> Claims by some scientists that humans in this century will have a life
> expectancy of 100 or even 120 are not realistic and not supported by the
> trends measuring the rates of death, said S. Jay Olshansky of the
> University of Illinois, Chicago.
> "We anticipate that many people here today will live long enough to
> witness a life expectancy of 85 years, but everybody alive today will be
> long dead before a life expectancy of 100 is achieved, if ever," said
> Olshansky.
Olshansky has an article in the March issue of Scientific American showing
a number of his (rather questionable) improvements to the human body that
would make it more suited to long life. Thicker bones, stronger disks,
extra muscles seem reasonable enough. But knees that bend backward
and don't lock in place would, he admits, make standing difficult.
Raising the trachea would reduce the risk of choking on food, but would
have the minor side effect of disrupting breathing and speech.
It's a valid point that the human body could be improved, but Olshansky
tries to draw the lesson from this that significant enhancements to
lifespan are impossible. The problem is that he is focusing on relatively
minor symptoms of old age: arthritis, disk problems, incontinence,
varicose veins, cataracts, etc. It will undoubtedly be a big job to
fix all these, but most of them are not life threatening. Even if we
couldn't do anything about all this, it wouldn't have implications for
life extension.
To make his point he needs to list conditions that actually kill people.
And there wouldn't be much difficulty in doing so; just look at the list
of the top 20 or 30 killers. Then he could argue that to extend lifespan
we'd have to have interventions that dealt with all of these problems,
which is going to be extremely difficult (pending a fix-everything pill).
But he doesn't do this. Admittedly his fanciful drawings of dwarvish
humans with backwards knees are more eye-catching than charts showing
the death rate from kidney failure. But if he wants to conclude that
significant life extension is unlikely, he needs to use a different
argument.
Hal
This archive was generated by hypermail 2b30 : Mon May 28 2001 - 09:56:46 MDT