366 THE SCIENCE OF LOGIC 



This is a case of A being B. 



Therefore, this is a case of C being D. 



Just as the Modus Ponens can thus be reduced to the first figure, 

 so can the Modus Tollens be reduced to the second figure, of the 

 categorical syllogism. 



This process can be similarly applied to the pure hypothetical 

 syllogism. Disjunctive syllogisms we have already seen to be 

 reducible to hypothetical ; and, through these latter, they may be 

 reduced to categoricals. In all those cases, however, reduction 

 only serves the general purpose of showing a generic kinship 

 between naturally and specifically distinct forms of inference : 

 it cannot totally eliminate the difference there is between these. 



We have already alluded to Mr. Joseph s definition of the syllogism as 

 excluding hypothetical arguments (148 n., 149). He also objects to the re 

 duction of the latter to categorical (or syllogistic) form, to the use of the 

 expression &quot; middle term &quot; in reference to an antecedent or consequent, and 

 to the assimilation of the fallacies committed in hypothetical reasonings to 

 &quot;illicit process&quot; or &quot;undistributed middle&quot;. 1 The question is largely, 

 though not entirely, one of nomenclature. It cannot be denied that many 

 reasonings which fall naturally into the hypothetical form require &quot; linguistic 

 tours de force &quot; 2 to reduce them to categorical syllogisms. 



The real inherence of an attribute in a substance apparently underlies 

 the logical relation of predicate to subject in the categorical judgment ; and 

 that inherence is different from the real production of an effect by a cause : 

 this real dependence of effect on cause being apparently the main foundation 

 for our conception of the logical dependence of consequent on antecedent in 

 the hypothetical judgment. In neither case, however, is the parallelism be 

 tween the real and the logical order complete : what is really the effect^ for 

 example, often stands logically as antecedent in the judgment : the order in 

 which things are known often differs from the order in which they are or 

 happen. Similarly, the logical subject of a categorical judgment is not always 

 a substance of which the predicate is an attribute or quality. Mr. Joseph 

 emphasizes the fact that the relation of logical dependence (of consequent on 

 antecedent), expressed in the hypothetical proposition, is different from that 

 of predicate to subject, expressed in the categorical. This, no doubt, is true ; 

 but, withal, it is not impossible to conceive the production of an effect, or the 

 dependence of a consequent, as an attribute of a cause, or of an antecedent. If 

 categorical and hypothetical judgments may be regarded as distinct modali 

 ties or sub-forms of the same generic form of thought, the judgment : it is 

 permissible to regard hypothetical arguments as kinds or forms of syllogism. 

 Though Aristotle did not call the arguments considered in the present chapter 

 &quot;hypothetical syllogisms,&quot; 3 yet this nomenclature has become practically uni 

 versal. That, however, does not alter the fact that the resemblance between 

 them and categorical syllogisms is one which conceals important differences. 



l op. f.,pp. 312 sqq. z ibid. t p. 313. 3 ibid., p. 316, n. 



