What kinds of genetic differences should we expect between populations?

Epistemological Status: A little out of my depth.

Kevin Mitchell’s blog came to my attention because of his skeptical posts on epigenetic inheritance in humans. Even more interesting is his recent post on race and IQ, and the likely lack of genetic differences between races.

I think this is an extremely important argument. The strongest arguments for innate racial IQ differences generally run like so:

  1. We observe large differences in IQ between racial groups in the human population.
  2. No known environmental factor could explain such large differences.
  3. Genetic differences between races are large enough to explain the differences.
  4. Therefore, we should assume that most racial IQ differences are due to genetics.

In my posts on the Flynn Effect, I showed that Flynn and Sowell have disproved premise (2) – it’s true that no family-level environmental factors can explain such large differences, but that environmental factors at the level of culture and subculture have demonstrably explained large differences in the past.

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