842 Prof. L. T. More on the Postulates and 



simple criticism of Maxwell that, how ever interesting and 

 erudite the theory might be, no conclusion derived from the 

 postulate that matter was a motion of an hypothetical aether 

 could ever satisfy the mind as a substitute for matter. The 

 same is true of the even more subjective and idealistic hypo- 

 theses of the present time. The theory of energetics, the 

 theory of electricity as matter, and still more, the annihilistic 

 theory of Einstein, are all doomed to be discarded because 

 they do not postulate- matter as a substratum of reality, — as 

 a thing independent of our varying sensations. The authors 

 of these hypotheses unconsciously bear witness to this ; for, 

 however they may disguise their terms, they always endue 

 their substitutes, — energy, electricity, or aether, — with all the 

 properties of inertia of matter. Can w T e expect to carry 

 conviction and increase the reasonableness and exactness of 

 science by a juggling of words ; by transferring reality from 

 matter to an evidently less concrete entity ? We are merely 

 widening the unfortunate gap between theoretical and expe- 

 rimental physics; the experimentalist still translates electricity 

 and aether into the inertia of matter. 



The effect which the acceptance of the theory of relativity 

 would have can be readily shown from Einstein's own words. 

 It is better to obtain these from his non-mathematical expo- 

 sition of the theory *, as he has there spared no pains to make 

 his philosophical ideas simple and clear. 



The theory of relativity arose from the need to link up 

 certain phenomena of light and electricity, or rather of 

 radiation, with mechanics ; that is, to explain these phe- 

 nomena of a different category, so far as our sense perceptions 

 are concerned, on a mechanical basis. This implies, of course, 

 that we are still to consider the explanation of all objective 

 phenomena as, in form, a problem of mechanics ; whether 

 these phenomena appeal to our sense of sight, of temperature, 

 or what not, mechanical analogies will continue to be the 

 simplest and the most satisfactory to our minds. The mecha- 

 nical link which we find running through all phenomena is un- 

 doubtedly energy, either appearing directly in a mechanical 

 form or else reducible to that form by Joule's equivalent. At 

 first sight, it would seem that the natural procedure would be 

 to establish the laws of pure mechanics, that is, the laws of the 

 positions and motions of tangible bodies, and to modify the 

 laws of light, electricity, and radiation to agree with the 

 established laws of mechanics. Now, the laws of rational 

 mechanics, or of classical mechanics, as they are called, have 



* • Relativity,' by Albert Einstein. Translated by Robert W. Lawson. 



