Should We Live Forever?

The Ethical Ambiguities of Aging

Gilbert Meilaender

• Publisher: Eerdmans
• Year: 2013
• ISBN:
  9781467437547
• Topic: Theology & Religion
• Subtopic: Ethics & Religion

In Should We Live Forever? Christian ethicist Gilbert Meilaender puzzles over the implications of the medical advances that have lengthened the human life span, wrestling with what this quest for living longer means for our conception of living well and completely. As he points out in his introduction, "That we often desire, even greedily desire, longer life is clear; whether what we desire is truly desirable is harder to say."The six chapters of this book take multiple perspectives on issues surrounding aging and invite readers to consider whether "indefinitely more life" is something worth pursuing and, if humans are created for life with God, whether longer life will truly satisfy our underlying hunger.

CHAPTER ONE

How Shall We Think about Aging?

The anti-aging medicine of the not-so-distant future would treat what we have usually thought of as the whole, the healthy, human life as a condition to be healed.

The President’s Council on Bioethics, Beyond Therapy

The highest expression of human dignity and human nature is to try to overcome the limitations imposed on us by our genes, our evolution, and our environment.

Ronald Bailey, Liberation Biology

AS THE NUMBER of our years increases, as we age in that simple chronological sense, we also age in a more important and profound sense. Gradually but progressively our bodies begin to function less effectively, and that increasing loss of function makes us more vulnerable to disease and death. Nevertheless, we should distinguish aging from disease. Unlike disease, aging is a normal stage of life that seems “built in.” It makes us more vulnerable to disease but is not itself pathology. No one dies because his hair turns gray, and the diseases often associated with old age can occur even apart from aging. Hence, to say that someone died “from old age” simply means, as biologist Tom Kirkwood puts it, that his hold on life had “become so precarious that, had it not been this particular cause of death today, it would have been another tomorrow.”¹

Aging might be said to be natural for human beings in the sense that it happens to all of us (unless, of course, we die before getting a chance to age). And while few people seem to relish growing old, even fewer want to die young, without the opportunity to age. Nor is aging natural only for human beings. All mammals age, and with only rare possible exceptions (such as the sea anemone), so do all living organisms (though in the wild most of them die too soon to age). We grow, we experience puberty, we mature — and we age. That is the course of a healthy human life. If we do not think of the other, earlier stages of our development as problems to be overcome, and if aging itself is not a disease, then why think of it as a problem that needs solving?

One reason we hesitate to adopt such a benign view of aging is, of course, that it seems so inextricably connected to death. Thus, Lewis Thomas, imagining in one of his elegant essays that ours might someday be a species free of disease, is quite naturally driven to ask: How then will we die? And, by way of answer, he tries to picture how we might simply wear out without breaking down in any particular way — without, that is, falling prey to any disease. Aging then becomes “an orderly, drying up process, terminated by the most natural of events.”²

The moral would seem to be: Aim to cure or ameliorate the diseases associated with old age but accept aging itself. Aim not at more years but at better, healthier years. To be sure, better health will probably mean a somewhat longer average life span, but it will not necessarily alter the maximum life span for human beings. The result will be platitudinous: adding life to years, not necessarily years to life.

Sensible as this seems in many ways, it may not “make sense.” If it is good to extend life by curing illness and relieving infirmity — knocking off age-associated diseases one by one in a way almost everyone seems to approve — why not also try to slow the aging process itself and extend life still further? Moreover, if we want to preserve health and overcome specific diseases, one way to do it would be to retard the process of aging, which is closely tied to increased vulnerability to illness. Indeed, doing that (were we really able) might be a more effective way of enhancing health than simply overcoming diseases one at a time.

Thus, even if aging — unlike disease — is natural, a part of “the whole, the healthy, human life,” as the President’s Council on Bioethics put it,³ as long as we cannot say the same of disease we may find it hard to argue against work that retards aging and (in so doing) extends the maximum life span. Though theoretically separate, disease and aging are inextricably intertwined in our lives. We seem driven — sometimes, at least, for the best of reasons — to try to overcome even the limit of years imposed on us “by our genes, our evolution, and our environment.”⁴ Whether doing so is, as Ronald Bailey puts it, the highest expression of our dignity, I doubt. But it is not easy to argue that we should entirely forego the attempt.

From the start, we need to think about how to think about growing old — and, in particular, how to think not simply of aging but of human aging. This will require that we learn from but also move beyond what has become the standard way to think about aging. Scholars study both why we age and how we age. The first seems to invite talk about a purpose, the second about a mechanism. The first is more germane to my inquiry here.

Why do we age? The dominant answer today is that of evolutionary biology, which goes something like this: We age because nature has relatively little stake in keeping us alive beyond our reproductive years. Insofar as we may speak of our lives having a point, it is to be carriers of DNA. Having passed that on to the next generation, we are dispensable. Any genetic trait harmful enough to cause death before the reproductive years will have difficulty surviving the filter of natural selection. Those who have such traits are less likely to reproduce, less likely to be effective carriers and transmitters of DNA. And, by contrast, natural selection will have relatively little effect upon harmful genes if those harms appear only later in life in the post-reproductive years.

Of course, we may continue to hang around for a while after we have produced the next generation, but as we do we inevitably suffer from genes whose harmful effects manifest themselves only in those later years. Natural selection having less need to eliminate them, they accumulate and start to take a toll on us. We begin to experience the effects of a gradual and generalized physical deterioration. Because nature’s interest in us all along has been simply an interest in reproduction, in the transmitting of our genes, it has paid relatively less attention to maintaining us beyond the years crucial for that task. Focusing on reproduction rather than maintenance, nature has not bothered to weed out changes that make us more vulnerable to disease and death: a weakening immune system, increasingly brittle bones, a clogged cardiovascular system, deteriorating sensory systems. These are part of the natural process of aging; but, of course, they are also closely linked to a wide range of diseases — pneumonia, fractures, heart disease, hearing and vision loss.

