Hence it is easy to conceive, how many well-meaning persons may frequently deceive themselves and others with the belief of having seen spectres, heard voices, &c. in the dead of the night; and it is not very improbable that a well-grounded conviction in the mind of any person, of having received a supernatural warning of their approaching fate, should, under certain circumstances, be productive of the very event which was thus foreboded and dreaded. I could relate a number of instances where the visions accompanying paroxysms of _Incubus_, have been of the most terrific kind.[3] I think enough has been said on that subject to shew how easily a person may be deceived where he thinks he has the evidence of his own senses; and I have selected such histories in my own case to illustrate this truth by, as were least likely to be suspected of arising from fright or terror, or any cause that could be much aided by the imagination. I wish it, however, to be understood, that I by no means intend to explain by this hypothesis, all the extraordinary accounts of supernatural operations which are given us on indubitable authority, and supported by unquestionable evidence. I am aware that there are a great many cases to which it will not apply, neither can any one principle possibly explain them all. I have been very much surprised to see a late medical writer on the subject of apparitions, attempt to explain all the cases he has adduced, by supposing the disease to exist, so ably described by Nicolai, and of which several cases have been given by Dr. Alderson of Hull. He has himself recorded several instances of spectres, which appear to be closely connected with the death of persons at a distance, and with some of the most important circumstances in the lives of the persons who saw these appearances: he even admits the truth of these instances, yet ascribes the most important circumstances attending them to chance. Of all the modes of solving difficulties, which mankind have ever had recourse to, this is certainly the least _philosophical_. In the present age however it appears to be considered still more _unphilosophical_ to acknowledge that any phenomenon, however extraordinary, is above our comprehension.