“Aging,Geroscience,and Freedom”

Introduction

The prospect of developing an applied gerontological intervention—such as a new drug that mimics the effects of caloric restriction (i.e., delays the onset of chronic disease) or activates the longevity genes already present in the longest lived humans—has been heralded by many scientists as the ultimate form of preventative medicine. ^{1 –4} Instead of simply postponing human death by treating or preventing a specific disease of aging, the burgeoning field of “geroscience” promises to increase the number of healthy years humans can live. Extending the healthspan, and compressing the frailspan, is a much more novel and morally laudable goal, than the current aspirations of the costly, disease-specific approach to medical research. The latter keeps people alive longer by managing multimorbidity without altering the aging process itself. To help translate the social significance, and distinctive appeal, of an aging intervention, this article will frame the social significance of an applied gerontological intervention within the parameters of a normative analysis of freedom.

The history of humanity has been one of a struggle for freedom. Diverse policies, institutions, and cultural practices have been championed to help facilitate the freedom of human populations. These include dismantling practices of segregation, limiting the scope of censorship of free speech, challenging the gendered norms of the traditional family, and mitigating the economic vulnerabilities of market capitalism through the creation of the welfare state.

Within the history of political thought, the two most prominent conceptions of freedom are “negative” and “positive” liberty. ⁵ The negative conception of liberty equates freedom with the absence of interference. Coercive measures like limiting free speech or enforcing a “one-child” policy are obvious examples of a violation of negative liberty because both involve the imposition of external obstacles on our menu of options.

This negative account of freedom can be contrasted with the “positive” conception of freedom, which equates freedom with having the capacity to be self-determining. The positive conception of freedom is often invoked to help emancipate collective groups of people (e.g., low-paid workers). Marxists, for example, endorse this account of freedom in their attempts to reveal how a whole class of people (e.g., the proletariat—persons who must sell their labor power to survive) remain unfree despite the removal of many external obstacles (e.g., slavery and the monarchy). Also, the principle of self-government appeals to this positive conception of freedom when it is invoked to diagnose the moral deficiency of nondemocratic regimes. Democracy promotes our freedom because it permits us, as a people, to be self-determining, or at least more self-determining than any other political system that lacks the checks, balances, and accountability of democratic governance.

Science and science policy are not typically considered to be domains of inquiry that help or hinder freedom. When such concerns are raised, it is typically only incidentally, such as when government policies infringe upon the free inquiry needed to conduct scientific research. However, the knowledge and innovation yielded by scientific advances, especially in the medical sciences, have substantively increased the freedom humans enjoy today. A population enjoys more freedom when it is less susceptible to the harms of infectious diseases like small pox or malaria. The freedom of future generations can be constrained when we eschew adopting environmental regulations today, which could help us reduce the negative consequences of climate change in the future. Can the same be said of an applied gerontological intervention that retards, perhaps even eliminates, aging? Would such an intervention promote human freedom?

In this article, I will critically examine both the negative and positive conceptions of liberty and argue that senescence does violate our liberty, on both accounts of freedom. Also, if this is correct, then the development of an aging intervention ought to be considered an integral commitment of a society dedicated to freedom. An aging intervention holds great emancipatory potential for the world's aging populations.

The Aging of Human Populations

The aging of human populations is a tale of two contrasting stories. The first story is a success story of human knowledge, innovation, and determination. Historically, human populations did not age. Humans had a life expectancy at birth of 30 years or less for more than 99.9% of the time that we have inhabited this planet. ⁶ However, by reducing the risks of common causes of morbidity and mortality—those that arise from severe poverty, infectious disease, war, and accidents—humans have now escaped a world plagued by early death. The World Health Organization estimates that life expectancy for a child born in the world in 2016 was 72 years. ⁷ This is a staggering achievement.

In addition to this success story, the aging of the global population is also a story of a novel and pressing moral predicament. Growing, aging populations mean that unprecedented numbers of humans are susceptible to frailty, disability, and chronic disease. Unlike previous historical epochs, where the main obstacles impeding our liberty came from natural external hazards (e.g., the small pox virus or bacteria in water) or authoritarian political regimes (e.g., monarchy or dictatorships), the aging populations of today face the internally imposed limitations that arise from living beyond our “biological warranty period” ⁸ of ∼7 decades of life. This predicament is made vivid by the statistics on the rapid rise of chronic diseases associated with aging, such as cancer, heart disease, and stroke.

