vi CONCERNING NECESSARY TRUTHS 



If what are called necessary truths are rigidly 

 analysed, they will be found to be of two kinds. 

 Either they depend on the convention which 

 underlies the possibility of intelligible speech, 

 that terms shall always have the same meaning; 

 or they are propositions the negation of which 

 implies the dissolution of some association in 

 memory or expectation, which is in fact indis- 

 soluble; or the denial of some fact of immediate 

 consciousness. 



The " necessary truth " A = A means that the 

 perception which is called A shall always be called 

 A. The " necessary truth " that " two straight 

 lines cannot inclose a space," means that we have 

 no memory, and can form no expectation of their 

 so doing. The denial of the " necessary truth " 

 that the thought now in my mind exists, involves 

 the denial of consciousness. 



To the assertion that the evidence of matter of 

 fact is not so strong as that of relations of ideas, 

 it may be justly replied, that a great number of 

 matters of fact are nothing but relations of ideas. 

 If I say that red is unlike blue, I make an asser- 

 tion concerning a relation of ideas; but it is also 

 matter of fact, and the contrary proposition is 

 inconceivable. If _I remember * something that 

 happened five minutes ago, that is matter of 

 fact; and, at the same time, it expresses a relation 



* Hume, however, expressly includes the " records of our 

 memory " among his matters of fact. (IV. p. 33.) 



