SCIENTIFIC STUDY OF HUMAN TESTIMONY. 329 



although it is relative to the human faculties. The revision of human 

 testimony that physiological science now requires, and is qualified to 

 undertake, is radical and revolutionary, but it is not suicidal ; it is dis- 

 criminating, not sweeping ; not destructive, but constructive. 



The demand is not for the rejection but for the reconstruction of 

 human testimony ; and the spirit with which this should be undertaken 

 is not skeptical, but scientific. 



This reform of logic, like all revolutions in science, should advance 

 under the guidance of the scientific method. By the scientific method, 

 I mean that method of obtaining and organizing knowledge which 

 consists in defining, so far as is possible to expert human faculties, the 

 boundaries between the possible and the probable, between the knoicn 

 and the unknown. 



The scientific method can only be successfully used by those who 

 are endowed with, or by discipline have acquired, what I am accustomed 

 to call the scientific sense, by which phrase I mean the power of seeking 

 truth through the intellect alone, uninfluenced by the emotions. For the 

 tendency of truth, the scientific sense has no hopes and no fears, except 

 so far as it may help to find the truth. 1 



The scientific method is a part of the evolution of culture, of sci- 

 ence, and of civilization ; to absolute savagery everything is absolutely 

 known ; all natural phenomena are pronounced supernatural ; with the 

 beginning of knowledge there is a recognition of ignorance, which, in 

 time, gradually subdivides so as to include all phenomena that can be 

 brought to the attention of the human mind in one of these four grand 

 divisions the possible, the probable, the known, and the unknown. 

 The constant effect and sign of progress in knowledge is the narrowing 

 of the area of the known and the probable, and the extension of the 

 areas of the unknown and the possible. 



I. The corner-stone of the reconstructed edifice of the principles of 

 evidence must be the recognition of the necessity of the testimony only 

 of experts in all matters of science, and consequent absolute rejection 

 of all testimony of non-experts, without reference to their number or 

 the unanimity of their testimony. 



A few definitions are here needed : 

 Science is systematized knoicledge. 

 An expert is one who can see all sides of a subject. 

 A non-expert is one who sees but one or a few sides of a subject that 

 has many sides. 



1 The philosophy of the world has almost always been the servant of delusions. The 

 most eloquent passage in Sir William Hamilton's " Logic " is that in which he enjoins on 

 the philosopher the duty of seeking truth for its own sake, and there are few or no phi- 

 losophers who would not in the abstract subscribe to this sentiment, but concretely and 

 practically nearly all human reasoning on logic and the principles of evidence has been 

 exercised for the special purpose of proving what is absolutely undemonstrable or abso- 

 lutely untrue. 



