I and many other scientists now believe that in around 20 years we will have the means to reprogramme our bodies’ stone-age software so we can halt, then reverse, ageing. Then nanotechnology will let us live for ever… Within 25 years we will be able to do an Olympic sprint for 15 minutes without taking a breath, or go scuba-diving for four hours without oxygen. Nanotechnology will extend our mental capacities to such an extent we will be able to write books within minutes.
Micro-manufacturing has promised us the moon, and it continues to aim higher and higher. While the capacity to do as Kurzweil says should theoretically exist, I find it difficult to believe that we are within two decades of such a revolution in terms of implementation. Tiny machines could indeed be utilized to scavenge free radicals and aid mitosis and do a myriad of other intracellular housekeeping functions, but aging is a process effecting so many systems and physiological pathways and cells that its complete cessation or reversal would seem out of reach.
The body has a large head start over engineers when it comes to its own maintenance. Even if this technology were somehow able to keep us in perennial youth, the diseases and abnormalities that can arise in our bodies are so diverse that some “malfunction” would undoubtedly occur over time. The corrections of these deleterious changes would need to be accounted for in any in vivo machine. For instance, the nano-bots would need to allow the external administration of potentially lifesaving bronchodilators in the event of a severe asthmatic attack; the robots could not be allowed to rectify the artificially high levels of medication. This is just a single example of what is an immensely difficult problem.
There are many more issues that would need to be sorted out, and the painstakingly long approval process for human clinical trials is not the least of these (20 years should seem a stretch to any imagination). Ethical dilemmas will undoubtedly arise. Men have been able to achieve some inconceivable things, but there have also been conceivable things that men could not achieve; I believe this “fountain of youth” to be one such disappointment.