Page:Popular Science Monthly Volume 13.djvu/65

Rh testimony of witnesses depends upon, firstly, their honesty; secondly, their ability; thirdly, their number and the consistency of their testimony; fourthly, the conformity of their testimony with experience; and, fifthly, the coincidence of their testimony with collateral circumstances." Here we observe that honesty is placed before ability, while under ability no distinction is drawn between general and special ability—in other words, between the non-expert and the expert. In the formulated statement of the principles of evidence from which this extract is taken, not only is there no distinction made between expert and non-expert, but no recognition of the fact that the senses of honest and unbiased witnesses may be, through a variety of causes, untrustworthy.

The mistakes in the administration of justice are already numerous, but they would have been more so if judges and juries had not instinctively rejected the principles of evidence thus taught by the highest authorities in jurisprudence.

All modern science is the product of exclusively expert evidence: until an expert develops, there can indeed be no science; and yet, one may look in vain through all the authors on logic for a satisfactory definition of an expert, or for any detailed arrangement of tests by which expertness is to be estimated.

The subject of human testimony has, in short, never been scientifically studied; practical rules for the guidance of those who employ it are all that either logic or law has yet given to the world. As some of these practical rules are based on incorrect assumptions in regard to the value of human testimony, they frequently lead to serious error, and, as they fail to draw just distinctions between the good and bad in evidence, or to give special suggestions for special cases, they are oftentimes of no assistance whatever. This criticism is not made in the way of complaint, for only within the past few years has it been possible to even begin the scientific study of human testimony, while nearly all of our writers on this subject belong to the past generations, and the few later authors mostly copy the errors and imperfections of their predecessors.

Human testimony comes from the human brain: the scientific study of human testimony is only possible through a knowledge of the human brain in health and disease, and is therefore a department of cerebro-physiology and pathology. Only recently have the laws of cerebro-physiology and pathology been sufficiently understood, even by