Support First Things by turning your adblocker off or by making a  donation. Thanks!

Few problems have so vexed the human spirit over the centuries as those of aging and death. Why are we afflicted with them? Are they forever part of our fate? Is there any way out? Yet hope has never been lost that there might be a way of transcending those seemingly final milestones. While not everyone longs to pass beyond bodily limits, it is for many people a deeply rooted desire. It can be construed most narrowly as a fear of death, but more richly as a longing for a different vision of life’s possibilities—a life that does not end, that remains engaging and fulfilling, and that unites us once and forever with those we love, whether divine or human. As William James put it, “The fact that we can die, that we can be ill at all, is what perplexes us . . . . We need a life not correlated with death, a health not liable to illness, a kind of good that will not perish, a good that flies beyond the Good of nature.”

Historically, there have been three routes taken to explore that possibility: the philosophical examination of the idea of immortality; various religious beliefs and speculations on an eternal life; and, most recently, a reinvigorated scientific dream of overcoming aging and death. I will not rehearse the long philosophical debate on immortality. My own sense is that the philosophical arguments in favor of immortality have not carried the day. Nor has there been of late any lively intellectual interest in the topic. At least one distinguished commentator, the late philosopher Hans Jonas, surely sympathetic to religion, judged that “the modern temper is uncongenial to the idea of immortality.”

Yet public opinion surveys show that there is a widespread belief in immortality among the American public. And even as Jonas was writing those words in the mid-1960s, the genetic revolution was gaining momentum. One persistent dream is that of a genetic modification of aging, at the least to take the sting out of it by improving its quality, and more boldly by radically increasing life expectancy, and perhaps even to achieve immortality. If the modern temper is not congenial to the idea of immortality as a philosophical concept, many scientists and their enthusiastic lay followers—usually indifferent to philosophical discussions—have become excited about the prospect of new combat against aging and death.

My aim in what follows is to compare various scientific visions of life extension, encompassing possible immortality, with the Christian vision of life eternal and the resurrection of the body. I could have chosen different religious traditions, but in the Christian tradition there are some well-articulated depictions about what life eternal might look like. There are also many Jewish thinkers who believe it to be part of their tradition, and in a form similar to Christian belief. The graveside prayer, the Kaddish, says “May God’s great name be exalted and sanctified in the world which will be renewed, and where God will revive the dead and raise them to eternal life.”

I will use the language of “vision” because, though it is easily reducible to cliché, it best captures the nature of the discussion, which in both the religious and scientific cases is exceedingly speculative. No one can say what the future world of scientific life extension, if it comes, will be like. It is at best an imaginative extrapolation from our present life. Apart from scriptural clues and theological reflection, no one can say what life eternal with God will be like either. At best in each instance we can find a few hints, but that is all—though the Christian tradition has elaborated its vision over a much longer period.

The scientific vision of immortality is a comparatively new entrant in thinking about the future of our lives. To be sure, there have always been some scientific visions of a medically transformed human life, going back to Francis Bacon and René Descartes. But few were so hopeful as the French philosophe Condorcet in his 1795 history of human progress. “Would it be absurd then to suppose,” he asked, “that this perfection of the human species might be capable of indefinite progress; that the day will come when death will be due only to extraordinary accidents or to the decay of the vital forces, and that, ultimately, the average span between birth and decay will have no assignable value? Certainly man will not become immortal, but will not the interval between the first breath that he draws and the time when in the natural course of events . . . he expires increase indefinitely?”

Yet there has been a change in science since the end of the eighteenth century. The earlier speculations were based on a belief in the unlimited power of science to effect human progress, however that might be brought about. But there were not any specific insights into how an indefinitely extended life span might actually be accomplished. Contemporary genetics and cell biology have begun to fill in the necessary details, setting out some plausible road maps to that end.

A comparison with the earlier philosophical debate on immortality offers an insight into the importance of the change in perspective. The philosophical debate on immortality trailed off, I believe, for a specific reason. Cartesian dualism, sharply separating mind and body, had long been rejected by the twentieth century and with it the Platonic idea of a soul, or mind, that could exist independently and forever apart from a body. Philosophical proponents of immortality could offer no plausible way of explaining how the decayed body of a dead person could ever be rejoined with his mind, lost along with the body, to make again a full person.

