This was brilliant. A really good depth of analysis and the kind of statistical forecasting that I like, but I'm not sure that it holds too much water.

Sure the analysis holds for current types of anti-aging, life prolonging techniques, but does it hold for the future?

It's like charting the average 100m run of Humans since the dawn of time, and then claiming that, as a race, we'll never break the sound barrier. But then someone invents the car.

And I think that's a good, strong analogy, because the things we're looking into now aren't just life-prolonging, they are age-defying. It's a complete shift. As Marks remarks perhaps we can't predict how it's going to happen, you can't predict everything after all, especially not new technology.

To me a better analysis would have looked at statements about what is required to stop the aging process altogether and analysed our progress in those fields. For instance does it require the accurate mapping of our DNA? A task that can be completed, and isn't an endless goal like 'living to X years' is.

There are also completely off the wall developments that don't fit in the trend lines that Marks has forecast like the role of replacing our bodies with machines. Such things deserve their own trend line, and again such a thing wouldn't progress towards infinity, cumulatively, but would have an end point in terms of allowing us to live indefinitely. There may be endless improvements we could make to a synthetic body, but making it endlessly maintainable would be a relatively early goal.