Christopher Hitchens has a famous quote* in which he claims that homo sapiens had a life expectancy of about about 25, from dying of their teeth. I have not found evidence to support this claim. Is it true?

* YouTube, "Christopher Hitchens Eviscerates Christianity (Condensed)"

It is true that historical humans had much shorter life spans.

Before I go further keep in mind that if my answer isn't relevant to Mr. Hitchen's argument because his picking on a single detail like that (the exact cause of short life spans in humans of that era) doesn't address his argument. Therefore it takes the form of a logical fallacy called a "staw man argument."

The truth is that the condition of the teeth depend on the population, lifestyle, diseases, diet, and other relevant traits regarding the individual human remains being examined.  

Teeth can give you a lot of information, for example they can point to age, diet (ex. did the person eat foods containing grit from grinding grains in a mill?), manner of death, etc. 

There is some evidence that in hunter gatherer societies people develop fewer cavities.  See http://cast.uark.edu/local/icaes/conferences/wburg/posters/cslarsen/larsen.html
The explanation offered for this observation is most often that hunter gatherer diets are low in grain and complex sugars which human oral flora like to feed on. 

So did early man only live to about 25? Yes. Because of his teeth? Probably not. One of the quadrillion other nasty things that happen to humans likely got him.

Much of the discussion depends on what you define as "early man". If you go back not to the earliest radiation of Homo sapiens, but stick to the earliest civilizations (sedentary, agricultural civilizations, to be exact), you get quite a different picture than what Jonathan described.

The problem early farmers faced was grinding cereal seeds. With stone tools you're quite limited with regards to what material you can shape into a grinder. Sandstones are often the best compromise between tough and shape-able. They are make for rough grinding surfaces, which grind well, and stay rough. This is because they erode during grinding. And this places an aweful lot of tiny quartz balls in your food, and that is a prime way of grinding your teeth down. I have seen quite a few skulls dug up by archaeologists even from medieval times (but also Roman, and pre-Roman, so we are talking bronze and iron age, too!), skulls of poor farmers or low-skill (tiny village) craftsmen with horribly eroded teeth, at young age. Down to the gums, in some cases, before the age of ~20.

So yes, in earlier times, many humans had serious tooth trouble at relatively young age, which certainly may have contributed to their early deaths.


As you see, it all depends a bit on what Mr. Hitchens was talking about exactly!

Last edited by Heinrich Mallison (5th Jul 2010 01:16:05)