Re-posted from a comment to Arnold Kling:
You are obviously correct that the political class thinks they know more than they really do.
Murray is right that the elites are completely isolated from some of the most basic parts of the human experience. And I really mean that. And I think this explains why they think they know more than they do.
For example, one of the reasons why there is such a huge "buy organic/local" trend is because the people who believe in that garbage have no concept of how little food we really have with respect to the global population. They have never seen or worked on a real, commercial farm in the West or Mid-West, they have never seen pests wither up an entire crop of otherwise beautiful apples or lettuce... etc.
Their opinions are based on the "everything comes from the grocery store" school of epistemology. The people who actually grow food for a living (or mine coal, or drill for oil, or ship/receive, or build houses, or whatever) are baffled that people so rich and educated know so little about where stuff comes from and what that means about public policy.