PREFACE. ix 



I have, in fact, almost restricted myself to showing that 

 all classification is fundamentally carried out upon the 

 principles of Formal Logic and the Logical Abecedarium 

 described at the outset. 



In certain concluding remarks I have expressed the 

 conviction which the study of Logic has by degrees forced 

 upon my mind, that serious misconceptions are entertained 

 by some scientific men as to the logical value of our know- 

 ledge of nature. We have heard much of what has been 

 aptly called the Reign of Law, and the necessity and uni- 

 formity of natural forces has been not uncommonly inter- 

 preted as involving the non-existence of an intelligent and 

 benevolent Power, capable of interfering with the course 

 of natural events. Fears have been expressed that the 

 progress of Scientific Method must therefore result in dis- 

 sipating the fondest beliefs of the human heart. Even the 

 ' Utility of Religion ' is seriously proposed as a subject of 

 discussion. It seemed to be not out of place in a work on 

 Scientific Method to allude to the ultimate results and 

 limits of that method. I fear that I have very imper- 

 fectly succeeded in expressing my strong conviction that 

 before a rigorous logical scrutiny the Reign of Law will 

 prove to be an unverified hypothesis, the Uniformity of 

 Nature an ambiguous expression, the certainty of our 

 scientific inferences to a great extent a delusion. The 

 value of science is of course very high, while the con- 

 clusions are kept well within the limits of the data on 

 which they are founded, but it is pointed out that our 

 experience is of the most limited character compared with 

 what there is to learn, while our mental powers seem to 

 fall infinitely short of the task of comprehending and 

 explaining fully the nature of any one object. I draw the 

 conclusion that we must interpret the results of Scientific 

 Method in an affirmative sense only. Ours must be a 

 truly positive philosophy, not that false negative philo- 



