THE PROBLEMS OF EVIDENCE

 THE present chapter is closely connected with the preceding, for the nature of the problem largely determines the nature of the evidence. But the problem has been so complicated by concern with religion and magic that these subjects are inevitably brought into the discussion; various problems of abnormal psychology are also involved. So many facts are erroneously claimed by unsophisticated minds to be proof of the intervention of spirits, that a very large field has to be canvassed in the search for evidential material.

 Besides, the sifting of evidence is a very complex matter. A fact in relation to another fact may be evidence, but out of that relation the same fact might not be evidence at all. It is therefore necessary briefly to examine the law of evidence. Let me take some concrete illustrations.

 A human body is found with a bullet hole in the head and a revolver lying near the body. If nothing is known about the person either suicide or murder may account for the situation. If the man is known to have been despondent, to have failed in business or some other project, or to have been generally disappointed with life, the suspicion of suicide becomes stronger, and anything like knowledge of a previous threat of it would weaken the hypothesis of murder. On the other hand, if the man is known to have been an upright person in the community, a religious man, successful in business, with a happy family and nothing to make him unhappy, the theory of suicide would be less tenable. Not the mere fact of death by a bullet wound decides the question, but other general facts in the person's life are included in the evidence.

 Suppose, however, that we know nothing about the man and his life and have to seek evidence from other sources. If, then, we find that the revolver was purchased at a certain store, not by the victim, this discovery would provide circumstantial evidence that the man had not committed suicide. It would not constitute proof, as the victim might have secured the weapon after its purchase. Suppose, however, that finger prints on the weapon are those not of the victim but those of the purchaser. This fact would greatly strengthen the suspicion of murder. Only an alibi or proof that these same finger marks had been observed on the revolver before the man's death could remove that suspicion. If now we should discover boot tracks near the body, and these tracks could be identified with those of the purchaser of the weapon, we should have additional, though not conclusive, evidence of his guilt. If to this we could add evidence that he had previously threatened the man with death, had been a personal enemy, and had actually been in the vicinity at the time, the case would be very nearly established. The convergence of a large number of incidents, each of which alone might look like chance coincidence, would prove the deed. All the facts must consist with the hypothesis. Mere coincidence between two events does not prove a connection between them, though it may suggest a hypothesis. This coincidence must be associated with a number of others, all of which hang together. But the uneducated mind rests content with a single coincidence and in this way is led into all sorts of errors.

 When it considers evidence for the existence of spirits the untrained mind has always been accustomed to appeal to every "wonderful" occurrence as proper evidence. It frequently regards any unusual fact as an incentive to apply explanations that do not fit. It is not merely the unusual character of a fact that gives it evidential interest or force. It must be unusual if it is to be evidence of a fact hitherto unknown, but it need not be any more unusual than the fact which it attests. This is perhaps a truism; but, because prejudiced people try to represent as miraculous or supernatural the facts which psychic research adduces as evidence of spirits, it is necessary to make clear two things: (1) that no one regards as supernatural the new discoveries constantly being made in physical science; (2) that the idea of spirits is no more strange than that of a new element in chemistry. They are but the continuation of the consciousness we formerly knew as embodied.

It was the work of the Society for Psychical Research to discriminate among the phenomena it was investigating. Its first task was to classify them and to distinguish between those relevant to the hypothesis of spirits and those that have no bearing on the subject. The spiritualists had classed together all unusual phenomena, physical and mental, claiming all of them as spiritistic.

 Before we have any right to assert or suppose the existence of spirits, we must adduce facts that imply supernormal knowledge, and this supernormal knowledge must be such as could be obtained only by communication from the dead. The term normal is purely relative. We can best give its meaning by illustrations. For instance, we can normally see a house some miles distant, but we could not normally see a fly at the same distance. The term normal is relative to the conditions limiting the activity of our senses. The existence of the normal, as well as of the supernormal, has to be proved by evidence. Only because this proof is easily within the reach of every one, we forget the grounds on which it rests. The limits of the supernormal are also determined by evidence, not by definition. If a man in America should have an accurate vision of events in Europe, we should call his perception supernormal, whatever the process involved. Whether such a vision has actually occurred is only a matter of evidence; we cannot say that it is impossible.

