But when we come down to the lower levels of the domain of the spiritual we find ourselves on firmer ground. Here we are dealing with the finite, not with the infinite, and nothing that is finite can lie beyond the boundaries of investigation, however long it may take to reach it. The question of the existence of spirits, for instance,—that much mooted problem of the immortality, or at least of the future existence, of man, which forms so prominent an element in modern religion,—dwells within the possible reach of science, and the attempt to deal with it by scientific evidence may reasonably be made. When we pass beyond the realm of the senses we find ourselves in a kingdom peopled by stupendous forms and forces,—space, time, matter, energy, and perhaps infinite consciousness,—all in their ultimate conditions too vast for the finite mind to grasp, all presenting problems open to speculation, but beyond the reach of demonstration. But below these lie finite possibilities which the human mind may now be, or may become, capable of comprehending, and prominent among these lies the problem just mentioned, that of the existence of a spiritual substratum in man, a soul which is capable of surviving the death of the body. This is a subject with which all of us are deeply and intimately concerned, and it may be well to close this volume with a brief glance at its status as a scientific question.
The belief in the immortality of man is comparatively modern in origin. There is no satisfactory evidence that any such belief existed among the old Jews, or that it arose in Palestine before the time of Christ. It arose at an earlier period in India and Persia, but everywhere it was late in its appearance as a well-defined doctrine. Yet, while positive evidence is wanting, there can be little doubt that crude and vaguely formulated ideas of the existence of man after death have been very long entertained. The traditions of all peoples that have a faith above that of fetichism contain stories of the apparition of spirits of human origin, and when we reach civilized peoples and more advanced religions we find these in abundance. The annals of Christendom are full of them. They are equally abundant in the centres of other developed forms of faith. If we could accept these legends of the emergence of spirits through the thin veil that separates time from eternity as established facts, the problem would no longer need solution. As it stands, however, the great mass of such narratives are utterly lacking in evidence of a character which science can admit. They are bare, unsustained statements, thousands of which would be far outweighed by a single one fortified by demonstrated facts. Occasionally, indeed, the story of an apparition has been closely investigated, and there are a few cases of this kind handed down from the past which seem reasonably well established. But any statement coming from prescientific days is open to doubt; methods of investigation then were not what they are now; the dogma of the existence of spirit is too important a one to be accepted on any but incontrovertible evidence, and the vast sum of statements of apparitions which have come to us from the past, or from the non-scientific peoples of the present, must be dismissed with the one verdict, not proven.
There is one important fact, however, connected with the question of spiritual appearances, which is worthy of some consideration. It is a fixed rule in the history of opinions that beliefs founded on imagination or misconception have declined with the advance of enlightenment, and many conceptions, once strongly entertained, have faded and vanished in the light of new thought, or where retained have been so only by the ignorant and unreasoning. It is of interest to find that this has not been the case with the belief in spiritual manifestations. This has held its own to the present time, and, while it is largely sustained by the unintelligent and credulous, it can claim a considerable body of intelligent adherents to-day, even in the most enlightened nations. This belief, known as spiritism, with the manifestations upon which it is founded, lies open, therefore, to modern scientific investigation; and this has been, to some extent, applied to it, with, in various instances, rather startling results.
It is certainly of significance to find that a number of prominent scientists, thoroughly skilled in the arts of investigation, have attacked this problem with the purpose of annihilating it, and have ended in becoming convinced of the truth of spiritism. It may suffice to mention two of the most striking instances of this. In the early days of the spiritist propaganda, Robert Hare, a famous chemist of Philadelphia, entered upon an investigation of the so-called spiritual phenomena with the declared purpose of proving them to be fraudulent. His observations were long continued, his tests varied and delicate, and he ended by himself ardently adopting the belief he had set out to abolish. Somewhat later William Crookes of London, an equally famous chemist and physicist, entered upon a similar investigation, and with like results. The tests applied by these men were strictly scientific, and of the exhaustive character suggested by their long experience in chemical investigation; and their conversion to the tenets of spiritism, as a result of their experiments, was a marked triumph to the advocates of the doctrine. Various others of admitted high intelligence, who made a similar investigation and were similarly converted, might be named. Two of the best known of these were Judge Edmonds, of the circuit court of New York, and Alfred Russel Wallace of England, who shared with Darwin the honor of originating the theory of natural selection.
