SKEPTICISM AND IDOLATRY 203 



vivid his thought is when he is not involved in these 

 pitfalls to accurate reasoning : " Is not each great ad- 

 vance accomplished precisely the day someone has 

 discovered under the complex aggregate shown by our 

 senses something far more simple, not even resembling 

 it as when Newton replaced Kepler's three laws by 

 the simple law of gravitation, which was something 

 simpler, equivalent, yet unlike ?" 



To this excellent question, he gives the following 

 lamentable answer : 



" One is justified in asking if we are not on the eve 

 of just such a revolution or one even more important. 

 Matter seems on the point of losing its mass, its solid- 

 est attribute, and resolving itself into electrons. Me- 

 chanics must then give place to a broader conception 

 which will explain it, but which it will not explain. . . . 

 The ether it is, the unknown, which explains matter, 

 the known; matter is incapable of explaining the 

 ether." 



How can Poincare justify himself? When we re- 

 call how Newton refrained from giving any hypoth- 

 esis regarding the cause or nature of gravitational 

 force, because he felt such an hypothesis would be out- 

 side the field of science; and how the subsequent veri- 

 fication of the law of gravitation by innumerable 

 experimental observations has established it as one of 

 the few great and universal laws; and when we recall 

 what Poincare says about electrons, the ether, and 



