LESSON IX

In Contradictions of Modal Propositions the Negation Must Be

Added to the Modes, Not to the Verb

             21b 23 Therefore, the negation of "possible to be" is "not possible to be." The reasoning is the same in regard to "contingent to be," for its negation is "not contingent to be." So, too, in the others, that is, the necessary and the impossible.

             21b 26 For just as "to be" and "not to be" are the determining additions in the former [i.e., absolute enunciations] and the things subjected are "white" and "man," so here "to be" is as the subject and "is possible" and "is contingent" are determining additions; and just as "to be" and "not to be" determine the true [and the false] in the former, in like manner these determine the true [and the false] in regard to what is possible and not possible.

             21b 33 The negation, then, of "possible not to be" is "not possible not to be." Wherefore "possible to be" and "possible not to be" would appear to be consequent to each other; for the same thing is "possible to be" and "possible not to be," since these are not contradictory to each other. But "possible to be" and "not possible to be" are never true at once of the same subject, for they are opposed. Nor are "possible not to be" and "not possible not to be" ever true at once of the same subject.

             The case is the same with respect to the necessary. The negation of "necessary to be" is not, "necessary not to be" but, "not necessary to be"; and the negation of "necessary not to be," "not necessary not to be."

             Likewise, the negation of "impossible to be" is not, "impossible not to be" but, "not impossible to be"; and of "impossible not to be," "not impossible not to be."

             22a 8 And universally, as has been said, "to be" and "not to be" must be posited as the subject, and those that produce affirmation and negation [i.e., possible, not possible, contingent, not contingent, etc.] must be joined to "to be" and "not to be." And these are the words that are to be considered opposed:

possible   -- not possible necessary -- not necessary

contingent -- not contingent true  -- not true

impossible  -- not impossible

             1. Aristotle now determines where the negation must be placed in order to obtain contradiction in modals. He first determines the truth summarily; secondly, he presents the argument for the truth of the position, which is also the answer to the reasoning induced for the opposite position, where he says, For just as "to be" and "not to be" are the determining additions in the former, and the things subjected are "white" and "man," etc.; thirdly, he makes this truth evident in all the modals, where he says, The negation, then, of "possible not to be" is "not possible not to be," etc.; fourthly, he arrives at a universal rule where he says, And universally, as has been said, "to be" and "not to be" must be posited as the subject, etc.

             Since the negation must be added either to the verb or to the mode and it was shown above in virtue of an argument from division that it is not to be added to the verb, he concludes: Therefore, the negation of "possible to be" is "not possible to be"; that is, the mode is negated. The reasoning is the same with respect to enunciations of the contingent, for the negation of "contingent to be" is "not contingent to be." And the judgment is the same in the others, i.e., the necessary and the impossible.

             2. When he says, For just as "to be" and "not to be" are the determining additions in the former, and the things subjected are "white" and "man," etc., he gives the argument for the truth of his position. To obtain contradiction among any enunciations the negation must be applied to the determining addition, i.e., to the word that joins the predicate with the subject; but in modals the determining additions are the modes; therefore, to get a contradiction in modals, the negation must be added to the mode.

             The major of the argument is subsumed; the minor is stated in Aristotle's wording by a further similitude to absolute enunciations. In absolute enunciations the determining additions, i.e., the predications, are "to be" and "not to be," i.e., the verb signifying "to be" or "not to be" (for the verb is always a sign of those things that are predicated of another). The things subjected to the determining additions, i.e., to which "to be" and "not to be" are applied, are "white," in "White is," or "man," in "Man is." This happens in modals in the same way but in a manner appropriate to them. "To be" is as the subject, i.e., the dictum signifying "to be" or "not to be" holds the place of the subject; "is possible" and "is contingent," i.e., the modes, are the predicates. And just as in absolute enunciations we determine truth or falsity with "to be" and "not to be," so in modals with the modes. He makes this point when he says, determining additions, i.e., these modes effect truth just as "to be" and "not to be" determine truth and falsity in the others.

             3. Thus the response to the argument for the opposite position, which he gave first, is evident. That argument concluded that the negation should be added to the verb as it is in absolute enunciations. But since the modal enunciates a mode of a dictum--as the absolute enunciation enunciates "to be" or "not to be" such, for instance, "to be white" of a subject--the mode holds the same place here that the verb does there. Consequently, the negation falls upon the same thing proportionally here and there, for the proportion of mode to dictum is the same as the proportion of verb to subject.

