Humans have long sought the elixir of youth, so it is not surprising that even non-scientists closely follow the latest research into ageing. But is the ageing process, which most people simply consider a fact of life, actually a disease that can be conquered? Or is there some insurmountable limit to the lifespan of human bodies?
Of course almost everyone, as they get older, yearns for at least a moderate extension of their lifespan – provided that they retain their health and faculties. If we could be kept alive only with the help of extreme measures, many of us would opt instead for non-resuscitation and solely palliative treatment. We might also find comfort in having the option of assisted dying as soon as our quality of life and our prognosis dipped below a certain threshold. We would dread the fate of the Struldbrugs depicted in Swift’s Gulliver’s Travels – remaining alive, but in a decrepit state repulsive to those with normal lifespan.
But suppose that the ravages of ageing could be held at bay, would you then opt to live for centuries? Doubts are raised by the famous fictional example of Karel Čapek’s Makropulos, who succumbs to ennui after a few centuries as an opera singer. But her response doesn’t necessarily ring true. You would surely not have been bored – at least if your station in life were fortunate – if you’d participated in the changing pageant of European history over the centuries.
Makropulos is envisaged as unique, living on in a world where all around her die. But what if the elixir had been taken by others too? There would obviously be a fundamental inequality between those who had taken the elixir and those who had not. And if everyone’s life was extended, how could an overcrowded and unsustainable world be avoided? And how much does this depend on the magnitude of lifetime-enhancement, from a mere doubling of lifespan to a near-permanent indestructibility? It’s a philosophical issue whether personal identity can be preserved indefinitely, so that after thousands of years you would still be you in any meaningful sense.
But these issues are no longer fantasy. Some could soon be part of practical ethics, just as euthanasia is today. Biologists are exploring seriously whether ageing can be cured, so that our physical bodies remain in good repair for centuries. And futuristic technologists argue that AI and robotics are advancing so fast that one day human brains may be downloadable into near-immortal electronic simulacra that would perpetuate their consciousness and memories with a precision that would preserve the personality of their flesh-and-blood precursors.
Near-term research focuses on telomeres – stretches of DNA at the end of chromosomes – that shorten as people age. By adjusting the telomeres of nematode worms, for example, experimenters have managed to increase the lifespan of these creatures tenfold, although the same approach has less effect on more complex animals. The only effective way to extend the life of rats is to give them a near-starvation diet. (That said, the naked mole rat may hold special lessons for us; some of them live more than 30 years – several times longer than the lifespan of other small mammals.)
The powerful desire for a longer lifespan creates a ready market for exotic therapies of untested efficacy. For example, Ambrosia, a US start-up founded in 2016, offered Silicon Valley executives transfusions of young blood, although the company halted the treatment following a warning from US regulators. Another recent life-extending craze was metformin, a drug intended to treat diabetes, but which some claim can stave off dementia and cancer in otherwise healthy people.
[See also: Do you want to live forever?]
More credibly, human genome analysis has yielded insights into our vulnerability to some diseases. And there’s a realisation that the thousands of species of bacteria in our gut constitute an internal ecosystem whose balance may be crucial to our health.
Recently three laboratories have been set up by a company called Altos – two in California and one in Cambridge – to focus on extending the healthy lifespan. They’re well funded by billionaires and have poached researchers of high repute from other institutions. Even though few experts are optimistic about achieving drastic lifespan enhancement, there is at least a hope of beneficial spin-offs – just as President Nixon’s war on cancer in the 1970s wasn’t won but nonetheless usefully boosted our understanding of cell biology. But this kind of piecemeal progress probably won’t satisfy the founders of these labs. When they were young they wanted to be rich. Now they’re rich they want to be young again.
But what if a breakthrough were indeed achieved? Some would view a huge and widespread increase in life expectancy with foreboding: it could have undesirable and far-reaching consequences for society as a whole. If it were affordable only to the rich, we’d confront a fundamental new form of inequality: a privileged long-lived caste (its members would be less unacceptable if they actually became wiser with age). But if life-extension were available to everyone its implementation would drastically alter population projections and create a massive demographic shock.
The social effects, while obviously huge, would depend on whether the years of senility were prolonged too; whether women’s age at menopause would increase; and how families would be structured if many generations were alive at the same time. (And unless childhood development were to be slowed, children would be a smaller and more precious segment of the population; any accidental death would deprive the victim of centuries of life, not just decades.)
Hardcore longevity enthusiasts hope to achieve a metaphorical escape velocity, when medicine advances so fast that life expectancy increases by more than a year each year, offering the prospect of immortality. But some worry that this take-off won’t be achieved before they face natural death. They therefore want their bodies frozen until the technology advances; I know some academics in the United Kingdom who have signed up for such cryonics. The contract is with an Arizona based company called Alcor. They carry a pendant round their necks, signifying that if they die their blood should be drained and replaced with liquid nitrogen. They accept that the chance of resurrection is small, but point out that it would be zero otherwise.
I find it hard to take this aspiration seriously, and I would rather end my days in an English churchyard than an American freezer. And I don’t think it would be good if cryonics ever did succeed. Let’s suppose Alcor stays in business and dutifully cares for its cryogenically frozen bodies for the requisite number of centuries. The corpses would then be revived in a world where they would be strangers – refugees from the past. Perhaps they would be treated generously, as most people believe asylum seekers or displaced Amazonian tribespeople should be treated today. The difference, however, is that the thawed-out corpses would be burdening future generations by choice, so it is not clear how much consideration they would be seen to deserve.
But I don’t want to end on a sceptical note. As an astronomer I’m aware of the immense future lying ahead. The marvellous biosphere of which we’re a part is the outcome of about four billion years of Darwinian evolution. But our sun is less than half way through its life and the wider cosmos has a still longer – perhaps infinite – future. So we’re nearer the beginning than the end of the emergence of increasingly intricate complexity, which may well encompass near-immortal intelligences.
[See also: There is no such thing as the self]