CLASSIFICATION. 379 



Here we see that wherever A is is also found, so that C 

 is a generic property ; D occurs always with B, so that it 

 constitutes a specific property, while E is indifferently 

 present and absent, so as not to be in any way correlated 

 with any of the other letters ; it represents, therefore, an 

 accident. It will now be seen that the Logical Abece- 

 darium leally represents an interminable series of subor- 

 dinate genera and species ; it is but a concise symbolic 

 statement of what was involved in the ancient doctrine of 

 the Predicables. 



Summum Genus and Tnfima Species. 



As a genus means any class whatever which is re- 

 garded as composed of minor classes or species, it follows 

 that the same class will be a genus in one point of view 

 and a species in another. Metal is a genus as regards 

 alkaline metal, a species as regards element, and any 

 extensive system of classes consists of a series of subor- 

 dinate, or as they are technically called, subaltern genera 

 and species. The question, however, arises, whether any 

 such chain of classes has a definite termination at either 

 end. The doctrine of the old logicians was to the effect 

 that it terminated upwards in a genus generalissimum or 

 summum genus, which was not a species of any wider 

 class. Some very general notion, such as substance, object 

 or thing, was supposed to be so comprehensive as to in- 

 clude all thinkable objects, and for all practical purposes 

 this might be so. But as I have already explained (vol. i. 

 p. 88), we cannot really think of any object or class 

 without thereby separating it from what is not that object 

 or class. All thinking is relative, and implies discrimina- 

 tion, so that every class and every logical notion must 

 have its negative. If so, there is no such thing as a summum 



