命題論

Notwithstanding it is evident that of one affirmation there is one negation, for it is necessary that the negation should deny the same thing which the affirmation affirmed, and also from the same, (i. e.) either from some singular or some universal, universally or not universally; I say, for instance, that "Socrates is white," "Socrates is not white." If however there is something else from the same thing, or the same thing from something else, that (enunciation) will not be opposite, but different from it; to the one, "every man is white," the other (is opposed) "not every man is white," and to the one, "a certain man is white," the other, "no man is white;" and to the one, "man is white," the other, "man is not white." That there is then one affirmation contradictorily opposed to one negation, and what these are, has been shown, also that there are other contraries, and what they are, and that not every contradiction is true or false, and why and when it is true or false. Chapter 8 The affirmation and negation are one, which indicate one thing of one, either of an universal, being taken universally, or in like manner if it is not, as "every man is white," "not every man is white," "man is white," "man is not white," "no man is white," "some man is white," if that which is white signifies one thing. But it one name be given to two things, from which one thing does not arise, there is not one affirmation nor one negation; as if any one gave the name "garment" to a "horse," and to "a man;" that "the garment is white," this will not be one affirmation, nor one negation, since it in no respect differs from saying "man" and "horse" are "white," and this is equivalent to "man is white," and "horse is white.…