334 THE POPULAR SCIENCE MONTHLY. 



two or three years since by Mr. Edison, the renowned inventor of the 

 phonograph. This claim belonged primarily to physics, and secondarily 

 to physiology, and was carefully investigated by many physicists and 

 some physiologists of this country and Europe, and by them it was de- 

 cided, rightly or wrongly, that the claim was not proved, that the spark 

 supposed to indicate a new force represented a hitherto undetected 

 phase of induced electricity. 1 



IV. Claims which, from the limitations of the human faculties, can 

 never be proved or disproved. 



Claims of this kind may be indulged in as speculations, with the 

 understanding that they are merely speculations ; but to seriously dis- 

 cuss them, with the purpose of ascertaining their truth or falsity, is un- 

 scientific. 



Under this head all supernatural claims must be included, for the 

 reason that it is impossible for the human faculties to distinguish be- 

 tween what is unknown in Nature and what is above Nature. The 

 narrow limitations of our knowledge of Nature all will admit. What 

 expert professes to exhaustively know Nature even in his own depart- 

 ment? What, indeed, is all our knowledge but an infinitesimal frac- 

 tion of our ignorance ; a flower or so plucked from a boundless garden ; 

 a few ores dug from measureless mines ; a slight clearing in an infinite 

 wilderness ; "a film on the ocean of the unknown?" Leaving out of 

 view all questions of supernaturalism and all the phenomena of life, 

 what do we know, or, in this world, have we reason to expect to know, of 

 inorganic Nature ? What is light ? What is heat ? What is gravity ? 

 Why should one mode of motion make one form of force and not an- 

 other ? Toward the solution of these primal questions that the infant 

 can ask and the philosopher cannot answer the sciences and reasoning 

 of all the centuries have made, and are destined to make, no advance. 



Even if an expert could be supposed who should exhaustively know 

 Nature in his own department, how could he know that he knew it ? 

 Not knowing that he knew all Nature in his own realm, what tests 

 would he have could he have to distinguish between the supernatural 

 and what might be unknown in Nature ? If, to go to the outermost 

 verge of conceivability for illustration, the clock of the universe were 

 turned back to-morrow, and the sun should thereafter rise in the west 

 instead of the east, how would it be possible to prove, in a scientific 

 sense, that a supernatural event had occurred ? 



Every phenomenon that can be brought to the attention of the 

 human faculties must be referred to one of these three classes : 



1. The known in Nature. 



2. The unknown in Nature. 



1 Mr. Edison's views, as he writes me, are unchanged. His experiments, and my own 

 made in cooperation with him, as well as a discussion of the bearings of the claim on 

 the principles of evidence, were published two years since. 



