26 PROGRESS OF SCIENCE IN THE CENTURY. 



aim of science-teaching, which is a culture of the 

 scientific mood and an appreciation of scientific 

 method, seems more likely to be attained by a 

 thorough study of some one order of facts than by 

 an intellectual ramble through the universe; on the 

 other hand, the true dignity and value of science can- 

 not be appreciated if the unity of nature and of 

 knowledge be practically denied. Superficiality re- 

 sults from lack of specialisation, and pedantry from 

 too much of it. Let us briefly consider some of the 

 classifications which have been found convenient. 

 Francis Bacon (1561-1626) recognised three de- 

 partments of human learning: (1) History (based 

 on memory) both "natural" and "civil"; (2) 

 Poesy (based on imagination) ; and (3) Philosophy 

 or the Sciences (based on reason), including Divin- 

 ity, which has to do with revelation, and Natural 

 Philosophy, which deals with God, Nature, and 

 Man! There is little in this classification which 

 can be of service to us to-day in mapping out 

 the territory of science, but it is interesting (as 

 Karl Pearson points out) to notice the suggestion 

 that " The divisions of knowledge are not like 

 several lines that meet in one angle, but are rather 

 like branches of a tree that meet in one stem." 

 Auguste Comte (1798-1857) recognised six fun- 

 damental sciences: Mathematics, Astronomy, Phys- 

 ics, Chemistry, Biology, Sociology and a supreme 

 or final science of Morals. He sought to eliminate 

 from his system all that is not based on experience, 

 and he introduced the important conception of a 

 hierarchy of knowledge, that is to say the idea that 

 one department of science is dependent on another, 

 sociology on biology, biology on chemistry, chemis- 

 try on physics, and so on. Without pretending that 



