CLASSIFICATION A\D THE PREDICABLES. 81 



if those names had. preceded, Instead of gi'owing out of, his Classifica- 

 tion of Animals. The only peculiarity of the case is, that the conve- 

 nfence of classification was here the primary motive for liitioducing the 

 n'aimes ; while in other cases the name is introduced as a means of 

 predication, and the formation ef a class denoted by it is only an indi- 

 rect consequence. 



The principles which ought to regulate Classification as a logical 

 process subservient to the investigation of truth, cannot be discussed to 

 any pm-pose until a much later stage of oui* inquiry. But, of classifi- 

 cation as resulting from, and im2)lied in, the fact of employing general 

 language, we cannot forbear to treat here, without leaving the theory 

 of general names, and of their employment in oredication, mutilated 

 and formless. 



§ 2. This portion of the theory of general language is the subject of 

 what is teiTned the doctrine of the Predicables ; — a set of distinctions 

 handed down from Aristotle and his follower. Porphyry, many of 

 which have taken a finn root in scientific, and some of them even in 

 popular, phraseology. The Predicables are a five-fold division of Gen- 

 eral Names, not grounded as usual upon a difference in their mean- 

 ing, that is, in the attribute which they connote, but upon a difference 

 in the kind of class which they denote. We may predicate of a thing 

 five different varieties of class-name :-— 



A genus of the thing {yevog). 



A species (eldog). 



A differentia (dicupopd). 



A proprium {I6i6v^. 



An accidens (avfi[3E(i7]K6g). 



It is to be remarked of these distinctions, that they express, not 

 what the predicate is in its own meaning, but what relation it bears to 

 the subject of which it happens on the particular occasion to be predi- 

 cated. There are not some names which are exclusively genera, and 

 others which are exclusively species, or differentia? : but the same 

 name is refen-ed to one or another Predicable, according to the sub- 

 ject of which it is predicated on the particular occasion. Animal, for 

 instance, is a genus with respect to Man, or John ; a species with re- 

 spect to Substance or Being. Rectangular is one of the Differentia of 

 a geometrical square : it is merely one of the Accidentia of the table 

 on which I am wiiting. The words, genus, species, &c., are therefore 

 relative terms ; they ai'e names applied to certain predicates, to ex- 

 press the relation between them and some given subject : a relation 

 grounded, as we shall see, not upon what the predicate connotes, but 

 upon the class which it denotes, and upon the place which, in some 

 given classification, that class occupies relatively to tlie particular 

 subject. 



§ 3. Of these five names, two. Genus and Species, arc not only used 

 by naturalists in a technical acceptation not precisely agreeing with 

 their philosophical meaning, but have also acquired a popular accep- 

 tation, much more general than either. In this popular sense any two 

 classes, one of which includes the whole of the other and. more, may 

 l)e called a Genus and a Species. Such, for instance, are Animal and 

 Man; Man and Mathematician. 'Animal is a genus; Man and Brule 

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