 But before we admit the existence of anything so unusual we require that the evidence be critically tested and that the facts be inexplicable by any known law. To call such a phenomenon as the vision of events in Europe clairvoyance, is to give the fact a name, not an explanation. If the claim to the vision could not be confirmed by testimony from some one else than the visionary, we should not regard it as proved. The veracity of the person might not be questioned, but some illusion or mistake of judgment might stand in the way of our accepting his statement. If the reporter and subject of the experience were a scientific man, the statement would have more weight than if he were an ignorant layman, simply because the scientific man has the habit of accurate observation and statement. But even then there would be the possibility of error unless his account could be confirmed by the testimony of others. If a scientific man were to relate such an experience in a detailed manner, before the objective facts could become known to him and those in his vicinity, corroboration by others would exempt him from the suspicion of error, illusion, or mendacity. The facts would then stand out as unusual, and perhaps as requiring a new law to explain them.

 Conclusive evidence of an hypothesis must exclude every interpretation except the one supposed; it must conform to two conditions, one positive and the other negative. The exclusion of a given interpretation is negative evidence; the applicability of the hypothesis to the facts is positive evidence. Thus the exclusion of fraud would be negative evidence for spiritism, if that were the theory in question. But the fitness of the facts to prove the special theory concerned, say the survival of personal identity, would be positive evidence. If spirits are to be proved to exist, the facts must indicate the continued personal identity of deceased persons, must be verified by living people, and provably supernormal in their origin.

 In estimating the alleged evidence for the existence of spirits we have first to eliminate the explanations grouped under the name of fraud. This may take the form of lying about the facts, or trickery in performing feats claimed to be of spirit origin. But we must be exact in our conception of fraud. Fraud is not the act performed, but the motive of the act. It implies the conscious purpose to deceive, whether by false statements or by acts calculated to lead one to form incorrect judgments as to the facts. If a man should make a false statement in his sleep, or in a trance, or under hypnosis, I should have no right to ascribe lying or fraud to him. He himself might be deceived by dreams, hallucinations, or illusions. Hence many actions and statements are exempt from the suspicion of fraud, for instance, all actions and statements during somnambulism, trance, hysteria (if of an automatic type), ordinary sleep, intoxication, insanity (if of the hallucinatory type), and similar abnormal mental conditions. We must have proof that the person is normally conscious in order to attribute fraud to him.

Moreover we must not confuse the deception of the observer with the purpose of the actor. The fraudulent person aims at deception by misrepresentation. The deception of the conjurer, on the other hand, is legitimate enough, because he does not claim any supernormal elements in his exhibitions. The observer lets himself be deceived by what the conjurer frankly avows is a trick. But the fraudulent person maintains that the apparent facts are real, despite his knowledge to the contrary. If the person is normal, his honesty may be judged by his acts; but if the subject is abnormal, the phenomena are in the domain of abnormal psychology, not of trickery.

 We are concerned, however, solely with the cause and the explanation of experiences, not with the motive of the subject. That cause may be subjective or objective. If the experience has no discoverable sensory stimulus and yet coincides with some objective event out of the reach of normal sense-perception it is supernormal. Honesty has no importance in determining the nature of the phenomena. Only tests to exclude normal knowledge and sensation can decide whether the facts are supernormal or not. For this reason the scientist does not care whether he is dealing with frauds or not, if only he can determine the conditions under which the phenomena are produced. The fraudulent person, of course, will not usually, if ever, permit this sort of experiment. But if the dishonest subject will submit to scientific conditions we shall not enter into the consideration of character or motives. However, in the work of persuading the public it is important to be assured that the subject of experiment is honest, because the public wrongly assumes that phenomena are genuine if the subject is honest.

 But we have not satisfied all the conditions of evidence for the supernormal merely by removing the fact or the relevance of fraud. We must reckon with the subconscious or subliminal functions of the mind. At one time subconscious mental activities were as yet undiscovered. We could not then reckon with subconscious action as an alternative to genuine supernormal experience. The choice lay between the fraudulent and the genuine in all normal persons. But the discovery that the mind has subconscious activities has completely altered the situation. We have all along known what we called "unconscious," by which we meant merely involuntary, actions, whose meaning we ourselves learned as they proceeded.

