A word remains to be said regarding the speed of communication in telepathy and tele-mnemoniky. Many persons hesitate to credit the reports of experiments showing that two persons at a considerable distance from each other--located, say, in London and Manchester respectively--are able to exchange thoughts without any appreciable delay. When, however, it is remembered that the velocity with which light travels is 186,000 miles per second, there should not be any difficulty in supposing that thought-vibrations, or whatever they may be, are propagated through space at an equal or even greater rate of speed. It is not a question, in either case, of any substance being transmitted, or of the absolute simultaneity of emission and reception. And to believe that thoughts may be communicated from soul to soul with the velocity of light does not compel the belief that souls are able to travel from place to place in an equally speedy manner. CHAPTER IV DISCARNATE SPIRITS The existence of discarnate spirits has been proved in Chapter I. It is desirable now to state what is known as to the conditions in which they exist. These conditions have been for thousands of years the subject-matter of positive statements. The sacred writings and inscriptions, and the traditions of the various religions that have flourished in olden times or are still professed are full of descriptions of the religions in which discarnate spirits pass their time and of the manner of their lives in the spirit-world. Magicians, wizards, witches and necromancers of all kinds have, it is said, received copious information to the same effect. And during the last seventy years Spiritualistic literature has added abundantly to the common stock. In spite, however, of all this, great uncertainty prevails. The statements to which reference has been made are, in well-nigh all cases, of what is called an “unverifiable” character; that is to say, they are not capable of test and confirmation by any mundane methods of enquiry. But although an unverifiable assertion is incapable of normal proof it may still be capable of disproof. If, for example, it be self-contradictory it must, of course, be rejected. And if two separate unverifiable statements contradict each other it is obvious that they cannot both be true: one of them, at least, must be false, while the other remains doubtful. Furthermore, if an unverifiable piece of information be opposed to some clearly-established fact or well-proved doctrine no reasonable person will regard it as worthy of credence.