Bryan Caplan critiques Greg Clark

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Bryan Caplan has initiated a series of posts where he will critique some aspects of Greg Clark’s book A Farewell to Alms. Caplan starts by disputing Clark’s implication that the Four Horsemen can increase per capita income simply by reducing population. I would say he makes some good points, but he does leave an opening:

A plague might do the trick – it kills some outright, and weakens the rest. In the long-run, the survivors will have a higher material level of living. But this hardly makes the plague a “friend of mankind.” All it means is that after mass death, the frail, disfigured survivors will get to eat some extra calories beside the graves of their families. With friends like this, mankind doesn’t need enemies.

The after effects of disease vary quite a bit from pathogen to pathogen and person to person. Additionally, to some extent plague might be a partly exogenous variable, on occasion cutting through populations like a scythe for a few short years and then abating mysteriously for decades. I think this is why the conditions after the Black Death are a good case study which probably leans toward Clark’s contention. 25% of Europe’s population disappeared, but the survivors were not 25% less healthy or productive. In any case, add Econlog to your RSS to keep track of the debate.

Update: Arnold Kling is feeling Clark more than Caplan.



  1. I’m about 110 pages through Clark’s book and just finished his description of the plague. It didn’t leave many frail disfigured survivors for the simple reason that it didn’t leave many survivors, with death rates among the infected in excess of 75%.

  2. Peter, 
    Of course, in an economic rather than physiological sense, it did leave plenty of “disfigured survivors”: widows, orphans, poorly defended villages, etc.

  3. Caplan’s big claim is that almost anything that persistently raises death rates is likely to persistently reduce output per living worker. It that true?  
    One possible source of persistent increases in death rates that have no impact on productivity: Many kinds of infectious disease.  
    I’d welcome medically-informed comments on the topic, but it seems possible for infectious disease (from, say the bad sanitation that Clark emphasizes) to raise the chance of dying any given month without appreciably hurting your productivity most of the time.  
    Scenario: You get sick for a week or two every couple of years, and if you survive, you go back to being productive. If you don’t survive, well then, you’re pushing up the death rate.  
    My vague sense is that lots of infectious diseases are of the quick variety (dead or healthy within a few weeks) rather than the persistent and debilitating variety. Am I wrong about that?