The new scientific speculations offer a solution to that problem: the body itself will be saved and with it the inextricably joined brain and mind that are the essence of personhood. It is, so to speak, useless to think about saving a separate mind or soul. They can only be saved by arresting or reversing the hitherto natural entropy of the body, seemingly programmed to decline and die, taking with it the mind. For many scientists, and even more for their eager lay followers, it has become realistic to hope to change that program.

The way into the new scientific optimism is through research on aging. While many diseases kill people prematurely, the majority of people in developed countries die after the age of sixty-five, with more and more reaching the eighties, nineties, and beyond. If death is ever to be conquered medically, then the royal road to death, that of aging bodies and fading minds, must be dealt with. I will not here recount in detail the various theories and experiments being pursued to bring about that end. They include going after the damage to cells done by free radicals, making use of hormone therapy, or caloric restrictions, or vitamin supplements, or, most dramatically, healthy gene selection through pre-implantation genetic diagnosis and even repairing the entire human genome.

The possibilities are broad and tantalizing. They raise the question of whether aging is best understood as a natural, permanent stage of life or a disease. That question is now being answered not by directly asserting that it is a disease, but rather by treating it as if it were one. This can be done by distinguishing between the process of aging itself, on the one hand, and the reduced biological capacities, the diseases, and the disabilities that have traditionally been the correlates of aging, on the other. If the latter can be radically reduced or eliminated, then one has the functional equivalent of a cure for aging. As one geneticist, Michael R. Rose, has tellingly put it, if we could gain for the elderly the health of those between the ages of ten and fifteen in developed countries, most Americans would have a life expectancy of 1200 years, and some would live 2000 years.

A cautionary note is necessary at this point. Few scientists of any serious reputation project a clean cure for aging and its partner, death. They are most likely to talk of a great increase in average life expectancy, of the conquest of the diseases of aging, and of preserving the capacities and vigor of youth. Recall the phrase from Condorcet predicting a time when “the average span between birth and decay will have no assignable value.” That is not immortality, but is edging close to it. I suspect that a similar way of talking helps the more utopian scientists in our day to speculate freely while not looking foolish to their colleagues.

Hardly any serious medical scientist will talk about achieving life eternal, but they are perfectly comfortable in projecting cures in the future for all of the important lethal diseases. The Human Genome Project, not long ago completed at a cost of $3 billion, was often presented by its promoters as opening the way to discovering the ultimate genetic causes of all diseases, thus setting the stage for their cure. The logical trajectory of such visions is tantamount to immortality. If nothing can kill us biologically, then (barring war and social violence) we should be able to live indefinitely.

The ambivalence on the part of many scientists about what they ultimately hope for, and the ambiguity of their language about it, is matched by similar tip-toeing by some seasoned science reporters. One such reporter, Ronald Bailey of Reason magazine, deftly handled the ambiguity recently by quoting in one paragraph a prominent researcher, Leonard Hayflick, to the effect that “there is no intervention that has been proven to slow, stop, or reverse aging. Period.” Then, in the next paragraph, Bailey said, “Despite that, researchers are making a lot of progress.” The title of his article was “Forever Young: The New Scientific Search for Immortality,” and it did convey the flavor of the article even if Bailey skirted the word “immortality” in the text itself. At the end of the article, he added to the ambiguity by quoting approvingly a demographic researcher, Jay Olshansky, who has said that “we don’t want to make ourselves older longer, we want to make ourselves younger longer.” Just how much longer was not specified.

There are at least three possible goals for such research. One of them, the normalizing of aging, would aim to get everyone up to an average life expectancy of that now enjoyed by Japanese women, that of eighty-five years. The American average is now 76.9 years and is steadily increasing (with the gap between men and women now diminishing). Another goal, which I think of as the optimalization of aging, would be to get everyone to the age of about 120 or so, matching the life span of the French woman who died a few years ago at 122; it has become increasingly common already for some people to make it to 105-110 years old. A third goal can be called maximizing life expectancy, aiming for life spans beyond 150 years and then indefinitely long after that.

