90 Criteria of Truth in Mental Science. 



The principles of nature and the modes of mental 

 action are the same for all men. It necessarily 

 follows from the essential nature of truth and the in- 

 variability of the chief methods of detecting it, that 

 the criteria of truth in mental science, and the mental 

 powers and processes by which truth is arrived at and 

 detected in that science, are essentially the same as in 

 the physiological, chemical, and physical ones. In 

 each of these subjects, we first, either with or without 

 the aid of experiment, make observations, record 

 facts, compare them, and draw conclusions from our 

 comparisons ; we also group the facts, and the con- 

 clusions, in every possible way, and then draw other 

 conclusions ; we also analyse, combine, and permu- 

 tate the various truths arrived at, and cross examine 

 the evidence in every possible manner in order to ex- 

 tract from it the greatest amount of new knowledge. 

 And in each case we employ as the criteria of truth, 

 the test of consistency with the whole of the evidence 

 bearing upon the case, and especially with the great 

 principles of science. We determine what is true,, 

 chiefly by comparison with those principles, because 

 they are the most firmly established true ones and 

 the most universal. There is no royal road to truth, 

 and no special mental faculty for detecting it in any 

 subject ; and it is in consequence of our mental 

 faculties being so very finite that we have no easier 

 way of arriving at truth. 



No dogmatic teaching can ever, except by accident, 

 fully explain to man the true nature of mind ; and 



