116 The Higher Usefulness of Science 



upon living beings generally with great effect some- 

 thing that can occupy itself very interestingly and 

 profitably with such things, but it is not obliged to 

 be so used. 



Logic goes to nature to get illustrations of how 

 thought works rather than actually to learn nature. 

 Reverting to Jevons's sttement that logic may be de- 

 fined as the theory of classification, we may remark 

 that, so far as external nature is concerned, while logic 

 may be defined as the theory of classification, it can not 

 be defined as the practise of classification. It is im- 

 portant to call attention to this distinction between 

 logic and biology since even biologists frequently fail 

 to recognize it and are beguiled into trying to impose 

 the laws of thought upon nature by asserting that 

 such and such a supposition about nature is a "logical 

 necessity." Although logic is so important to the 

 natural scientist as an instrument, quite as important 

 is it never to forget that it is only an instrument. 

 Logic is one of the many children of nature; it is not 

 its parent or ruler. 



A practical point to be noticed here is that right 

 regard for logic in the business of the taxonomist 

 clearly reveals both the unwarrantableness and misfor- 

 tune of the view, so widely held, that synoptic descrip- 

 tions and classifications are artificial or puerile, and 

 devoid of scientific value. If such a definition of man 

 as that just given does not express his nature is not 

 a natural definition in what terms, pray, can he be 



