20 MENTAL EVOLUTION IN MAN 



CHAPTER IV. 



LOGIC OF CONCEPTS. 



The device of applying symbols to stand for ideas, and then 

 using the symbols as ideas, operates to the formation of more 

 highly abstract ideas in a manner that is easily seen. For 

 instance, because we observe that a great many objects 

 present a certain quality in common, such as redness, we 

 find it convenient to give this quality a name ; and, having 

 done so, we speak of redness in the abstract, or as standing 

 apart from any particular object. Our word "redness" then 

 serves as a sign or symbol of a quality, apart from any 

 particular object of which it may happen to be a quality \ 

 and having made this symbolic abstraction in the case of a 

 simple quality, such as redness, we can afterwards compound 

 it with other symbolic abstractions, and so on till we arrive 

 at verbal symbols of more and more abstract or general 

 qualities, as well as qualities further and further removed 

 from immediate perception. Thus, seeing that many other 

 objects agree in being yellow, others blue, and so on, we 

 combine all these abstractions into a still more general 

 concept of Colour, which, qua more abstract, is further 

 removed from immediate perception — it being impossible 

 that we can ever have a percept answering to the amalgamated 

 concept of colour^ although we have many percepts answering 

 to the constituent concepts of colours. 



So in the analogous case of objects. The proper names 

 Peter, Paul, John, &c., stand in my mind as marks of my 

 individual concepts : the term Man serves to sum up all the 



