CLASSIFICATION AND THE PREDICABLE& 



11 



primary motive for introducing the 

 names ; while in other cases the name 

 is introduced as a means of predica- 

 tion, and the formation of a class de- 

 noted by it is only an. indirect con- 

 eequence. 



The principles which ought to regu- 

 late Classification as a logical process 

 subservient to the investigation of 

 truth, cannot be discussed to any 

 purpose until a much later stage of 

 our inquiry. But of Classification, 

 as resulting from, and implied in, 

 the fact of employing general lan- 

 guage, we cannot forbear to treat 

 here, without leaving the theory of 

 general names, and of their employ- 

 ment 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 

 Predi cables ; a set of distinctions 

 handed down from Aristotle, and his 

 follower Porphyry, many of which 

 have taken a firm root in scientific, 

 and some of them even in popular, 

 phraseology. The predicables are a 

 fivefold 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 genui of the thing (-yeVof). 

 (elSos). 



A species 

 A differentia 

 A proprium 

 An accidens 



(Si.a<f>opa). 

 (<n;M/3e/3i)K6s). 



It is to be remarked of these dis- 

 tinctions, that they express, not what 

 the predicate is in its own meaning, 

 but what relation it bears to the sub- 

 ject of which it happens on the par- 

 ticular occasion to be predicated. 

 There are not some names which are 

 exclusively genera, and others which 

 are exclusively species, or differentiae ; 

 but the same name is referred to one 

 or another predicable, according to 

 ^be 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 geo- 

 metrical 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 re- 

 lation 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 Species, are not only used 

 by naturalists in a technical accepta- 

 tion not precisely agreeing with their 

 philosophical meaning, but have also 

 acquired a popular acceptation, much 

 more general than either. In this 

 popular sense any two classes, one of 

 which includes the whole of the other 

 and more, may be called a Genus and 

 a Species. Such, for instance, are 

 Animal and Man ; Man and Mathe- 

 matician. Animal is a Genus ; Man 

 and Brute are its two species ; or we 

 may divide it into a greater number 

 of species, as man, horse, dog, &c. 

 Biped, or two-footed animal, may also 

 be considered a genus, of which man 

 and bird are two species. Taste is 

 a genus, of which sweet taste, sour 

 taste, salt taste, &c. are species. 

 Virtue is a genus ; justice, prudence, 

 courage, fortitude, generosity, &c., 

 are its species. 



The same class which is a genus 

 with reference to the sub-classes or 

 species included in it, may be itself a 

 species with reference to a more com- 

 prehensive, or, as it is often called, a 

 superior genus. Man is a species with 

 reference to animal, but a genus with 

 reference to the species Mathema- 

 tician. Animal is a genus, divided 

 into two species, man and brute; 