Here lies the borderland of the subconscious. Strictly speaking, subconscious or subliminal actions are those of which the subject is wholly unaware. Our thoughts and actions in sleep, hypnosis, or trance are illustrations. In our normal state, we have no recollection of them. The distinctive marks of subconscious activities are anaesthesia and amnesia, i.e., insensibility and inability to remember. In sleep, trance, somnambulism, hysteria and various forms of insanity these phenomena are constant. They show the continuance of mental action after normal sensibility or consciousness has been suppressed.

 Now we may exclude fraud from the explanation of alleged supernormal phenomena and yet have subconscious action of the subject to reckon with in explaining them. If apparently supernormal phenomena can be explained by the resurrection of subconscious memories or the production of automatic actions the claims of supernormality must be abandoned. Suppose, for instance, that John Smith reported to us that he had seen the ghost of Mary Jones. Having established his honesty, we should then wish to know whether he knew that Mary Jones was dead. If he did, we might explain the circumstance as a casual hallucination or a dream. The operation of memory would suffice to explain it, or to classify it with known facts. If Mary Jones were found to be alive, the case would be strengthened. If Mary Jones had died without John Smith's knowledge, we might still consider the vision a chance coincidence. It would be more difficult to explain it thus, if we found that the apparition occurred very close to the time of death. The time element is always an important factor in eliminating chance; close correspondence of the experience with the event indicated by it strengthens the case. But the question of chance coincidence and guessing enters only after we have eliminated the subconscious.

 Many visions and hallucinations are referable to the subconscious, because their content can be reduced to previous experiences. We cannot assume that there are supernormal dreams or visions until we have eliminated the influence of previous experience upon the contents of the incidents. Hence, until we can report dreams or visions of verifiable facts not previously known to the subject, we are obliged to suspect subconscious memory as a sufficient explanation.

 We must remember, however, that the nature and limits of the subconscious have not been accurately determined. This is both an advantage and a difficulty to the defender of the supernormal. It is an advantage because it challenges the advocate of subconscious action to show whether the process has been proved to include cases of the kind in question. It is a disadvantage, however, because the defender of the subconscious as an explanation may insist that its unassigned limits permit him to suppose its power to be unlimited.

 Scientific method, however, does not allow us to use the subconscious as an explanation beyond its proved capacities. We have no evidence that the subliminal, of its own power and apart from normal sensory stimuli, can acquire any knowledge. It has no known transcendental powers. It is a name for mental action below the threshold of consciousness, or above it, if you wish to include hyperaesthetic conditions, but it is always dependent on normal stimuli for its contents, unless the supernormal be at once granted as a fact. Its capacity is thus as limited as that of the normal mind, and it exhibits no functions other than those of the normal mind, even when real or alleged supernormal phenomena filter through it.

 This limitation of subliminal activity is a restriction on the skeptic who wishes to apply it as a universal explanation. He must first show the relevance of the application, which depends on showing that the previous knowledge supplied the subject with the data for subliminal use; and his application must be strictly limited by the proved capacities and habits of the subconscious.

 It is important to note that the subconscious may be the vehicle for the transmitting supernormal knowledge. It may be the medium between the transcendental world, if there be such a thing, and the physical world, and so may respond to stimuli from both sources. This view of the subconscious makes it the medium or vehicle for the acquisition of supernormal knowledge; the only refuge of the skeptic is to deny the source of the contents claimed to be supernormal. If he proves that the contents have been sub consciously acquired from normal experience, he can disqualify the evidence for the supernormal. In fact it is contents that must furnish the evidence. No assumption or discussion of the powers of the subliminal will decide the matter. If the phenomena are not traceable to physical stimuli, their explanation must be sought in the transcendental. The conditions under which the facts occur can alone decide the question, not the assumed or proved functions of the mind, conscious or subconscious.

