Prior Analytics - Book I   

particular: e.g. if all B is A and some C is not B, or if not all C is

B. For the major term may be predicable both of all and of none of the

minor, to some of which the middle term cannot be attributed.

Suppose the terms are animal, man, white: next take some of the

white things of which man is not predicated-swan and snow: animal is

predicated of all of the one, but of none of the other. Consequently

there cannot be a syllogism. Again let no B be A, but let some C not

be B. Take the terms inanimate, man, white: then take some white

things of which man is not predicated-swan and snow: the term

inanimate is predicated of all of the one, of none of the other.

Further since it is indefinite to say some C is not B, and it is

true that some C is not B, whether no C is B, or not all C is B, and

since if terms are assumed such that no C is B, no syllogism follows

(this has already been stated) it is clear that this arrangement of

terms will not afford a syllogism: otherwise one would have been

possible with a universal negative minor premiss. A similar proof

may also be given if the universal premiss is negative.

Nor can there in any way be a syllogism if both the relations of

subject and predicate are particular, either positively or negatively,

or the one negative and the other affirmative, or one indefinite and

the other definite, or both indefinite. Terms common to all the

above are animal, white, horse: animal, white, stone.

It is clear then from what has been said that if there is a

syllogism in this figure with a particular conclusion, the terms

must be related as we have stated: if they are related otherwise, no

syllogism is possible anyhow. It is evident also that all the

syllogisms in this figure are perfect (for they are all completed by

means of the premisses originally taken) and that all conclusions

are proved by this figure, viz. universal and particular,

affirmative and negative. Such a figure I call the first.



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