156 REASONING. 



§ 9. The preceding considerations enable us to understand the true na- 

 ture of what is termed, by recent writers, Formal Logic, and the relation 



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

 known to us, is the datum from which all who discuss this subject must set out. The ques- 

 tion 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 lan- 

 guage 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. Who- 

 ever 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 suc- 

 cess or failure of an attempt to remove the difficulty. That he had reflected very little on the 

 point when he wrote his remarks, is shown by his oversight respecting the dictum de omni et 

 nullo. lie acknowledges that this maxim as commonly expressed — "Whatever is true of a 

 class, is true of every thing included in the class," is a mere identical proposition, since the 

 class is nothing but the things included in it. But he thinks this defect would be cured by 

 wording the maxim thus — "Whatever is true of a class, is true of every thing which can be 

 shown to be a member of the class :" as if a thing could " be shown " to be a member of the 

 class without being one. If a class means the sum of all the things included in tiie class, the 

 things which can "be shown" to be included in it are part of the sum, and the dictum is as 

 much an identical proposition with respect to them as to the rest. One would almost imagine 

 that, in the reviewer's opinion, things are not members of a class until they are called up pub- 

 licly to take their place in it — that so long, in fact, as Socrates is not known to be a man, he 

 is not a man, and any assertion which can be made concerning men does not at all regard 

 him, nor is affected as to its truth or falsity by any thing in which he is concerned. 



The difference between the reviewei-'s theory and mine may be thus stated. Both admit 

 that when we say, All men are mortal, we make an assertion reaching beyond the sphere of 

 our knowledge of individual cases ; and that when a new individual, Socrates, is brought with- 

 in the field of our knowledge by means of the minor premise, we learn that we have already 

 made an assertion respecting Socrates without knowing it : our own general formula being, to 

 that extent, for the first time interpreted to us. But according to the reviewer's theory, the 

 smaller assertion is proved by the larger : while I contend, that both assertions are proved to- 

 gether, by the same evidence, namely, the grounds of experience on which the general asser- 

 tion was made, and by which it must be justified. 



The reviewer says, that if the major premise included the conclusion, "we should be able 

 to affirm the conclusion without the intervention of the minor premise ; but every one sees 

 that that is impossible." A similar argument is urged by Mr. De Morgan (^Formal Logic, p. 

 259) : "The whole objection tacitly assumes the superfluity of the minor; that is, tacitly as- 

 sumes we know Socrates* to be a man as soon as we know him to be Socrates." The objec- 

 tion would be well grounded if the assertion that the major premise includes the conclusion, 

 meant that it individually specifies all it includes. As, however, the only indication it gives is 

 a description by marks, we have still to compare any new individual with the marks ; and to 

 show that this comparison has been made, is the office of the minor. But since, by supposi- 

 tion, the new individual has the marks, whether we have ascertained him to have them or 

 not ; if we have affirmed the major premise, we have asserted him to be mortal. Now my 

 position is that this assertion can not be a necessary part of the argument. It can not be a 

 necessary condition of reasoning that we should begin by making an assertion, which is after- 

 ward to be employed in proving a part of itself. I can conceive only one way out of this dif- 

 ficulty, viz., that what really forms tlie proof is the other part of the assertion ; the portion of 

 it, the truth of which has been ascertained previously : and that the unproved part is bound 

 up in one formula with the proved part in mere anticipation, and as a memorandum of the 

 nature of the conclusions which we are prepared to prove. 



Witii respect to the minor premise in its formal shape, the minor as it stands in the syllo- 

 gism, predicating of Socrates a definite class name, I readily admit that it is no more a neces- 

 sary part of reasoning than the major. When there is a major, doing its work by means of a 

 class name, minors are needed to interpret it : but reasoning can be carried on without either 

 the one or the other. They are not the conditions of reasoning, but a precaution against er- 

 roneous reasoning. The only minor premise necessary to reasoning in the example under 



* Mr. De Morgan says "Plato," but to prevent confusion I have kept to my own exemplum. 



