TENDENCIES OF MODERN PHYSICS 67 



is frequently made by scientific theorists who recognize 

 the artificiality of their hypotheses but who feel that, in 

 some way, they tend to good. They forget that the 

 growth of science has always been largely due to the 

 discovery and the elimination of error. If we wish to 

 make a garden, the first necessity is to clear away the 

 weeds, and the same is true of science ; it is as impor- 

 tant to know what is wrong as what is right. But 

 even this claim is not correct, the better method is 

 known and is in use. Have they forgotten the work of 

 Galileo, of Newton, of Franklin, and of many others, 

 who employed the abstractive method, or, at least, kept 

 their hypotheses well in the background? Nor is it 

 difficult, if one studies the history of physics, to out- 

 line the basis of a method in harmony with my ideas, 

 as I shall do in a later chapter. 



Nothing has been more convincing to me of the 

 advantages of the abstractive over the hypothetical 

 method than a study of Descartes's Principia Naturae. 

 Modern theorists have acknowledged their debt to 

 him ; how great is this obligation can be seen from the 

 discussion of Descartes's system which follows. A 

 comparison of his postulates and conclusions with 

 those of our modern theory shows them to be almost 

 identical, if we change his antiquated knowledge and 

 his discarded metaphysical language into modern 

 terminology. And lastly we should compare Descartes 

 with modern physicists ; his knowledge of the phenom- 