Perhaps this last possibility might better be called incremental immortality—Condorcet’s “no assignable value’’—since it promises to add ever more years with no envisioned stopping point. That seems to be the utopian goal and one which, as I have suggested, is built into the eschatological trajectory of the quest to subdue aging, even if not as an explicit aim. In the general context of these three possible aims, it is worth mentioning that some demographers project an average life expectancy of close to 100 within fifty years or so even without any specific effort to achieve that outcome. There is solid evidence that, for at least 160 years, average life expectancy has increased at a rate of three months per year every year. Why is this happening? It is coming about because of improved socioeconomic conditions, the main determinant of population health; because of higher general standards of living that reduce the mortality rate of every age group; and because of technologies that improve the quality of life of the elderly, an indirect effect of which is to increase average life expectancy.

Two features of these various scientific speculations, particularly the most utopian, are worth some comment. One of them is the assumption that science will overcome what was long taken to be the most worrisome possibility of a much longer life, that of increased disability and dependence. Two decades ago it was common for epidemiologists to posit, with good evidence, the proposition “longer life, worse health.” The ideal of what was called a “compression of morbidity,” that of a long life in good health followed by a quick death, seemed a fanciful and unlikely outcome of medical progress.

But this pessimism has switched to optimism. More recent evidence has shown that, as average life expectancy has increased, the disabilities traditionally associated with aging have actually decreased. There are simply more healthy older people these days than there were just a few years ago. As even casual observation reveals, those who live to be ninety or older have, typically, not spent much time in the company of doctors and high-technology medicine. Good genes and a healthy lifestyle enable those fortunate people to do an end run around the health care system.

In short, the long history of cautionary tales about the implications of a radically longer life has now given way to a newly envisioned, upbeat old age. We can put aside the struldbrugs in Gulliver’s Travels, who had lived for hundreds of years and “who had not only all the follies and infirmities of other old men, but many more, which arose from the dreadful prospect of never dying.” The scientific believers confidently assume that the commonly expected burdens of aging bodies will be lifted, and that this has already begun to happen to some extent. The new cautionary tales center on how life may have to be brought to an end if people live indefinitely long in good health and just get tired of it all. Would not opposition to euthanasia, for instance, have to be reconsidered if bodies no longer ran down?

The other—and, I think, more important—feature of the scientific speculations about greatly extended life spans is a pervasive vagueness about what our lives and our societies might be like if we lived dramatically longer lives. The rationale for pursuing much longer life is not presented as if it were some kind of social necessity, as if we would have better societies if everyone lived much longer, or that it would help solve some pressing social problems. Instead, the rationale appears to be that an extended life span would simply satisfy many private desires: first, hardly anyone wants to die; second, as a basic human good, life is worth extending indefinitely; and, third, it would be remiss of science not to respond to that ancient expression of human hope and desire.

When potential problems are mentioned, they are rarely confronted directly. Just as there is a working assumption that medical progress will deal successfully with the long-standing disabilities associated with aging, there is an analogous assumption that, somehow or other, the social problems occasioned by much longer lives will be solved as well. After all, it might be said, we are not going to jump instantly into an era of radically longer lives. We will have plenty of time to gradually learn how to cope with any problems that might come up. Along the way it is possible, even likely, that whole new realms of unexplored, hitherto inaccessible human experience may open up to us. If a gain of fifty years of life expectancy during the past thousand years—and a thirty-year jump in the twentieth century alone—has immeasurably improved the quality and security of our lives, why shouldn’t we envision similar benefits from much longer lives? As two demographers have written, “Increases in longevity are conducive to improvements in wealth and thus create a virtuous spiral.”

That kind of uplifting rhetoric manages to neatly bypass one of the most telling worries about immortality. The philosopher Bernard Williams has noted the “profound difficulty of providing any model of an unending, supposedly satisfying, state or activity which would not rightly prove boring to anyone who remained conscious of himself and who has acquired a character, interests, tastes, and impatience in the course of living, already, a finite life.” Likewise, in his 1922 play The Makropulos Secret, Karel Capek has one of his characters, Emilia, now 337 years old, say that “no one can love for three hundred years—it cannot last. And then everything tires one. It tires one to be good, it tires one to be bad. The whole earth tires one. And then you find out there is nothing at all: no sin, no pain, no earth, nothing.” As the theologian Carol Zaleski has noted, “To be given everlasting longevity without being remade for eternal life is to live under a curse.”

