By stripping the emotions from pressing problems, economists can often illuminate the most practical ways to tackle them—but only if ordinary people and their representatives are prepared to listen.
There is a gulf between small-scale society and large-scale society. Use the Dunbar number as a breaking point, so small scale means less than 150 people and large scale means more than that. At small scale, coordination problems can be solved by intuition and mutual recognition. You do not need markets or centralized command. But at small scale you cannot have much specialization, and you cannot provide complex goods and services.
At large scale, the coordination problem becomes much more complex. Economists pay attention to this, and that makes them wiser than non-economists who do not.
But many economists are far too oriented toward the possibilities of centralized command (government regulation) as a coordinating mechanism. And they are too smug about what they can accomplish using math and statistics.
For my perspective on the topic of Ip’s essay, see How Effective is Economic Theory?
Arnold’s approach here makes one wonder whether he, or some other scholars, have consider “scale” as having an impact on the rate of development (or actual achievement) of an Open Access society (per North, Wallis & Weingast).
Economists do favor math, mostly for screening, but I think most economists recognize how politics can skew policy to both more regulation favoring powerful interests and to less regulation when it runs against them, but their job is to attempt to let the cards fall where they will unless their paycheck depends on their acting otherwise. It isn’t without its ‘true believers’ though, whose paycheck allows them to do what they want, oblivious to reality.
One of the greatest proofs of mathematical mumbo jumbo is this Basel Committee explanation of the portfolio invariant risk weighted capital requirements for banks in Basel II. That which came up with a minor 20% risk weight for what is so dangerous to the system by being rated an ultra safe AAA, and a whopping 150% to what is so innocuous given that it is rated an extremely risky below BB- http://www.bis.org/bcbs/irbriskweight.pdf