“That is a simple rule, and easy to remember. When I, a thoughtful and unbiased Presbyterian, examine the Koran, I know that beyond any question every Mohammedan is insane; not in all things, but in religious matters. When a thoughtful and unbiased Mohammedan examines the Westminster Catechism, he knows that beyond any question I am spiritually insane. I cannot prove to him that he is insane, because you never can prove anything to a lunatic–for that is part of his insanity and the evidence of it. He cannot prove to me that I am insane, for my mind has the same defect that afflicts his.
All democrats are insane, but not one of them knows it; none but the republicans and mugwumps know it. All the republicans are insane, but only the democrats and mugwumps can perceive it. The rule is perfect; in all matters of opinion our adversaries are insane. When I look around me I am often troubled to see how many people are mad [gives long list]… This should move us to be charitable toward one anothers lunacies.”