Tom Kirkwood has labeled this account of why we age the “disposable soma” theory.⁵ The idea is that, from the point of view of genes trying to transmit their DNA to the next generation, the body is little more than a carrier and is not made to survive indefinitely. It will eventually die anyway, so not a lot should be invested in sustaining it beyond that reproductive task. “Disposable soma” is a label worth pondering. It may sound mechanistic, but it is pervasively marked by metaphors drawn from human experience. For example, it is human beings, not genes, who have a point of view. It is not genes but living organisms that have purposes and goals. It is human beings, not genes, who care about a “next generation.” And if the body seems from the perspective of this theory to be disposable, we should remember what body is being so characterized. It is our body — which is the place of our personal presence, through which we are linked to our world and to others, apart from which we can scarcely imagine our own continuing identity. “Before I was conceived there was no me,” philosopher Christine Overall writes, “and no possibility of being a me. Some philosophers have claimed that my genetic material might have come into being earlier than it did. But even if this is empirically possible, the me that exists now is the product of the whole complex of experiences that have occurred since my birth or even since my conception.”⁶ Hence, whatever the usefulness of the disposable soma theory — and no doubt it is useful for many purposes — we may wonder whether it is well suited to help us think about how long it is good for us to live.

It is also instructive to underscore the close connection this standard explanation discerns between aging and reproduction. “The rule, simply stated,” as John Medina puts it, “is this: If you have sex, you will eventually die.”⁷ From the perspective of the well-being of our species, there is little reason to devote the body’s energies to tasks of cell repair and maintenance aimed at sustaining any of us into an old age that extends well beyond our reproductive years. A favorite example of evolutionary biologists is the contrast between semelparous species (which reproduce only once) and iteoparous species (which may reproduce repeatedly). Semelparous organisms generally die after reproducing and, therefore, will not be around to provide care for their offspring. (They usually produce a large number of offspring, which compensates for the fact that they will not live to provide care.) If, however, they are prevented from reproducing, they will live much longer than their normal life span. Thus, science itself invites us to think about the intertwining of reproduction with length of life and the relation between the generations.

The same lesson can be drawn from studies of caloric restriction in rodents (and, more recently, in rhesus monkeys). Indeed, a rather drastic reduction in calories seems to be the one certain method for retarding the aging process, even if we cannot say for certain how it works. Since the mid-1930s researchers have known that dietary restriction extends life. A diet containing normal healthy ingredients but with 30-40 percent fewer calories than usual has been shown to extend the life span of some mice and rats well beyond that of others whose food intake has not been so restricted. The standard explanation seems reasonable: If food is scarce, the body’s energy resources focus on cell maintenance rather than reproduction, increasing the animal’s chances of surviving longer and making time for the animal to reproduce when food becomes more readily available. Delaying reproduction extends the period of life when natural selection is effective. But, of course, a price is paid: Caloric restriction is closely tied to delayed puberty and reduced fertility. Moreover, it is not impossible that we might one day be able to manipulate the genome in ways that regulate reproduction in order to extend youthfulness and retard aging. At any rate, however we account for the connection, it indicates that aging affects not only individuals or a single generation; it has implications for the relation between the generations.

If, then, we take the standard account of why we age and try to derive moral advice from it, one’s first thought might be: Don’t have children, and I’ll live longer. But that would be to misunderstand, for nature is focused not on our well-being but on that of our genes. So, instead, the moral advice that might seem to follow is: Have children, the more the better, the sooner the better. In that way we can be effective transmitters of our DNA and take our place in nature’s larger and grander undertaking. If this happens to make life burdensome for us, we can take comfort in knowing that we have played our part well. Indeed, anything — including living well into old age — that makes us less likely or less eager to have children seems contrary to nature’s ongoing project. “From an evolutionary point of view, the name of the game is,” as Robert Arking puts it, “to play again (i.e., the whole point of being a reproductive adult is to pass copies of your genes on to the next generation).”⁸

We are disinclined to draw such moral lessons from the account evolutionary biologists give of why we age — and with good reason. That account may be able to tell us about changes that have occurred during our natural history, but it cannot tell us whether these are improvements. The fact that we can and do appeal to “nature” to support quite different versions of moral advice should, as Stephen Jay Gould once wrote, “teach us two lessons: first, that we have a remarkable capacity for self-delusion in projecting our hopes and fears on nature and re-deriving them as ‘fact,’ and second, that nature is sufficiently rich and multifarious to say yes (in part) to any human vision.”⁹

In a remembrance of his friend and colleague C. S. Lewis, Nevill Coghill recounted a conversation that took place once when he and Lewis were dining with Rector Marett of Exeter College.

Marett was a man of abundant geniality and intelligence, always ready with friendly freshets of conversation and new gambits of gossip to entertain a guest. Presently he turned to Lewis and said:

“I saw in the papers this morning that there is some scientist-fellah in Vienna, called Voronoff — some name like that — who has invented a way of splicing the glands of young apes onto old gentlemen, thereby renewing their generative powers! Remarkable, isn’t it?”

Lewis thought.

“I would say, ‘unnatural.’ ”

“Come, come! ‘Unnatural’! What do you mean, ‘unnatural’? Voronoff is a part of Nature, isn’t he? What happens in Nature must surely be natural? Speaking as a philosopher, don’t you know” — (Marett taught Philosophy) — “I can attach no meaning to your objection; I don’t understand you!”

“I am sorry, rector; but I think any philosopher from Aristotle to — say — Jeremy Bentham, would have understood me.”

“Oh, well, we’ve got beyond Bentham by now, I hope. If Aristotle or he ...