Happy 2011, everyone!
We do not expect a biologist to forecast how many squirrels will be alive in ten years if we increase the number of trees in the United States by 20%. A biologist would laugh at you. But that is what people ask of economists all the time.
I find this idea to be a very useful corrective to the sentiments of many (including some economists) who have condemned the entire discipline of economics for, say, not predicting the recent financial crisis. However, Roberts makes a larger point that economics has gone astray though pretensions of “scientism”–the belief that economics resembles hard sciences like physics. As he says in his follow-up post,
The problem is that too many economists and others treat it [economics] as if it were like physics.
I think that Roberts overstates his case, but it certainly is interesting to read his half-defense, half-indictment of economics. Roberts repeatedly asserts that economics is closer to evolutionary and ecological biology than to physics. I find this argument particularly appealing because, as readers of my post on Leigh Van Valen will recall, evolutionary biology was my first intellectual love. At this point, I can’t directly rebut Roberts’s argument comparing economics to evolutionary biology, but I can say that there is another possibility, namely, that economics is young science, closer to physics in the late 19th Century than to modern physics.
Here is Arnold Kling commenting on the same Roberts post.