Archive for August 7th, 2009

7th August
written by simplelight

A sobering thought: I have about 0.8% chance of dying next year and that probability is doubling every 8 years.

[A] startling fact was first noticed by the British actuary Benjamin Gompertz in 1825 and is now called the “Gompertz Law of human mortality.”  Your probability of dying during a given year doubles every 8 years.

Surprisingly enough, the Gompertz law holds across a large number of countries, time periods, and even different species.  While the actual average lifespan changes quite a bit from country to country and from animal to animal, the same general rule that “your probability of dying doubles every X years” holds true.  It’s an amazing fact, and no one understands why it’s true.

There is one important lesson, however, to be learned from Benjamin Gompertz’s mysterious observation.  By looking at theories of human mortality that are clearly wrong, we can deduce that our fast-rising mortality is not the result of a dangerous environment, but of a body that has a built-in expiration date.

All this reminds me of the cat, Oscar (pictured below) who, according the New England Journal of Medicine can apparently calculate double exponentials with great accuracy in his feline head.