11(5 HUME iv 



Descartes as an " innate idea " would bear to that 

 idea put into words. 



The fact that the beliefs of memory precede 

 the use of language, and therefore are originally 

 purely instinctive, and independent of any rational 

 justification, should have been of great importance 

 to Hume, from its bearing upon his theory of 

 causation; and it is curious that he has not ad- 

 verted to it, but always takes the trustworthiness 

 of memories for granted. It may be worth while 

 briefly to make good the omission. 



That I was in pain, yesterday, is as certain to 

 me as any matter of fact can be; by no effort of 

 the imagination is it possible for me really to 

 entertain the contrary belief. At the same time, 

 I am bound to admit, that the whole foundation 

 for my belief is the fact, that the idea of pain is 

 indissolubly associated in my mind with the idea 

 of that much past time. Any one who will be at 

 the trouble may provide himself with hundreds of 

 examples to the same effect. 



This and similar observations are important 

 under another aspect. They prove that the idea 

 of even a single strong impression may be so 

 powerfully associated with that of a certain time, 

 as to originate a belief of which the contrary is 

 inconceivable, and which may therefore be prop- 

 erly said to be necessary. A single weak, or 

 moderately strong, impression may not be repre- 

 sented by any memory. But this defect of weak 



