2. Claims as to general or special facts of science that are already established by the investigations of experts.
Here we rise in the scale of evidence, but do not require experts. What is bad or useless evidence for original demonstration may be satisfactory, or at least tolerable, for confirmation. The phonograph, prior to its invention, was credible only on expert authority; stories relating to it may now be received on the statements of non-experts, for, although they may be erroneous, they do not in any way affect science.
III. Claims as to facts or phenomena which have not yet been established by experts in the special science to which they are to be referred, but which may yet be proved true by the experts of the future.
Here we take a long step in the ascending scale of evidence; we come to claims that cannot be proved by any amount of non-expert evidence; which may be true, or may be untrue, as experts only shall determine. A type of this class of claims is that of the sea-serpent, of whose existence there is now no proof, but which zoölogists might possibly introduce into science. Testimony which is sufficient to arouse the attention of experts, and induce them to investigate claims that are made by non-experts, may yet of itself have no value in science.
Types of this class of claims are supposed new forces in Nature, the existence of which can only be established by the highest experts in the branches of science to which they respectively belong. The claims of "odic" force and "psychic" force, and of "animal magnetism," are excellent illustrations: although believed by thousands and thousands of people of average intelligence, and by a number of eminent non-experts in science, they are yet instinctively rejected, not because there is any positive deduction against them, but for the reason that experts have never been able to find a shadow of proof of their existence, but, on the contrary, have been easily and abundantly able to show that all the real phenomena supposed to indicate the presence of these unknown forces can be explained by the laws of forces already known. An illustration, belonging in part to a different branch of science, was that of the alleged new force, between light and heat on the one hand, and magnetism and electricity on the other, said to have been discovered
and pathology of the nervous system do not, in their experiments, even suspect the elements of error involved. During the past year one of the very ablest of neurologists—Charcot, of Paris—has published accounts of experiments in so-called "metalloscopy" and "metallotherapy," in the making of which, according to his own statements, one of the most important of the six elements of error (as indicated in a paper on "Mindreading," in a previous number of this Monthly), mind acting on body, seems to have been ignored or ill understood, or at least not scientifically provided for. The experiments of the committees of the French Academy with "animal magnetism," "mesmerism," and "clairvoyance," of Crookes with Home, of Wallace and Zollner with Slade, are open to the same and also numerous other criticisms. From such accounts of such experiments, even an expert cannot tell what did or what did not happen; it is therefore unscientific to discuss them.