ESSAYS 



THE EINSTEIN THEORY OF XIELATIVITY (D. Laugharne- 



Thornton, M.A.). 

 The Newtonian conceptions of physical phenomena have been considered as 

 of universal validity for so long a period that the introduction of the Einstein 

 theory of Relativity is regarded by some students of science as an instrument 

 of destruction towards the classical mechanics. This view, in itself, is a natural 

 reaction and of but passing moment ; there is a more serious form of this 

 reaction, and this is the tendency to regard this new interpretation as an idea 

 which is to be resisted. This last-mentioned view-point is a thing to be de- 

 plored. For if the doctrine of evolution itself forbids one to admit any 

 transcendental source of knowledge, then such a thing as a universal truth is 

 merely a fictitious picture of the human brain. Bearing this in mind, we see 

 the futility of the assertion that Einstein's work has taken away any of the 

 brilliance which is shown in Newton's monumental labours in the world of 

 physics. One may say that what Vesalius was to Galen, what Lobatchewsky 

 was to Euclid, that is Einstein to Newton. In short, the new Relativity 

 comprises the old, but, in addition, it includes considerations which are not 

 part of Newtonian Relativity. 



It may be well to remember that the classical mechanics brought together 

 many of the natural forces and their implications, but failed to include in 

 its scheme of centralisation the forces attributed to gravitation. These latter 

 forces were treated as constant, and, as such, it appeared that they could be 

 added to the net result of all the other forces. As a contrast, we see that the 

 new conception of natural phenomena has accounted for all the attributes of 

 gravitation as a function of the other forces, and thus we may say that, what 

 projective geometry has done for geometry, the same " focusing " efiect 

 has been done by the new relativity for the science of mechanics. 



Great difficulties are encountered by many students in studying this new 

 interpretation of facts, this in a large measure being due to the philosophical 

 views held in the past regarding the material structure of the universe. 

 From Mill's work, one may defiine matter as a permanent possibility of sensa- 

 tion, but in so doing we are apt to forget that the spectator of nature observes 

 discrete quantities while the brain makes out a continuous phenomenon of 

 such a group of facts. Further, any system of inference in science depends on 

 the uniformity of the natural facts concerned, and thus we see that between 

 the observed fact as comprehended and the natural state of nature a complex 

 path of reasoning and interpretation intervenes. It is in this mental passage 

 that much diflSculty manifests itself to the reader of Einstein's work. 



From the above line of thought it follows that the knowledge of an exact 

 law in the theoretical sense would be equivalent to an infinite observation. 

 By this we do not mean that such a knowledge is impossible to man ; but we 

 do say that it would be absolutely different in form from any knowledge that 

 we possess at the present time. As a compromise to an infinite investigation, 

 which is impossible, we shall later see that a process of taking average values 

 is carried out, and that within certain limits this process is justifiable. The 

 study of the " quantum theory," which involves, ipso facto, the science of 



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