INTRODUCTORY—SPECIAL GROUNDS OF CAUTION.

It is salutary sometimes to reflect how recent is the growth of our scientific cosmos, and how brief an interval separates it from the chaos which went before. This may be seen even in Sciences which deal with matters of common observation. Amongst material phenomena the facts of Geology are assuredly not least calculated to excite the curiosity or impress the imagination of men. Yet until the middle of the last century no serious attempt was made to solve the physical problems they presented. The origin of the organic remains embedded in the rocks had indeed formed the subject of speculation ever since the days of Aristotle. Theophrastus had suggested that they were formed by the plastic forces of Nature. MediÆval astrologers ascribed their formation to planetary influences. And these hypotheses, with the alternative view of the Church, that fossil bones and shells were relics of the Mosaic Deluge, appear to have satisfied the learned of Europe until the time of Voltaire, who reinforced the rationalistic position, as he conceived it, by the suggestion that the shells, at any rate, had been dropped from the hats of pilgrims returning from the Holy Land. Yet Werner and Hutton were even then preparing to elucidate the causes of stratification and the genesis of the igneous rocks. Cuvier in the next generation was to demonstrate the essential analogies of the fossils found in the Paris basin with living species; Agassiz was to investigate the relation of fossil fishes and to show the true nature of their embedded remains. Nay, even in the middle of the present century, so slow is the growth and spread of organised knowledge, it was possible for a pious Scotchman to ascribe the origin of mountain chains to a cataclysm which, after the fall of Man, had broken up and distorted the once symmetrical surface of the earth;[4] for a Dean of York to essay to bring the MediÆval theory up to date and prove that the whole series of geological strata, with their varied organic remains, were formed by volcanic eruptions acting in concert with the Mosaic Deluge;[5] and for another English divine to warn his readers against any sacrilegious meddling with the arcana of the rocks, because they represented the tentative essays of the Creator at organic forms—a concealed storehouse of celestial misfits![6]

The subject-matter of the present inquiry has passed, or is now passing, through stages closely similar to those above described. "Ghosts" and warning dreams have been matters of popular belief and interest since the earliest ages known to history, and are prevalent amongst even the least advanced races at the present time. The Specularii and Dr. Dee have familiarised us with clairvoyance and crystal vision. Many of the alleged marvels of witchcraft were probably due to the agency of hypnotism, which in later times, under the various names of mesmerism, electrobiology, animal magnetism, has attracted the curiosity of the unlettered, and from time to time the serious interest of the learned. These phenomena indeed were made the subject of scientific inquiry, first in France and later in England, during the first half of the present century; have now again, after a brief period of eclipse, been investigated for the last two decades by competent observers on the Continent, and are at length winning a recognised footing in scientific circles in this country. Yet within the last two or three years we have witnessed the spectacle of more than one medical man, of some repute in this island, laughing to scorn all the researches of Charcot and Bernheim, just as their prototypes a generation or two ago ignored the results of Cuvier and Agassiz, and held it an insult to the Creator to accept the scientific explanation of coprolites.

And as regards the other subjects, to which must be added the alleged marvels of the Spiritualists, there have indeed been one or two isolated series of observations by competent inquirers, but for the most part the learned have held themselves free to ascribe the phenomena without investigation to fraud and hysteria, and the unlearned to "magnetism," "psychic force," or the Devil. For whilst men of science, preoccupied for the most part with other lines of inquiry, have kept themselves aloof, the vacant ground was naturally occupied by the ignorant and credulous, and by those who looked to win a harvest from ignorance and credulity. It is not of course implied that all persons who interested themselves in such matters came under one or other of these categories. There were many sensible men and women amongst them, but they lacked for the most part the special training necessary for such inquiries, or they failed through want of co-operation and support. No serious and organised attempt at investigation was made until, in 1882, the Society for Psychical Research was founded in London, under the presidency of Professor Henry Sidgwick. He and his colleagues were the pioneers in the research, and their example has been widely followed. Two years later an American society under the same title (now a flourishing branch of the English society) was founded in Boston; and there are at the present time societies with similar objects at Berlin, Munich, Stockholm, and elsewhere. Moreover, the SociÉtÉ de Psychologie Physiologique, which was founded in Paris, under the presidency of M. Charcot, in 1885, has devoted much attention to some forms of telepathy.

