166 THE LIMITATIONS OF SCIENCE 



to each other, the phenomena of the forces developed 

 are observed to depend only on the relative motion of 

 the magnet and the conductor, but Maxwell's theory 

 requires a different explanation, according to which is 

 moved and which remains at rest. Besides this dis- 

 crepancy between observation and theory, experiments, 

 devised with sufficient accuracy, fail to show any effect 

 of the earth's motion through space on the phenomena 

 of light. 



It will be convenient to grant these postulates and 

 follow Professor Einstein's deductions before attempt- 

 ing any criticism. In the first place, their adoption 

 does away with the possibility of an ether and revives 

 the postulate of space as a vacuum. Both theory and 

 experiment show that an ether, if there be one, must 

 be in absolute rest with respect to the motion of the 

 earth, and the first postulate denies the possibility of 

 absolute rest and motion. Again, the failure of New- 

 tonian mechanics lies in the assumption, which is 

 always tacitly made, that moving bodies are subject 

 to the same mechanical laws as those at rest. As I 

 have already pointed out, the modification to be made 

 in the laws for ordinary bodies is very minute and 

 would probably never have become of importance if 

 modern theory had not been interested in the properties 

 of bodies moving with velocities approximating that of 

 light. 



v The root of the error in the mechanics of moving 



