LOGIC AS THE ESSENCE OF PHILOSOPHY 45 



sider those simpler forms which inference presupposes. 

 Here the traditional logic failed completely : it believed 

 that there was only one form of simple proposition (i.e. 

 of proposition not stating a relation between two or more 

 other propositions), namely, the form which ascribes a 

 predicate to a subject. This is the appropriate form in 

 assigning the qualities of a given thing we may say 

 " this thing is round, and red, and so on." Grammar 

 favours this form, but philosophically it is so far from 

 universal that it is not even very common. If we say 

 " this thing is bigger than that," we are not assigning a 

 mere quality of " this," but a relation of " this " and " that." 

 We might express the same fact by saying " that thing 

 is smaller than this," where grammatically the subject is 

 changed. Thus propositions stating that two things have 

 a certain relation have a different form from subject-pre- 

 dicate propositions, and the failure to perceive this 

 difference or to allow for it has been the source of many 

 errors in traditional metaphysics. 



The belief or unconscious conviction that all proposi- 

 tions are of the subject-predicate form in other words, 

 that every fact consists in some thing having some quality 

 has rendered most philosophers incapable of giving any 

 account of the world of science and daily life. If they 

 had been honestly anxious to give such an account, they 

 would probably have discovered their error very quickly ; 

 but most of them were less anxious to understand the 

 world of science and daily life, than to convict it of 

 unreality in the interests of a super-sensible " real " 

 world. Belief in the unreality of the world of sense 

 arises with irresistible force in certain moods moods 

 which, I imagine, have some simple physiological basis, 

 but are none the less powerfully persuasive. The con- 

 viction born of these moods is the source of most 



