60 JOHN WESLEY POWELL. 



manner by his philosophy. Science does not invent, but discovers; 

 and that which has been discovered needs only to be published in 

 order to become a part of the world's knowledge. It differs in this 

 respect from metaphysics, which postulates its principles and then 

 by the methods of formal logic undertakes to prove its results. In 

 metaphysics demonstration is proving ; in science demonstration is 

 merely pointing out. So that all that is absolutely necessary to 

 the presentation of a scientific result is its statement; if the result 

 is worthy of acceptance, it will ultimately be received, for it will 

 be found to accord invariably with the results of new observation. 

 The absolute generality of a conclusion can be established only by 

 comparing it with all the phenomena, and as this is impossible, 

 such comparison as is made serves only to illustrate. The citation 

 of particular instances usually assists the comprehension of a gen- 

 eral idea, and illustration is thus a useful adjunct to statement. 

 Powell's philosophical writings thus consist of the statement of re- 

 sults, with a small amount of illustration, and in many instances 

 without illustration. They are for the most part highly concise, 

 and as they often lead the ordinary reader into novel realms of 

 thought, much study is sometimes necessary to their full compre- 

 hension. On the other hand, some of his generalisations are so 

 simple as compared to the theories or postulates which they sup- 

 plant, and are so readily grasped, that they are accepted as axioms 

 and not recognised as the results of laborious research and pro- 

 found thought. 



His style has been further influenced by the loss of his right 

 hand, and by a remarkable power of controlling his attention. The 

 loss of his hand in early manhood led him to depend to an excep- 

 tional degree on amanuenses. All of his scientific writings have 

 been dictated to shorthand writers, and escaping thus the delay 

 and the divided attention involved in the personal use of the pen, 

 he has been able to select words with unusual care. 



His power to control his attention is exemplified in the daily 

 transaction of business at his official desk. The dictation of a let- 

 ter or of an essay will be interrupted by a question from a subordi- 

 nate or by a visitor, and as soon as the temporary business has 

 been transacted the dictation is resumed at the point of leaving off 

 without apparent effort. Through this remarkable power he is 

 able to direct his attention to any selected subject of thought and 

 there concentrate it for an indefinite period. The intellectual labor 

 necessary to the arrangement of a subject for composition is per- 

 formed without the aid of notes, and the entire subject is elabo- 



