Steve, I believe that many of brock's remarks are driven by phylosophical skepticism. I am sure that in former incarnations brock studied at the schools of Phyrro of Elis, Sextus Empiricus, Carneades and Arcesilaus. All of'em!
From wiki
In philosophical skepticism, pyrrhonism is a position that refrains from making truth claims. A philosophical skeptic does not claim that truth is impossible (which itself would be a truth claim), instead it recommends "suspending belief". The term is commonly used to describe philosophies which are similar to philosophical skepticism, such as academic skepticism, an ancient variant of Platonism that claimed knowledge of truth was impossible. Empiricism is a closely related, but not identical, philosophy to philosophical skepticism. Empiricists claim empiricism is a pragmatic compromise between philosophical skepticism and nomothetic science; philosophical skepticism is in turn sometimes referred to as "radical empiricism."