260, 1985;

Jay Olshansky, Bruce A. Carnes, The Quest for Immortality. Science at the Frontiers of Aging, W.W. Norton and Co., New York, 2001.

[2]. Richard P. Feynman, “What Is and What Should be the Role of Scientific Culture in Modern Society,” presented at the Galileo Symposium in Florence, Italy, in 1964, in Richard P. Feynman, The Pleasure of Finding Things Out: The Best Short Works of Richard P. Feynman, Perseus Books, NY, 1999, p. 100.

[3]. Michael R. Rose, Evolutionary Biology of Aging, Oxford University Press, New York, 1991;

Richard Cutler, “Evolution of human longevity and the genetic complexity governing aging rate,” Proceedings of the National Academy of Sciences USA, 72(11), 4664-4668, 1975,;

Anca Iovita, The Aging Gap Between Species, Longevity Letter, 2015,

[4] James C. Riley, Rising Life Expectancy: A Global History, Cambridge University Press, Cambridge, 2001.

[5]. World Health Organization, World Health Statistics 2014: Large gains in life expectancy, 2014,

[6]. Stephen J. Kunitz, “Medicine, mortality, and morbidity,” in: William F. Bynum and Roy Porter (Eds.), Companion Encyclopedia of the History of Medicine, Routledge, London and New York, 2001, pp. 1693-1711.

[7] David Ansell, The Death Gap: How Inequality Kills, University of Chicago Press, 2017.

[8]. Aubrey D.N.J. de Grey, Michael Rae, Ending Aging. The Rejuvenation Breakthroughs That Could Reverse Human Aging in Our Lifetime, St. Martin’s Press, New York, 2007;

SENS Research Foundation, “A Reimagined Research Strategy for Aging,” accessed May 2017,

[9]. Healthspan Campaign, “NIH Geroscience Interest Group (GSIG) Releases Recommendations from the October 2013 Advances in Geroscience Summit,” 2013,;

Brian K. Kennedy, Shelley L. Berger, Anne Brunet, Judith Campisi, Ana Maria Cuervo, Elissa S. Epel, Claudio Franceschi, Gordon J. Lithgow, Richard I. Morimoto, Jeffrey E. Pessin, Thomas A. Rando, Arlan Richardson, Eric E. Schadt, Tony Wyss-Coray, Felipe Sierra, Geroscience: linking aging to chronic disease, Cell, 59(4), 709-713, 2014,

[10]. Carlos López-Otín, Maria A. Blasco, Linda Partridge, Manuel Serrano, Guido Kroemer, “The hallmarks of aging,” Cell, 153(6), 1194-1217, 2013,

[11]. Alan A. Cohen, “Complex systems dynamics in aging: new evidence, continuing questions,” Biogerontology, 2016, 17(1), 205-220,;

David Blokh, Ilia Stambler, “The application of information theory for the research of aging and aging-related diseases,” Progress in Neurobiology, S0301-0082(15)30059-9, 2016, doi:

[12]. Ilia Stambler, “Elie Metchnikoff – the founder of longevity science and a founder of modern medicine: In honor of the 170th anniversary,” Advances in Gerontology, 28(2), 207-217, 2015 (Russian), 5(4), 201-208, 2015 (English).

[13]. Ilia Stambler, “The unexpected outcomes of anti-aging, rejuvenation, and life extension studies: an origin of modern therapies,” Rejuvenation Research, 17(3), 297-305, 2014.

[14]. Ray Kurzweil, The Singularity Is Near: When Humans Transcend Biology, Penguin Books, New York, 2005.

[15] A partial list of authors and works ostensibly opposing the idea of a significant life extension on ethical grounds, due to various hypothesized negative social and personal outcomes, includes the following. Of course, the list can be greatly expanded.

Thomas Malthus, An Essay on the Principle of Population, as it Affects the Future Improvement of Society with Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers, J. Johnson, London, 1798, reprinted in Project Gutenberg,;

William Osler, “Farewell address on leaving the Johns Hopkins University” (1905), Scientific American, March 25, 1905, reproduced in full in Stanley Hall, Senescence, the Last Half of Life, D. Appleton & Company, New York, 1922, pp. 3-5;

Morris Fishbein, The Medical Follies, Boni and Liveright, New York, 1925;

Bertrand Russell, “The Menace of Old Age” (1931), pp. 18-20, “On Euthanasia” (1934), pp. 267-268, in Bertrand Russell, Mortals and Others, American Essays 1931-1935, Volumes I and II, Routledge Classics, London and New York, 2009 (first published in 1975);

