Life Expectancy

From the West Hunter blog:

      Fairly often, I’ve seen people misunderstand things about life expectancy. They would talk about the olden days  ( Rome, for example ) , when the average life expectancy ( at birth !) could be as low as 25 years.  They mistakenly thought this implied that people died around 25, that few people lived longer than that, that around 25 years your warranty ran out, like a salmon. Not so: most of the difference stemmed from higher infant mortality, and evil old farts existed and often played a key part in history.  Augustus died at the age of 75,  Tiberius at 77,  Claudius at 63, Galba at 72 ( murdered), while Vespasian became a god at 69, baby. Certainly some emperors  died young, of malaria or strangulation, but it was by no means rare for people to live into their 70s.

      Narses started his successful military career at age 60, and lived to at least 86.

I had an argument with an archaeology professor (at BYU of all places!) on this point at one time when he tried to assert increasing life expectancy as evidence of continued human evolution. I pointed out that life expectancy had gone up because of factors such as lower infant mortality, better sanitation, better food, and medical advances, and not because people actually were able to live for a longer duration. He thought I was stupid. You can probably guess what I thought of him. Luckily the class was large enough that he didn't know my name and so it didn't influence his grading.