But the forces of superstition and charlatanry, to which this vast territory has been ceded for so long, have bequeathed an unfortunate legacy to those who would now colonise it in the name of Science; and the preliminary difficulties of the undertaking can perhaps most effectually be met by a frank recognition of that fact. On the one hand, a large number of thinking men have been repelled, and still feel repulsion, from a subject whose record is so unsavoury. On the other hand, the appetite for the marvellous which has been so long unchecked is not easily restrained. The old habits of inaccuracy, of magnifying the proportions of things, of confusing surmises with facts, cannot be eradicated without long and careful discipline. To one writer, indeed, those dangers seemed so serious that he solemnly warned the Society for Psychical Research, at the outset of its career, against the risk of stimulating into disastrous activity inborn tendencies to superstition, by even the semblance of an inquiry into these matters. Without going to such lengths, it may be conceded to the critic that even with those who endeavour to apply scientific methods to the investigation the mental attitude is liable to be warped by the environment, and that here, as elsewhere, evil communications may corrupt. As regards the actual investigators this difficulty is growing less serious, as more men who have received their training in other branches of science are attracted to the inquiry, and as the affinities of the subject to long-recognised departments of knowledge become daily more apparent. In another direction, however, this mental attitude presents still a more or less formidable obstacle. Many of the observations on which students of the subject are compelled to rely are derived from persons who have had no training in such habits of accuracy as are required in scientific research. When accounts of the ornithorhynchus first reached this country naturalists laughed at the traveller's tale of a beast with the tail of a beaver and the bill and webbed feet of a duck. In the same way scientific men for long refused to admit the existence of aerolites, as they now decline to credit the reports of a Sea Serpent of colossal proportions. In all these cases, so long as the alleged facts rest solely on the testimony of men untrained in habits of close observation and accurate reporting, a suspension of judgment seems to be justified. And if these considerations are valid in ordinary cases, a much higher degree of caution may be reasonably demanded of investigators who leave the neutral ground of the physical sciences to enter upon a field in which the emotions and sympathies are most keenly engaged, and in which the incidents narrated may have served to afford support to the dearest hopes and sanction to the deepest convictions of the narrator. So insidious, in such a case, is the work of the imagination, so untrustworthy is the memory, so various are the sources of error in human testimony, that it may be doubted whether we should be justified in attaching weight to the phenomena of telepathic hallucination and clairvoyance, to which a large part of this book is devoted, if the alleged observations were incapable of experimental verification. Certainly in such a case, though the recipient of an experience of this kind might cherish a private conviction of its significance, it would hardly be possible for such a view to win general assent.