That is not an inspiring picture. But don’t worry, the optimists seem to be saying, we can deal with that. Such optimism ignores one fundamental problem, hardly ever alluded to, that of the social, not biological, pathologies that have in the past and in the present ruined so much of life and brought about so much misery and so many deaths. I believe that sickness and biological death represent a lesser evil than those we human beings bring upon ourselves. Is a death from cancer at eighty worse than death at the same age in a concentration camp from murder or deliberate starvation? Or is death at age five from a genetic disease worse than death from a nuclear bomb? Or is the pain of a broken marriage, or spousal abuse, or child molestation, necessarily less than the pain of arthritis or congestive heart failure?

Without solving enduring human problems, a medically extended life span could simply set the stage for more of the same social miseries. A cure for cancer or heart disease or Alzheimer’s is not a cure for death from social pathologies or a guarantee that life without illness and disease will necessarily be marked by greater happiness. That is not to say that cures for major diseases would be irrelevant for happiness. They would surely help. It is only to say that, if the aim is to radically change live expectancies, then there are many things to be considered other than the benefits of health and mortality.

In the end, the enthusiasts simply ignore these problems. The visionary thrust of those hoping to extend life expectancy appears to come down to one simple idea: more time in our lives is sought by almost everyone; science can bring that about; therefore science ought to bring it about. In the face of that kind of argument, buttressed by an expectation that, problems or not, the research on life extension will go on anyway, those whom Ronald Bailey has called “the mortalists” must especially be taken to task for standing in the way of progress.

The argument of the mortalists is that death is not necessarily an ultimate evil, and that efforts to conquer it offer no obvious social benefits. Those efforts may, in fact, do harm to our understanding of the meaning of life and human nature. Leon R. Kass, Chair of the President’s Council on Bioethics, has presented the most developed argument along these lines.

While Kass touches on the most common anxieties about a greatly extended average life expectancy—its potentially dire impact on work patterns, parenthood, the social security system, and species renewal, for instance—his main approach is to ponder the value of mortality and the finitude of life. In his recent book, Life, Liberty, and the Defense of Dignity, he offers “four benefits” of mortality: interest and engagement, suggesting that adding, say, twenty years to the human life span would not proportionately increase the pleasures of life; seriousness and aspiration, proposing that the knowledge that our life is limited is what leads us to take life seriously and passionately; beauty and love, presenting the idea that it is precisely their perishability that makes, for instance, flowers beautiful to us, just as the coming and going of spring makes that season all the more meaningful; and, finally, virtue and moral excellence, by which he means the virtuous and noble deeds that mortality makes possible, including the sacrifice of our own life for a worthy cause. (See also Kass’ article “L’Chaim and Its Limits: Why Not Immortality?” FT, May 2001.)

For my part, I find these benefits of uncertain value, suggestive but not wholly persuasive; and, in any event, Kass seems intent more on evoking insights or feelings than in rigorously proving the case for mortality. Most tellingly, he concludes that “the immortals cannot be noble” and that “immortality is a kind of oblivion—like death itself.” At the least, that first conclusion seems to me unproven by his own arguments in favor of mortality. If people were genetically programmed for immortality, for instance—that is, if they were born that way and did not voluntarily choose immortality—then why could they not be prepared to give their life for others? Not every biologically immortal person need succumb to an obsession with survival. Moreover, even if immortality was given to us by a pill taken voluntarily, that possibility need not entail an unwillingness to serve others and to die for them if necessary.

But Kass’ more important contention is that “immortality is a kind of oblivion.” “Mortality as such,” he writes, “is not our defect nor bodily immortality our goal. Rather, mortality is at most a pointer, a derivative manifestation, or an accompaniment of some deeper deficiency . . . . [T]he human soul yearns for, longs for, aspires to some condition, some state, some goal toward which our earthly activities are directed but which cannot be attained in earthly life . . . . [M]an longs not so much for deathlessness as for wholeness, wisdom, goodness, and godliness.” The immortality that medical science would make possible could not satisfy this kind of longing, he says, and here he seems right on target.

