“Just how charitable are you supposed to be when criticizing the views of an opponent?”
“In disputes upon moral or scientific points,” Arthur Martine counseled in his magnificent 1866 guide to the art of conversation, “let your aim be to come at truth, not to conquer your opponent. So you never shall be at a loss in losing the argument, and gaining a new discovery.”
Read more at Brain Pickings: http://www.brainpickings.org/2014/03/28/daniel-dennett-rapoport-rules-criticism/