XXX.] CLASSIFICATION. 679 



after trying many modes that it is possible to approximate 

 to the best. 



Natural and Artificial Systems of Classification. 



It has been usual to distinguish systems of classifica- 

 tion as natural and artificial, those being called natural 

 wliich seemed to express the order of -existing things as 

 determined by nature. Artificial methods of classification, 

 on the other hand, included those formed for the mere 

 convenience of men in remembering or treating natural 

 objects. 



The difference, as it. is commonly regarded, has been well 

 described by Ampere,^ as follows: " AVe can distinguish 

 two kinds of classifications, the natural and the artificial. 

 In the latter kind, some characters, arbitrarily chosen, 

 serve to determine the place of each object; we abstract 

 all other characters, and the objects are thus found to be 

 brought near to or to be separated from each other, often 

 in the most bizarre manner. In natural systems of classi- 

 fication, on the contrary, we employ concurrently all the 

 characters essential to the objects with which we are 

 occupied, discussing the importance of each of them ; and 

 the results of this labour are not adopted unless the 

 objects which present the closest analogy are brought 

 most near together, and the groups of tlie several orders 

 which are formed from them are also approximated in pro- 

 portion as they offer more similar characters. In this way 

 it arises that there is always a kind of connexion, more or 

 less marked, between each group and the group which 

 follows it." 



There is much, however, that is vague and logically 

 false in this and other definitions which have been pro- 

 posed by naturalists to express their notion of a natural 

 system. We are not informed how the, importance of a 

 resemblance is to be determined, nor what is the measure 

 of the closeness of analogy. Until all the words employed 

 in a definition are made clear in meaning, the definition 

 itself is worse than useless. Now if the views concerning 

 classification here upheld are true, there can be no sharp 



' Essai gur la Philosophie des /Sciences, p. 9. 



