Catherine Crowe, The Night-Side of Nature; Or, Ghosts and Ghost-Seers
“ I allude to the fact that, in numerous reported cases of ghost-seeing, the forms were visible to only one person, even though others were present, which, of course, rendered them undistinguishable from cases of spectral illusion, and indeed unless some additional evidence be afforded, they must remain so still, only we have gained thus much, that this objection is no longer unanswerable; for whether the phenomenon is to be referred to a mutual rapport, or to the opening of the spiritual eye, we comprehend how one may see what others do not. ”
