Surely there had been no figure leaning on the back of his chair; no face looking over it. It is certain that no gliding footstep touched the floor, as he lifted up his head, with a start, and spoke. And yet there was no mirror in the room on whose surface his own form could have cast its shadow for a moment; and, Something had passed darkly and gone!
Alas for the affairs of men! When they are fortunate you might compare them to a shadow; and if they are unfortunate, a wet sponge with one dash wipes the picture away.
There is another way of disqualifying the metaphysicians.... Judge them by their works. What have they done for mankind beyond the spinning of airy fancies and the mistaking of their own shadows for gods?