misfortune to talk with people in the heart or on the edge of mental disorder, knows that their most sinister quality is a horrible clarity of detail; a connecting of one thing with another in a map more elaborate than a maze.  If you argue with a madman, it is extremely probable that you will get the worst of it; for in many ways his mind moves all the quicker for not being delayed by the things that go with good judgment.  He is not hampered by a sense of humour or by charity, or by the dumb certainties of experience.  He is the more logical for losing certain sane affections.  Indeed, the common phrase for insanity is in this respect a misleading one.  The madman is not the man who has lost his reason.  The madman is the man who has lost everything except his reason.

The madman’s explanation of a thing is always complete, and often in a purely rational sense satisfactory.  Or, to speak more strictly, the insane explanation, if not conclusive, is at least unanswerable; this may be observed specially in the two or three commonest kinds of madness.  If a man says (for instance) that men have a conspiracy against him, you cannot dispute it except by saying that all the men deny that they are conspirators; which is exactly what conspirators would do.  His explanation covers the facts as much as yours.  Or if a man says that he is the rightful King of England, it is no complete answer to say that the existing authorities call him mad; for if he were King of England that might be the wisest thing for the existing authorities to do.  Or if a man says that he is Jesus Christ, it is no answer to tell him that the world denies his divinity; for the world denied Christ’s.

Nevertheless he is wrong.  But if we attempt to trace his error in exact terms, we shall not find it quite so easy as we had supposed.  Perhaps the nearest we can get to expressing it is to say this:  that his mind moves in a perfect but narrow circle.  A small circle is quite as infinite as a large circle; but, though it is quite as infinite, it is not so large.  In the same way the insane explanation is quite as complete as the sane one, but it is not so large.  A bullet is quite as round as the world, but it is not the world.  There is such a thing as a narrow universality; there is such a thing as a small and cramped eternity; you may see it in many modern religions.  Now, speaking quite externally and empirically, we may say that the strongest and most unmistakable mark of madness is this combination between a logical completeness and a spiritual contraction.  The lunatic’s theory explains a large number of things, but it does not explain them in a large way.  I mean that if you or I were dealing with a mind that was growing morbid, we should be chiefly concerned not so much to give it arguments as to give it air, to convince it that there was something cleaner and cooler outside the suffocation of a single argument.  Suppose, for instance, it were the first case that