VERBAL AND REAL PROPOSITIONS. 



75 



k 



Nothing has probably contributed 

 more to the opinion so long prevalent 

 of the futility of the school logic, 

 than the circumstance that almost all 

 the examples used in the common 

 school-books to illustrate the doctrine 

 of predication and that of the syllo- 

 gism consist of essential propositions. 

 They were usually taken either from 

 the branches or from the main trunk 

 of the Predicamental Tree, which in- 

 cluded nothing but what was of the 

 essence of the species : Omne corpus est 

 substantia, Omne animal est corpus, 

 Omnis homo est corpus, Omnis homo 

 est animal, Omnis homo est rationalis, 

 and so forth. It is far from wonder- 

 ful that the syllogistic art should 

 have been thought to be of no use 

 in assisting correct reasoning, when 

 almost the only propositions which, 

 in the hands of its professed teachers, 

 it was employed to prove, were such- 

 as every one assented to without 

 proof the moment he comprehended 

 the meaning of the words ; and stood 

 exactly on a level, in point of evi- 

 dence, with the premises from which 

 they were drawn. I have, therefore, 

 throughout this work, avoided the 

 employment of essential propositions 

 as examples, except where the nature 

 of the principle to be illustrated speci- 

 fically required them. 



§ 5. With respect to propositions 

 which do convey information — which 

 assert something of a Thing, under a 

 name that does not abeady presuppose 

 what is about to be asserted ; there 

 are two different aspects in which 

 these, or rather such of them as are 

 general propositions, may be con- 

 sidered : we may either look at them 

 as portions of speculative truth, or 

 as memoranda for practical use. Ac- 

 cording as we consider propositions 

 in one or the other of these lights, 

 their import may be conveniently ex- 

 pressed in one or in the other of two 

 formulas. 



According to the formula which 

 we have hitherto employed, and which 

 is best adapted to express the import 



of the proposition as a portion of our 

 theoretical knowledge, All men are 

 mortal, means that the attributes of 

 man are always accompanied by the 

 attribute mortality : No men are gods, 

 means that the attributes of man are 

 never accompanied by the attributes, 

 or at least never by all the attributes, 

 signified by the word god. But when 

 the proposition is considered as a 

 memorandum for practical use, we 

 shall find a different mode of express- 

 ing the same meaning better adapted 

 to indicate the office which the pro- 

 position performs.; The practical use 

 of a proposition is, to apprise or re- 

 mind us what we have to expect in 

 any individual case which comes with- 

 in the assertion contained in the pro- 

 position. In reference to this purpose, 

 the proposition. All men are mortal, 

 means that the attributes of man are 

 evidence of, are a mark of, mortality ; 

 an indication by which the presence 

 of that attribute is made manifest. 

 No men are gods, means that the 

 attributes of man are a mark or evi- 

 dence that some or all of the attri- 

 butes understood to belong to a god 

 are not there ; that where the former 

 are, we need not expect to find the 

 latter. 



These two forms of expression are 

 at bottom equivalent ; but the one 

 points the attention more directly to 

 what a proposition means, the latter 

 to the manner in which it is to be used. 



Now it is to be observed that Rea- 

 soning (the subject to which we are 

 next to proceed) is a process into which 

 propositions enter not as ultimate re- 

 sults, but as means to the establish- 

 ment of other propositions. We may 

 expect, therefore, that the mode of ex- 

 hibiting the import of a general pro- 

 position which shows it in its applica- 

 tion to practical use, will best express 

 the function which propositions per- 

 form in Reasoning. And accordingly, 

 in the theory of Reasoning, the mode 

 of viewing the subject which con- 

 siders a Proposition as asserting that 

 one fact or phenomenon is a mark 

 or evidence of another fact or pheno- 