Bertrand Russell, “How to Grow Old” (written in 1944), in Bertrand Russell, Portraits from Memory: And Other Essays, Simon and Schuster, New York, 1956, pp. 50-53;

Norbert Wiener, God and Golem, Inc. A Comment on Certain Points where Cybernetics Impinges on Religion, The MIT Press, Cambridge, Massachusetts, 1964, pp. 66-67;

Frank Macfarlane Burnet, The Biology of Aging, Auckland University Press, Auckland NZ, 1974, pp. 63, 66;

Leonard Hayflick, “Address to the Select Committee on Aging, Washington, Feb, 1978,” quoted in William G. Bailey, Human Longevity from Antiquity to the Modern Lab, Greenwood Press, Westport CN, 1987, p. ix;

Leonard Hayflick, “’Anti-aging’ is an oxymoron,” Journal of Gerontology, 59(6), B573-578, 2004;

Leonard Hayflick, How and Why we Age, Ballantine Books, NY, 1994, “No More Aging: Blessing or Nightmare?” pp. 336-338;

Leon Kass, “L’Chaim and Its Limits: Why Not Immortality?” First Things, 113, 17-24, May 2001;

Daniel Callahan, What Price Better Health? Hazards of the Research Imperative, University of California Press, Berkeley, 2003, Ch. 3. “Is research a moral obligation? The war against death,” pp. 64-66;

Koïchiro Matsuura, “Of sheep and men,” The Daily Star, 4 (113), September 16, 2003;

Francis Fukuyama, Our Posthuman Future. Consequences of the Biotechnological Revolution, Picador, New York, 2002, Ch. 4. “The prolongation of life,” pp. 57-71;

Michael Shermer, “The Immoralist,” Science, 332(6025), 40, 2011;

Ezekiel J. Emanuel, “Why I hope to die at 75,” The Atlantic, October 2014.

[16]. Ilia Stambler, “Has aging ever been considered healthy?” Frontiers in Genetics, 6, 00202, 2015,;

Ilia Stambler, A History of Life-Extensionism in the Twentieth Century, Longevity History, 2014,

[17] Some of the ethical works countering anti-life-extensionist arguments include:

Robert Veatch, Death, Dying, and the Biological Revolution. Our Last Quest for Responsibility, Yale University Press, New Haven CT, 1977, Ch. 8. “Natural death and public policy,” pp. 293-305;

John Harris, “Immortal Ethics,” presented at the International Association of Biogerontologists (IABG) 10th Annual Conference “Strategies for Engineered Negligible Senescence,” Queens College, Cambridge, UK, September 17-24, 2003, reprinted in: Aubrey de Grey (Ed.), Strategies for Engineered Negligible Senescence: Why Genuine Control of Aging May Be Foreseeable, Annals of the New York Academy of Sciences, 1019, 527-534, June 2004;

Christine Overall, Aging, Death, and Human Longevity: A Philosophical Inquiry, University of California Press, Berkeley CA, 2003;

Frida Fuchs-Simonstein, Self-evolution: The Ethics of Redesigning Eden, Yozmot, Tel Aviv, 2004;

Richard A. Miller, “Extending life: scientific prospects and political obstacles,” The Milbank Quarterly: A multidisciplinary journal of population health and health policy, 80(1), 155-174, 2002;

James Hughes, Citizen Cyborg: Why Democratic Societies Must Respond to the Redesigned Human of the Future, Westview Press, Cambridge MA, 2004, “Living longer,” pp. 23-32;

Sebastian Sethe, João Pedro de Magalhães, “Ethical Perspectives in Biogerontology,” in: Maartje Schermer, Wim Pinxten (Eds.), Ethics, Health Policy and (Anti-) Aging: Mixed Blessings, Springer, Dordrecht, 2012, pp. 173-188.

[18]. Ilia Stambler, “Life extension – a conservative enterprise? Some fin-de-siècle and early twentieth-century precursors of transhumanism,” Journal of Evolution and Technology, 21, 13-26, 2010,,;

Ilia Stambler, “Life-Extensionism as a Pursuit of Constancy,” Institute for Ethics and Emerging Technologies (IEET), August 18, 2015,;

Ilia Stambler, A History of Life-Extensionism in the Twentieth Century, Longevity History, 2014,

[19]. Angus Deaton, “Health, inequality, and economic development,” Journal of Economic Literature, 41(1), 113-158, 2003.

