CHAPTER II 



THE REFORMED CONCEPTS OF SPACE AND TIME 



Summary. — It is not only in organic Evolution that the old 

 fixed concepts and counters of thought are breaking down. Recent 

 advances in physical science have extended the revolution to the 

 domain of the inorganic; the fixity of the atom has followed that 

 of species into the limbo of the obsolete. In many directions new 

 concepts, more in harmony with the fluid creative process of 

 nature, are called for. 



We begin with the new concepts of Space and Time, which in 

 the system of Relativity are taking the place of the old Newtonian 

 concepts still commonly accepted. The new ideas of Space and 

 Time arose from researches in the higher mathematics and physics, 

 and were primarily concerned with the relative character of all 

 actual motion in the universe, and the mathematical and physical 

 consequences of this relativity. Thus according to the mathe- 

 matical physicists to a moving observer a moving body appears to 

 contract or to be shorter than it would be to a stationary observer, 

 and the faster either of them moves the greater the contraction 

 becomes. Time varies similarly, but in the opposite direction; 

 while the space of the moving body appears to contract, its time 

 appears to expand, so that it takes a longer time to pass a point 

 than it would do if viewed by a stationary observer. This joint 

 and inseparable variation of Space and Time was not only most 

 important 'in itself, but led directly to the revolutionary concep- 

 tion that neither of them existed independently, but that together 

 they form the Space-Time medium of the real physical world. 

 From this point of view bodies and things as merely spatial are 

 not real but abstractions, while events, which involve both Space 

 and Time, Action in Space-Time, are real and form the units of 

 reality. The deposition of the old Space and Time and their 

 replacement by Space-Time have been tested in the most search- 

 ing way both in the immense world of astronomy and in the most 

 minute world of the atom, and in both cases the new concepts 

 have been found to work satisfactorily. 



The variation of Space and Time has led to the further conclu- 

 sion that in a world of relative motion such as ours all standards of 

 measurement and all clocks of Time are themselves variable and 



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