James Surowiecki is now reviewing books in Foreign Affairs.

The fact that every country's experience is different does not mean that there are not deeper truths to be uncovered by looking at the experience of the world as a whole. But the truths thus far uncovered are relatively few in number and often limited in impact. So, yes, free trade is a good thing, subsidies to agriculture and official corruption are bad things, and so on. And policymakers should be aggressive in implementing those practices and policies that there is a good reason to think will work. But they also need to be cautious about taking theoretical pronouncements for reality, and they should be pragmatists rather than evangelists. After decades of misplaced certainty, it may be time to recognize the limits of our own knowledge -- at least if we want the state of the world to continue improving.