While these, and others of scientific education, were converted to spiritism, many investigators came to an opposite conclusion, while a similar negative result was reached in the investigations of several committees of scientists. The latest and most persistent attempt to search into the reality of phenomena of this character has been that made by the London Society for Psychical Research, whose investigations have extended over years and have yielded numerous striking and suggestive results. The most important conclusion at which the members of this society have so far arrived is the hypothesis of Telepathy, or the seeming power of one mind to influence the thoughts of another, occasionally over long distances, in a method that appears analogous to that of wireless telegraphy. The evidences in favor of this doctrine are so numerous that it has been somewhat widely accepted, and the title applied to it has come into general use. It indicates, if true, remarkable powers in the mind of man, capabilities that seem far to transcend those of the ordinary intellectual activities.
This is one side of the case. The other side now calls for presentation. This is that the great body of scientists utterly reject the theory of spiritism, and look upon its manifestations as due to fraud, misconception, credulity, or some other of the weaknesses to which human nature is liable. As regards the opinions arrived at by the prominent scientists mentioned, these men are looked upon by their fellows of the great scientific body as mentally warped, or as having allowed themselves to be victimized by impostors. The fact that Professor Crookes has continued one of the most acute and deep searching of investigators into the phenomena of physics, and that his results in this direction are accepted without question, and that Professor Wallace is acknowledged to be one of the leading thinkers of the day, has not sufficed to clear them of the doubt which rests upon their sanity or their critical judgment in this particular, and the very attempt of any one to investigate the so-called spiritual manifestations is widely looked upon as an evidence of credulity or some greater mental weakness.
This result may seem singular, yet it is not without abundant warrant. It must be borne in mind that the phenomena in question differ essentially in character from those with which science is usually concerned. The field of scientific investigation is distinctly the material; the facts with which it deals are those apparent to the senses, or which can be tested by material instruments; its discoveries are generally susceptible of but one interpretation; its methods are capable of being indefinitely repeated, and its results, if justly interpreted, are unvarying in character. None of these postulates fully applies to the spiritistic investigation. Here the conditions differ, the results vary, the methods can rarely be exactly repeated, conscious beings, instead of unconscious instruments, are the agents employed, and the secret thoughts and purposes of such agents are very likely to vitiate the result, and open a field of doubt which does not exist in the investigation of the inorganic world.
This is one of the causes of the doubt of scientists. It is not the only or the chief cause. The latter is the fact that the claims of spiritism lift man into an entirely new domain of the universe, remove him from the great field of the material with which he is physically affiliated and to which his senses are closely adapted, and place him in a region beyond the scope of the senses, a vast kingdom which is held to underlie or subtend the physical, and which the ordinary outlook of the scientist fails to perceive. It requires no strain of the imagination to admit the existence of a new constituent of the atmosphere. It requires a great strain to admit the existence of a new constituent of the universe, a vast spiritual substratum to the domain of matter. Religion, with its ideal tests, has long maintained this to be a fact. Science, with its rigid material tests, sternly questions it, and demands that the existence of an inhabited spiritual realm shall be incontestably proved by scientific evidence before it can be accepted.
This demand is a reasonable one. The world is growing rapidly more scientific, and the old method of arriving at conclusions is daily losing strength. Beliefs based on ideal or imaginative postulates, once strong, are now weak. Faith founded on ancient authority is active still, but promises to become obsolete. The way of science is growing to be the way of the world, and in the time to come intelligent men will doubtless demand incontestable evidence of any fact which they are asked to accept.
As regards the phenomena in question, however, it cannot be said that they have been fairly or fully investigated by scientists. They have been set down as the work of charlatans, and their apparent results ascribed to fraud, collusion, credulity, and mental obliquity in general. The fact, that of the scientists who have exhaustively investigated the spiritistic phenomena, a considerable number have accepted them as valid, has had no effect upon scientists as a body, who, in this particular, occupy the position which they accuse non-scientists of maintaining, that of forming opinions without investigating phenomena.