CA TEGORICAL JUDGMENTS AND PROPOSITIONS. 2 1 1 



There has been much dispute among logicians as to the ad 

 visability, and even as to the correctness, of interpreting the cate 

 gorical judgment in this manner. Against the extreme advocacy 

 of this interpretation by Sir William Hamilton, there has been an 

 equally extreme reaction. 



It may be granted at once that in most of our judgments we 

 think of the intension of the predicate rather than of its extension, 

 and that, accordingly, the predicative interpretation gives a more 

 faithful expression of the psychological facts than the present 

 view gives. But it cannot be denied that in many of our judg 

 ments it is the extension, and not the intension, of the predicate 

 that is uppermost in our minds. In all those sciences and 

 departments of knowledge in which the classification of the 

 things considered is prominent, our judgments bring into con 

 sciousness class relations. For example, Irishmen are Celts ; 

 Whales are Mammals ; Palms are Endogens ; None but solid 

 bodies are crystals. Of course, the intension of the predicate is in 

 all cases more fundamental than its extension, even when the 

 class-inclusion interpretation is adopted : but the same is true of 

 the subject when it is read in extension in the predicative view. 



Then, again, it cannot be denied that in many logical pro 

 cesses which will come up for discussion in the conversion of 

 propositions, and in syllogistic reasoning, for example we attend 

 explicitly to the denotation of the predicate. We have already 

 considered rules for the distribution of the latter (91). 



Finally, the proposition, interpreted in this way, lends itself 

 to diagrammatic representation. It is only the class-relations of 

 terms that can be instructively illustrated by diagrams. The 

 possible relations of two objectively determined classes will be 

 seen to be neither more nor less than the following five : 

 (i) (2) (3) 







All S is all P ; All S is some P ; Some S is all P ; 

 (4) (5) 



S 



Some S is some P ; No S is any P. 



14* 



