Most people know Ray Kurzweil as an IT boffin. Not only did he invent the CCD flatbed scanner, print-to-speech software for the blind and omni-font optical character recognition, but he also created the first commercially marketed, large vocabulary speech recognition software. As if that wasn't enough, he is also known for his IT predictions. Massachuset's Institute of Technology's Marvin Minsky described Kurzweil as a "leading futurist of our time".
So it may come as a bit of a surprise that Kurzweil's latest book is about health and longevity.
Kurzweil co-authored Fantastic Voyage - Live Long Enough to Live Forever with Terry Grossman, founder and medical director of the Frontier Medical Institute, a longevity clinic. The book purports to make the scientific case that immortality is within our grasp thanks to modern technology, and that it can be reached via three so-called "bridges".
The first bridge relies on the latest medical research into ageing and how to counteract the process of getting older with "nutritionals" (food and food supplements), meditation and exercise.
The second bridge is about bioengineering and how we will soon be able to grow a new heart in situ, or be vaccinated against diseases that kill millions of people, such as cancer.
The third bridge is where we step into more familiar Kurzweil territory: it is about the benefits of technologies such as nanobots, strong artificial intelligence and full-immersion virtual reality, of the kind experienced in the Hollywood blockbuster the Matrix.
Health and technology, it turns out, have been twin passions of Kurzweil's for some time - 21 years, in fact. At the age of 35, he was diagnosed with Type 2 diabetes, and found that the necessary insulin injections made him gain weight, exacerbating his health problems. Being a restless inventor, Kurzweil wasn't about to sit around and let the condition get the better of him.
"I read all the scientific literature and came up with my own approach," Kurzweil says. "I have been free of any indications of diabetes since."
His methods might seem bizarre, but he insists there is solid reasoning behind them: to Kurzweil, reprogramming biochemistry is much the same as reprogramming computers.
"For the first time, we are actually understanding these diseases and ageing processes as information processes," he says.
Having noticed the failings of his own body, Kurzweil was a little disappointed with the inefficiencies of human body version 1.0, the flesh-and-blood creation designed by nature. Watching under a microscope, he saw his own white blood cells surround a pathogen and destroy it. But what struck Kurzweil was the sluggish response: the process of killing a germ takes more than an hour. He believes that in the future, nanobots - tiny robots implanted in our bodies - will do the same job in just a few seconds.
Neuronal responses don't impress Kurzweil either. The connections in our brain compute at 200 transactions per second, which might have served the human race well over the years, but is millions of times slower than the electronic circuits that power our computers.
Not only that, but the human body, particularly the heart, breaks down too easily. All these things can be improved, says Kurzweil, and improved through technology.
When we cross the third bridge, he says, nanobots will replace our digestive systems, we will dispense with our heart and - yes, you guessed it - replace it with nanobots that shuffle oxygen and carbon dioxide around our bodies.
In Kurzweil's future, we will be able to upgrade our bodies over the internet, downloading new programs to make us fitter, stronger and healthier. The human body version 1.0 is suited to Palaeolithic times and is urgently in need of an upgrade.
Unsurprisingly, his claims have caused consternation among some observers. And his assertion that he expects to live forever might be tactics more aimed at grabbing headlines than grabbing hold of the future.
But Kurzweil insists that the inherent risks of adopting these technologies will be worth facing. And for a 56-year-old man with a genetic predisposition to heart disease and Type 2 diabetes, he is doing pretty well. According to numerous physiological measures, Kurzweil has the body of a 40-year-old. And he's getting younger all the time.
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