Older populations are vulnerable to arthritic pain, sleep disruption, dementia, frailty, and disability. Promoting the liberty of humans living beyond the biological warranty period is very distinct from preventing the specific causes of death that helped humanity escape a world plagued by early death. The latter involved targeting the proximate causation of morbidity. The rise of geroscience, an interdisciplinary scientific field of inquiry, “which strives to understand how aging enables chronic disease and seeks to develop novel multidisease preventative and therapeutic approaches,” ⁹ offers a different approach to health promotion than the disease-specific approach. Rather than seeking to treat or prevent a specific disease, geroscience is poised to offer us the potential to alter the aging process itself, thus extending the biological warranty of persons beyond what we inherited from our evolutionary history.

I believe that one of the greatest threats to human freedom in the 21st century is senescence itself. To say this does not necessarily imply that we will be able to eliminate aging. Nor does it imply that everything about being older is negative or bad. It just implies what it states—that aging diminishes the menu of options available to people in late life. It is a basic truism no one ought to deny. Living beyond the biological warranty period of 70 years means that humans will have diminished opportunities for health, cognitive functioning, sound sleep, mobility, pain-free existence, and so on. These are not trivial constraints on our freedom. Also, given that aging is universal, the inborn aging process will impact the freedom of people living in all countries of the world, rich and poor alike. Thus, we should take seriously the prospect that geroscience could help emancipate humanity from some of the limitations imposed upon us by an evolved biology that prioritized reproductive success over longevity.

Biological aging is “the progressive loss of function accompanied by decreasing fertility and increasing mortality with advancing age.” ¹⁰ Stated in this way, it is not hard to conceptualize how aging imposes constraints upon a person's “menu of options” in life. If you wish to have children, for example, there is a biological clock you must consider as the age of a prospective parent is one of the most significant factors affecting the chances of our having offspring. Deciding to try to conceive at 25 years of age is very different from trying to conceive at 45 or 55 years of age. Aging impacts the fertility of both men and women, but not to the same extent. Women's fertility begins to decline in the late 20s with substantial declines by the late 30s. Fertility for men is less affected by age, but shows significant decline by the late 30s. ¹¹

The risk of offspring having chromosomal abnormalities also increases with the age of parents. Attention has typically been given to maternal age, especially for conditions like Down syndrome. However, recent findings in epigenetics reveal that paternal age can also have impacts on the biology of offspring. One study found that paternal age accounted for ∼2% of the total variance in IQ scores, with later paternal age lowering nonverbal IQ scores more than verbal IQ scores. ¹² The age of the father also influences the probability of their offspring having autistic-like traits. ¹³

In addition to impacting fertility, one could point to the fact that aging has an impact on our ability to get adequate sleep, something that is significant for our physical and mental health. Sleep apnea, for example, is more prevalent in older persons than young adults. As important as the examples of infertility and sleep are, they are only the tip of the iceberg of the impact aging has on the opportunities available to humans after they reach the age of sexual maturity. The most significant impact aging has on us is our risk of chronic disease—such as cancer, heart disease, and stroke— as well as chronic pain, cognitive decline, and dementia. Multimorbidity—which refers to the existence of more than one disease—is much more prevalent among persons older than 65 years.

All of these chronic diseases and disabilities interfere with the quality of life of older persons, often on a daily basis. Suffering a stroke can interfere with our ability to verbally communicate our thoughts. The arthritic pain triggered by walking or exercising interferes with our enjoyment of physical play. Dementia interferes with our cognition and well-being. Senescence imposes much more limitations on the menu of options available to older persons, limitations that even the most authoritarian government could not impose upon its citizenry. And yet, philosophers and policy advocates do not typically consider aging itself as a threat to human liberty. Why not?