Kass’ analysis could of course be used to make the case for a union with God, and eternal life in His presence, as the true end of that kind of desire. This is what the longing has traditionally been taken to mean. He does not, however, go in that direction, though he glancingly notes it as a possibility. He says instead that our perpetuation through procreation is a valid way of satisfying our yearning for something more than sheer mortality. “One cannot,” he writes, “pursue agelessness for oneself and remain faithful to the spirit and meaning of procreation.” Procreation is, then, the most promising positive route to immortality: we pass on to our children and then to their children not only our genes, but also our values and worldviews, and so we live on.

There is much that can be said for such a belief. But, as a parent, it conflicts with my idea and experience of parenthood, which has everything to say in favor of the future lives of those children and their happiness, and nothing whatever to do with perpetuating me. Kass’ view thus strikes me as fundamentally flawed. Children are their own persons, not clones, and, despite the genes I pass on (whose value is unclear), I will not live on in my children other than (I hope) as a fond memory and as the originator of a few hardly original ideas and virtues. Even more, I cannot hope to live on in my great-great-grandchildren in any meaningful way whatever. Kass, moreover, characterizes the deep longing as something that “cannot be attained in earthly life,” which is just where procreation is located. It thus fails to meet his own standard.

Nevertheless, Kass is right, I believe, to think that none of the secular versions of immortality, the kind science might give us, can satisfy our deeper yearnings, assuming we have them as part of our human nature. Leaving aside wholly imaginary musing about the new possibilities for human liberation that might accompany infinitely expanded life spans—multiple psychological lives, multiple careers, multiple hobbies, and multiple spouses—the essence of the secular and scientific ideal is simply more time on this earth. We will live lives not too different from those we now live. But that outcome will likely not satisfy the longings to which Kass rightly points.

If we take seriously the desire for something more than an immortal life brought to us by science, then the theological—and specifically Christian—alternative would seem to be worthy of our attention. Indeed, leaving aside the matter of whether the Christian view of eternal life is true or not, it is remarkable how sensitive it is to the various objections that can be leveled against the scientific vision. At the same time, it is no less sensitive to the desire of human beings not to sicken and die, to be relieved of social strife and injustice, to be forever in the company of their loved ones, to have their deepest yearnings satisfied, and to have an infinitely long life, one that is infinitely and interestingly worth having.

Let me say at once that those virtues do not give any added plausibility to the Christian vision in contrast to the scientific vision. A skeptic could say that the scientific view is incomplete and problem-ridden, while the Christian vision is just outlandish. But what I find interesting about the Christian vision is how over the centuries it has worked out most, and maybe all, of the conceptual pitfalls that go along with the concept of an eternal life.

At the core of the Christian belief in eternal life is the bodily resurrection of Jesus Christ from the dead. Christ’s resurrection is not only the promise of our resurrection but also a promise that we will, though transformed, still be ourselves in all of our uniqueness, in body and soul, when we are reborn. The Jesus who came back from the dead was the same Jesus who was crucified. Just as the scientific vision has understood that it is the preservation of the body that is the key to the preservation of our personhood—not an abstract, disembodied saving of our soul alone—so also Christian belief has insisted on the necessity of embodiment. In its condemnation of the Cathars, the Second Lateran Council of 1215 required heretics and other dissenters to agree to the proposition that “all rise with their own individual bodies, that is, the bodies they now wear.”

But just what is the body we now wear? Young, middle-aged, or old? Recall the judgment of Jay Olshansky, quoted above, that the scientific aim is to “make ourselves younger longer.” Thomas Aquinas would have agreed with that aim. “But all must rise in the age of Christ,” he wrote, “which is that of youth, by reason of the perfection of nature which is found in that age alone. For the age of boyhood has not yet achieved the perfection of nature through increase; and by decrease old age has withdrawn from the perfection.” While some might disagree with the view that “boyhood” is not old enough as an ideal for our body, few are likely to dispute another feature of eternal life, that of “freedom from noxious passions, internal and external.”

Nor is St. Bernard of Clairvaux’s twelfth-century description of our body objectionable. As the historian Caroline Walker Bynum has summarized Bernard’s views, “the glorified body . . . will possess immortality so it does not become dust, impassibility so that it does not experience suffering or disorder, lightness so it will have none of the downward pull of weight, and beauty so it will be clear and shining, with no spot of shadow or dirtiness.”

