Page:Popular Science Monthly Volume 13.djvu/346

332 established phenomena of an old one; the passing from death into life is to be received with as little question as the passing from life into death. Under this feature of current logic delusionists of all kinds have consistently and persistently found refuge.

The different classes of claims in regard to real or alleged phenomena, in their relation to the quality and quantity of evidence needed to prove them, may be thus presented in order of climax:

1. Claims as to unsystematized knowledge or matters of every-day life.

Under this head comes most of the testimony commonly given in courts of justice. For claims of this kind experts are not usually required, and the mistakes which are constantly made, every hour and every moment, are of comparatively trifling account, since they affect individuals and not general principles.

It is one of the innumerable proofs of the limitations of the human brain, that the rules of evidence in our courts of justice, although practically, on the average, as good, with some exceptions, as can be expected for the obtaining of legal justice, necessarily imperfect and uncertain, are yet, in many respects, to the last degree unscientific. The exclusion, for example, of hearsay testimony, and of the testimony of a wife against her husband, and the modes of questioning and cross-questioning of witnesses make it oftentimes impossible to obtain justice. The scientific man, desirous not of gaining a point but of ascertaining the truth, and recognizing the untrustworthiness or uncertainty of nearly all human testimony, would in many cases prefer hearsay to direct statements, and would give more for the evidence of a near relation or a wife than for that of all the world besides.

One needs but to follow the details of a few great causes, as the McFarland trial, the Beecher-Tilton, the Tichborne, and the Vanderbilt cases, to see that by the rules of evidence, or at least by the actual practice of courts, testimony which scientifically is valueless is admitted, while the only testimony that is, or promises to be, of any scientific value is systematically excluded.

The great advances in science have not been made in courts of justice. Even when on questions of science experts are called to testify, their testimony is obtained in such a way as to impair, if not destroy, its value, and to obscure more than to reveal the truth.

From the scientific point of view, a legal trial is really an experiment with living human beings, and, like all experiments of that kind, is liable to six sources of error, all of which must be guarded against if we are to find the exact truth. The science and art of experimenting with living human beings are not yet understood, even by physiology and pathology, to which department they belong.