CHAPTER VI.

GENERAL CRITICISM OF THE EVIDENCE FOR SPONTANEOUS THOUGHT-TRANSFERENCE.

If the reader has been able to accept my estimate of the evidence brought forward in the preceding chapters, the possibility of the transmission of ideas and sensations, otherwise than through the known channels of the senses, must be held to be proved by the experiments there recorded. That proof can be impugned only on the ground that the precautions taken against communication between agent and percipient by normal means were insufficient. For if the precautions are admitted to have been sufficient, there can be no question that the results were not due to chance. It is not necessary here to enter into nice calculations of the probabilities. If, for instance, the odds in favour of some other cause than chance for the results recorded on pp. 66-69 were to be expressed in figures, the total sum would compete with or outstrip the stupendous ciphers employed by the astronomer to denote the distance of Sirius, or the weight of the Sun. But the kind of evidence now to be considered--the coincidence of some spontaneous affection of the percipient with some event in the life-history of the person presumed to be the agent, as when one sees the apparition of a friend at the time of his death--is of inferior cogency in two ways. The coincidences are neither so numerous nor so exact; and the risk of error in the record is far greater. On the one hand, therefore, there is a greater probability that the percipient's affection, even if correctly described, was unconnected with the state of the person supposed to be the agent; on the other hand we have, in most cases, less assurance that the description given of his experience is in its essential features accurate. The part played by coincident hallucination in the question of telepathy may be illustrated from another branch of scientific inquiry. For some years the "Germ Theory" rested mainly on observations of the distribution of certain diseases, their periodic character and their mode of propagation and development; phenomena which, though sufficiently striking, are not in themselves susceptible of exact interpretation. It was not until the minute organisms, whose existence had been so long suspected, had been actually isolated in the laboratory, and had been proved capable of reproducing the disease, that the connection of certain maladies with the presence of certain microbes in the body became, from a plausible hypothesis, an accepted conclusion of Science. So here it is important to bear in mind that dreams, visions, and apparitions, however captivating to the imagination, do not form the main argument for believing in some new mode of communication between human minds. If all the cases of the kind hitherto recorded could be shown one by one to be explicable by more familiar causes,--though the result would indeed be to add a remarkable chapter to the history of human error; though it would be a singular paradox that so many intelligent witnesses should have been so mistaken, and with such undesigned unanimity; and that a whole class of alleged phenomena should have sprung up without any substantial basis,--the grounds for the belief in telepathy would not be seriously affected; we should merely have to modify our conceptions of its nature, and restrict its boundaries. But in fact there is no reason to anticipate so lame a conclusion. The incidents, of which examples will be adduced in the succeeding chapters, though their value will be differently estimated by different minds, are yet in their aggregate not such as can plausibly be attributed to misrepresentation or chance coincidence. And, first, it is important to note that the cases must be considered in the aggregate. Separately, no doubt, each particular case is susceptible of more or less adequate explanation by some well-known cause; and in the last resort it would be unreasonable to stake the credit of any single witness, however eminent, against what Hume would call the uniform experience of mankind. But as a matter of fact the experience of mankind is not uniform in this matter; and when we are forced by the mere accumulation of testimony to go on adding one strained and improbable explanation to another, and to assume at last an epidemic of misrepresentation, perhaps even an organised conspiracy of falsehood, a point is at length reached in which the sum of improbabilities involved in the negation of thought-transference must outweigh the single improbability of a new mode of mental affection. If to any reader that point should seem not yet to have been reached--and the position could scarcely be held an unreasonable one--I would remind him that the cases quoted in this book form but a small part of the evidence so far accumulated; and I would ask that he should reserve his judgment until he has studied the whole of the evidence recorded in _Phantasms of the Living_, in the _Proceedings_ of the American Society for Psychical Research, the scattered cases appearing from time to time in the pages of various English and Continental periodicals dealing with this subject, and the ever-growing mass of testimony printed in the _Proceedings_ and _Journal_ of the Society for Psychical Research in this country.[71] He will then perhaps be prepared to endorse the verdict of a shrewd and genial critic on the evidence presented in _Phantasms of the Living_, viz., that it "can only be rejected as a whole by one who is prepared to repeat at his leisure what David is reported to have said in his haste."[72]

It is of course not possible with our present knowledge to estimate with any precision the probabilities for the coincidence by chance of such a vision as that recorded by Dr. Dupré (No. 47), or such a dream as Mr. Hamilton's (No. 58), with the event represented. Neither the nature of the percipient's impression in these and similar cases, nor the event to which the impression corresponds, are sufficiently well defined to admit of any numerical argument being based upon them. We can only recognise that whilst dreams and mind's-eye pictures are not very uncommon experiences, dreams and visions which faithfully reflect external events of an unlikely kind occur, if rarely, with sufficient frequency to give us pause. The common sense which in such cases leads us to infer a connection between the event and the corresponding mental experience is our only guide. But one large class of our spontaneous evidences is susceptible of more exact treatment. Sensory hallucinations are affections at once well marked and unusual. If we can ascertain their relative frequency it is possible to calculate with more or less exactness the probabilities of the coincidence by chance with some definite event. Such a calculation has been attempted in