[20] John Harris, “Immortal Ethics,” presented at the International Association of Biogerontologists (IABG) 10th Annual Conference “Strategies for Engineered Negligible Senescence,” Queens College, Cambridge, UK, September 17-24, 2003, reprinted in: Aubrey de Grey (Ed.), Strategies for Engineered Negligible Senescence: Why Genuine Control of Aging May Be Foreseeable, Annals of the New York Academy of Sciences, 1019, 527-534, June 2004.

[21]. Colin Clark, “Agricultural productivity in relation to population,” in: Gordon Wolstenholme (Ed.), Man and His Future: A CIBA Foundation Volume, Gordon, Little, Brown and Co., Boston, 1963, pp. 23-35.

According to this work, the ability to feed at least 45 billion people a year globally, even with the agricultural capabilities of the 1960s, was based on the following simple assumptions and calculations:

“Our land requirements, using the best agricultural methods now available – though great further improvements will be possible” are 1800 square meters/person or 5.5 persons/hectare, when allowing for an average food requirement of “500 kilograms per person per year or 1,370 grams per person per day.” Notably, in 1960, about the time Man and His Future was published, the yield of wheat in the UK was ~3.5 ton per hectare (3,500 kilograms dry weight grain per 10,000 square meters). Allowing for the 500 kg of food per person per year (1,370 g per person per day) to come exclusively from nutritious crops, that yield would very roughly suffice for 7 people per hectare to be fed from a single harvest, equivalent to 1400 square meters per person. Allowing for additional milk and meat consumption would somewhat increase the land requirements, though the land resources would nonetheless be quite sufficient. According to the author’s estimate, “The world has the equivalent of 6,600 million hectares of good agricultural land.” With the addition of potential agricultural land in the wet tropics of Africa, Latin America and Asia, “we must have 8,200 million hectares in all, capable of giving a diet containing meat and dairy products on a North American scale to 45,000 million people.” The estimated area of usable agricultural land in the world of “8,200 million hectares” (82 million square kilometers) is approximately half of the Earth’s dry land area (~148.94 million square kilometers), out of ~510.072 million square kilometers of the entire Earth surface area, including the water surface. Thus, further amelioration of the dry land, developing ocean farming, and further increases of agricultural yields and new technologies for biomass and food production – may dispel the fears of food shortage completely.

[22]. For example, the yield of wheat in the UK increased from 3,500 kg per hectare in 1960 to 8,000 kg per hectare in 2000 (128% increase). At the same 40 year period, the increase of population in the UK was just 15% (from 52 million to 60 million) and the increase in life expectancy was 10% (from 70.85 to 78.04 years). In 2011, the world’s greatest yield of cereal grains generally was almost 19,000 kg per hectare, and was achieved in Oman.

Based on: Food and Agriculture Organization of the United Nations, FAOSTAT, 2013,;

Human Mortality Database, University of California, Berkeley & Max Planck Institute for Demographic Research, 2013,

[23]. Peter Walker, Famine Early Warning Systems: Victims and Destitution, Earthscan Publications Ltd, London, 1989.

[24] Ilia Stambler, “The pursuit of longevity – The bringer of peace to the Middle East,” Current Aging Science, 6, 25-31, 2014.

[25]. Sofiya Milman, Nir Barzilai, “Dissecting the mechanisms underlying unusually successful human health span and life span,” Cold Spring Harbor Perspectives in Medicine, 6(1), a025098, 2015;

Natalia S. Gavrilova, Leonid A. Gavrilov, “Search for mechanisms of exceptional human longevity,” Rejuvenation Research, 13(2-3), 262–264, 2010.

[26] Kunlin Jin, James W. Simpkins, Xunming Ji, Miriam Leis, Ilia Stambler, “The critical need to promote research of aging and aging-related diseases to improve health and longevity of the elderly population,” Aging and Disease, 6, 1-5, 2015,

[27] Ilia Stambler, “Recognizing degenerative aging as a treatable medical condition: methodology and policy,” Aging and Disease, 8(5), 2017,;

Ilia Stambler, “Human life extension: opportunities, challenges, and implications for public health policy,” in Alexander Vaiserman (Ed.), Anti-aging Drugs: From Basic Research to Clinical Practice, Royal Society of Chemistry, London, 2017, pp. 535-564.

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