64 SPECIALIZATION IN NATURAL SCIENCE. 



philosophy covers the study of material forces alone, 

 that is, of forces commensurable by foot-pounds, there 

 is no fault to be found with this statement in so far as it 

 signifies that these are the proper working limits con- 

 ventionally and universally assigned by scientists to 

 this department. There are other, subtler, psycholog- 

 ical forces permeating and shaping nature, which are 

 conventionally gathered up into another department 

 called psychology, and most effectually studied as a 

 special department by themselves. Confusion would 

 doubtless arise from the promiscuous mingling of these 

 forces in special study. But when the naturalist asserts, 

 as is often done, that this department of natural philos- 

 ophy is the study of nature, and that natural forces are 

 material forces; when he makes the word "natural" 

 habitually synonymous with the word "material;" 

 when he stubbornly refuses, in his studies of nature, 

 even to recognize the inseparable interweaving effects of 

 psychological forces on the material, he is endangering 

 truth by carrying his provisional working classifications 

 into the higher philosophy of things ; he is misleading 

 younger students, and preparing a crop of needless con- 

 troversies. 



The truth is, that the expression "natural philoso- 

 phy, 1 ' a term founded on the Latin name for nature, and 

 the term "physics," founded on the Greek word of iden- 

 tical meaning, as now conventionally limited, mean only 

 the study of the objects and material forces of nature and 

 their laws ; also that the word "natural" is not really 

 and essentially synonymous with the word "material," 

 since natural forces include the inseparable intermingling 

 of psychological and material forces. Some recognition 

 of these facts by naturalists and physicists in their treat- 

 ises, would aid, rather than prevent, the truth. 



I am happy, in reinforcing my views on this point, to be 

 able to quote words uttered, not long ago, by one of the 



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