FUNCTIONS AND VALUE OF THE SYLLOGISM. 



129 



doctrine that the syllogistic art is use- 

 less for the purposes of reasoning. 

 The reasoning lies in the act of gene- 

 ralisation, not in interpreting the 

 record of that act ; but the syllogis- 

 tic form is an indispensable collateral 

 security for the correctness of the 

 generalisation itself. 



It has already been seen, that if we 

 have a collection of particulars suflB- 

 cient for grounding an induction, we 

 need not frame a general proposition ; 

 we may reason at once from those 

 particulars to other particulars. But 

 it is to be remarked withal, that 

 whenever, from a set of particular 

 cases, we can legitimately draw any 

 inference, we may legitimately make 

 our inference a general one. If, from 

 observation and experiment, we can 

 conclude to one new case, so may we 

 to an indefinite number. If that 

 which has held true in our past experi- 

 ence will therefore hold in time to 

 come, it will not hold merely in some 

 individual case, but in all cases of 

 some given description. Every induc- 

 tion, therefore, which suffices to prove 

 one fact, proves an indefinite multi- 

 tude of facts : the experience which 

 justifies a single prediction must be 

 such as will suffice to bear out a 

 general theorem. This theorem it is 

 extremely important to ascertain and 

 declare in its broadest form of gene- 

 rality, and thus to place before our 

 minds, in its full extent, the whole of 

 what our evidence must prove if it 

 proves anything. 



This throwing of the whole body of 

 possible inferences from a given set of 

 particulars into one general expression 

 operates as a security for their being 

 just inferences, in more ways than 

 one. First, the general principle pre- 

 sents a larger object to the imagina- 

 tion than any of the singular proposi- 

 tions which it contains. A process of 

 thought which leads to a compnehen- 

 sive generality is felt as of greater 

 importance than one which terminates 

 in an insulated fact ; and the mind 

 is, even unconsciously, led to bestow 

 greater attention upon the process, and 



to weigh more carefully the sufficiency 

 of the experience appealed to for 

 supporting the inference grounded 

 upon it. There is another, and a more 

 important, advantage. In reasoning 

 from a course of individual observa- 

 tions to some new and unobserved 

 case, which we are but imperfectly 

 acquainted with, (or we should not be 

 inquiring into it,) and in which, since 

 we are inquiring into it, we probably 

 feel a peculiar interest, there is very 

 little to prevent us from giving way 

 to negligence, or to any bias which 

 may afifect our wishes or our imagina- 

 tion, and, under that influence, accept- 

 ing insufficient evidence as sufficient. 

 But if, instead of concluding straight 

 to the particular case, we place before 

 ourselves an entire class of facts — the 

 whole contents of a general proposi- 

 tion, every tittle of which is legiti- 

 mately inferrible from our premises, if 

 that one particular conclusion is so ; 

 there is then a considerable likelihood 

 that if the premises are insufficient, 

 and the general inference, therefore, 

 groundless, it will comprise within it 

 some fact or facts the reverse of which 

 we already know to be true ; and we 

 shall thus discover the error in our 

 generalisation by a reductio ad im- 

 possibile. 



Thus if, during the reign of Mar- 

 cus Aurelius, a subject of the Roman 

 Empire, under the bias naturally given 

 to the imagination and expectations 

 by the lives and characters of the 

 Antonines, had been disposed to ex- 

 pect that Commodus would be a just 

 ruler ; supposing him to stop there, he 

 might only have been undeceived by 

 sad experience. But if he reflected 

 that this expectation could not be 

 justifiable unless from the same 

 evidence he was warranted in con- 

 cluding some general proposition, as, 

 for instance, that all Roman emperors 

 are just rulers ; he would immediately 

 have thought of Nero, Domitian, and 

 other instances, which, showing the 

 falsity of the general conclusion, and 

 therefore the insufficiency of the pre- 

 mises, would have warned him that 



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