One response to the points noted above is to complain that I am conflating freedom with capacity. When a person has freedom of speech, for example, that does not necessarily mean they have the capacity to speak. The liberty only precludes the government constraining a person's speech, which is distinct from the claim that the government ought to ensure everyone has the capacity to speak. Max Hucott explains the difference between freedom and capacity as follows:

Freedom does not insure facility, as the following case shows. Jones is free, any time he wishes, to press five hundred pounds. There is no law against it and nobody will object if he makes the attempt. Nevertheless, Jones, who weighs only a hundred pounds himself, is unable to lift fifty pounds, much less five hundred, and must fail if he tries. Again, the distinction is that between “may” and “can.” Jones may lift five hundred pounds; he can't. He has the prerogative but not the power; he has the right but not the strength. ¹⁴

Hucott's point presumes that freedom entails what is often referred to as the “negative” conception of liberty. We shall now address this account in greater detail, and then consider the case of senescence to see if it is plausible to declare that aging contravenes our negative liberty.

Negative Liberty

The most prominent conception of freedom championed in liberal political theory is the negative conception of liberty, which equates freedom with non-interference. A society where citizens can enjoy freedom of conscience and freedom of religion is more free than a theocracy, for example, that mandates compliance with a particular religion under threat of coercion. For the negative conception of liberty, coercion is the paradigmatic example of a threat to our freedom.

In Isaiah Berlin's ⁵ famous essay “Two Concepts of Liberty,” he argued that we lack political liberty or freedom only if we are prevented from attaining a goal by human beings. Not being able to fly, for example, does not constitute a violation of our liberty as this limitation is not imposed upon us by any person or state. Furthermore, a violation of negative liberty only occurs when the goal we are prevented from attaining by someone is something we have a right to. For example, if you are prevented from expressing your political viewpoint because the government censors such expressions, that would constitute a violation of your liberty because you have a right to express your political beliefs. However, what if what the government prevents you from doing is driving on the wrong side of the road? That does not constitute a violation of your liberty because you do not have a right to drive as you please on public roads. There are regulations in place, concerning speed, side of the road to drive on, and so on, which must be obeyed to ensure public safety and efficient road travel.

What might we say about aging and human freedom? As I tried to establish in the previous section, senescence certainly interferes in our lives by limiting the opportunities available to humans, but does it constitute a violation of our freedom, understood as negative liberty? Defenders of negative liberty may highlight a number of features of this account of freedom that rule out construing senescence itself as something that restricts our freedom. First, the paradigmatic example of violations of negative freedom involves coercion. Policies like segregation or censorship of speech are the types of interference we typically think of when referring to negative liberty. Second, not all limitations on our actions constitute being described as violations of freedom. The fact that I cannot start flying when I flap my arms up and down vigorously does not mean the laws of aerodynamics violate my liberty. The constraint or limitation at issue must be created by humans, rather than be a reality simply imposed upon us by our biology or the laws of nature (e.g., gravity). Aging is a fact of life for humans and other sexually reproducing species. And thus, one might argue, it is a mistake to construe aging as something that violates human freedom. And third, when the negative conception of freedom is invoked to denounce a limitation on freedom, the limitation must violate a moral right we have as humans, such as the right to free speech or freedom of movement. And, because there is no right to be biologically immortal, the critic might contend, we cannot say that senescence violates anyone's liberty.

These three features of the negative conception of liberty can be listed as follows:

The paradigmatic threat to freedom is coercion.

Let us now critically examine these three premises in greater detail, to see if the case for construing senescence as liberty-impairing can be endorsed by even proponents of the negative conception of liberty. First, while coercion is typically the paradigmatic case of “interference” for negative liberty, there is no reason to make it a necessary, rather than sufficient, condition for an intervention to count as liberty-restricting. The menu of options available to us could be adversely impacted by government actions that are careless, neglectful, or negligent, in addition to coercive. For example, a government that fails to take the action necessary to combat climate change will impose limitations on the menu of options available to future generations, even though these limitations are not coercive. Alternatively, a government that fails to provide adequate national security could make a country vulnerable to invasion by hostile neighbors. Or a government that did not provide adequate safe drinking water to its population would adversely impact that opportunities available to a population at greater risk of water-borne diseases. In each of these three cases, the government's inactions interfere with the menu of options available to others, even though the interference is not coercive. If a government purposely added water-borne diseases to the drinking water of a population, such heinous actions could be considered liberty-restricting. So why not interpret the same outcome from noncoercive inaction in the same manner?

