ioo DEVELOPMENT AND PURPOSE CHAP. 



for more developed thought in the logical categories. We 

 may then consider the first stage in human thought to be 

 one in which the process of organising experience into the 

 common categories is incomplete, and the evidence for the 

 truth of an idea is not yet separate from the qualities which 

 make it pleasant. The transition to the second stage, which 

 we have called that of common sense, witnesses (i) the 

 organisation of ideas in accordance with the categories, and 

 (2) the differentiation of belief from feeling. Neither of 

 these processes is to be understood as being derived as yet 

 from any abstract principle. The categories are not known 

 in the abstract, and there are no laws or formulae of truth, 

 only experience has begun to shape the world of ideas and 

 of language into that form in which logic finds it the form 

 in which concrete substances and their functions, attributes 

 and relations are clear enough and are quite distinct from 

 one another : the world again where proof is already one 

 thing and liking another. These are the simple essentials 

 of that empirical order which represents the workaday 

 world as it presents itself to the average civilised man, out- 

 side the scientific laboratory, the church or the lecture room. 

 (3) Now this order and the methods which establish it 

 are exposed to attack from more than one angle. On the 

 one hand, there is the risk of self-criticism. This may be 

 said to begin with the demand for exactitude, a demand to 

 which practical interests cannot always close their ears. 

 But the criterion of exactitude applied to loose generalisa- 

 tion means criticism and definition, and opens the road to 

 science and philosophy, wherein the structural categories 

 themselves will not escape attention. To this road we 

 must return later. Let us notice first the other angle of 

 attack. The world of common sense is not the whole 

 world. Some would say it is not the real world at all. 

 Whether that is so or not we shall have to enquire, but 

 granted for the moment that its world is real, still it is not 

 the whole world. Worse, it is not a world that explains 

 itself. The forces that produce the play of action visible 

 within it are not themselves within it. This is no meta- 

 physical dogma, but, for us, provable fact. Take the 

 course of a disease. Common sense moving on the plane 



