IMPORT OF PROPOSITIONS. 125 



perspicuously expressed, may almost be said to have 

 taken the rank of an established opinion. The most 

 generally received notion of Predication decidedly is, 

 that it consists in referring something to a class, i. e., 

 either placing an individual under a class, or placing 

 one class under another class. Thus, the proposition, 

 Man is mortal, asserts, according to this view of it, 

 that the class man is included in the class mortal. 

 " Plato is a philosopher," asserts that the individual 

 Plato is one of those who compose the class philo- 

 sopher. If the proposition is negative, then instead 

 of placing something in a class, it is said to exclude 

 something from a class. Thus, if the following be the 

 proposition, The elephant is not carnivorous; what is 

 asserted (according to this theory) is, that the elephant 

 is excluded from the class carnivorous,, or is not 

 numbered among the things comprising that class. 

 There is no real difference except in language, between 

 this theory of Predication and the theory of Hobbes. 

 For a class is absolutely nothing but an indefinite 

 number of individuals denoted by a general name. 

 The name given to them in common, is what makes 

 them a class. To refer anything to a class, therefore, 

 is to look upon it as one of the things which are to 

 be called by that common name. To exclude it from 

 a class, is to say that the common name is not appli- 

 cable to it. 



How widely these views of predication have pre- 

 vailed, is evident from this, that they are the basis of 

 the celebrated Dictum de omni et nullo. When the 

 syllogism is resolved, by all who treat of it, into an 

 inference that what is true of a class is true of all 

 things whatever that belong to the class ; and when 

 this is laid down by almost all professed logicians as 

 the ultimate principle to which all reasoning owes its 



