LOGIC AS THE ESSENCE OF PHILOSOPHY 57 



Socrates and man and mortal are empirical terms, only 

 to be understood through particular experience. The 

 corresponding proposition in pure logic is : " If anything 

 has a certain property, and whatever has this property 

 has a certain other property, then the thing in question 

 has the other property." This proposition is absolutely 

 general : it applies to all things and all properties. And 

 it is quite self-evident. Thus in such propositions of 

 pure logic we have the self-evident general propositions 

 of which we were in search. 



A proposition such as, " If Socrates is a man, and all 

 men are mortal, then Socrates is mortal," is true in virtue 

 of its form alone. Its truth, in this hypothetical form, 

 does not depend upon whether Socrates actually is a man, 

 nor upon whether in fact all men are mortal ; thus it is 

 equally true when we substitute other terms for Socrates 

 and man and mortal. The general truth of which it is an 

 instance is purely formal, and belongs to logic. Since it 

 does not mention any particular thing, or even any 

 particular quality or relation, it is wholly independent of 

 the accidental facts of the existent world, and can be 

 known, theoretically, without any experience of particular 

 things or their qualities and relations. 



Logic, we may say, consists of two parts. The first 

 part investigates what propositions are and what forms 

 they may have ; this part enumerates the different kinds of 

 atomic propositions, of molecular propositions, of general 

 propositions, and so on. The second part consists of 

 certain supremely general propositions, which assert the 

 truth of all propositions of certain forms. This second 

 part merges into pure mathematics, whose propositions 

 all turn out, on analysis, to be such general formal truths. 

 The first part, which merely enumerates forms, is the 

 more difficult, and philosophically the more important ; 



