Authors/Ockham/Summa Logicae/Book III-1/Chapter 45

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Latin English
Cap. 45. De mixtione necessarii et possibilis in secunda figura Chapter 45. On the mixture of necessary and possible propositions in the second figure.
In secunda figura, si illa de necessario sumatur in sensu compositionis et illa de possibili in sensu divisionis, si negativa fuerit de necessario sequitur conclusio de possibili. Sicut sequitur nullum hominem esse asinum est necessarium; omne rudibile potest esse asinus; igitur ƿ omne rudibile potest non esse homo'. Similiter, si utraque sit in sensu compositionis, sequitur conclusio de possibili. Et utrumque patet, quia conversa negativa de necessario, sequitur conversa conclusionis in prima figura. In the second figure, if the proposition of necessity is taken in the sense of composition and the proposition of possibility in the sense of division, if the one of necessity is negative, the conclusion of possibility follows. Just as it follows that it is necessary that no man is a donkey; every trainable thing can be a donkey; therefore it is possible that every trainable thing is not a man'. Similarly, if both are in the sense of composition, the conclusion of possibility follows. And both are clear, because the negative of necessity inverted follows the converse of the conclusion in the first figure.
Similiter, si affirmativa fuerit de necessario, sequitur conclusio de possibili. Sequitur enim 'omne corpus triangulare esse substantiam est necessarium; omne corpus potest non esse substantia; igitur omne corpus potest non esse corpus triangulare’. Similiter sequitur si illa de possibili sumatur in sensu compositionis. Et utrumque probatur, quia a quocumque potest negari superius vel convertibile, ab eodem potest negari inferius vel convertible. Nunc autem quando universalis affirmativa est necessaria, necessario praedicatum est superius vel convertibile cum subiecto, et ideo si praedicatum potest removeri ab aliquo, subiectum poterit removed ab eodem. Similarly, if the affirmative is of necessity, the conclusion of possibility follows. For it follows that ‘every triangular body is necessarily a substance; it is possible for every body not to be a substance; therefore it is possible for every body not to be a triangular body’. Similarly, it follows if a proposition of possibility is taken in the sense of composition. And both are proven, because from whatever a superior or convertible can be denied, from the same an inferior or convertible can be denied. Now, however, when the universal affirmative is necessary, the predicate is necessarily superior or convertible with the subject, and therefore if the predicate can be removed from something, the subject can be removed from the same.
Secundo videndum est quando illa de necessario sumitur in sensu divisionis et illa de possibili in sensu compositionis. Et tunc similiter sequitur conclusio de possibili, sic 'omnis homo de necessitate non est Deus; quamlibet personam divinam esse Deum est possibile; igitur quamlibet personam divinam non esse hominem est possibile’. Similiter sequitur si affirmativa fuerit de necessario. Similiter, si utraque sumatur in sensu compositionis, sequitur conclusio de possibili. Secondly, we must see when the latter is taken of necessity in the sense of division and the former of possibility in the sense of composition. And then similarly follows the conclusion of possibility, thus 'every man is not God of necessity; it is possible for any divine person to be God; therefore it is possible for any divine person not to be man'. Similarly, it follows if the affirmative is of necessity. Similarly, if both are taken in the sense of composition, the conclusion of possibility follows.

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