486 Mr DE morgan, ON THE SYLLOGISM, No. V. AND 



inference. Hamilton sees all this (VI. 630*), speaks of my treatment of his syllogism, repre- 

 hends me for my alleged mistake about his canon of inference, &"c. But what of all this ? 

 Hamilton had the old system as well as the new. This is the point. He goes on to show 

 that his head is so full of his own new plan that he cannot read an opponent in any other 

 sense ; that he cannot understand an opponent who knows nothing of his ' some at most', 

 which he was then giving /or the first time in print. He goes on to say (VT. 631*) " I shall 

 first consider the objections [i. e. my objections] to the pro])ositiorial forms, which I have pecu- 

 liarly adopted. But it is proper to premise a general enumeration of these;..." He then 

 proceeds to lay down what I have already called his clearest explanation of the forms involv- 

 ing his new sense of ' some'. Having done this, he proceeds with " Of the four proposi- 

 tional forms specially recognised by me (l, S, 6, 8) Mr De Morgan questions only two... ;" 

 Surely, because I took the other two, as I said, to be converted Aristotelians ; but Hamilton 

 clearly supposes that I had taken him in his own peculiar sense throughout. Thus when he 

 comes (VI. 633''') to assail me for compounding " All Xs are all Ys" out of " all Xs are some 

 Ys" and " Some Xs are all Ys" he charges me with compounding " incom possible propositions" : 

 that is, he supposes me to be taking his own propositions in his own sense. He proceeds 

 thus — '• But unless some be identified with all [as it may be in the old system], if either of 

 the latter propositions is true the other must be false ; — nay, in fact, if either be true, the 

 very proposition which they are supposed to concur in generating is false likewise." I 

 now see what all this means : it says in effect — ' You pretend to argue about my propositions 

 and their connexion, while you are advancing objections which are valid only on the supposi- 

 tion that some of my forms are the old ones.' 



It would have been absurd in Hamilton to have argued against me that my conjunction 

 required some to be identified with all, unless he had supposed me to be employing a ' some' 

 which could not be so identified. It stands thus. I was representing Hamilton's system to 

 the best of my knowledge. Hamilton had not, so far as I knew, any but the common mean- 

 ing of 'some'. But he had another meaning, of which his own head wrfs so full that 

 he took it as of course that in my representation of him I adopted that meaning. He did not 

 object to my collection of syllogistic forms — and they are identical with those on which this 

 discussion has arisen. By failure of objection he accepts these forms, and quarrels with 

 nothing but the form I had given of the canon of inference. If Mr Baynes be correct, 

 Hamilton ought to have told me that his own new use of 'some' was partial ; that it is for par- 

 ticular cases and for special objects; that it is on}y for isolated propositions and immediate 

 inference; that I was wrong in assuming it intended for syllogism at all, and still more wrong 

 in carrying it into every detail. Instead of all this, he opens his fire by charging me with 

 having taken the rule of mediate inference from Ploucquet, and then proceeds to a detailed 

 exposition of his own new forms, of which he makes me receive six, and object to two. It is 

 now for Mr Baynes to make Hamilton contradict me without making him contradict himself. 



There is one point which many persons may misconceive : and on which I therefore 

 notice Mr Baynes again. Wishing to give an account of all the strength of his answer, I 

 reminded him of the difficulty which would exist, a hundred years hence, in confrontino- the 

 weekly journal with the scientific quarto ; and I suggested that he should substantiate certain 



