CHAPTER VIII. 



OF CLASSIFICATION BY SERIES. 



1. THUS far, we have considered the principles of 

 scientific classification so far only as relates to the formation 

 of natural groups ; and at this point most of those who have 

 attempted a theory of natural arrangement, including, among 

 the rest, Dr. Whewell, have stopped. There remains, however, 

 another, and a not less important portion of the theory, which 

 has not yet, as far as I am aware, been systematically treated 

 of by any writer except M. Comte. This is, the arrangement 

 of the natural groups into a natural series.* 



The end of Classification, as an instrument for the investi- 

 gation of nature, is (as before stated) to make us think of 

 those objects together, which have the greatest number of 

 important common properties ; and which therefore we have 

 oftenest occasion, in the course of our inductions, for taking 

 into joint consideration. Our ideas of objects are thus brought 

 into the order most conducive to the successful prosecution of 

 inductive inquiries generally. But when the purpose is to 

 facilitate some particular inductive inquiry, more is required. 

 To be instrumental to that purpose, the classification must 

 bring those objects together, the simultaneous contemplation 



* Dr. Whewell, in his reply (Philosophy of Discovery, p. 270) says that he 

 "stopped short of, or rather passed by, the doctrine of a series of organized 

 beings," because he " thought it bad and narrow philosophy.' 1 If he did, it 

 was evidently without understanding this form of the doctrine ; for he proceeds 

 to quote a passage from his "History," in which the doctrine he condemns is 

 designated as that of " a mere linear progression in nature, which would place 

 each genus in contact only with the preceding and succeeding ones." Now the 

 series treated of in the text agrees with this linear progression in nothing what- 

 ever but in being a progression. 



It would surely be possible to arrange all places (for example) in the order 

 of their distance from the North Pole, though there would be not merely a 

 plurality, but a whole circle of places at every single gradation in the scale. 