Some might want to resist my suggestion that some inactions are analogous to coercive action by invoking the second criteria of negative liberty—that threats to freedom must come from human-created limitations. The limitations imposed by a hurricane or earthquake, they might retort, are not considered liberty-restricting states of affair because they are not limitations caused by humans. In the case of the government purposely adding water-borne diseases into the water supply, this criterion for “human-created limitations” is easily met, thus warranting saying that such action violates our freedom. However, in the case of government inaction to address the limitations imposed by invasion, infectious disease, or climate change, the limitations in question are not created by the people we are claiming have violated our freedom.

The weakness with this line of reasoning is that it presumes all potential limiting actions or events fall into one of two categories: i.

Human-created limitations (e.g., government coercion).

However, there is a third category of limiting actions or events that are a hybrid one (1) and (2):

iii. Limitations that are a combination of things humans are responsible for and things they are not responsible for.

Many limitations humans face in life are caused by a mix of things humans are responsible for and things beyond our control. This is perhaps most easily illustrated by the case of a society that fails to effectively implement public health measures like sanitation and immunizations, or building regulations/requirements designed to help mitigate some of the vulnerabilities posed by hurricanes and earthquakes. In such cases, a significant part of our vulnerability can be described as “human created,” and part of that vulnerability is due to the fact that the world is hostile to all forms of life. A society that fails to adequately treat the drinking water a population will consume does limit the menu of options available to the population, even though humans are not responsible for the existence of water-borne diseases themselves. What we are responsible for is the safety of our drinking water, and a failure to do so imposes unnecessary limitations on human actions and well-being by increasing the risk of disease and death.

Or consider the example of climate change. The rise in sea levels, warmer temperatures, and increased malaria transmission we may experience a century from now could possibly be mitigated if humans took urgent action now, to reduce our reliance on carbon emissions. Our inaction today will be partly responsible for the limitations climate change imposes upon future generations a century from now. Human-created limitations need not be equated with the specific cause of the risk in question (e.g., such as Cholera or malaria), but with the more general risk of higher rates of morbidity and mortality than there need be if humans had pursued reasonable, cost-effective preventative measures.

Are the limitations senescence imposes upon us in some sense “human-created” limitations? There are two ways in which humans are (partially) implicated in such limitations. First, while humans are not responsible for senescence itself, we are responsible for global aging. So if we ask the question “Why do we age?” there are two explanatory lens we could utilize to answer this question. The first lens is provided by evolutionary biology and it is known as the disposable soma theory. ^15,16 This account of aging maintains that biological aging occurs because natural selection favors a strategy in which reproduction is made a higher biological priority (in terms of the utilization of resources) than the somatic maintenance needed for indefinite survival. The story of the intrinsic constraints of our biology thus begins with the story of the world's extrinsic risks.

One answer to the question “Why do we age?” is that evolution by natural selection favors a strategy in which reproduction is a higher biological priority over longevity. That answer does not implicate humans as being responsible for senescence. What does implicate human responsibility is the reality that, without human intervention, very few humans would actually age. The noble laureate Peter Medawar described senescence as something “revealed and made manifest by the most unnatural experiment of prolonging human life by sheltering it from the hazards of its natural existence.” ¹⁷ So by this second explanatory lens, while senescence is a consequence of our evolved biology, it is only manifest in large portions of the population when humans intervene to prevent early and mid-life mortality. This means that global aging, like global warming, is a result of human actions. “Humans, and the animals we choose to protect, are the only species in which large numbers experience aging”. ⁶ Without the benefits of the knowledge of hygiene and biomedicine, only a small percentage of people would live long enough to experience the constraints imposed by the inborn aging process.

There is also a second way in which human action is implicated in our susceptibility to aging. Our decisions about which types of scientific research should receive the largest investment of (limited) research dollars influences how successful we shall be at treating specific diseases of aging vs delaying the onset of age-related limitations more generally. Greater support for geroscience will influence when such interventions will be possible, as well as how successful they will be (e.g., slowing aging by a few years, decades, or more). This same point is frequently made to urge action on climate change, like geoengineering. So I think it is accurate to describe the limitations senescence imposes upon us now, and in the future, as at least partially caused by humans—in both the backward looking (i.e., we made population aging possible) and forward looking (we could plausibly modulate the rate of senescence) senses.

