314 OPERATIONS SUBSIDIARY TO INDUCTION. 



form our groups round certain selected Kinds, each of 

 which serves as a sort of exemplar of its group. But 

 though the groups are suggested by types, I cannot 

 agree with Mr. Whewell that a group when formed is 

 determined by the type; that in deciding whether a 

 species belongs to the group, a reference is made to 

 the type, and not to the characters; that the charac- 

 ters " cannot be expressed in words." This assertion 

 is inconsistent with Mr. Whewell's own statement of 

 the fundamental principle of classification, namely, 

 that "general assertions shall be possible." If the 

 class did not possess any characters in common, what 

 general assertions would be possible respecting it ? 

 Except that they all resemble each other more than 

 they resemble anything else, nothing whatever could 

 be predicated of the class. 



The truth is, on the contrary, that every genus or 

 family is framed with distinct reference to certain 

 characters, and is composed, first and principally, of 

 species which agree in possessing all those characters. 

 To these are added, as a sort of appendix, such other 

 species, generally in small number, as possess nearly 

 all the properties selected ; wanting, some of them one 

 property, some another, and which, while they agree 

 with the rest almost as much as these agree with one 

 another, do not resemble in an equal degree any other 

 group. Our conception of the class continues to be 

 grounded on the characters; and the class might be 

 defined, those things which either possess that set of 

 characters, or resemble the things that do so, more 

 than they resemble anything else. 



And this resemblance itself is not, like resem- 

 blance between simple sensations, an ultimate fact 

 unsusceptible of analysis. Even the inferior degree 

 of resemblance is created by the possession of common 