 It will thus be seen that we have to define carefully what we mean by the subconscious before we employ it as an explanation of the alleged supernormal. The believer in the supernormal has to prove that the normal senses were not the source or vehicle of the facts. The conditions under which the phenomena occur will determine this. The appeal to the subconscious will be irrelevant unless previous normal experience accounts for the special facts which appear to be supernormal. If these facts are based on such experience the claims for the supernormal are vitiated.

 All this is perhaps obvious to most people; but I thought it was necessary carefully to analyze the problem. We now have made it clear that when conscious fraud has been eliminated, we have still to test the claim of any alleged supernormal phenomenon, such as telepathy, clairvoyance, apparitions, mediumistic communications with the dead, and dousing, by their relation to the normal knowledge and process of the subject. All precautions must be taken to exclude these normal processes when we assert that we have a transcendental fact to be explained. Proximity in time or space of the subject to the fact supernormally known may raise doubts of its authenticity, though these can be settled by a number of conditions. But great distance in time and space and all the conditions that will exclude previous normal knowledge by the subject will make an appeal to subliminal memories of doubtful value. The use of strangers and the employment of controlled experiments will dislodge the doubts attachable to spontaneous phenomena, and will easily disprove the presumption of subconscious influences, especially when the facts are provably unknown by the subject.

 But assume that we have eliminated the subconscious from the explanation of the facts. The exclusion of subconscious influences will not prove that each individual phenomenon is genuine. There are still the possibilities of chance coincidence, or guessing. This, however, can easily be eliminated by any intelligent person. Bring two strangers together, and record what happens. Let A be the psychic and B the sitter. If A, without knowing the person present, without questions, without even seeing the person, who may have come for the first time from the other side of the globe, should give the sitter's name, state that he was a diamond miner, that his father's name was Chelmsford and that both his father and mother were dead, that the mother had given him a special picture of a little church on the corner of the street opposite their home—if these incidents should occur under such circumstances, we should have facts that would at least appear to exclude chance and guessing. Indeed it is easy to eliminate the supposition of coincidence by repeating the experiments. They may be exposed, though hardly in the present supposed circumstances, to the suspicion of fraud and subconscious knowledge; but they are not explicable by chance coincidence or guessing. Nevertheless we have always to think of these possibilities in estimating the value of the facts purporting to be supernormal. Isolated instances of these facts may be explained by chance or guessing, but a large collective mass of them, such as have appeared in the publications of the Societies for Psychical Research, cannot be so explained.

 The four objections previously mentioned are the four most usual objections to belief in supernormal experience. We may, perhaps, regard secondary personality as a fifth. But secondary or multiple personality is only an organized form of subconscious action. Ordinary subconscious actions are isolated and do not represent another person in their collective meaning. But the secondary personality presents all the appearance of a complete and different self. Illustrations of this are the Ansel Bourne, the Charles Brewin, the Sally Beauchamp, and the Wilson cases. I might add, too, the French cases, those of Lucie and Leonie. In them the person went into states resembling hypnosis, as completely separated from the normal personality as another human being would be. The normal self did not remember anything about the subnormal self, though in some cases the secondary personality was aware of the primary self as another person. In others the amnesia was complete on both sides. When any phenomena purporting to be spiritistic can be explained by dual or multiple personality, we have to exclude the hypothesis of spirits from the explanation. Other forms of the supernormal are not connected with secondary personality, or if connected with it, are not explicable by it. Many, perhaps most, cases of secondary personality have nothing to do with the question of the existence of spirits. Sometimes the claim is made of spirit agency; but if the contents of the subject's statements could be obtained by normal experience, the hypothesis of spirits is not legitimate. Any objection to spiritistic claims based on this form of phenomena is but an application of the explanation by subconscious influences, and we need to mention the fact only because it is not generally understood that dual personality is an example of the subconscious mind.

 But we have not decided the case in behalf of the supernormal when we have excluded fraud, chance, and guessing, subconscious action, secondary personality, hysteria and forms of insanity. We do, however, establish the possibility of it when we have excluded them; its proof thereafter depends on the quantity and quality of positive evidence. The exclusion of alternative explanation is only negative evidence; the possession 'of certain facts relevant to the kind of process supposed is required for positive evidence.