The third and final element of the negative conception of liberty is the stipulation that interference is a violation of freedom when it limits a moral right we have as humans. The case for arguing that aging itself violates a moral right humans have is easy enough if one believes that humans have a moral right to health. This right would underpin the support for things like the provisions of immunizations and clean drinking water, as well as access to a family doctor, drugs to help treat the progression of chronic conditions, and so on. The Constitution of the World Health Organization includes the following principles that embody a robust right to health:

The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition.

…. The extension to all peoples of the benefits of medical, psychological and related knowledge is essential to the fullest attainment of health.

Governments have a responsibility for the health of their peoples which can be fulfilled only by the provision of adequate health and social measures. ¹⁸

These principles suggest that aging itself, to the extent that it threatens our health opportunities, does interfere with a moral right that ought to be protected when possible. The WHO does not declare that a right to health only applies to children or adults before mid-life. The goal of attaining the highest attainable standard of health is an aspiration we should strive for at all stages of the human life span, including the postreproductive stage of life.

An Objection: Negative Versus Positive Rights

The critic might object to the examples of health, sanitation, and climate change by arguing that the only moral rights protected by negative liberty are so-called “negative rights,” such as the right not to be tortured, censored, or imprisoned without a fair trial. Alan Gewirth explains the distinction between “negative” and “positive” rights as follows:

Negative rights entail negative duties, i.e., duties to forbear or refrain from interfering with persons having the objects of their rights. The right to life, for example, requires that one refrain from interfering with persons' continuing to live; the right to free speech requires that one refrain from preventing persons' speaking. Positive rights, on the other hand, entail positive duties, i.e., duties to help persons to have the objects of their rights. The right to education requires that one helps persons to get an education; the right to healthcare requires that persons be given healthcare in appropriate circumstances, and so forth. ¹⁹

Invoking the distinction between negative and positive rights, the critic might argue that the examples I have employed above, concerning a right to sanitation, to combating climate change, and any gerontological intervention that mitigates the harms of senescence, are positive and not negative rights. Thus, our critic will conclude, only human-caused limitations that deprive someone of a negative right constitute being called “violations of freedom.”

The distinction between the so-called “negative” and “positive” rights has been criticized by those who question the tenability of the distinction. The most effective argument against the viability of the distinction that I have come across is the argument deployed by Stephen Holmes and Cass Sunstein in The Cost of Rights. ²⁰ In this book, Holmes and Sunstein address a variety of examples that reveal that the so-called “negative rights” are, in fact, “positive rights” when you consider what it means to legally enforce such rights. For example, the protection of private property does not simply entail putting people in jail, who steal someone's property, but also protecting property from things like forest fires or invasion from foreigners. The right not to be tortured can only be credibly enforced by ensuring inmates have access to impartial medical assessment when they report injuries in prison.

The right to vote is a basic liberty and a right that was, historically, limited to only males. Even the right to vote can be construed as a “positive right” because the exercise of the right entails more than just prohibiting obvious interference like denying women the vote. The distribution of polling stations within a geographical territory, the hours of operation of a polling station, and the language the ballot is written in will also have an impact on the opportunity citizens have to exercise the right to vote. A government might limit the opportunities citizens have to vote by only having polling stations open during the hours most people are at work or making polling stations more easily available to access for citizens living in certain areas (e.g., cities) than other areas (e.g., rural regions). So I do not believe that there is a credible basis for proponents of negative liberty to object to positive rights being among the rights that constitute violations of liberty since all (legally enforceable) rights are, as Holmes and Sunstein conclude, in fact positive rights.

If, as I have suggested it is, the right to health is a fundamental moral right (even if a positive right), indeed, it may be the most fundamental of all rights, then limitations on that right that are at least partially caused by humans should be considered violations of liberty even by the negative conception of freedom. We shall now turn to the positive conception of liberty, an account that is much more naturally suited to supporting the conjecture that mitigating senescence promotes our freedom.

