THE COMPOSITION OF MIND 



longs to the class of mammals ; and, as having 

 an internal bony skeleton, it belongs to the 

 sub-kingdom of vertebrates. What, now, is the 

 mental act which is repeated at each stage of this 

 description? It is " a cognition of the fact that 

 the relation between particular attributes in this 

 animal is like the relation between homologous 

 attributes in certain other animals." To confine 

 ourselves to the first clause of the description — 

 " the attributes implied by the term ruminant 

 can be known only as previously observed or 

 described ; and the predication of these, as pos- 

 sessed by the animal under remark, is the predi- 

 cation of attributes like certain before -known 

 attributes. Once more, there is no assignable 

 reason why, in this particular case, a relation of 

 coexistence should be thought, between ' such 

 attributes as the possession of four stomachs and 

 the possession of horns and cloven hoofs,' un- 

 less as being like certain relations of coexistence 

 previously known ; and, whether the think- 

 ing of this relation can be otherwise accounted 

 for or not, it is clear that the predication can- 

 not otherwise have any probability, much less 

 certainty." ^ The case is the same with the 

 remaining clauses of the description. In each 

 instance the mental operation performed by the 

 naturalist is the recognition of the likeness be- 



^ Spencer, Principles of Psychology, vol. ii. p. 69. [Part 

 VI. chapter vii. § 298.] 



149 