             Again, since truth and falsity follow upon affirmation and negation, the affirmation and negation of an enunciation and its truth and falsity must be controlled by the same thing. In absolute enunciations truth and falsity follow upon "to be" or "not to be," hence in the modals they follow upon the mode; for that modal is true which modifies the dictum as the composition of the dictum permits, just as that absolute enunciation is true which signifies that something is as it is. Therefore, negation is added here to the mode just as it is added there to the verb, since the power of each is the same with respect to the truth and falsity of an enunciation.

             Notice that he calls the modes "determining additions," i.e., predications--as "to be" is in absolute enunciations--understanding by the mode the whole predicate of the modal enunciation, for example, "is possible." As a sign of this he expresses the modes themselves verbally when he says, "is possible" and "is contingent" are determining additions. For "is contingent" and "is possible" comprise the whole predicate of the modal enunciation.

             4. When he says, The negation, then, of "possible not to be" is [not, "not possible to be" but] "not possible not to be," etc., he makes this truth evident in all the modals, i.e., the possible, the necessary, and the impossible (the contingent being convertible with the possible). And since any mode makes two modal affirmatives, one having an affirmed dictum and the other having a negated dictum, he shows what the negation of each affirmation is in each mode. First he takes those of the possible. The negation of the first affirmative of the possible (the one with an affirmed dictum), i.e., "possible to be," was assigned as "not possible to be." Hence, going on to the remaining affirmative of the possible he says, The negation, then, of "possible not to be" [wherein the dictum is negated] is, "not possible not to be." Then he proves this. The contradictory of "possible not to be" is either "possible to be" or "not possible not to be." But the former, i.e., "possible to be," is not the contradictory of "possible not to be," for they can be at once true. Hence they are also thought to follow upon each other, for, as was said above, the same thing is possible to be and not to be. Consequently, just as "possible not to be" follows upon "possible to be," so conversely "possible to be" follows upon "possible not to be." But the contradictory of "possible to be," which cannot be true at the same time, is "not possible to be," for these, as has been said, are opposed. Therefore, the negation of "possible not to be" is, "not possible not to be," for these are never at once true or false.

             Note that he says, Wherefore "possible to be" and "possible not to be" would appear to be consequent to each other, and not that they do follow upon each other, for it is not true that they follow upon each other universally, but only particularly (as will be said later); this is the reason they appear to follow upon each other simply.

             Then he manifests the same thing in the modals of the necessary, and first in the affirmative with an affirmed dictum: The case is the same with respect to the necessary. The negation of "necessary to be" is not, "necessary not to be" (in which the mode is not negated) but, "not necessary to be." Next he adds the affirmative of the necessary with a negated dictum: and the negation of "necessary not to be" is "not necessary not to be."

             Next, he takes up the impossible, keeping the same order. The negation of "impossible to be" is not, "impossible not to be" but, "not impossible to be," in which the mode is negated. The negation of the other affirmative, "impossible not to be" is "not impossible not to be." The negation, therefore, is always added to the mode.

             5. Then he says, And universally, as has been said, "to be" and "not to be" must be posited as the subject, and those that produce affirmation and negation must be joined to "to be" and "not to be," etc. Here he concludes with the universal rule. As has been said, the dictums denoting "to be" and "not to be" must be posited in the modals as subjects, and the one making this an affirmation and negation, i.e., the opposition of contradiction, must be added only to the selfsame mode, not to diverse modes, for the selfsame mode which was previously affirmed must be denied if there is to be a contradiction. He gives examples of how this is to be done when he adds, And these are the words that are to be considered opposed, i.e., affirmations and negations in modals, possible--not possible, contingent--not contingent.

             Moreover, when he said elsewhere but in another way that the negation must be applied only to the mode, he did not exclude the copula of the mode, but the copula of the dictum. For it is unique to modals that the same opposition is made by adding a negation to the mode and to its verb. The contradictory of "is possible to be," for instance, is not only "is not possible to be," but also "not is possible to be." There are two reasons, however, for his mentioning the mode rather than the verb: first, for the reason we have just given, namely, so as to imply that the negation placed after the verb of the mode, the mode having been put first, accomplishes the same thing as if it were placed before the modal verb; and secondly, because the modal enunciation is never without a mode; hence the negation can always be put on the mode. However, it cannot always be put on the verb of a mode, for the modal enunciation may lack the verb of a mode as for example in "Socrates runs necessarily," in which case the negation can always be adapted to the verb.

             In adding "true" and "not true" at the end he implies that besides the four modes mentioned previously there are others that also determine the composition of the enunciation, for example, "true" and "not true," "false" and "not false"; nevertheless he did not posit these among the modes first given because, as was shown, they do not properly modify.