CLASSIFICATION. 305 



questions, whether such and such organisms are specifically 

 or generically distinct, and whether this or that peculiarity 

 is or is not of ordinal importance, imply that the conviction 

 is entertained even where it is not avowed. Yet that dif- 

 ferences of opinion like these continually arise, and remain 

 unsettled, except when they end in the establishment of sub- 

 species, sub-genera, sub-orders, and sub-classes, sufficiently 

 shows that no such conviction is justifiable. And this is 

 equally shown by the impossibility of obtaining an}^ definition 

 of the degree of difierence, which warrants each further eleva- 

 tion in the hierarchy of classes. 



It is, indeed, a wholly gratuitous assumption that organ- 

 isms admit of being placed in groups of equivalent values ; 

 and that these may be united into larger groups that are 

 also of equivalent values ; and so on. There is no a priori 

 reason for expecting this; and there is no a posteriori evi- 

 dence implying it, save that which begs the question — that 

 which asserts one distinction to be generic and another to be 

 ordinal, because it is assumed that such distinctions must be 

 either generic or ordinal. The endeavour to thrust plants 

 and animals into these definite partitions, is of the same 

 nature as the endeavour to thrust them into a linear series. 

 Not that it does violence to the facts in anything like the ' 

 same degree ; but still, it does violence to the facts. Doubt- 

 less the making of divisions and sub-divisions, is extremely ' 

 useful ; or rather, it is absolutely necessary. Doubtless, too, 

 in reducing the facts to something like order, they must be 

 partially distorted. So long as the distorted form is not 

 mistaken for the actual form; no harm results. But it is 

 needful for us to remember, that while our successively 

 subordinate groups have a certain general correspondence 

 with the realities, they inevitably give to the realities a 

 regularity which does not exist. 



§ 102. A general truth of much significance is exhibited 

 in these classifications. On observing the natures of the 



