RATIOCINATION, OR SYLLOGISM. 193 



of a class) belongs to, or is included in, the class respecting 

 which something was affirmed or denied in the major premise. 

 It follows that the attribute affirmed or denied of the entire 

 class may (if that affirmation or denial was correct) be 

 affirmed or denied of the object or objects alleged to be in- 

 cluded 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 ratiocination 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 whatever 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 principle of 

 reasoning, appears suited to a system of metaphysics once 

 indeed generally received, but which for the last two centuries 

 has been considered as finally abandoned, though there have 

 not been wanting in our own day attempts at its revival. 

 So long as what are termed Universals were regarded as a 

 peculiar kind of substances, having an objective existence 

 distinct from the individual objects classed under them, the 

 dictum de omni conveyed an important meaning ; because it 

 expressed the intercommunity of nature, which it was neces- 



of being a means of bringing out more clearly the meaning of the proposition, 

 actually leads the mind out of the proposition, into another order of ideas. For 

 when we say, All men are mortal, we simply mean to affirm the attribute mor- 

 tality of all men ; without thinking at all of the class mortal in the concrete, or 

 troubling ourselves about whether it contains any other beings or not. It is 

 only for some artificial purpose that we ever look at the proposition in the aspect 

 in which the predicate also is thought of as a class-name, either including the 

 subject only, or the subject and something more. (See above, p. 104.) 



For a fuller discussion of this subject, see the twenty-second chapter of a 

 work already referred to, "An Examination of Sir William Hamilton's Philo- 

 sophy." 



VOL. I. 13 



