Back in 1882, German biologist August Weismann floated the notion of a mechanism, evolved over centuries in our species and others, which would enhance the survival of those species by contriving for its old and presumably worn-out members to perish according to an internal clock. After wrestling with the question, he decided that the clock was operated by cell division:

Life span is connected with the number of somatic cell generations which follow after each other in the course of an individual life, and that this number, like the life span of individual generations of cells, is already determined in the embryonic cell. [Über die Dauer des Lebens, 1882.]

It turned out that Weismann was right about the limit on cell division. However, the failure to divide apparently did not necessarily result in the death of the cell. And Weismann eventually backpedaled on the other half of his theory, deciding that old and worn-out members of a species weren't such a tragedy after all, but merely part of the process:

[I]n regulating duration of life, the advantage to the species, and not to the individual, is alone of any importance. This must be obvious to any one who has once thoroughly thought out the process of natural selection. It is of no importance to the species whether the individual lives longer or shorter, but it is of importance that the individual should be enabled to do its work towards the maintenance of the species. [Essays Upon Heredity and Kindred Biological Problems, 1889.]

In 2002, Leonid A. Gavrilov and Natalia S. Gavrilova described how to test the death-clock scenario:

One way of testing the programmed death hypothesis is based on a comparison of lifespan data for individuals of a single species in natural (wild) and protected (laboratory, domestic, civilized) environments. If the hypothesis is correct, there should not be very large differences in the lifetimes of adult individuals across compared environments. Indeed, for a self-destruction program to arise, take hold, and be maintained in the course of evolution, it must at least have some opportunity, however small, of expression in natural conditions.

At present, the mean life expectancy in developed countries is about 70 to 80 years while the documented record for longevity is 122 years. If we take these figures as an estimate for age range in which the death program is switched on, we are forced to admit that such a program could not have arisen in human evolution since, according to palaeodemographic data, virtually nobody survived to such an age. For example, only half of those born in the Late Palaeolithic (30,000 to 10,000 B.C.) reached 8 to 9 years, and only half of those born in the Neolithic (6,000 to 2,000 B.C.) reached 26 years. Moreover, even in the Middle Ages (9th to 12th centuries), life expectancy at birth was no greater than 27 to 29 years. Investigations of the skeletons of American Indians have shown that only 4% of the population survived to age 50 even as late as in the 18th century. Note for comparison that the probability of surviving to this age in the developed countries is 94 to 96%.

So maybe we don't harbor a ticking time bomb within ourselves. But that's a long way from this prediction by Bill Quick:

If you can survive until 2020 in good health and physical condition, you stand a 50-50 chance of maintaining or even improving your condition for at least another hundred years.

My own condition isn't so wonderful that I'd like to prolong it for a century, but what's the alternative? Right. I'm not even ready for that. And Quick asks, point-blank:

If you were a sixty-year-old guy who was given a treatment today that, six months down the road, restored you to the health, energy, and physical condition you enjoyed at thirty, do you honestly think your life would continue in the same well-worn tracks?

He's got me there. Okay, I'm a tad short of sixty yet, but even rolling back to forty-five or so would be a decided improvement, the very definition of a "life-changing" experience. Of course there are no guarantees; there never are. It may be that the rejuvenation process, or whatever it's eventually called, will not work on some of us for any number of reasons: we may be too badly damaged already, genetic factors might cause our bodies to reject the treatment, or the treatment itself may be mishandled. But none of these is a good enough reason to dismiss the whole idea out of hand, or to declare oneself unalterably opposed to it. The year 2020 is only eleven years away, and if there's one thing I've learned in the age of Moore's Law, it's that things happen faster and faster. (And if there's another, it's not to bet against Bill Quick, who came up with the idea of the Matrix back in the 1980s.)

Which leaves me one question: Is it possible that Dylan predicted all this?

"We'll meet on edges, soon," said I
Proud 'neath heated brow.
Ah, but I was so much older then,
I'm younger than that now.

I may have many more back pages to come.

The Vent

  14 March

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 Copyright © 2009 by Charles G. Hill