230 REASONING. 



realized in the cases A, B, C, would be as much justified in 

 concluding directly to the Duke of Wellington as in conclud- 

 ing to all men. The general conclusion is never legitimate, 

 unless the particular one would be so too ; and in no sense, 

 intelligible to me, can the particular conclusion be said to be 

 drawn from the general one. Whenever there is ground for 

 drawing any conclusion at all from particular instances, there 

 is ground for a general conclusion ; but that this general con- 

 clusion should be actually drawn, however useful, cannot be 

 an indispensable condition of the validity of the inference in 

 the particular case. A man gives away sixpence by the same 

 power by which he disposes of his whole fortune ; but it is not 

 necessary to the legality of the smaller act, that he should 

 make a formal assertion of his right to the greater one. 



Some additional remarks, in reply to minor objections, are 

 appended.* 



* A writer in the "British Quarterly Review" (August 1846), in a review 

 of this treatise, endeavours to show that there is no petitio principii in the 

 syllogism, by denying that the proposition, All men are mortal, asserts or 

 assumes that Socrates is mortal. In support of this denial, he argues that we 

 may, and in fact do, admit the general proposition that all men are mortal, with- 

 out having particularly examined the case of Socrates, and even without knowing 

 whether the individual so named is a man or something else. But this of course 

 was never denied. That we can and do draw conclusions concerning cases 

 specifically unknown to us, is the datum from which all who discuss this subject 

 must set out. The question is, in what terms the evidence, or ground, on which 

 we draw these conclusions, may best be designated whether it is most correct 

 to say, that the unknown case is proved by known cases, or that it is proved by 

 a general proposition including both sets of cases, the unknown and the known ? 

 I contend for the former mode of expression. I hold it an abuse of language to 

 say, that the proof that Socrates is mortal, is that all men are mortal. Turn it 

 in what way we will, this seems to me to be asserting that a thing is the proof 

 of itself. Whoever pronounces the words, All men are mortal, has affirmed 

 that Socrates is mortal, though he may never have heard of Socrates ; for since 

 Socrates, whether known to be so or not, really is a man, he is included in the 

 words, All men, and in every assertion of which they are the subject. If the 

 reviewer does not see that there is a difficulty here, I can only advise him to 

 reconsider the subject until he does : after which he will be a better judge of 

 the success or failure of an attempt to remove the difficulty. That he had re- 

 flected very little on the point when he wrote his remarks, is shown by his over- 

 sight respecting the dictum de omni et nullo. He acknowledges that this maxim 

 as commonly expressed, " Whatever is true of a class, is true of everything in- 



