Page:O. F. Owen's Organon of Aristotle Vol. 1 (1853).djvu/301

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B will be true, but the other false. The same will happen if the negative is transposed, for what is in no A, will neither be in any B; if then C is assumed not present with the whole of A, but present with the whole of B, the proposition A C will be true, but the other false. Again, also, it is false to assume that what is present with every B, is with no A; for it is necessary, if it is with every B, that it should be also with a certain A; if then C is assumed present with every B, but with no A, the proposition C B will be indeed true, but C A false. Hence, it is evident that when both propositions are false, and when one only is so, there will be a syllogism deceptive in individuals.

Chapter 17

In those which are not individually present, or which are not present, when a syllogism of the the false is produced through an appropriate medium, both propositions cannot be false, but only the major. But I mean by an appropriate medium, that through which there is a syllogism of contradiction. For let A be with B through the medium of C, since then we must take C B as affirmative, if there is to be a syllogism, it is clear that this will be always true, for it is not converted. A C, on the other hand, will be false, for when this is converted, a contrary syllogism arises. So also if the middle is assumed from another affinity, as for instance, if D is in the whole of A, and is predicated of every B, for the proposition D B must necessarily remain, but the other proposition must be converted, so that the one (the minor) will be always true, but the other (the major) always false. Deception also of this kind is almost the same