Sketches of the Philosophy of Apparitions (1824)

Or an attempt to trace such illusions to their physical causes. The plan of this work is as follows. In the first place, a general view is given of the particular morbid affections with which the production of phantasms is often connected. In a second part of this work, Dr. Hibbert's object was to point out that in well-authenticated ghost stories of a supposed supernatural character, the ideas which are rendered so unduly intense as to induce spectral illusions, may be traced to such fantastical objects of prior belief as are incorporated in the various systems of superstition, which for ages have possessed the minds of the vulgar. In the succeeding and far most considerable portion of this treatise, the research is of a novel kind. Since apparitions are ideas equaling or exceeding in vividness actual impressions, there ought to be some important and definite laws of the mind which have given rise to this undue degree of vividness.