Experts and intellectual trespassing

Richard Posner has some typically sensible thoughts on the recent Copenhagen conference and the role of expertise:

My posting on the Copenhagen conference, and its downgrading of global warming, provoked a neat hostile comment: you (Posner) criticize these economists for opining outside their fields, but isn’t that what you do all the time? Well, yes, but here’s my defense: you don’t have to be an expert in a field to criticize the experts, provided you know enough about the field to understand what the experts are saying and writing, to be able to spot internal contradictions and other logical lapses, sources of bias, arguments obviously not based on knowledge, carelessness in the use of evidence, lack of common sense, and mistaken predictions. These are the analytical tools that judges, who in our system are generalists rather than specialists, bring to the task of adjudicating cases in specialized fields of law.

I don’t have to be a climate scientist to realize that assembling a group of economists none of whom is a specialist in the science, politics, or economics of global warming, and asking them to reach a consensus on where to rank global warming among the world’s worst ills without conducting any research of their own, but instead by discussing a position paper commissioned from another economist by the organizer of the conference, is not a rational procedure.