CHAPTER XLIV. 



KEMAEKS ON THE HISTOEY OF SCIENCE, 



ACCOEDINGr to the principles laid down in the pre- Agree- 

 ceding chapter, the logical order of arrangement for ^j^e his- 

 the sciences is an arrangement in series, beginning with toncal 



° . . order of 



those whereof the subject-matter is most simple and the evolu- 

 general, and going on to those whereof it is more com- *|,ig^°gg* ^ 

 plex and special. with their 



This, which is the logical order, is also in a great degree o°|gr^ 

 the historical order. Those sciences whereof the subject- 

 matter is simple and general have for the most part come 

 into existence as sciences earlier than those whereof the 

 subject-matter is more complex and special. This is what 

 we might have expected, and for two reasons. In the first 

 place, the simplest subject-matter is the easiest to master; 

 and in the second place, it is necessary to understand the 

 more general laws before the more special ones can be 

 understood. Thus, mathematics is necessary as the key 

 to dynamics ; general dynamics as the key to the laws of 

 heat and electricity ; the sciences of heat and electricity 

 as the key to chemistry ; and chemistry as the key to 

 physiology. In a word, the most general truths were the 

 first to be discovered. As in painting a picture, the artist Ilhistra- 

 first sketches the outline, and completion does not mean painting a 

 covering more canvas, but filling in the outline with more pictm-e. 

 detail ; so in the history of science the widest truths have 

 been laid down first ; and progress consists in the dis- 

 covery of a constantly increasing number of more special 

 truths, and in the ascertainment of their relation to the 

 general ones. Thus, for instance, the most important 