Positive Liberty

Unlike negative liberty, which focuses a moral analysis on the individual stakes at risk with interference, the positive conception of freedom places the emphasis on the well-being of a collectivity (e.g., a country). For example, the Swiss-born philosopher Jean-Jacques Rousseau (1712–78) invoked the positive conception of freedom to defend the notion of living in accordance with what he called “the general will.” Rousseau's account of freedom inspired the French Revolution and helped provide the normative foundations for democratic government. Also, Karl Marx (1818–83) endorsed a conception of freedom that sought to emancipate the common worker from the exploitative and alienating labor of the capitalist system.

Positive liberty is equated with self-determination or self-mastery—having control over one's destiny. Also, in the history of political thought, different institutional arrangements have been characterized as threatening to the positive liberty of humans, from nondemocratic political arrangements (e.g., monarchy) to capitalism. Unlike the negative conception of liberty, which equates freedom with noninterference, positive liberty can interpret states of affairs as a threat to liberty even when there is no interference. For example, in the early capitalist economic system, before the creation of the protections of the welfare state like a minimum wage, the average proletariat (or worker) faced the stark choice between working in potentially dangerous conditions for a meager subsistence wage or risking starvation. Marx believed the worker in capitalism was not truly free, even though the decision to sell their labor power did not involve the kind of interference (i.e., coercion) typical of producers in slave societies, for example. In the latter, the worker is forced, under threat of coercion, to produce. In capitalism, there is no overt coercive interference, but the lack of real options (i.e., sell your labor or risk starvation) meant that the proletariat was in the same kind of predicament that other producing classes found themselves in historically, like the serfs and slaves. All of these producing classes lacked self-determination.

The positive conception of freedom more naturally presents advocates of geroscience with an account of freedom that can readily explain why tackling senescence itself, rather than just specific diseases of aging, would promote freedom for the world's aging populations. Also, this is so because positive liberty emphasizes the importance of the internal factors necessary for living an autonomous life. That autonomy might be compromised, for example, when an individual has a drug addiction and thus lacks self-determination. Or collective autonomy might be compromised when a class of persons (e.g., proletariat) must sell their labor power doing work they find alienating or when citizens lack the ability to contribute to their own self-governance.

How might the story of the aging of humanity be integrated into this account of positive liberty? Perhaps the most natural way of doing so is to emphasize the connection between our physical and mental health and our autonomy. The latter means having the ability to act on one's free will. And thus, the positive conception of liberty, unlike the negative conception, equates freedom with possessing a capacity, the capacity to be self-determining.

When a person is younger, in the prime of health during their 20s, for example, they will have many capacities that diminish later in life. Capacities such as running long distances without experiencing serious joint pain, playing contact sports without risking serious injury, and possessing a higher cognitive processing speed, better memory, and attention that help aid with many cognitive tasks in life. Because senescence has detrimental effects on a person's physical and mental health, it can be said to diminish a person's ability to be self-determining. Also, this means that, according to the positive conception of freedom, aging reduces our freedom. Our menu of options is diminished as we acquire more and more physical and cognitive limitations.

Three Objections

This positive freedom argument for tackling aging might face opposition from critics coming from three different directions. One line of criticism is the popular belief that exercise itself is sufficient for liberating humans from the limitations/harms of senescence. And a second objection might come from those who believe my argument promotes a negative stigma about aging—that getting older brings only negative things for society and older persons as individuals. Thus, my suggestion that aging diminishes our freedom is, the critic might charge, “agist.” And finally, some might object that my argument mistakenly values the quantity of life rather than the quality of life. Let me expand, and respond to, each of these lines of objection.

Are environmental interventions, such as healthy diet and regular exercise, sufficient for emancipating humans from the limitations of senescence? And if the answer is “no,” then what types of intervention, short of biological immortality, could be said to promote our positive freedom with respect to aging?

Both nature and nurture influence our risks of morbidity in late life. Exercising, for example, has been shown to increase the life expectancy of both men and women.

