I dropped all my own views of sense and nonsense. I told him that, taking all that he had told me as fact, the Presences might be either ordinary minds traversing Space in sleep; or minds such as his which had independently captured the sense of Space's quality; or, finally, the spirits of just men made perfect, behaving as psychical researchers think they do. It was a ridiculous task to set a prosaic man, and I wasn't quite serious.
Space (1912)