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John_Maxwell_IV comments on Brain Preservation - Less Wrong
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That used to be the standard wisdom, but it is now disputed. There is evidence that aging stops. True, for humans it does so only when we are already decrepit and stand a substantial chance per year of dying, but some other animals stop aging before that point. So it is not beyond hope that we might make our bodies last much, much longer.
ETA: Googling further, I found Michael Rose's 55 theses.
And one of the things he writes about is the cessation of aging, of how earlier cessation can be bred for in experimental animals (don't let them breed after a certain age: the earlier they stop reproducing, the earlier their cessation of aging evolves to be), and of measures the individual can take to promote their personal cessation of aging.
I have only glanced through this enough to think it worth posting here.
That seems bizarre. Is it possible that aging is a means for individuals to signal fitness? (I look really old; I must be really good at surviving!)
Only if you're going to carry on reproducing at that age.
BTW, I may have misstated the method of breeding for earlier cessation of aging. I can't find again what I was reading that I described in those words, but other papers of Rose talk about promoting longevity by selecting for late offspring.
I found this bizarre too. So I looked up a paper by the same authors who wrote the book in the "aging stops" hyperlink to investigate.
By aging they mean the increase in mortality rate as a person gets older. Ie an 80 year old is more likely to die this year than a 60 year old.
The theory is that there is a given high rate of mortality that would prevail for the whole of life if natural selection did not exist. However, natural selection does exist and so for the early part of an organism's life the mortality rate is lower than it would be otherwise. This lowering reduces over the reproductive part of the organisms life. Thus before reproductive maturity the lowering is maximum, and at the end of its reproductive life the lowering is gone and the organism reaches the (high) unadjusted level of mortality. Thus species that stop reproducing earlier reach this high level of mortality earlier.
From our perspective, and using this definition, it would be better if "aging stopped" later, because then we would live longer before reaching the higher mortality rate.
Of course, what we really want is to simly reduce that higher mortality rate permanently.