And so it is with psychic research; and so it is with the theory under discussion. No single incident, taken by itself, can be said to prove anything; only the great mass of facts, taken together, and all pointing in the same direction, can be said to do so. One can quite see how this would be the case, e.g. in Mrs. Piper's automatic utterances or writings. No matter how conclusive any individual "test" might be, it would prove nothing by itself. No matter how well attested an apparition at the moment of death, singly it would indicate no telepathic communication nor other supernormal factor at work. But together these cases form a strand[30] which becomes too strong to be broken, and which, taken together, practically prove telepathic communication at the moment of death--at least so thought Professor Sidgwick's Committee, of which Miss Johnson was one member. (See _Proceedings, S.P.R._, vol. x. p. 394.) In Home's case, then, the evidence for his levitation phenomena rests, not on any one case taken by itself, but on the mass of cumulative testimony offered by scores of witnesses. However completely one case might be explained away, the other cases still remain to us--each case standing on its own merits, and many of them excellently observed, if not so well recorded. For example, the cases mentioned by Sir. William Crookes (_Journal, S.P.R._, vol. vi. p. 342) are certainly far superior, in point of observation, to the famous case so severely criticized by Miss Johnson. And I think that if one is going to offer any hypothesis at all, it must be one that covers _all_ the facts, and not merely one which explains only some of them. The hallucinatory nature of Home's phenomena is certainly not inclusive--it does not include many of the more striking incidents to say nothing of the lesser phenomena. For this reason, it does not appear to me to be conclusive either. After a brief discussion of Home's fire-tests, which Miss Johnson practically admits are inexplicable by any process either of fraud or of hallucination known to her (p. 498), she passes on to what are called "quasi-hypnotic" effects. To many of the incidents classed by Miss Johnson as due to suggestion, I should be inclined to give an entirely different interpretation. Some of them doubtless resemble hallucinations in a striking degree, but what evidence is there that, e.g., passes made over the heads of the sitters can induce identical hallucinations in all of them; or that, because one of the circle becomes hysterical, the others are thereby rendered susceptible to suggestion? However, I shall defer this question until we come to discuss hallucination in general.