It frequently happens, however, that, instead of adding links to the chain of the Ego, we withdraw them. Thus the sick man, when his mind is wandering, supposes that the words he hears are spoken by a strange voice, or endows his inward visions with an outward reality, as Luther did when he saw the devil in his room in the Wartburg; and the madman not only partly, but entirely confuses himself with some one else. In a state of reason, then, the Ego is an artificial production, the result of association of ideas. I am certain of my own identity--in the first place, because I associate my name, that sound which I call my name, with the chain of my inward experiences, and secondly, because I keep all the links of this chain connected by the association of ideas, by virtue of which they produce each other. But, since the Ego is thus not an innate but an acquired conception, founded upon an association of ideas which has to maintain itself against the constant attacks of sleep, dreams, imaginations, hallucinations, and mental derangement, it is by its nature exposed to manifold dangers. Just as disease is ever lying in wait for our bodies, so madness lies in wait at the threshold of the Ego, and every now and again we hear it knock. It is of this correct psychological theory, originally propounded by Hume, that the Romanticists, though they do not define it scientifically, nevertheless have a presentiment. Dreams, dipsomania, hallucinations, madness, all the powers which disintegrate the Ego, which disconnect its links, are their familiar friends. Read, for instance, Hoffmann's tale, _The Golden Jar_, and you will hear voices issue from the apple-baskets, and the leaves and flowers of the elder-tree sing; you will see the door-knocker make faces, &c., &c. The strange, striking effect is here specially due to the way in which the apparitions suddenly emerge from a background of the most humdrum, ordinary description, from piles of legal documents, or from tureens and goblets. All Hoffmann's characters (like Andersen's Councillor in _The Galoshes of Fortune_, which is an imitation of Hoffmann) are considered by their neighbours to be either drunk or mad, because they always treat their dreams and visions as realities.