In short, we observe how in each of these cases the wish to see a thing happen misguided the judgment, and the same thing occurs in spiritistic seances, but more especially with respect to the way in which the minutes are kept. Even in the case of doubters the experiments cause such a tension of the apparatus of attention that their mental condition cannot be said to favour the exercise of criticism. We have also to consider that the whole environment rarely or never favours the formation of an objective decision. With some people it provokes laughter, but on others the emotional effect is such that they cannot judge the proceedings from a cold-blooded point of view.

As I have already mentioned, we need not attach much importance to the fact that a few savants uphold the reality of occultistic phenomena. I myself formerly attached a certain amount of importance to this fact. But since I have observed the utter helplessness of savants directly they enter on methods of investigation with which they are not thoroughly acquainted, I have become convinced that mediums easily lead great savants by the nose. After one or two seances, mediums easily recognize what will satisfy one person but not another. I remember once meeting a savant of my acquaintance, who was a believer in occultistic phenomena and especially in the miracles of Eusapia Palladino, and how instructive that rencontre proved to me. When he explained to me that he had seen objects move and tables which were not attached to the medium jump up in the air, I told him that I had witnessed similar phenomena, but did not consider them convincing, as the whole proceeding could very well be worked by means of a string. He thereupon assured me that he had examined the subject, and was therefore convinced that she had no string about her. I then asked him how long the examination lasted, and his answer showed that it only took up a few minutes.

I then told him how astonished I was that he should think himself able to discover in a minute or two whether a woman had a string concealed about her person, and I further assured him that all professional jugglers would agree with me that a thorough examination was extremely difficult.

But he remained obdurate; it was enough for him that he had examined the woman. This only shows how careful we should be to avoid being imposed on by authorities!

When I come to look through the vast literature of occultism, I find that I am totally unable to discover even one single series of experiments that carries with it a convincing proof of the reality of occultistic phenomena; nothing but casual observations or unchecked experiments. There was a time when some of the telepathic experiments carried out in England - more especially those made by Guthrie and Birchall - appeared to me, relatively speaking, free from error. Nevertheless, when I take into consideration the way in which the reports are drawn up, I am compelled to admit that those experiments are not convincing. As Max Dessoir has pointed out, it is only when a single experiment is selected and then performed under varying conditions that we can speak of a scientific investigation (cf. p. 533).

There is nothing to be said against the present investigation of inexplicable things. Almost all great steps in natural science have been made by some one who had the courage to contest existing views, in spite of the danger of looking ridiculous. Harvey was obliged to struggle with the prejudices of his colleagues for years before the circulation of the blood was accepted. The fall of meteors projected by other celestial bodies was long denied. Modern anatomy was founded by Andreas Vesalius, who had to fight hard against the prejudices of his day. Helmholtz relates that a very distinguished surgeon told him he would never use the ophthalmoscope, because it was dangerous to throw a glaring light into a patient's eye. Another declared that the instrument might do for doctors afflicted with weak sight, but his eyesight was good and did not require such assistance. As we see, the fact that a thing is attacked ought not to prevent its being investigated. The assertion that a thing is contrary to the laws of nature and therefore wrong should not be considered conclusive.

The contradiction is often merely apparent, and the laws of nature, as we call them, are only derived from facts we have observed When new facts are observed which do not agree with laws of nature we have been accustomed to accept, it is our duty not to deny the facts, but to modify those laws. Theories never precede facts. Observation and experience come first, then theory (Spencer). The electric current does not cause muscles to contract because the book says so; the book says so because the current causes the contraction.

In spite of scientific doubt, truly great men always endeavour to avoid dogma and a priori conclusions. If they cannot examine everything themselves, they yet consider a scientific examination even of the improbable necessary. An example which Delbceuf brings forward may be mentioned. Darwin once wished, it is said, to examine the influence of music on the growth of plants, because such an influence had been spoken about before him, and he therefore made some one play the bassoon for several days, close to some planted beans. If this anecdote is not true, it is well invented. The non-recognition of dogma distinguishes science from blind faith, but to say a fact is impossible because it is opposed to the laws of nature is to dogmatize.

Our knowledge of nature is still very defective. No one has ever explained even the simplest mental process. No one has explained how an ovum, fertilized but soulless, develops into a being with a soul., We have not the remotest notion what goes on in the brain when the will acting through it and the nerves causes the muscles to contract. Indeed, we do not even know why an apple falls to the ground. The most elementary processes are inexplicable wherever we look, and most people do not think them inexplicable because they see them every day. Some one has justly said that dreams, as well as hypnotism, might be called swindles if they did not happen every day. The world still puts so many riddles before us that it is quite inadmissible to attempt to shirk the investigation of certain processes on the ground that they are contrary to the laws of nature. Science is still very far from having achieved a position that would Justify such an attitude.

We do, indeed, flatter ourselves that knowledge has reached an extraordinarily high degree of perfection. But if we look back, we find that the same opinion was held in the past. "No one acquainted with universal history and the ever-increasing field of scientific research can doubt that our century which is now drawing to a close, and more especially the last ten years of it, will be placed by an impartial posterity at the head of the most brilliant and marvellous epochs in the annals of mankind. . . . No matter whether we direct our attention to the domain of the sciences or the realms of nature, we are filled with astonishment and wonder at the extraordinary progress made in our days." That was the opinion expressed by Fikenscher in 1799. And Wieland wrote in his essay on magnetism, published in 1787: - "At a period in which knowledge is so much more general than it used to be, and science stands on a higher pedestal than it ever did before, etc" Belief in the unparalleled development of science is common to all ages, and for this very reason it is our duty to discover whether it is justified.

Our knowledge is so incomplete, and whichever way we look so many riddles meet our gaze, that we have no right to flatly refuse to recognize any domain of research.

In spite of the progress which the exact sciences have made, we must nevertheless admit that the inner connection between the body and the mental processes is utterly unknown to us. Under these circumstances we should not refuse to examine the apparently inexplicable. Let us, however, impose severe conditions, and not accept any facts on authority without proof.