Is medical control of human aging a worthy goal?
Despite the moisturisers you can buy it is impossible to reverse the damage of aging and very few of us will live to anywhere near the theoretical maximum of human age, estimated to be 125. Yet some people think the first person who will live substantially longer than this is alive today.
Aubrey de Grey is one of them. He was recently speaking at a debate at the Oxford University Scientific Society, for the motion “This house wants to defeat aging entirely.” De Grey is the chief scientific officer of the SENS foundation and a cheer leader for bringing aging under medical control. “This is no longer a radical heretical idea” he says; for de Grey defeating aging is at the heart what medicine is about. And when we treat aging, longevity is a welcome side effect.
Methods to extend human lifespan are speculative and de Grey’s ideas are controversial. Calorie restriction is shown to increase the lifespan of several species, including rodents and fish, but there is no evidence that this will translate to humans. Nanomedicine is a futuristic strategy, with constant corporeal repair provided by microscopic robots. Another proposal is for cloning to generate cells, body parts, or even entire replacement bodies.
De Grey is bullish about the future and the emergence of new technologies “if you tried to predict the rate of improvement in the Atlantic crossing by looking at ocean going liners you’d have been wrong” he says. Another of his proposals is of a “human longevity escape velocity” which supposes that initial life extension therapies will only grant a modest life extension. This extra lifespan will see a recipient through until the development of more advanced therapies. In this way the first person to live to 150 might also be first person to live to 1000.
I find this reasonably persuasive. Colin Blakemore, professor of neuroscience at Oxford University, does not. He was speaking against de Grey. “Utterly unrealistic” is how he describes de Grey’s proposals and says that to defeat aging an “incredible range of age related disorders would have to be defeated.” He thinks that talk such as de Grey’s is a distraction from the real work of medical research.
Blakemore also says that the emergence of technology that will substantially prolong human life will be a “disaster for humanity and the planet.”
I agree. I don’t think that it’s inherently unethical to seek to extend human lifespan. It may actually be immoral not to do so as it denies future generations the chance of extended lives. Diseases of old age (which is most of them) kill 50 million people a year old worldwide and these will be preventable deaths like any other.
But I am worried about the consequences. Even the prophets of life extension such as de Grey concede that, without a drop in birth rate, problems of rising population will become even more acute. We will need to choose between living longer and having children, as doing both will be catastrophic.
As for my profession, I fear the emergence of life extending technology will divide the medical world. At present many doctors do not consider aging to be a “disease,” and it is therefore a questionable target for our attentions. Despite this objection, many doctors’ careers do not focus on acquired disease but on treating the consequences of age related decay. Either way, once we are able to arrest aging, life extension will be the only show in town.
Population explosion and doctors’ objections aside, how else would living to 150, 300, or 1000 affect us and our societies? There are many potential pitfalls. Progress in many spheres—scientific, political, commercial—happens when its opponents die. Life extension will profoundly affect power structures as death will no longer serve as the ultimate solution to entrenched authority. If life extension were to be restricted to a wealthy few then this will further exacerbate our already deep social divisions.
Perhaps most fundamentally, without a sense of urgency, what sense will we make of our lives? Will longer lifespan allow us to live all the lives we want, or will boredom overtake us leading to widespread demoralization? Maybe with so many more years to lose we will all become more careful with our bodies, reflective in our relations, and optimistic in our outlook.
First published on BMJ Blogs