446 THE POPULAR SCIENCE MONTHLY 



famous world-postulate practically assumes a four-dimensional space in 

 which all phenomena occur, and this say the objectors, on account of the 

 construction of the human mind, can never be intelligible to any one in 

 spite of its mathematical simplicity.- They insist that the words space 

 and time, as names for two distinct concepts, are not only convenient, 

 but necessary. ISTor can any description of phenomena in terms of a 

 time which is a function of the velocity of the body on which the time 

 is measured ever be satisfactory, simply because the human mind can 

 not now nor can it ever appreciate the existence of such a time. To sum 

 up, then, this model of the universe which the relativists have constructed 

 in order to explain the universe, can never satisfactorily do this, for the 

 reason that it can never be intelligible to everybody. It is a mathe- 

 matical theory and can not be satisfactory to those lacking the mathe- 

 matician's sixth sense. 



A second serious objection urged against the relativity theory is that 

 it has practically abandoned the hypothesis of an ether, without furnish- 

 ing a satisfactory substitute for this hypothesis. As has been previously 

 stated, the very experiment which the relativity theory seeks to explain 

 depends on interference phenomena which are only satisfactorily ac- 

 counted for on the hypothesis of an ether. Then too, there are in electro- 

 magnetism certain equations of fundamental importance, known as the 

 Maxwell equations, and it is perhaps just as important that the relativity 

 theory retain these equations, as it is that it explain the Michelson and 

 Morley experiment. But the electro-magnetic equations were deduced 

 on the hypothesis of an ether, and can be explained, or at least have 

 been explained only on the hypothesis that there is some such medium 

 in which the electric and magnetic forces exist. So, say the objectors to 

 the relativity theory, the relativists are in the same illogical (or worse) 

 position that they occupy with reference to the Michelson and Morley 

 experiment, in that they deny the existence of the medium which made 

 possible the Maxwell equations, which equations the relativity theory 

 must retain at any cost. Professor Magie, of Princeton, who states with 

 great clearness the principal objections to the theory, waxes fairly indig- 

 nant on this point, and compares the relativists to Baron Munchausen, 

 who lengthened a rope which he needed to escape from prison, by cutting 

 off a piece from the upper end and splicing it on the lower. The 

 objectors to the relativity theory point out that there have been advo- 

 cated only two theories which have explained with any success the propa- 

 gation of light and other phenomena connected with light, and that of 

 these two, only the ether theory has survived. To abandon it at this time 

 would mean the giving up of a theory which lies at the foundation of all 

 the great advances which have been made in the field of speculative 

 physics. 



It remains finally to ask and perhaps also to answer the question, 



