It is never fallacious to point out the historical unreliability of a source. It is doubly never fallacious to point out the unreliability of a source, on a giv

It is never fallacious to point out the historical unreliability of a source. It is doubly never fallacious to point out the unreliability of a source, on a given topic, when discussing a new claim, on that topic, from that source, because that information is relevant to how we approach and evaluate the new claim (i.e., claims from historically-unreliable sources should be subjected to greater initial scrutiny). Also, you've presented no actual rebuttal of whether Gibson's history is relevant to evaluating his present claims. Rather you've merely stated the name of a logical fallacy. Which is, itself... http://en.wikipedia.org/wiki/Argument_from_fallacy http://en.wikipedia.org/wiki/Argument_from_fallacy