On the Threshold of the Unseen: An Examination of the Phenomena of Spiritualism and of the Evidence for Survival After Death. E-book. Formato PDF William F. Barrett   -  Forgotten Books, 2017  - 

Even those who do not go so far as this, regard psychical research, whether it be telepathy or Spiritualism, as unworthy of serious attention, because the phenomena are either impossible or utterly trivial; therefore in either case a Sheer waste of time. There are some things, I admit, which it would be utter folly to waste our time upon, such as circle squaring, or perpetual motion, &c. These things are beyond the pale of rational investigation at the present day on account of the extent of our knowledge in those particular regions. But there are other things which to-day appear impossible only from the extent of our ignorance in those directions. Such, for example, as, say, the sea serpent, thought-transference, or Spiritual istic phenomena a few years ago we should also have included the telephone and wireless telegraphy. The essential difference between these two classes of improbable events is that the first involves a contradiction of experience or of laws well established, the second involves an unforeseen extension, but no contradiction, of existing knowledge and experience.