80 THE FOUNDATIONS OF SCIENCE 



which may not have been associated before in time 

 or space. Here a new formative process appears 

 the process of comparison. We see a tiger, and it 

 suggests to our mind the remembrance of a cat. We 

 thus consciously compare the cat and the tiger, and 

 form a concept of a feline or cat-class of animals 

 of which the tiger and the cat are varieties, and all 

 tigers and cats we know are members. Such a 

 concept also involves the possibility of the existence 

 of other animals of the class, unknown to us, and 

 assists us in any search for them and in the identi- 

 fication of them. 



And here we see the psychological importance of 

 language : the possibility of giving all similar animals 

 the general name of cat, assists the mind to frame the 

 idea of a universal or general concept of cat. In 

 this it merely helps to clarify the results of sense- 

 perceptions ; but it may also be used to inform us 

 that cats have many interesting properties, such as 

 the possession of nine lives, which we have not our- 

 selves had the benefit of testing, and may incorporate 

 these qualities in our future concept of cat. Thus 

 may be elaborated a process of conceptual synthesis. 



The mental processes of which we are conscious do 

 not represent the whole of the workings of our minds. 

 Sub-conscious changes, apparently independent of 

 voluntary control, may go on, and their results emerge 

 into consciousness at a future time. A problem 



