From: Damien Broderick (d.broderick@english.unimelb.edu.au)
Date: Thu Aug 29 2002 - 18:36:41 MDT
At 09:35 AM 8/29/02 -0700, Robert wrote:
>Lowering the accident rate to
>get us to even 10's of thousands of years (I think this number shows up
>in the Spike) is *very* difficult.
That was quoted (*very* cautiously) in THE LAST MORTAL GENERATION, actually:
====================
In 1988, the cryonicist Hugh Hixon published a fascinating analysis of the
prospects for an otherwise immortal population. His bottom line, offered
with all proper reservation, was astoundingly optimistic.
Let's look first at what the biogerontology specialists have said. Leonard
Hayflick, in his 1996 edition of How and Why We Age, took a conservative
posture. Eliminate all present causes of death, he said, and we would get
`the hypothetical ultimate curve', a Gompertz slump tugged upward until it
was almost rectangular. `The world would then be one in which no one died
from causes now written on death certificates... no one would die young;
all would slip peacefully away during a narrow span of years, say between
age 110 and age 115.'2 It was a view earlier put in 1981 by James Fries,
and vigorously debunked by Professor Roger Gosden in 1996. `Most evidence
is to the contrary,' Gosden stated, `and it is nonsense to separate the
underlying aging process from its manifestations. If anything, we are
currently gaining more years of disability than of vigor.'
That bleak opinion is undoubtedly correct, but we might well be in a
transitional epoch. Simply abolishing the current causes of death will just
be the start. We might expect a great deal more once medications are
available that draw upon antioxidant and telomerase research, for example.
Allow the possibility, then, that more is achieved than the mere (mere!)
removal of all known diseases and disorders. Suppose we have an enhanced
immune system, and other repair gadgetry - either genomic or
nanotechnological - that keep us as young as we wish. What then?
In 1964, the British gerontologist Alex Comfort (in his study The Process
of Aging) estimated an average cut-off date of 600 or 700 years, although
he did not indicate how he arrived at this interval. `If we could stay as
vigorous as we are at 12, it would take about 700 years for one-half of us
to die, and another 700 years for the survivors to be reduced by one-half
again.' Hixon disputes this figure as pessimistic, based on a death rate
from a period early in the century when childhood mortality figures were
worse than today's. His own analysis, based on standard mathematical
methods, uses the same idea of `half-life' - the time during which half a
population is still alive (or in the case of radioactive particles, where
the measure is also familiar, during which half the atoms have decayed into
stability.)
Using 1981 data from Vital Statistics of the United States, Hixon removes
all but death by accident and homicide (assuming that suicide is a
preventable mental condition), and finds `41.9 deaths per 100,000 in the
white population (64.9 for males, 19.5 for females... Which gives us a
half-life for our population of 1654 years.' In other words, if you are one
of these immortals, you'd have an even chance of surviving more than a
millennium and a half!
That estimate, however, is still very conservative, since it assumes that
1981's fatality statistics are valid for all time. As Hixon notes, we
already have the technology for medical pagers linked to the Global
Positioning Satellite System, able (in principle) to fetch emergency aid to
accident scenes anywhere in the world at maximum speed. In a long-lived
world, you can be assured that money would not be stinted in servicing this
facility. In short, the main risk of permanent death in an `immortal' world
would be massive cranial damage, the extinguishment of the neural basis of
consciousness. Hixon guesses that this might be just one case in a hundred
thousand. If so, you'd have `a population half-life of 69,315 years.
However,' he adds instantly, and wisely, `anyone who quotes this figure
without including a statement of its very speculative nature is on their own.'
====================
Damien Broderick
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