In fact, however, the clue to the interpretation of the more striking phenomena, in the case of which, since they occur for the most part spontaneously, direct experiment or even methodical and continuous observation are rarely possible, is furnished by actual experiment on a smaller scale and with mental affections of a less unusual kind. The thesis which these pages are designed to illustrate and support is briefly: that communication is possible between mind and mind otherwise than through the known channels of the senses. Proof of the existence of such communication, provisionally called Thought Transference or Telepathy (from tele = at a distance, and pathos = feeling), will be found in a considerable mass of experiments conducted during the last twelve years by various observers in different European countries and in America. Before proceeding, in the course of the next four chapters, to examine this part of the evidence in detail, it will be well to consider its various defects and sources of error—defects common in some degree to all experiments of which living beings are the subject, and sources of error for the most part peculiar to this and kindred inquiries. The word experiment in this connection usually, and rightly, suggests the most perfect form of experiment, that in which all the conditions are known, and in which the results can be predicted both quantitatively and qualitatively. If, for instance, we add a certain quantity of nitric acid under given conditions to a certain quantity of benzine, we know that there will result a certain quantity of a third substance which is unlike either of its constituents in taste, smell, and physical properties. Or if we burn a given quantity of coal in a particular engine, we can predict, within narrow limits of error, the total amount of energy which will be evolved. That we cannot in the second instance predict with absolute accuracy the amount of energy produced is simply due to the difficulty of measuring with precision all the factors in the case. But when we leave the problems of chemistry and physics and approach the problems of biology, the difficulties increase a hundredfold. Here not only are we unable to measure the various factors, we cannot even name them. No skill or forethought would have enabled an observer, from however patient a study of parentage and environment, to have predicted the appearance, say, of Emanuel Swedenborg or Michael Faraday. Of the seven children of John Lamb and his wife it might have seemed easier to conjecture that the majority would not survive childhood, and that one would become insane, than that another should take his place amongst those whose writings the world would not willingly let die. And even where, as in most biological researches, the results drawn from observation can be to some extent checked and controlled by direct experiment, generations may elapse before the balance of probabilities on one side or the other becomes so great as to lead to unanimity amongst the inquirers. One of the most interesting, and certainly not the least important, of the questions now occupying biologists, is that of the transmission to the offspring of characters acquired in the lifetime of the individual. Observations have been accumulated on the subject since before the days of Lamarck; and these observations, interpreted and confirmed by experiment, have been adduced and are still held by many as evidence that such transmission occurs. On the other hand, Weismann and his followers contend that no such inference can legitimately be drawn from the observations and experiments quoted, and that the occurrence of such transmission is irreconcilable with what is known of the growth and development of the germ. And for all that has been said and written the opinion of competent biologists is still divided upon the question.

But in many biological problems the conditions are much simpler, and the questions at issue can more readily be brought to the test of experiment. Yet even so various unknown factors are included, and the results obtained are correspondingly difficult of interpretation. No question affects us more nearly than the part played by the several kinds of food in repairing the daily waste of the human body. Statistics and analyses have been collected of workhouse, prison, and military dietaries; innumerable experiments have been conducted on fasting men and hypertrophied dogs and rabbits; and yet the precise function of nitrogenous substances in nutrition is still undetermined. Again, the import of the experiments made during the last few decades by Goltz, Hitzig, Ferrier, Horsley, and others on the functions of various areas of the brain substance, and the exact nature and degree of localisation which those experiments imply, are still matter of debate amongst the physiologists concerned.

To take yet another instance, and one which has a more intimate bearing upon the experiments to be discussed. Some years ago Dr. Charlton Bastian claimed to have proved experimentally the fact of abiogenesis, or the generation of living organisms from non-living matter. He had placed various organic infusions in glass tubes, which were heated to the boiling point and then hermetically sealed. When the tubes were, after a certain interval, unsealed, the contained liquid was found in some cases to be swarming with bacteria. Believing that these micro-organisms and their germs were invariably destroyed by the heat of boiling water, Dr. Bastian saw no other conclusion than that the bacteria were formed directly from the infusion. His conclusions were not accepted by the scientific world. But they were rejected, not because the fact of abiogenesis was regarded as in itself improbable, nor yet because Dr. Bastian was unable to indicate by what steps or processes the transformation of an infusion of hay into living organisms of definite and relatively complex structure could be conceived to take place, but because Pasteur, Tyndall, and others showed that the germs of some of these micro-organisms are capable of sustaining for some minutes the heat of boiling water; and further, that when elaborate precautions were taken, by filtering and otherwise purifying the air, tubes containing similar infusions would remain sterile for an indefinite period.

