256 ELEMENTS OF SCIENCE 



qualities may be distinctly recognised as really being 

 qualities of the object observed. 



The power by which we thus ideally separate qualities 

 is called abstraction, and by it our mind isolates (in order 

 to apprehend them distinctiy) the various qualities and 

 conditions which really exist in any object perceived. 

 Thus if the object perceived be a horse, we may notice 

 that it has the characters of " a quadruped," that it is 

 " a living creature," that it is " a solid body," or at least 

 that it is " a something." Each such conception, though 

 applicable to a multitude of individuals of the same 

 kind, is a conception which, considered in itself, is one. 

 It is a single notion, not of any one separate and sub- 

 sisting thing, but it refers to a group of objects, to each 

 of which the notion is applicable. It is an abstract idea 

 of a lower or higher degree of abstraction ; thus the term 

 " horse " is an abstract idea formed through all we may 

 have learned about horses. The term quadruped is more 

 abstract, and is applicable to a vastly larger group of 

 creatures. The same is again the case with the abstract 

 ideas " living creature " and " solid body," while in the 

 idea " something," which is the idea of " being," we 

 arrive at the highest possible degree of abstraction, the 

 most abstract of all " abstract ideas." 



That feelings and "ideas" are fundamentally distinct,* 

 is shown by the fact that the same idea may be called up 

 in the mind by either sight, hearing, or feeling (e.g., the 

 idea " triangle "), while one set of sense impressions may 

 give rise to a great number of different ideas, as the sight 

 of a single photograph of the Queen may give rise to the 



* The reader is referred for much further information on this 

 subject to our work entitled " The Origin of Human Reason." 

 Kegan Paul, Trench & Co., 1889, p. 45. 



