Authors/Ockham/Summa Logicae/Book III-1/Chapter 23

Latin	English
[Cap. 23. De uniformi de possibili in prima figura]	[Chapter 23. On uniform de possibili syllogisms in the first figure]
Post uniformem modum generationis syllogismorum de necessario dicendum est de uniformi generatione syllogismorum de possibili. Et accipio hic ‘possible’ pro possibili quod est commune omni propositioni quae non est impossibilis.	After the uniform mode of generation of syllogisms of necessity, we should speak of the uniform generation of syllogisms of possibility.  And I take 'possible' here for the 'possible' which is common to every proposition which is not impossible.
Et est sciendum quod in omni figura, si accipiantur omnes propositiones de possibili in sensu compositionis vel accipiantur eis aequivalentes, non valet syllogismus, quia tunc argueretur per istam regulam ‘praemissae sunt possibiles, ergo conclusio est possibilis’, quae regula est falsa. Unde non sequitur ‘omne coloratum esse album est possibile; omne nigrum esse coloratum est possibile; igitur omne nigrum esse album est possibile’. Nec sequitur ‘omne animal esse hominem est possibile; omnem asinum esse animal est possibile; igitur omnem asinum esse hominem est possibile’. Et ita ista regula est falsa ‘praemissae sunt possibiles, ergo conclusio est possibilis’; sed ista regula vera est ‘si praemissae sunt possibiles et compossibiles, conclusio est possibilis’. Nunc autem aliquando praemissae sunt possibiles et sunt incompossibiles, et ideo numquam forma syllogistica uniformis ex illis possibilibus tenet in sensu compositionis.	And it should be known that in every figure, if all propositions of possibility, or propositions equivalent to them, are understood in the sense of composition, the syllogism is not valid, for then one would be arguing by the rule of "the premises are possible, therefore the conclusion is possible", which rule is false.  Hence "it is possible that every coloured thing is white, it is possible that every black thing is coloured, therefore it is possible that every black thing is white" does not follow.  Nor does "it is possible that every animal is a man, it is possible that every donkey is an animal, therefore it is possible that  every donkey is a man" follow. And so that rule "the premises are possible, therefore the conclusion is possible" is false.  But the rule "if the premises are possible and co-possible, the conclusion is possible" is true.  Now sometimes the premises are possible and not co-possible, and therefore the syllogistic form of a uniform syllogism from those possibles is never true in the sense of composition.
ƿ Sed si illa de possibili sumatur in sensu divisionis vel accipiatur aliqua aequivalens, cuiusmodi sunt tales propositiones ‘omnis homo potest esse albus’, ‘album potest esse nigrum’ et huiusmodi, tunc est ista propositio distinguenda penes tertium modum aequivocationis, eo quod subiectum potest supponere pro his quae sunt vel pro his quae possunt esse, hoc est, eo quod subiectum potest supponere pro his de quibus verificatur per verbum de praesenti vel pro his de quibus verificatur per verbum de possibili; sive denotatur posse supponere pro talibus, quod dico ad excludendum unam cavillationem. Sicut si dicam sic ‘omne album potest esse homo’: unus sensus est iste ‘omne quod est album, potest esse homo’, et iste sensus est verus si nihil sit album nisi homo. Alius sensus est iste ‘omne quod potest esse album, potest esse homo’; et hoc est falsum, sive tantum homo sit albus sive aliud ab homine.	But if the proposition of possibility, or something  equivalent to it, is understood in the sense of division - of which sort are "every man can be white", "a white thing can be black" and so on, then that proposition is to be distinguished in the third mode of equivocation, in that the subject can supposit for things which exist, or things which can exist, that is, in that the subject can supposit for things of which it is verified by a verb of possibility (or it is denoted that it can supposit for such things, which I say to exclude a certain cavil).  For example, if I say "every white thing can be a man", one sense is "everything which is white, can be a man", and that sense is true if nothing but a man is white.  The other sense is "everything which can be white, can be a man", and that is false, whether only a man is white, or something other than a man.
Ista distinctione visa videndum est quomodo ex talibus potest syllogizari et quomodo non. Et primo in prima figura.	Having looked at that distinction, we should look at how we can syllogize from such things, and how not.  And first, in the first figure.
