Furthermore living beings [cannot be divided] by the functions 

 common to body and soul, by Flying, for instance, and Walking, 

 as we see them divided in the current dichotomies. For some 

 groups, Ants for instance, fall under both divisions, some ants 

 flying while others do not. Similarly the division into Wild and 

 Tame [must be rejected] ; as it also would involve the disruption 

 of a species into different groups. For in almost all species in 

 which some members are tame, there are other members that 

 are wild. Such for example is the case with Men, Horses, 

 Oxen, Dogs in India,' Pigs, Goats, Sheep ; groups which, if 

 double, ought to have what they have not, namely, different 

 appellations ; and which, if single, prove that Wildness and 

 Tameness do not amount to specific differences. And whatever 

 single element we take as a basis of division the same difficulty 

 will occur. 



The method then that we must adopt is to attempt to recog- 

 nise the natural groups, following the indications afforded by the 

 instincts of mankind, which led them for instance to form the 

 class of Birds and the class of Fishes, each of which groups 

 combines a multitude of differentiae, and is not defined by a 

 single one as in dichotomy. The method of dichotomy is either 

 impossible (for it would put a single group under different 

 divisions or dissimilar groups under the same division) ; or it 

 only furnishes a single ultimate differentia for each species, which 

 either alone or with its series of antecedents has to constitute 

 the whole essence. 



If, again, a new differential character be introduced at any 

 stage into the division, the necessary result is that the unity of 

 the whole, and the continuity of the division, become merely a 

 unity and continuity of agglomeration, like the unity and con- 

 tinuity of a series of sentences coupled together by conjunc- 

 tive particles. For instance, suppose we have the bifurcation 

 Feathered and Featherless, and then divide Feathered into Wild 

 and Tame, or into White and Black. Tame and White have no 

 essential relation to Feathered, but are the commencement of 

 an independent bifurcation, and are foreign to the series at the 

 end of which they are introduced. 



As we said then, we must define at the outset by a multi- 

 plicity of differentiae. If we do so, privative terms will be 

 available, which are unavailable to the dichotomist. 

 643 b. 



