CLASSIFICATION AND THE PBED1CABLES. 131 



and of their employment in predication, mutilated and 

 formless. 



2. This portion of the theory of general language is 

 the subject of what is termed the doctrine of the Predicables ; 

 a set of distinctions handed down from Aristotle, and his fol- 

 lower Porphyry, many of which have taken a firm root in 

 scientific, and some of them even in popular, phraseology. The 

 predicables are a five-fold division of General Names, not 

 grounded as usual on a difference in their meaning, that is, in 

 the attribute which they connote, but on 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 



A species 



A differentia (StaQopa). 



A propriwm (ISiov). 



An accidens 



It is to be remarked of these distinctions, that they ex- 

 press, 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 predicated. There are not some 

 names which are exclusively genera, and others which are 

 exclusively species, or differentia ; but the same name is re- 

 ferred to one or another predicable, according to the subject of 

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

 instance, is a genus with respect to man, or John ; a species 

 with respect to Substance, or Being. Rectangular is one of 

 the Differentiae of a geometrical square ; it is merely one of 

 the Accidentia of the table at which I am writing. The words 

 genus, species, &c. are therefore relative terms; they are 

 names applied to certain predicates, to express the relation 

 between them and some given subject : a relation grounded, 

 as we shall see, not on what the predicate connotes, but on 

 the class which it denotes, and on the place which, in some given 

 classification, that class occupies relatively to the particular 

 subject. 



3. Of these five names, two, Genus and Snecies, are 

 92 



