Yesterday, I found myself baffled by Gregory Clark's argument that people in contemporary Malawi are worse-off than were stone age hunter-gatherers. I picked up his book in the afternoon, and now I understand the claim better. In particular, if you compare median individuals, then the fact that the contemporary Malian elite is far better-off than are stone age elites vanishes into the background.
The more interesting move is that dead people don't have "standards of living." Clark sees Malawi, like much of contemporary sub-Saharan Africa and the entire world before 1800, as trapped in a Malthusian trap. Improved technologies lead initially to an increase in living standards, but eventually the gains are dissipated into an increase in the number of living people rather than an improved average. Under the circumstances, improvements in health care or public health techniques have a perverse impact. By increasing the ability of marginal cases to survive, they reduce the minimum material conditions required to live. Over the long run, that simply means that average living standards fall back down to the new, lower subsistence level.
Needless to say, this raises some difficult moral questions and makes me want to revisit my Parfit.