THE EXPLANATION OF LAWS 103 



conceived his symphony had no need to test it in order 

 to discover if it was " right," while Newton had to com- 

 pare the results of his theory with the external world, 

 before he was sure of its true value. Does not this show 

 that Newton's achievement was not so perfectly personal 

 and imaginative as Beethoven's ? 



I do not think so. First, Beethoven's work had to be 

 tested ; the test of artistic greatness is appeal to succeed- 

 ing generations free from the circumstances in which the 

 work was conceived ; it is very nearly the test of universal 

 agreement. But it is another point of view I want to 

 emphasize here. It is said that Newton's theory was 

 not known to be true before it was tested ; but Newton 

 knew that it was true of that I am certain. To our 

 lesser minds there seems no imperative reason why the 

 force on the moon and the force on the apple should be 

 related as closely as the theory of gravitation demands, 

 merely because it would be so delightfully simple if they 

 were ; but Newton probably felt no doubt whatever on 

 the matter. As soon as it had occurred to him that the 

 fall of the apple and the fall of the moon might be the 

 same thing, he was utterly sure that they were the same 

 thing ; so beautiful an idea must be true. To him the 

 confirmation of numerical agreement added nothing to 

 the certainty ; he examined whether the facts agreed 

 with the object of convincing others, not himself. And 

 when the facts as he knew them did not agree, we may be 

 sure that his faith in the theory was in no way shaken ; 

 he knew that the facts must be wrong, but he had to wait 

 many years before evidence of their falsity was found 

 which would appeal to those who had not his genius and 

 could not be sure of harmony between their desires and 

 the external world. 