 We may indeed prove dousing, telepathy, clairvoyance, telekinesis, and perhaps some other forms of the supernormal without admitting the existence of the discarnate; these facts may even be used in opposing spiritistic theories, as in the case of telepathy, which has been invoked to displace spiritistic interpretations. So long as it is conceivably applicable to the phenomena, it will stand as an objection to the hypothesis of spirits. When coincidence between the thoughts of two persons can account for the facts without the assumption of the personal identity of the dead, the hypothesis of telepathy is an objection to the application of spiritistic explanations. Telepathy, therefore, has the force of an objection in certain cases. The facts taken as evidence for spirits must run the gauntlet of all the previous objections named, whether these objections take the form of normal or supernormal explanations. Spiritistic evidence consists of facts which can be explained only by the continued personal identity of deceased persons, involving memories possessed by the deceased person and transmitted to the living by supernormal means. That is, we cannot believe in the existence of spirits until they are able to prove their personal identity, their conscious memory, by transmitting facts of their terrestrial lives to the living by apparitions, mediums, telekinesis, or some other supernormal method.

 The one best means of proving this personal identity is the transmission of facts, for these are least likely to be referable to normal channels of knowledge. The more trivial the better; that is, the more likely to characterize the one person whose identity is concerned. A single trivial incident will not suffice. There must be a number of them which articulate rightly and have had a psychological or other interest for the person claiming to communicate. If a man should enumerate the books he had written, the statement would have no value at all, as it would be obtainable from the normal knowledge of the psychic or person offering it as evidence. The man's important deeds or the conspicuous events of his life are worthless as evidence of his survival, unless you can prove they were not known to the psychic. It is more difficult to prove ignorance of these events than of private and trivial facts of his career. Trivial incidents are the best evidence of identity. The ridicule applied to the triviality of communications from the dead is therefore unjustified.

 The reason why most people object to the triviality of the facts adduced is that they assume that these communications indicate the character of life in the spiritual world. But in proving the existence of spirits we are not concerned about their status or life in the transcendental world. We are not investigating that problem. We are trying to prove that spirits exist, not that they are wise or exalted in their intelligence; and the materialistic theory itself prescribes for us, as we have seen, the nature of the problem and of the evidence for its solution. We have long been taught that the next life is an idyllic one, a life which throws off the limitations of the present. This may be true or it may not be true. With that question we have no concern in the scientific problem of a spiritual existence. We are trying to ascertain whether consciousness survives, not whether it is transcendentally exalted in intelligence or placed in an ideal world. Materialism makes it necessary to prove the survival of personal identity as the condition of any spiritual existence at all. Nothing but trivial facts will prove this; they are not brought forward as evidence in any respect of the spirit's intelligence.

 The popular objections to triviality in the evidence explains why so many run after revelations of the nature of the future life. They suppose that, if communication between the spiritual and the physical world is possible at all, all sorts of revelations and communications about it are accessible. But no revelation of such a world can be evidence of its existence, unless verifiable by methods which will show that it is trustworthy. Thousands accept such revelations as evidence and pay no attention to trivial facts in proof of identity or scientific methods of investigation and criticism. They are only preparing to be deceived. Verification is an important feature of evidence, and verification is possible only by the testimony of the living or by a vast system of cross references and repetitions of messages impossible now to carry out. In proving identity, especially if we wish to exclude telepathy from the explanation, we must not only have trivial facts of a supernormal kind and illustrative of personal identity, but they must be verified by living people. This connects the past personality with a present consciousness and readily verifies the statement of the psychic. But any fact which cannot be verified by a living person is not worth a penny as evidence. Revelations are not verifiable by individual testimony of living people and occupy no place whatever in the scientific problem as affecting the existence of spirits.

 Telekinesis, or movement of physical objects without contact, is usually regarded as conclusive evidence of the existence of spirits; but, in reality, it is not evidence of it at all. Only mental phenomena will prove the existence of spirits. Physical phenomena unaccompanied by mental phenomena showing intelligence or personal identity are absolutely worthless as evidence. They may be very interesting phenomena, and they may arouse the lethargic physicist to revise some of his previous views, but they cannot be adduced in evidence of spirits until the existence of the latter has been otherwise proved and their association with telekinesis also proved.