… is this expert one by my old friend Roger Koppl; it’s from a recent post by Roger at EconLog  (original link):
Unfortunately, no one can be a grand meta-expert rising above the many lesser experts. The meta-expert would have to know everything, in which case we would not have a division of knowledge at all. Every expert is a lesser expert with prefabricated problems and solutions that define their expertise and apply only to one thin slice of reality. Their disciplinary expertise makes certain problems relevant and prescribes certain solutions to those problems, and only those problems. But this means that when politicians take the collective action recommended by their experts, somebody else is deciding for us “what is and is not relevant to us .” And those prefabricated “relevancies” will reflect some areas of expertise and not others, some slices of reality and not others.