As Alejandro Dubrovsky pointed out, yesterday's post on distinctions was missing a few points.
The distinction is not useful. Appealing to the word "normal" makes as much sense as people appealing to the word "natural". The human machine doesn't function in a vacuum (not for more than about 10 minutes anyway), so its environment always determines its lifespan. If caloric restriction is the environment which gives you the maximum lifespan, then that is the best possible lifespan, not an extension to the best possible lifespan. If eating badly shortens your lifespan, then that is just a shortening of your maximum lifespan, just like trying to breathe underwater would be. If better motor oil gets you a longer lifespan than no motor oil, then its a relative life extension to not having had your motor oil. Its especially irritating to see this distinction coming from this quarter since this distinction is the main argumentative recourse of the majority of doctors who are against life extension (ie they are against life extension, and all for maximum lifespan, considering curing cancer, and wiping heart disease as a good thing, since they are "diseases", while anything greater than this as unnatural, or not normal. 100 years ago of course, heart disease and cancer would have been considered normal aging).
Using "normal" in the following context:
The ultimate purpose of healthy life extension is to greatly lengthen the best possible life span you could have - not just to help you be healthier for longer within your normal life span.
was a slip of the keyboard, I think. I should have said "current" or "existing."
One can argue that any discussion of life span - such as how to increase it - is worthless without the context surrounding that life span. Let's look at cars, for example. We can't talk about the useful lifetime of a car without qualifying how much (and what sort of) repairs and preventative maintenance will be performed. With regard to the human body, we currently don't have a good toolkit to hand - we can make a fair difference to life span with preventative medicine and interventions, but not a great difference. Current medical science simply can't enable people to live beyond 120 years, or much beyond 100 for most. While this is an improvement over the 40 years (or less) we'd have without modern medicine, working to change these limitations is something that we should all look into.
In any case, I began this short trail of thinking aloud at the keyboard in search of a good way of distinguishing - for the casual visitor to this topic - between a) increasing healthy life span without increasing maximum life span, and b) increasing both. There are any number of groups touting the former (especially in the anti-aging marketplace) in a way that sounds, to many people, as though they are touting the latter. All that light and noise obscures serious work and scientific research that is, in the long run, far more important.
You can be as healthy as modern science can make you, but without access to future medical technologies for healthy life extension, you'll be just as dead as the next guy 100 years from now.
Obviously, living healthily for longer is a good thing in and of itself even without a boost to maximum life span. It is also something that we have a great deal of control over - unlike our maximum life span. When I say "living healthily for longer" at the Longevity Meme, however, I am talking about working towards the technologies that can greatly increase maximum life span. This sort of distinction is something that I believe I have to make far more clear in my writing and websites.