If the Christian vision presents an attractive view of our fate as individuals, it no less insists that our eternal life will be a life with others. As individuals on earth we always live in a close relationship with the rest of humanity; so also will it be in our immortality. Thus not only will we be reunited with our family and friends, but with all other persons. Our eternal life will be individual and collective, but now a collective life marked by peace and joy. No less importantly, the wholeness that is to be ours will see a restoration of the justice that was lacking in our temporal life. That is the meaning of the lovely phrase that in the final judgment “all tears will be wiped away.”

“For in the end,” as the English theologian Nicholas Lash has written, “God heals absolutely, makes all things new.” And if the desire for a final justice is part of our human longing, so too is that longing for something more, whatever it might be, that Kass and the Western tradition have long sought. It is a longing never mentioned, I might add, by the generation of aspiring scientists and not at all the same as a desire simply for more time on earth. For the Christian that longing is above all for an eternal life with God, who alone can satisfy that deepest of our needs. “All love,” Joseph Cardinal Ratzinger has written, “desires eternity; God’s love not only desires it, but effects it and is it.”

While the details of our eternal life with our glorified body, with each other, and with God are necessarily sketchy at best, it is clear that some thought has been given to Bernard Williams’ concern for boredom. The general belief seems to be that an eternal life with God and each other will, of its essence, be attractive and forever satisfying. But just how will that be? My favorite proffered solution to that puzzle comes in a passage from the fourteenth-century French nun and mystic, Marguerite of Oingt, who wrote that “the saints will be completely within their Creator as the fish within the sea: they will drink to satiety, without getting tired and without in any way diminishing the water . . . . [They] will drink and eat the great sweetness of God. And the more they eat, the more their hunger will grow. And this sweetness cannot decrease any more or less than can the water of the sea.”

Put in somewhat different terms, it might be said that our immortality will consist of infinitely renewed desires, but fresh desires infinitely and differently satisfied. Should you wonder if, in eternal life, you might be bound down to some fixed place, God will give to His friends “an agility so great that in an instant they can go wherever they wish . . . [and] they can enter and depart through closed doors, without any impediment, as Jesus Christ did after the resurrection.”

I have picked and chosen among a number of theologians and saints over the centuries to present this picture of the Christian belief in an afterlife. There have been many disputes, many fanciful tales, and of course a superheated imagination of a life no one has ever experienced on this earth. But it adds up to a much richer, more nuanced picture than anything the scientists and their followers have conjured up.

Caroline Walker Bynum’s concluding words in her splendid book, Resurrection of the Body, are worth citing: “For however absurd [the resurrection of the body] seems . . . it is a concept of sublime courage and optimism. It locates redemption there where ultimate horror also resides—in pain, mutilation, death, and decay . . . . Those who articulated [it] faced without flinching the most negative of all the consequences of embodiment: the fragmentation, slime, and stench of the grave . . . . [W]e may not find their solutions plausible, but it is hard to feel they got the problem wrong.” The crux of their “courage and optimism” was to make the body the center of their attention, turning their back on the Greek notion that the soul is the essence of personhood. Not so, the medievals held: it is the body.

There, in that belief, is the greatest commonality between the Christian and the contemporary scientific visions. Even if it entertained the idea of a soul, which it does not, science must of necessity work to reform the body and its wayward behavior. But if there is a critical confluence in the two visions of our possible future as embodied persons, there is also an enormous difference. Even if we believe the Christian doctrine of the resurrection of the body, it is beyond our power to alter or manipulate the glorified body that will come after our time on earth. That power is in the hands of God alone. That is not the case with the body that science can examine and change. There is something that can be done about that, something that medicine has always done in seeking cures from disease and the relief of suffering.

But as I hope my earlier analysis of the scientific writing on life extension made clear, there is no working picture or vision of what our lives, as individuals or living in common, might actually be like in the world that science might bring about. It is left vague and unexplored, papered over with assurances that there is more than enough time to work through lingering puzzles. This simply isn’t good enough.

I conclude with a message for the lay public and then one for the scientific community. I place myself in the mortalist camp because for the time being, and probably much longer, aging and death will remain our fate, put off and ameliorated perhaps, but not vanquished. We thus have no serious choice but to accept them, to find what virtues we can in them, and to live our lives in a way that integrates them as best we can. Even for those who believe in the Christian possibility of eternal life, death is still a reality and still stings. It is a myth that those who believe in the resurrection of the body are insouciant about death. It is, after all, the end of that which they know firsthand and a parting from those they love, even if temporary. Faith and hope must take over at that point—because only these can bridge the gap. Few believers can fail to be troubled by that gap, even if they believe it will be transcended.