The conclusion that under certain conditions thought-transference may occur rests upon reasoning similar to that by which Dr. Bastian sought to establish a theory of abiogenesis. Neither the organs by which nor the medium through which the communication is made can be indicated; nor can we even, with a few trifling exceptions, point to the conditions which favour such communication. But ignorance on these points, though a defect, is not a defect which in the present state of experimental psychology can be held seriously to weaken the evidence, much less to invalidate the conclusion. That conclusion rests on the elimination of all other possible causes for the effect produced. But at this point the analogy between the two researches fails. Dr. Bastian's conjecture was based on a short series of experiments conducted by a single experimenter under one uniform set of conditions. At the first breath of criticism the whole fabric collapsed. The experiments here recorded represent the work of many observers in many countries, carried on with different subjects under a great variety of conditions. The results have been before the world for about twelve years, and during that period have been subjected to much adverse and some instructive criticism. But no alternative explanation which has yet been suggested has attained even a momentary plausibility.

Whether the elimination of all other possible causes is indeed complete, or whether, as in Dr. Bastian's case, there may yet lurk in these experiments some hitherto unsuspected source of error, the reader will have the opportunity of judging for himself. To assist him in forming a judgment some of the main disturbing causes will be briefly indicated.

(1) Fraud.—In nearly all the experiments referred to in this book the agent was himself concerned in the inquiry as a matter of scientific interest. But it necessarily happens on occasion that neither agent nor percipient are by education and position absolutely removed from suspicion of trickery in a matter where trickery might to imperfectly educated persons appear almost venial. If any such cases have been admitted, it is because the precautions taken appear to us to have been adequate. At the same time, the investigators of the Society for Psychical Research have come across some instances of fraud in cases where they had grounds for assuming good faith, and it may be useful, therefore, to illustrate some of the less obvious methods of acquiring intelligence fraudulently. The conditions of the experiment should of course, as far as possible, preclude, even where there is no ground for suspecting fraud, communication between the percipient and the agent, or any one else knowing the idea which it is sought to transfer.

In the autumn of 1888 some experiments were conducted with a person named D., whose antecedents afforded, it was thought, justification for the belief that the claims which he put forward were genuine. D. acted as agent, the percipient being a subject of his own, a young woman called Miss N., who was apparently in a light hypnotic sleep during the experiment. It was soon discovered that the results were obtained by means of a code formed from a combination of Miss N.'s breathing with slight noises—a cough or the creak of a boot—made by D. himself. I have seen a somewhat similar code employed in Prince's Hall, Piccadilly, where the conjurer stood in the middle of the hall with a coin or other object in his hand, a description of which he communicated to his confederate on the platform by means of a series of breathings, deep enough visibly to move his dress-coat up and down on the surface of his white collar, punctuated by slight movements of head or hand. The novel feature in the first case, however, was that the percipient herself furnished the groundwork of the code, the punctuation alone being given by the conjurer. A still more elaborate form of collusion is described at length by Bonjean.[7] In this case the subject, a young woman named Lully, appears to have read the words to be conveyed after the fashion of a deaf mute, by the motion of the lips of the showman. Lully was apparently in a hypnotic trance, with the eyes fast closed. Another form of fraud, since it does not require the aid of a confederate, is perhaps worthy of note. Some years ago a young Australian came to this country with a reputation for "genuine thought-reading," based on the successful mystification of some members of a certain Colonial Legislature. The writer had a few experiments with this person, in which several small objects—a knife, a glass bottle, etc.—placed in the full light of a shaded lamp, were correctly named. The object was in each case placed behind the back of the "Thought-reader," who looked intently at the writer's eyes, which were in turn fixed upon the brightly illuminated object. Experiments made under more usual conditions, not dictated by the "Thought-reader," completely failed; and there can be little doubt that the initial successes were due to the "Thought-reader" seeing the image of the object reflected in the agent's cornea.