A helpful way to understand the difference between what exercise offers, and a potential gerontological intervention that modulates the inborn aging process, is to invoke the distinction between primary and secondary aging. ²² The definition of biological aging noted earlier by Kirkwood and Austad ¹⁰ (that aging = the progressive loss of function accompanied by decreasing fertility and increasing mortality with advancing age) refers to “primary aging.” We all experience, regardless of lifestyle and environmental factors, the loss of function, decreased fertility and increased mortality in late life. Primary aging is inevitable. Eating vegetables and exercising, for example, do not alter primary aging. However, these lifestyle modifications can of course improve one's health in late life, because they do have an effect on secondary aging. Secondary aging is the “deterioration in tissue structure and biological function that is secondary to disease processes and harmful environmental factors.” ²²

Secondary and primary aging both affect human freedom. And limiting the interventions we pursue only environmental modifications like exercise and a healthy diet is to limit our ability to improve our positive freedom to the benefits of ameliorating the limitations imposed by secondary aging. However, the field of geroscience offers us the prospect of also ameliorating the limitations imposed by primary aging itself. We can conceptualize three general freedom-based interventions as follows:

Exercise/diet: delaying the onset of disease and increasing the average maximum lifespan by a few years (e.g., up to 85 years).

When freedom is understood as a capacity—the capacity to be self-determining—it is easy to make the link between the measures noted above and human freedom. Disease and death undermine this capacity. Also, we should do whatever is feasible and cost-effective to reduce the threats to our self-determination. To ignore aging itself would be to arbitrarily ignore one of the single greatest threats to the health and freedom of humans this century.

A second line of objection against my argument might come from those who take offence with the suggestion that aging compromises our freedom. To characterize senescence as something we should aspire to emancipate humanity from, the critic might contend, implies that everything about getting older is bad. This is certainly not my intention. Thus, I want to take this objection seriously, as I do not want my reader to charge that the argument I advance is agist or expresses negative judgments about older persons.

This type of objection has been raised by disabilities' advocates, for example, who take issue with technological innovations (like prenatal genetic diagnosis or PGD) that permit prospective parents to select embryos that have the lowest risk of developing a disability. In From Chance to Choice: Genetics and Justice, Allen Buchanan et al. call this the Expressivist Objection. This objection maintains that the development of genetic interventions to prevent disabilities “expresses negative judgments about people with disabilities, and that these judgments constitute a profound injustice to those people.” ²³ And this critique is often conjoined with what Buchanan et al. call The Loss of Support Argument: “as the application of genetic science reduces the number of persons suffering from disabilities, public support for those who have disabilities will dwindle.” ²⁴ The Expressivist Objection and Loss of Support Argument could be utilized to oppose the argument I have been developing in this article as I am endorsing the position that aging itself is negative because it violates our freedom. This, the critic might argue, expresses negative judgments about older persons and it might dwindle support for specific diseases of aging.

Buchanan et al. formulate a nice response to this type of concern by drawing a distinction between devaluing disabilities without devaluing people with disabilities. And this response could be applied to aging as well. We already endorse policies and lifestyles that seek to prevent disability/chronic disease, such as requiring people to wear seat belts when in automobiles, to wear safety glasses when working with hazardous materials that could cause loss of vision, to wear helmets when riding a bike, to exercise, eat a balanced diet, and to stop smoking. Such measures are predicated upon the conviction that there is a pressing moral imperative to pursue cost-effective measures that reduce disability and chronic disease. However, disvaluing a disability- like vision or cognitive impairment does not mean that people who are visually or cognitive impaired are devalued. A society can legislate the wearing of eye protection in certain workplaces AND still be committed to the equality of all persons, visually impaired or not. The latter is determined not by the extent to which a society aspires to prevent a disability or disease, but by the support it offers to those living with the disability. The same is true of disvaluing senescence itself for the way it negatively impacts our health and freedom. This does not mean we ought to devalue older persons who might suffer a disability or chronic disease. Nor does it imply that people who are older and living with disability or a chronic disease do not have lives worth living. It only means that they have diminished liberty compared to the menu of options available to someone in the prime of their healthy years of life.

A third line of objection to my argument might come from the critic who argues that we ought to be more concerned with the quality of life versus quantity of life. Larry Temkin, ²⁴ for example, argues that we should value living well over living long. If that is so, one might conclude that, rather than making life extension a societal priority, perhaps we ought to preserve the “aging status quo” and instead tackle the substantive issues that impede the realization of meaningful and fulfilling lives.

