To return to Goslar.  “The highest principle is Reason,” said I soothingly to myself, as I slid into bed.  But it availed me nothing.  I had just been reading in Varnhagen von Ense’s German Tales, which I had brought with me from Clausthal, that terrible story of the son who went about to murder his father and was warned in the night by the ghost of his mother.  The wonderful truthfulness with which this story is depicted, caused, while reading it, a shudder of horror in all my veins.  Ghost-stories invariably thrill us with additional horror when read during a journey, and by night in a town, in a house, and in a room where we have never been before.  We involuntarily reflect, “How many horrors may have been perpetrated on this very spot where I now lie!” Meanwhile, the moon shone into my room in a doubtful, suspicious manner; all kinds of uncalled-for shapes quivered on the walls, and as I raised myself in bed and glanced fearfully toward them, I beheld—­

There is nothing so uncanny as when a man accidentally sees his own face by moonlight in a mirror.  At the same instant there struck a deep-booming, yawning bell, and that so slowly and wearily that after the twelfth stroke I firmly believed that twelve full hours must have passed and that it would begin to strike twelve all over again.  Between the last and next to the last tones, there struck in very abruptly, as if irritated and scolding, another bell, which was apparently out of patience with the slowness of its colleague.  As the two iron tongues were silenced, and the stillness of death sank over the whole house, I suddenly seemed to hear, in the corridor before my chamber, something halting and shuffling along, like the unsteady steps of an old man.  At last my door opened, and there entered slowly the late departed Dr. Saul Ascher.  A cold fever ran through me.  I trembled like an ivy leaf and scarcely dared to gaze upon the ghost.  He appeared as usual, with the same transcendental-grey long coat, the same abstract legs, and the same mathematical face; only this latter was a little yellower than usual, the mouth, which formerly described two angles of 22-1/2 degrees, was pinched together, and the circles around the eyes had a somewhat greater radius.  Tottering, and supporting himself as usual upon his Malacca cane, he approached me, and said in his usual drawling accent but in a friendly manner, “Do not be afraid, nor believe that I am a ghost.  It is a deception of your imagination, if you believe that you see me as a ghost.  What is a ghost?  Define one.  Deduce for me the conditions of the possibility of a ghost.  What reasonable connection is there between such an apparition and reason?  Reason, I say, Reason!" Here the ghost proceeded to analyze reason, cited from Kant’s Critique of Pure Reason, part II, section I, book 2, chap. 3, the distinction between phenomena and noumena, then went on to construct a hypothetical system of ghosts, piled one syllogism