190 NAMES AND PROPOSITIONS. 



whether it expounds the meaning of the name or not, 

 enables us to discriminate the things denoted by the 

 name from all other things, and consequently to 

 employ the term in predication without deviating 

 from established usage. This purpose is duly an- 

 swered by stating any (no matter what) of the attri- 

 butes which are common to the whole of the class, 

 and peculiar to it; or any combination of attributes 

 which may happen to be peculiar to it, although sepa- 

 rately each of those attributes may be common to it 

 with some other things. It is only necessary that the 

 definition (or description) thus formed, should be con- 

 vertible with the name which it professes to define ; 

 that is, should be exactly co-extensive with it, being 

 predicable of everything of which it is predi cable, and 

 of nothing of which it is not predicable ; although the 

 attributes specified may have no connexion with those 

 which men had in view when they formed or recog- 

 nised the class, and gave it a name. The following 

 are correct definitions of Man, according to this test : 

 Man is a mammiferous animal, having (by nature) two 

 hands (for the human species answers to this descrip- 

 tion, and no other animal does) : Man is an animal 

 who cooks his food: Man is a featherless biped. 



What would otherwise be a mere description, may 

 be raised to the rank of a real definition by the pecu- 

 liar purpose which the speaker or writer has in view. 

 As was seen in the preceding chapter, it may, for the 

 ends of a particular art or science, or for the more 

 convenient statement of an author's particular views, 

 be advisable to give to some general name, without 

 altering its denotation, a special connotation, different 

 from its ordinary one. When this is done, a definition 

 of the name by means of the attributes which make up 

 the special connotation, though in general a mere acci- 



