ioo Permanence and Evohition. 



in the way of putting this a mistake, arising from 

 a confusion between the methods of physical 

 science and those of historico-critical investi- 

 gation. Science seeks mainly for laws, history 

 for events. If the common descent of all the 

 species of one genus be a fact, this fact will be 

 the cause of the pervading likeness between 

 those forms which causes them to be rightly 

 placed in the same genus, but the justification 

 for their being so placed lies in the likeness 

 itself, whatever opinion we form as to its cause, 

 The distinction between likenesses which imply 

 systematic affinity and those which, however 

 conspicuous they may be, indicate nothing of 

 the kind, is that the one sort are indications of 

 resemblance of kind (see " Mill's Logic " ), that 

 is, of a profound principle of likeness pervading 

 the whole structure of the creature, as opposed 

 to being quite isolated likenesses, or associated 

 with nothing except what may be directly corre- 

 lated with them. The real question is whether 



