It is an insufficiently remarked-upon fact that John Maynard Keynes was a vigorous and lifelong promoter of eugenics. Outside of the immorality of this position, it can be said to cast a pall on his entire work because, as Bryan Caplan noted, support for eugenics betrays a fundamental misunderstanding of one of the foundational doctrines of economics, which is the law of comparative advantage. A society where everyone was a genius would be worse off than a society with both geniuses and non-geniuses, because of comparative advantage. Societies thrive when people have complementary skillsets so that each person can do what theyre best at. Everyone contributes. Without non-geniuses, geniuses could not be geniuses.

A second prolegomenon: believe it or not, I dont dislike Brad DeLong. He and I had mostly pleasant conversations when he followed me on Twitter. I praised his health care plan (although I remain puzzled by his support for Obamacare, which takes Americas healthcare system in precisely the opposite direction).

Anyhoo

Frequent readers will know that one of my persistent worries is the worlds underpopulation, and our slowing population growth.

On Twitter, Tyler Cowen pointed to a new piece of research which suggests global population might not be slowing as much as we thought. As he noted, this is good for people like the economist Julian Simon and myself who believe that more population leads to more prosperity since, as Simon memorably put it, people are the ultimate resource.

This is what DeLong had to say in response:

One is at a loss as to what to say, exactly.

Obviously, there is, first, the casual prejudice. The implicit subtext is clearly that women who want >3 children are idjits part if idjit cultures where people do idjit things like, for example, believing in God.

Obviously, there is the self-evident fact that even if DeLongs premise were true,maybe their children would be tied into idea-generating network[s], whatever that means, which is, presumably, one of the things that is desired when it comes to population growth.

Excerpt from:

Why Oh Why Can't We Have A Better Economist Corps?