From: Robin Hanson (rhanson@gmu.edu)
Date: Mon Feb 19 2001 - 13:52:56 MST
Hal Finney wrote:
> Age-specific mortality rates have fallen at a steady exponential
> rate for the entire last century. ...
>I think we need to challenge the validity of exponential extrapolations
>as a guide to future changes. My bet is that if you could look at most
>data sets over a longer period, you would find that steady exponential
>changes are NOT a good guide.
Well it is surely true that the exponential mortality trend didn't
continue for three centuries *before* 1900. More likely mortality
was pretty much constant for many millenia before 1500.
>Unfortunately I don't have much specific evidence for this, but an
>excellent example is population growth. Robin has an analysis at
>http://hanson.gmu.edu/longgrow.html which shows that population growth
>has gone through a series of exponential curves.
Actually, those are world product, not population, curves. They are
the same as population curves until a few centuries ago though.
>... In each case we saw an exponential curve go
>through a "phase transition" to a new curve with a higher exponent and
>more rapid change.
>My guess is that the same thing will happen with age specific mortality.
>We will enter a new regime in which the decreases in the past of about
>1% per year in mortality may increase to 10% or more per year due to
>a breakthrough in knowledge. Biology researchers often claim that the
>advent of genomics will be so dramatic as to represent a new paradigm
>for knowledge growth, so a breakthrough is plausible.
Yes, but we must admit that similar claims made in the past have been
dead wrong. The whole anti-biotic and vaccine revolution, for example,
long touted as producing a mortality revolution, apparently did nothing
of the sort.
Robin Hanson rhanson@gmu.edu http://hanson.gmu.edu
Asst. Prof. Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030-4444
703-993-2326 FAX: 703-993-2323
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