162 NAMES AND PROPOSITIONS. 



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 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 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. Rec- 

 tangular is one of the Differentiae of a geometrical 

 square: it is merely one of the Accidentia of the 

 table on 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 upon what the 

 predicate connotes, but upon the class which it de- 

 notes,, and upon the place which, in some given clas- 

 sification, 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 accep- 

 tation 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 Mathematician. Animal is a genus; 

 Man and Brute is 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 



