Authors/Ockham/Summa Logicae/Book III-3/Chapter 15

Latin	English
ƿ CAP. 15. DE OPPOSITIONE ET CONTINGENTIA PROPOSITIONUM DE CONTINGENTI.	Chapter 15. On the opposition and contingency of propositions of contingency.
Circa propositiones de contingenti oportet primo scire quod istarum propositionum `contingit omnem hominem esse animal', `contingit omnem hominem non esse animal', `contingit aliquem hominem esse animal', `contingit aliquem hominem non esse animal' non est quaerenda aequipollentia, eo quod sunt primae.	Regarding propositions about contingency, we must first know that the equivalents of these propositions: `it happens that every man is an animal', `it happens that every man is not an animal', `it happens that some man is an animal', `it happens that some man is not an animal' is not to be sought, as they are primary.
Possunt tamen tales propositiones exponi, quia quaelibet illarum aequivalet uni copulativae ex duabus propositionibus de possibili; sicut ista `contingit omnem hominem esse animal' aequivalet isti `possibile est omnem hominem esse animal et possibile est nullum hominem esse animal'.	However, such propositions can be explained, because each of them is equivalent to one of the two propositions of the possible. just as this, `it happens that every man is an animal' is equivalent to these, `it is possible for every man to be an animal' and 'it is possible for no man to be an animal'.
Et ita est de aliis. Et ideo semper negativa et affirmativa de contingenti, modo contingentiae remanente affirmato, convertuntur; sicut istae duae `contingit omnem hominem esse animal', `contingit nullum hominem esse animal' convertuntur. Et sic de aliis.	And so it is with others. And therefore the negative and the affirmative of the contingent are always reversed, as long as the contingency remains affirmed; just as these two, `it happens that every man is an animal', `it happens that no man is an animal' are reversed. And this is so of others.
Et ex istis faciliter potest sciri aequipollentia propositionum de contingenti. Sicut enim ipsa aequivalet uni copulativae, ita sua repugnans aequivalet uni disiunctivae compositae ex repugnantibus partibus illius copulativae.	And from these the equivalence of propositions about the contingent can easily be known. For just as it is equivalent to the one of the copulative, so its contradictory is equivalent to the one of the disjunctive composed of the contradictory parts of that copulative.
Et ideo inquirendo aequipollentiam propositionis de contingenti, resolvenda est illa in unam copulativam ex duabus de possibili; quo facto videndum est cui aequipollet una pars et alia, et ex illis formanda est una disiunctiva cui aequipollebit illa de contingenti. Hoc tamen non est faciendum nisi quando modus contingentiae est negatus.	And therefore, by inquiring into the equivalence of a proposition about the contingent, it must be resolved into one copulative from two about the possible; in which case it must be seen that one part and the other are equivalent, and from them one disjunctive must be formed to which those contingents are equivalent. This, however, is to be done only when the mode of contingency is denied.
Verbi gratia si accipiatur ista `non contingit omne animal esse hominem', ista affirmativa 'contingit omne animal esse hominem' resolvenda est in istam copulativam cui aequivalet `omne animal potest esse homo et omne animal potest non esse homo' et utrique illarum praeponenda est negatio sub disiunctione, sic `non omne animal potest esse homo vel non omne animal potest non esse homo'.	For example, if we take the statement `not every animal happens to be a man', this affirmative `every animal happens to be a man' must be resolved into this copulative which is equivalent to `every animal can be a man and every animal can not be a man' and both of them must be preceded by a negation under disjunction, thus, `not every animal can be a man or not every animal can not be a man'.
Et accipienda est aequipollens isti disiunctivae per regulam datam in praecedenti capitulo, scilicet ista `necesse est aliquod animal non esse hominem vel necesse est aliquod animal esse hominem'.	And it is to be taken as equivalent to these disjunctives by the rule given in the preceding chapter, namely, that 'it is necessary for some animal not to be a man, or it is necessary for some animal to be a man'.
Et ista ultima disiunctiva aequipollebit isti `non contingit omne animal esse hominem'. ƿ Eodem modo ista, per easdem regulas, `nullus homo contingenter est animal' aequipollebit isti de disiuncto praedicato `omnis homo de necessitate est animal vel de necessitate non est animal'.	And this last disjunctive will be equivalent to this `it does not happen that every animal is a man'. In the same way, by the same rules, `no man is contingently an animal' will be equivalent to the disjunctive predicate `every man is necessarily an animal or necessarily not an animal.'
Non enim in isto casu potest aequipollere disiunctivae, sicut patet de ista `nulla persona divina contingenter est Pater'; sed aequipollebit uni universali de disiuncto praedicato, ita tamen quod in utraque parte disiuncti addatur modus necessitatis.	For in this case it cannot be equivalent to disjunctives, as is clear from the fact that `no divine person is contingently the Father'; but it will be equivalent to the one universal predicate of the separated, so that the mode of necessity is added to each part of the separated.
Quando autem dictum propositionis de contingenti vel aequivalens ei mutatur in contradictorium, tunc particularis aequipollebit uni disiunctivae; et hoc, quia propositio particularis et indefinita disiunctiva et de disiuncto praedicato convertuntur.	But when the statement of the proposition is changed from the contingent or equivalent to it into the contradictory, then the particular will be equivalent to the one of the disjunctive; and this, because the particular proposition and the indefinite are disjunctive and converted from the disjunctive predicate.
Oportet autem scire quod quando modus contingentiae est affirmatus, accipienda est aequipollentia servato eodem modo ex parte residui, et eodem modo proportionaliter sicut dictum est de praecedentibus.	Now it is necessary to know that when the mode of contingency is affirmed, the equivalence must be taken, provided in the same way from the remaining part, and in the same way proportionally as was said about the previous ones.
Unde ista `contingit non omnem hominem currere' aequipollet isti `contingit aliquem hominem currere', et sic de aliis.	Hence this `it happens that not every man runs' is equivalent to this: `it happens that some man runs', and so on for the others.