(2) HyperÆsthesia.—But, after all, it is rarely necessary to take special precautions against fraud, for there are dangers to be guarded against of a more subtle kind. There are various, and as yet imperfectly known methods of communication by which indications may be unconsciously given and as unconsciously received. Thus, to take the last instance, it is pretty certain that cornea-reading does not always imply fraud, and that hints may be gained in all good faith from any reflecting surface in the neighbourhood of the experimenter; or the movements of lips, larynx, and even hands and limbs may betray the secret to eye or ear. We know little of the limits of our sensory powers even in normal life; and we do know that in certain subconscious states—automatic, hypnotic, somnambulic—these limits may be greatly exceeded, and that indications so subtle as frequently to escape the vigilance of trained observers may be seized and interpreted by the hypnotic or automatic subject. It is clear, therefore, that results which it is possible to attribute to deliberate fraud stand almost necessarily self-condemned. For if the precautions taken by the investigators left such an explanation open, much more were those precautions insufficient to guard against the subtler modes of communication referred to. It is not the friend whom we know whose eyes must be closed and his ears muffled, but the "Mr. Hyde," whose lurking presence in each of us we are only now beginning to suspect.

There is a case recorded by M. Bergson,[8] in which a hypnotised boy is said to have been able to state correctly the number of the page in a book held by the observer, by reading the corneal image of the figures. The actual figures were three millimetres high, and their corneal image is calculated by M. Bergson to have been O.1 mm., or about 1/250 of an inch in height! In some other experiments conducted by M. Bergson with the same subject the acuteness of vision is said to have exceeded even this limit. In another case, recorded by Dr. Sauvaire,[9] a hypnotised subject was able to recognise the King of Clubs, face downwards, in two different packs of cards. In the first of these cases the results, which could not have been attained by the senses under normal conditions, must apparently be attributed to hyperÆsthesia. Instances, especially of auditory hyperÆsthesia, are of course quite familiar to those who have studied the phenomena of hypnotism. In Dr. Sauvaire's case, however, the power of distinguishing the cards by touch may have been the result of practice. Mrs. Verrall records (Proceedings Soc. Psych. Research, vol. viii. p. 480) that she acquired such a power by means of "a longish series of experiments"; and Mr. Hudson, in Idle Days in Patagonia, tells of a gambler who by careful training had developed the same faculty in a very high degree.

It seems probable in the cases described by M. Bergson and Dr. Sauvaire, and possible also in the case of Mr. D.'s subject, that there was no intentional deception, and that the hypnotised person was not himself aware of the means by which his knowledge was attained.[10] The same remark probably applies to the following case, in which, though the conditions of vision were certainly unusual, it seems not clear whether the degree of success attained should be attributed to abnormal sensibility of the eyes, or to the facility acquired by long practice. In a series of experiments at which the writer assisted, in 1884, an illiterate youth named Dick was hypnotised, a penny was placed over each eye, and the eyes and surrounding features were elaborately bandaged with strips of sticking-plaster; a handkerchief being bound over all. Under these conditions Dick named correctly objects held in front of him, even at a considerable distance, a little above the level of his eyes. Normal vision appeared to be impossible. Mr. R. Hodgson, however, repeated the experiment upon himself, and found after several trials that he also could see objects, though fitfully and imperfectly, under the same conditions, the channel of vision being a small chink in the sticking-plaster on the line where it was fastened to the brow.

(3) Muscle-reading.—From this last case we may pass to the illustrations of "thought-reading" given by professional conjurers and others, where it seems clear that the skill exhibited in the interpretation of unconscious movements and gestures is due rather to long practice and careful observation than to any abnormal extension of faculty. It hardly needs saying that experiments in which contact is permitted between the agent and percipient can rarely be regarded as having evidential value. It has been demonstrated again and again that with the fullest intention of keeping the secret to themselves, most "agents" in such circumstances are practically certain to betray it to the professional thought-reader by unconscious movements of some kind. Indeed, it is difficult to place any limit to the degree of susceptibility to slight muscular impressions which may be attained. A careful experimenter has assured the writer that when acting as percipient in some experiments with diagrams the slight movements of the agent's hand resting upon her head gave her in one case a clue to the figure thought of. And Mr. Stuart Cumberland has exhibited feats still more marvellous before kings and commoners. Nor is it necessary, as already said, for successful muscle-reading that there should be actual contact in all cases. The eye or the ear can sometimes follow movements of the lips or other parts of the body. But though we can look for little evidence from experiments conducted with contact, or under conditions which allow of interpretation by gesture, etc., and their repetition in this connection can rarely be expected to serve any useful purpose, it seems worth pointing out that, if telepathy is a fact, we should expect to find it operating not merely where, from the conditions of the experiment, it must be presumed to be the sole source of communication, but also as an auxiliary to other more familiar modes of expression. It seems not improbable, therefore, that some of the more startling successes of the professional "thought-reader" and some of the results obtained in the "willing game" may be due to this cause.

