Page:Popular Science Monthly Volume 13.djvu/345

This page has been validated.
331
SCIENTIFIC STUDY OF HUMAN TESTIMONY.

Coöperation of Experts.—There are claims that can only be settled by a coöperation of experts, in different branches of science. In regard to the question of the relations of experts to each other in the investigations of claims, it is to be observed that a claim should primarily be referred to that specialty that is best capable of dealing with it by deductive reasoning. Claims that can be settled by the principles of logic, without the aid of special scientific knowledge—such as, from the limitations of the human faculties, can never be proved or disproved—are to be referred to logicians. If the known principles of any special science, to which a claim is referred, deductively disprove any claim, it is unscientific for any expert in that science to examine or discuss it, save as an amusement, or for the sake of the incidental facts that an investigation may develop. If the claim refer to an open question, the primary expert is to judge whether the coöperation of experts in other branches of science is needed. If the claim belong to a department not yet organized into science—the territorial or preëxploratory stage—in which there are no experts, there are none to decide upon its merits, and the world must remain in ignorance until the experts appear; but the world, in its impatience and ignorance of logic, practically refers such claims to leaders in various branches of science, or to men of general ability and honesty, who almost always reach erroneous, if not ludicrous, conclusions. Such was the origin of the delusions of "animal magnetism," and "odic" and "psychic" force—claims that belong to cerebro-physiology, a department of science that is now but just passing out of the territorial into the organized stage.[1] When experts blunder, as they may, their conclusions should be revised, not by the people, but by other and better experts.

II. The reconstructed principles of evidence require that the quality and quantity of evidence necessary for proof of any claim depends on the nature of the claim.

The principles of evidence that have heretofore commanded the world's acceptance make no distinction in the quality or quantity of testimony for different varieties of claims; the discovery of a new planet is as credible as the daily rising of the sun; the introduction of a new force needs no more and no better auspices than the observation of the

  1. Mr. William Crookes, in his kindly and complimentary remarks on my theory of trance, as republished in the London Quarterly Journal of Science, January, 1878, observes that there may be a physical side to physiological experiments. The suggestion is so far forth a valid one; the reply is found in the above analysis. The question whether there is in the human body a new and unknown force belongs to cerebro-physiology, and, not being disproved deductively, should be referred to those experts in that specialty who understand how to experiment with living human beings; and it is for these primary experts to decide whether the experiments they may make require the coöperation of physics, or chemistry, or other branches of science. There may also be a physiological or pathological side to physical experiments; thus the "etheric force" of Mr. T. A. Edison was primarily a question of physics, but for its investigation needed and obtained the coöperation of physiologists.