On Wed, 13 Oct 1999, Damien Broderick wrote:
Gee Damien, why don't you cut right to the heart of the matter? :-;
Actually *aging* in terms of its physiological effects does increase exponentially. Bruce Ames, one of the worlds leading experts in toxicology is often fond of pointing out that cancer rates increase with age to the 6th power. However, they may trail off in the oldest-old (perhaps because they have *really* good DNA repair systems). That doesn't help much because the incidences of other pathologies are probably increasing with age^# power as well.
So aging follows Moore's law in some respects. Longevity is on a relatively linear path (through human history with occasional dips for things like the plague/influenza epidemics). These trends are tracked by demographers and there is a hot debate as to whether or not the mean and maximum lifespans will continue to increase or whether there will be a "squaring" of the curve so that every gets to 120 and then rapidly dies off.
All bets are off however because our knowledge of our genetic program and molecular biology are increasing very rapidly. I wouldn't put them on exponential curves because they have a really funny S shape (1980 - little or no human genetic sequence, 1999 - lots of human genetic sequence, 2003 - all of human genetic sequence).