The History of Things 77 



tation or electricity is irreducible, it is illegitimate. 

 It is faint-hearted and premature to assume that 

 what is at present irreducible will remain irreduci- 

 ble, unless some good reason can be given for so 

 judging. It yields no permanent satisfaction when 

 we reflect on the past, when we consider the suc- 

 cess which has attended scientific efforts to reduce 

 the number of supposed separate entities or pow- 

 ers. The use of *' William of Occam's razor" — 

 Entia noil sunt multiplicanda prceter necessi- 

 tatem — has already had its reward. It has given 

 us a deeper conviction of the "oneness " of Nature. 

 We need simply recall how "Caloric" was elim- 

 inated, yielding to the modern interpretation of 

 heat "as a mode of motion"; how emanations of 

 "Light" had to follow, when the undulatory or 

 the electro-magnetic theory of their nature was 

 established; how "Force" itself has become a 

 mere measure of motion; and how even "Matter" 

 tends to be resolved into units of negative elec- 

 tricity, carrying with them a bound portion of the 

 ether in which they are bathed. By all means, let 

 us have a criticism of the categories of science — 

 which is indeed part of the business of a useful 

 philosophy — but let us avoid the dogmatism of 

 asserting that the scientific unification of nature 

 has reached its limits. "God said, 'Let Newton 

 be/ and there was light," and another Newton may 

 be born to-morrow. 



