Your Body’s Expiration Date

The web site, Gravity and Levity, has a great arti­cle on the Gompertz law and the odds of sur­viv­ing through your next year of life. At age 32, I’m look­ing at just over a 1 in 1500 chance of mak­ing it through the year.

Exponential decay is sharp, but an expo­nen­tial within an expo­nen­tial is so sharp that I can say with 99.999999% cer­tainty that no human will ever live to the age of 130. (Ignoring, of course, the upward shift in the life­time dis­tri­b­u­tion that will result from future med­ical advances)

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.

So, if you make it to the ripe, old age of 95,

you have the body of a 95-year-old with only a 2-in-3 chance of mak­ing it through the year.

Puts the whole idea of mak­ing the most out of every day in per­spec­tive.