CLASSIFICATION. 371 



Bifurcate Classification. 



Every system of classification ought theoretically to be 

 formed on the principles of the Logical Abecedarium. Each 

 superior class should be divided into two inferior classes, 

 distinguished by the possession and non-possession of a 

 single specified property. Each of these minor classes, 

 again, is divisible by any other property whatever which 

 can be suggested, and thus every classification logically 

 consists of an infinitely extended series of subaltern 

 genera and species. The classifications which we form 

 are in reality very small fragments of those which would 

 correctly and fully represent the relations of existing 

 things. But if we take more than four or five qualities 

 into account, the number of subdivisions grows imprac- 

 ticably large. Our finite minds are unable to treat any 

 complex group exhaustively, and we are obliged to 

 simplify and generalize scientific problems, often at the 

 risk of overlooking particular conditions and exceptions. 



Every system of classes displayed in the manner of the 

 Logical Abecedarium may be called In furcate, because every 

 class branches out at each step into two minor classes, 

 existent or imaginary. It would be a great mistake to 

 regard this arrangement as in any way a peculiar or 

 special method ; it is not only a natural and important 

 one, but it is the inevitable and only system which is 

 logically perfect, according to the fundamental laws of 

 thought. All other arrangements of classes correspond 

 to the bifurcate arrangement, with the implication that 

 some of the minor classes are not represented among 

 existing things. If we take the genus A and divide it 

 into the species AB and AC, we imply two propositions, 

 namely that in the class A, the properties of B and C 



B b 2 



