234 REASONING. 



as this is affirmative or negative, the conclusion is so 

 too. All ratiocination^ therefore, starts from a general 

 proposition, principle, or assumption : a proposition 

 in which a predicate is affirmed or denied of an entire 

 class ; that is, in which some attribute, or the nega- 

 tion of some attribute, is asserted of an indefinite 

 number of objects, distinguished by a common charac- 

 teristic, and designated, in consequence, by a common 

 name. 



The other premiss is always affirmative, and 

 asserts that something (which may be either an indi- 

 vidual, a class, or part of a class,) belongs to, or is 

 included in, the class, respecting which something 

 was affirmed or denied in the major premiss. It 

 follows that the attribute affirmed or denied of the 

 entire class may (if there was truth in that affirmation 

 or denial) be affirmed or denied of the object or 

 objects alleged to be included in the class : and this 

 is precisely the assertion made in the conclusion. 



Whether or not the foregoing is an adequate 

 account of the constituent parts of the syllogism, will 

 be presently considered; but as far as it goes it is a 

 true account. It has accordingly been generalized 

 and erected into a logical maxim, on which all ratio- 

 cination is said to be founded, insomuch that to 

 reason and to apply the maxim are supposed to be 

 one and the same thing. The maxim is, That what- 

 ever can be affirmed (or denied) of a class, may be 

 affirmed (or denied) of everything included in the 

 class. This axiom, supposed to be the basis of the 

 syllogistic theory, is termed by logicians the dictum 

 de omni et nullo. 



This maxim, however, when considered as a prin- 

 ciple of reasoning, appears suited to a system of meta- 

 physics once indeed generally received, but which for 



