82 



NAMES AND PROPOSITIONS. 



are' its two. species; or we may divide it into a greater number of 

 epecies, as man, horse, dog, &c. Biped,, ot two-footed anmuil, may 

 also be considered a genus, of which man and bird are two species. 

 Taste is a genus, of which sweet taste, sour taste, sak 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 comprehensive, 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 mathematician. Animal is a genus, divided into two 

 species, man and brute; but animal is also a species, which, with 

 another species, vegetable, makes up the genus, organized being. 

 Biped is a genus with reference to man and bird, but a species with 

 respect to the superior genus, animal. Taste is a genus divided into 

 species, but also a species of the genus sensation. Virtue, a genus 

 with reference to justice, temperance, &c., is one of the species of the 

 genus, mental quality; 



In this jjopular "sense the words Genus and Species have passed 

 into common discourse. And it should be observed that, in ordinary 

 parlance, not the name of the class, but the class itself, is said to be 

 the genus or species ; not, of course, the class in the sense of each 

 individual of that class, but the individuals collectively, considered as 

 an aggi-egate whole ; the names by which the class is designated being 

 then called not the genus -or species, but the generic or specific name. 

 And this is an admissible fonn of expression ; nor is it of any import- 

 ance which of the two modes of speaking we adopt, provided the rest 

 of our language is consistent with it ; but if we call the class itself the 

 genus, we must not talk of predicating the genus. We predicate of 

 man th6 name niortal ; and by predicating the name, we may be said, 

 in an intelligible sense, to predicate what the name expresses, the 

 attribute mortality ; but in no allowable sense of the word predication 

 do we predicate of man, the class mortal. We predicate of him the 

 fact of belongi'ng to the class. 



By the Ai-istotelian logicians, the terms genus and species were 

 used in a more restricted sense. They did not iidmit every' class 

 which could be divided into other classes to be a genus, or every class 

 which could be included in a larger class to be a species. Animal 

 was by them 'considered a genus : and man and brute co-ordinate 

 species under that genus : hiped would not have been admitted to be 

 a genus with reference to man, but a proprium or accidens ohly. It 

 was requisite, according to their theory, that geiius and speciesxshould 

 be of the essence of the subject. Animal was of the essence of man ; 

 hiped was not. And in every classification they considered some one 

 class as the lowest or injima species ; man, for instance, was a lowest 

 species. Any further divisions into which the class might be capable 

 of being broken down, as man into white, black, and red man, or into 

 priest and layman, they did not admit to be species. 



It has been seen, however, in the preceding, chapter, that the dis- 

 tinction between the essence of a class, and the attributes or properties 

 which are not of its essence^-^a distinction which has given occasion 

 to so much abstruse speculation, and to which so mysterious a charac- 

 ter was formerly, and by many wi'iters is still, attached, — amounts to 



