It is natural enough that man's instinctive feeling should have anticipated any argument of this speculative type. Men have in most ages believed, and do still widely believe, in the reality of prayer; that is, in the possibility of telepathic communication between our human minds and minds above our own, which are supposed not only to understand our wish or aspiration, but to impress or influence us inwardly in return.
So widely spread has been this belief in prayer that it is somewhat strange that men should not have more commonly made what seems the natural deduction—namely, that if our spirits can communicate with higher spirits in a way transcending sense, they may also perhaps be able in like manner to communicate with each other. The idea, indeed, has been thrown out at intervals by leading thinkers—from Augustine to Bacon, from Bacon to Goethe, from Goethe to Tennyson.
Isolated experiments from time to time indicated its practical truth. Yet it is only within the last few years that the vague and floating notion has been developed into definite theory by systematic experiment.
To make such experiment possible has indeed been no easy matter. It has been needful to elicit and to isolate from the complex emotions and interactions of common life a certain psychical element of whose nature and working we have beforehand but a very obscure idea.
If indeed we possessed any certain method of detecting the action of telepathy,—of distinguishing it from chance coincidence or from unconscious suggestion,—we should probably find that its action was widely diffused and mingled with other more commonplace causes in many incidents of life. We should find telepathy, perhaps, at the base of many sympathies and antipathies, of many wide communities of feeling; operating, it may be, in cases as different as the quasi-recognition of some friend in a stranger seen at a distance just before the friend himself unexpectedly appears, and the Phêmê or Rumour which in Hindostan or in ancient Greece is said to have often spread far an inexplicable knowledge of victory or disaster.
But we are obliged, for the sake of clearness of evidence, to set aside, when dealing with experimentation, all these mixed emotional cases, and to start from telepathic communications intentionally planned to be so trivial, so devoid of associations or emotions, that it shall be impossible to refer them to any common memory or sympathy; to anything save a direct transmission of idea, or impulse, or sensation, or image, from one to another mind.
The reader who has studied the evidence originally set forth in Chapters II. and III. of Phantasms of the Living will, I trust, carry away a pretty clear notion of what can at present actually be done in the way of experimental transferences of small definite ideas or pictures from one or more persons—the "agent" or "agents"—to one or more persons—the "percipient" or "percipients."[106] In these experiments actual contact has been forbidden, to avoid the risk of unconscious indications by pressure. It is at present still doubtful how far close proximity really operates in aid of telepathy, or how far its advantage is a mere effect of self-suggestion—on the part either of agent or of percipient. Some few pairs of experimenters have obtained results of just the same type at distances of half a mile or more.[107] Similarly, in the case of induction of hypnotic trance, Dr. Gibert attained at the distance of nearly a mile results which are usually supposed to require close and actual presence. [See Appendix V. C.]
We must clearly realise that in telepathic experiment we encounter just the same difficulty which makes our results in hypnotic therapeutics so unpredictable and irregular. We do not know how to get our suggestions to take hold of the subliminal self. They are liable to fail for two main reasons. Either they somehow never reach the subliminal centres which we wish to affect, or they find those centres preoccupied with some self-suggestion hostile to our behest. This source of uncertainty can only be removed by a far greater number of experiments than have yet been made—experiments repeated until we have oftener struck upon the happy veins which make up for an immense amount of sterile exploration. Meantime we must record, but can hardly interpret. Yet there is one provisional interpretation of telepathic experiment which must be noticed thus early in our discussion, because, if true, it may conceivably connect our groping work with more advanced departments of science, while, if seen to be inadequate, it may bid us turn our inquiry in some other direction. I refer to the suggestion that telepathy is propagated by "brain-waves"; or, as Sir W. Crookes has more exactly expressed it, by ether-waves of even smaller amplitude and greater frequency than those which carry the X rays. These waves are conceived as passing from one brain to another, and arousing in the second brain an excitation or image similar to the excitation or image from which they start in the first. The hypothesis is an attractive one; because it fits an agency which certainly exists, but whose effect is unknown, to an effect which certainly exists, but whose agency is unknown.
In this world of vibrations it may seem at first the simplest plan to invoke a vibration the more. It would be rash, indeed, to affirm that any phenomenon perceptible by men may not be expressible, in part at least, in terms of ethereal undulations. But in the case of telepathy the analogy which suggests this explanation, the obvious likeness between the picture emitted (so to say) by the agent and the picture received by the percipient—as when I fix my mind on the two of diamonds, and he sees a mental picture of that card—goes but a very short way. One has very soon to begin assuming that the percipient's mind modifies the picture despatched from the agent: until the likeness between the two pictures becomes a quite symbolical affair. We have seen that there is a continuous transition from experimental to spontaneous telepathy; from our transferred pictures of cards to monitions of a friend's death at a distance. These monitions may indeed be pictures of the dying friend, but they are seldom such pictures as the decedent's brain seems likely to project in the form in which they reach the percipient. Mr. L.—to take a well-known case in our collection (Phantasms of the Living, vol. i. p. 210)—dies of heart disease when in the act of lying down undressed, in bed. At or about the same moment Mr. N. J. S. sees Mr. L. standing beside him with a cheerful air, dressed for walking and with a cane in his hand. One does not see how a system of undulations could have transmuted the physical facts in this way.
A still greater difficulty for the vibration-theory is presented by collective telepathic hallucinations. It is hard to understand how A can emit a pattern of vibrations which, radiating equally in all directions, shall affect not only his distant friend B, but also the strangers C and D, who happen to be standing near B;—and affect no other persons, so far as we know, in the world.