(4) Thought-forms.—There remains one other source of error to be guarded against. An image—whether of an object, diagram, or name—which is chosen by the agent may be correctly described by the percipient simply because their minds are set to move in the same direction. It must be remembered that, however unexpected and spontaneous they may appear, ideas do not come by chance, but have their origin mostly in the previous experience of the thinker. Persons living constantly in the same physical and intellectual environment are apt to present a close similarity in their ideas. It would not even be prima facie evidence of thought-transference, for instance, if husband and wife, asked to think of a town or of an acquaintance, should select the same name. And investigation has shown that our thoughts move in grooves which are determined for us by causes more deep-seated and more general than the accident of particular circumstances. Thus it is found that individuals will show a preference for certain figures or certain numbers over others; and that the preference for some geometrical figures tends to be tolerably constant. The American Society for Psychical Research[11] made some interesting observations on this point in 1888. Blank cards were issued to a large number of persons, with the request that the recipients would draw on the card "ten diagrams." 501 cards were returned, and the diagrams inscribed on them were carefully tabulated. It was found that of the 501 persons no less than 209 drew circles, 174 squares, 160 equilateral triangles and crosses, while three only drew wheels, two candlesticks, and one each a corkscrew, a ball, and a knife. It was found that the simpler geometrical figures[12] occurred not only most frequently but as a general rule early in each series of ten. It follows, therefore, that in an experiment the success of the percipient in reproducing a circle, a square, or a triangle raises a much fainter presumption of thought-transference than if the object reproduced had been a corkscrew or a pine-apple. But so much was perhaps obvious even without a detailed investigation. From a similar analysis of the guesses made, it can be shown that some percipients have decided preferences amongst the simple numerals. And in the same way it seems probable that others have a preference for particular cards. An important illustration of the working of the "number-habit" has been brought forward by Professor E. C. Pickering of the Harvard College Observatory, U.S.A.[13] A revision of part of the Argelander Star-Chart had been undertaken by several observatories, of which the Harvard Observatory was one. For the purposes of the revision the assistant had the Argelander chart before him, whilst the observer, who was in ignorance of the magnitude assigned in the chart, made an independent estimate of the magnitude of each star. If no thought-transference or other disturbing cause affected the result, the amount of deviation of the later observations from the earlier in each tenth of a degree of magnitude would be represented by a smooth curve. As a matter of fact, it was found that the number of cases of complete agreement were much greater, with some observers more than 50 per cent. greater, than they should have been on an estimate of the probabilities. At first sight this excess of the actual over the theoretical numbers suggested the action of thought-transference between the assistant and the observer. But Professor Pickering shows, on a further analysis of the figures, that almost the whole of the excess was due to the preference of both the earlier and the later observers for 5 and 10 over all other fractions of a degree.

The practical deduction from this investigation is that in any experiment care should be taken to exclude, as regards the agent at any rate, the operation of any diagram or number-habit.[14] If an object is thought of, it should if possible be chosen by lot, and should not be an object actually present in the room. If a card, it should be drawn from the pack at random; if a number, from a receptacle containing a definite series of numbers; if a diagram, it is preferable that it should be taken at random from a set of previously-prepared drawings. It will be seen that in the majority of the cases quoted in the four succeeding chapters these precautions have been observed.