I believe such an objection posits a false dichotomy between valuing either the quality or quantity of life, as these two things are completely distinct. Our physical and cognitive health (which senescence threatens) do significantly impact our quality of life, by permitting us to remain autonomous and to exercise the intellectual virtues ²⁵ —such as the ability to recognize the salient facts, sensitivity to details, diligence, care, and thoroughness. The positive conception of freedom argument for tackling senescence is not predicated upon a desire to increase the length of time humans are alive. It is predicated upon a desire to ensure the opportunities for flourishing can be realized at all stages of the human lifespan, including the postreproductive stage of life. Also, a side effect of realizing this qualitative aspiration through an aging intervention is that people would live longer lives.

Conclusion

Emancipating the world's aging populations from the limitations of senescence, like emancipating the world from the constraints imposed by poverty, infectious disease, and climate change, ought to be a global priority. Framing the prospects of geroscience within the negative and positive conceptions of freedom detailed in this article should help extend the advocacy of this marginalized field of scientific research beyond the public health argument already made by scientists in the field. The stakes at risk in ignoring the moral imperative to retard the rate of our molecular and cellular decline are more than just our health. Aging also impacts the freedom we ought to have to enjoy flourishing lives.

I conclude by considering one last objection to the general argument developed in this article. Audrey Chapman has argued that “any new biomedical and genetic intervention that is likely to have profound consequences for human dignity, social relationships, and justice considerations should not be left solely to individuals to determine.” ²⁶ Justice, she argues, “has social as well as individual dimensions.” ²⁶ Do justice considerations buttress or undermine the aspiration to modulate human aging? Elsewhere ^{27 –29} , I examine the justice-based argument for tackling aging in some detail. My critic might argue that more freedom (by delaying or eliminating the onset of the limitations of senescence) is not necessarily desirable if it creates new, or exacerbates current, societal problems. For example, they might worry about an increase in the problems associated with overpopulation, or exacerbating the inequality between the rich and the poor in the world. My response to this “Justice Trumps Freedom” line of objection is twofold.

First, while I am willing to concede, these types of concerns should be taken seriously and addressed by policy makers when thinking about the impact of utilizing an aging intervention, a benefit of framing the imperative to mitigate aging within the normative lens of freedom is it compels us to also take stock of the human and economic toll of aging itself. This is often missed by critics who dismiss any aspiration to increase the human lifespan because of possible negative consequences of doing so. It can be instructive to remember that the freedom of both current and future generations will be impacted by many factors. Also, maintaining the “aging status quo” will, with 100% certainty, imposes significant limitations on the opportunities available to all humans (rich and poor alike) living beyond the biological warranty period of 70 years. The certainty, and severity, of the limitations imposed by senescence makes it a unique and pressing societal challenge, and this is typically ignored by the critics of increasing the human lifespan. Once we acknowledge the reality that senescence is one of the most significant threats to human freedom, the persuasive force of the critic's opposition is deflated significantly.

Second, many accounts of distributive justice—libertarian and liberal—define justice in a manner that prioritizes the value of liberty over other values (e.g., equality or the general welfare). John Rawls, ³⁰ the most influential political philosopher of the past half a century, argued that justice denies that the loss of freedom for some is made right by a greater good shared by others. So one response to the justice-related concerns that might arise when humans live significantly longer lives is to retort that there are pressing reasons, predicated upon justice itself, for delaying (if not eliminating) the diseases of aging, namely that aging restricts our freedom! Worries about equal access to an aging intervention ought to be addressed by ensuring there is universal access to such a technology rather than limiting human freedom by obstructing the development of an applied gerontological intervention. Also, with the potential problems that might arise from increases in the size of the human population, the appropriate response is not to curtail liberty (e.g., by limiting the number of offspring or forfeiting an aging intervention or any other public health measure), but instead to pursue empirically sound and morally defensible measures that can reduce fertility levels without threatening liberty, such as education (especially of women), better access to birth control, economic development, and alterations in social attitudes toward the family and gender.