But putting these considerations aside, it is not too early to begin thinking together what a much longer length of life on earth ought to be like. Even if aging and death were not deliberate research targets, the demographic trends strongly suggest that the lives of future persons will be much longer on average than they now are, surely long enough to cause serious social disruption if not wisely handled. Like it or not we might then be forced to live with a kind of knowledge and a set of technical skills we might rue, but which could not be eliminated—any more than our knowledge of how to build nuclear weapons can be eliminated. One way or another, then, we had best give thought to the consequences, deliberately pursued or not, of lives much longer than those we now enjoy (if “enjoy” is the right word).

For the scientists and their followers who welcome efforts to directly understand the mysteries of aging, and to take up decisively effective arms against them, two considerations need to be confronted. One of them is this: it is irresponsible to continue pushing for a cure to aging without thinking through the likely consequences. It is not enough to believe that all the problems will be taken care of in due course. They might indeed—but poorly for lack of serious prior reflection. It is not good enough to pursue ever-longer life just because many people want it. People want lots of things that are not good for them or those around them. Desire alone has never been an adequate guide to a life worth living.

Likewise, it is not enough to proceed without some picture of the kind of life that future generations would have if the quest for a cure for aging were successful. It is not enough to contend that research should be pursued in the name of scientific freedom and that, in the name of market freedom, people should be able to take it or leave it as they see fit. We should know by now that almost every major technology introduced in the name of expanded personal choice sooner or later is overtaken by cultural patterns and practices that finally shape everyone’s behavior, whittling away almost to nothing the range of the choice. How much choice do we really have about driving automobiles? Do women have about using prenatal diagnosis? Do we have for ignoring e-mail, the Internet, and television? It can be done, but most of us have neither the energy nor the psychological or economic resources to do with them exactly as we please.

The second consideration follows from the first. If scientists think through the consequences of their research, they will find considerable wisdom in the Christian doctrine of the resurrection of the body. I realize that the suggestion that science should turn to religion for guidance is unlikely to be welcomed. For many scientists, religion is viewed as an obstacle to doing good science and a constant threat to freedom of inquiry.

Nonetheless, in the doctrine of the resurrection of the body many generations of thoughtful and imaginative people have tried to envision what eternal life might be like; and, even more to the point, what it ought to be like if we are sensibly to desire it. It is not necessary to believe anything they have said about what eternal life will actually be like. It is sufficient that they have tried to go as far with their faith and imagination as they can—and with a sharp eye for the potential pitfalls that may accompany what they desire.

They have offered a vision that solves the problem of boredom; that solves the problem of our life in community with others and overcomes the pathologies of so-called civilized life, which finds us at each other’s throats as often as not; that solves the problem of our body and our personhood, positing a body that is the one we have always known but finally glorified and without its frailties and decay; and that solves the problem of satisfying those infinite desires that nothing now on earth can fulfill.

All in all, it is not a bad model. There are, in any event, no other models with such compelling solutions to long-standing puzzles, just as there are no comparable efforts to think things through in the long term. The truly intimidating feature of a greatly extended life span, much less earthly immortality, is that just about everything else in human life would have to be changed to make it worthwhile. We would need, in effect, nothing less than a glorified body, one where each and every part and organ functioned perfectly, resistant to wear and tear. We would no less need an analogous social order that was perfect in its own way but that, at a minimum, did not kill us by war and violence or spoil life by meanness and other forms of private misery. We would have to find ways of living with technologies that kept them from forcing us into ways of life that really give us no choice at all about taking or leaving them. We would, in a word, have to become different kinds of people—transformed, glorified people. A quasi-immortal life would not be the end of our problems with finitude. It could just as well be the beginning of new ones that would make us nostalgic for our mortal past.

Daniel Callahan is Director of the International Program at the Hastings Center and a Senior Lecturer at the Harvard Medical School. This article is based on his 2002 Ingersoll Lecture at the Harvard Divinity School. He is the author of the forthcoming book What Price Better Health: The Moral Hazards of Medical Research (University of California Press).