Page:O. F. Owen's Organon of Aristotle Vol. 1 (1853).djvu/220

 with every B, A is with a certain C, so that there is a syllogism produced contradictorily. In like manner it can be shown, if the premises are vice versâ, but if the syllogism is particular, the conclusion being converted contrarily, neither premise is subverted, as neither was it in the first figure, (if however the conclusion is) contradictorily (converted), both (are subverted). For let A be assumed present with no B, but with a (certain) C, the conclusion B C; if then B is assumed present with a certain C, and A B remains, the conclusion will be that A is not present with a certain C, but the original would not be subverted, for it may and may not be present with a certain individual. Again, if B is with a certain C, and A with a certain C, there will not be a syllogism, for neither of the assumed premises is universal, wherefore A B is not subverted. If however the conversion is made contradictorily, both are subverted, since if B is with every C, but A with no B, A is with no C, it was however present with a certain (C). Again, if B is with every C, but A with a certain C, A will be with a certain B, and there is the same demonstration, if the universal proposition be affirmative.

Chapter 10
the third figure, when the conclusion is converted contrarily, neither premise is subverted, according to any of the syllogisms, but when contradictorily, both are in all the modes. For let A be shown to be with a certain B, and let C be taken as the middle, and the premises be universal: if then A is assumed not present with a certain B, but B with every C, there is no syllogism of A and C, nor if A is not present with a certain B, but with every C, will there be a syllogism of B and C. There will also be a similar demonstration, if the premises