Flutterby™! : Check your premises

A few days ago, Rafe pointed to Arnold Kling's critique of Paul Krugman's arguments on the Bush Administration wackiness, the jist of which was that there are two types of arguments, those that attack the credibility of the source, and those that attack the conclusions of the source. My frist thought on reading that was "wow, the Republicans are asking us to consider all viewpoints, no matter how wacky or unsubstantiated, as valid, how fucking politically correct and postmodern of them". Now Rafe points to someone essentially making the same argument.