Great article. Paul provides a useful illumination of the issue. The great medieval theologian Thomas Aquinas operated at level DH6, often with devastating effect. He would formulate and state the argument he planned to refute with clarity, depth, accuracy, and precision. He often would make his opponent's case better than the opponent had done! I believe his secret was that he was humbly interested in the truth wherever it led. Given his lack of a pre-conceived agenda, he could take a proposition and explore its implications 20 plies deep, giving it the benefit of the doubt and making the best case for it at each step. Having fully plumbed an idea and 'grokked' it, then he could unwind the stack as it were, and state his conclusions in a powerfully convincing manner. Humility, detachment, an agenda-free willingness to listen and follow the truth where it leads, and strength in defending hard-won truth when found all seem to be good places to start.