Wednesday, June 06, 2007

Longer Lifespan?

Is the world getting better? Is the world becoming less violent? Are humans now living longer due to medical advances?

While some might be tempted to think that modern scientific medicine has increased the current lifespan for those of us living in the 21st century, the truth is more complex than often heard claims about an increase in the human lifespan.

In his book Biology as Ideology: The Doctrine of DNA, geneticist Richard C. Lewontin points out that we certainly live longer than our ancestors who lived in 1890 did. However, what has contributed to our seeming increased lifespan?

While Lewontin's book was first published in 1991, his research on this issue still comports with present-day work done on these issues. Lewontin argues that modern medicine has not "prolonged the life of elderly and sick people" (page 42). A reduction in infant mortality is what accounts for the expected life span, not an increase on the upper end of the age continuum. As for those have reached maturity, Lewontin notes that science has done "little to add years" to their lives (ibid).

So, while it is true that we now generally live to be at least 75 rather than 45 (as was the case in the 19th century), it seems important not to exaggerate what has actually happened. Certain diseases have become non-factors for a number of people and decreased infant mortality. But as history has shown, these diseases can also return with a vengeance. There are many reasons to believe that the world is not getting better. I hope to touch on some of these issues in the future.


tom sheepandgoats said...

I've heard it expressed before as the difference between lifespan and life expectancy. We've long had a lifespan that has declined to 75 or so. But in recent centuries you might not expect to live out that full span due to poor sanitation, infant mortality, hard living conditions, and so forth.

Edgar Foster said...

Your comemnts are very helpful. Lewontin is talking about life expectancy, but he seems to conflate it with our lifespan, which is a different matter. What you have written will help me revise the blog entry and sharpen it.