Et est sciendum quod si subiectum maioris sumatur pro his quae possunt esse, vel denotetur sumi pro his quae possunt esse, qualitercumque sumatur subiectum minoris, semper est syllogismus uniformis bonus et regulatus per dici de omni vel de nullo, et hoc servatis principiis communibus syllogismo de inesse. Unde sic arguendo ‘omne album potest esse homo; - hoc est omne quod potest esse album, potest esse homo -; omnis asinus potest esse albus; igitur omnis asinus potest esse homo’, qualitercumque sumatur subiectum minoris vel conclusionis, est syllogismus regulatus per dici de omni, quia per maiorem denotatur quod de omni illo de quo potest verificari subiectum quod de omni illo potest verificari praedicatum. Et eodem modo patet quod iste syllogismus regulatur per dici de nullo ‘nullum album potest esse homo; omnis asinus potest esse albus; igitur nullus asinus potest esse homo’; vel sic ‘omne album potest non esse homo; omnis asinus potest esse albus; igitur omnis asinus potest non esse homo’.	And you should know that if the subject of the major is understood for things which can exist (or if it is denoted to be understood for things which can exist), then however the subject of the minor is understood, it is always a good uniform syllogism, and governed by dici de omni (to be said of all), and this is kept by the common principles of an assertoric (of inherence) syllogism. Hence, in arguing "every white thing can be a man (that is, everything that can be white, can be a man), every donkey can be white, therefore every donkey can be a man", in whatever way the subject of the minor or of the conclusion is understood, it is a syllogism  governed by dici de omni, because it is denoted by the major that of everything of which the subject can be verified, the predicate can be verified of. And in the same way it is clear that the syllogism "no white thing can be a man, every donkey can be white, therefore no donkey can be a man", or "everything white can possibly not be a man, every donkey can be white, therefore every donkey can  possibly not be a man" is governed by dici de omni.
ƿ Si autem subiectum maioris supponat pro his quae sunt, tunc talis uniformis non valet. Non enim sequitur ‘omne quod est album potest esse homo; omnis asinus potest esse albus; igitur omnis asinus potest esse homo’, quia si nihil sit album nisi homo, praemissae sunt verae et conclusio falsa. Eodem modo non sequitur ‘omne producens potest est Deus; omnis ignis potest esse producens; igitur omnis ignis potest esse Deus’, quia si nihil produceret aliquid nisi Deus, quod est possibile, praemissae essent verae et conclusio falsa.	But if the subject of the major supposits for things which exist, then such a uniform syllogism is not valid.  For "everything which is white can be a man, every donkey can be white, therefore every donkey can be a man" does not follow, for if nothing is white but a man, the premises are true and the conclusion false. In the same way, "everything producing can be God, every fire can be producing, therefore every fire can be God" does not follow, for if nothing produced anything but God, which is possible, the premises would be true and the conclusion false.
Si autem maior sit de possibili in sensu compositionis et minor de possibili in sensu divisionis, nulla sequitur conclusio; sicut non sequitur ‘omnem hominem esse Deum est possibile; aliqua humanitas potest esse homo; igitur aliqua humanitas potest esse Deus’ vel ‘aliquam humanitatem esse Deum est possibile’.	But if the major is of the possible in the sense of composition and the minor is of the possible in the sense of division, no conclusion follows; just as it does not follow that 'it is possible for every man to be God; some human can be man; therefore some human can be God' or 'it is possible for some human to be God'.
Si autem maior accipiatur in sensu divisionis et minor in sensu compositionis, non sequitur conclusio nec in sensu compositionis nec in sensu divisionis, nisi minor sit singularis. Sed si minor sit singularis, semper sequitur conclusio si subiectum maioris supponat pro his quae possunt esse; si autem supponat pro his quae sunt, non valet.	But if the major is taken in the sense of division and the minor in the sense of composition, the conclusion does not follow either in the sense of composition or in the sense of division, unless the minor is singular. But if the minor is singular, the conclusion always follows if the subject of the major supposits for things that can be; but if it supposits for things that are, it is not valid.
Primum patet. Quod enim non sequatur conclusio in sensu compositionis patet, nam istae praemissae sunt verae ‘omne quod potest esse verum contingens ad utrumlibet potest esse falsum; omne verum contingens ad utrumlibet esse verum contingens ad utrumlibet est possibile’, et tamen haec conclusio est falsa ‘omne verum contingens ad utrumlibet esse falsum est possibile’, ipsa accepta in sensu compositionis. Quod etiam non sequatur conclusio in sensu divisionis patet manifeste. Nam istae praemissae sunt verae ‘omne quod potest esse album, potest esse coloratum; omnem substantiam creatam esse albam est possibile’, et tamen haec conclusio est falsa ‘omne quod potest esse substantia [creata], potest esse coloratum’, nam angelus potest esse substantia [creata] et tamen non potest esse coloratus.	The first is clear. For it is clear that the conclusion does not follow in the sense of composition, for these premises are true, ‘everything that can be true contingent on either side can be false; every truth contingent on either side is possible to be true contingent on either side’, and yet this conclusion is false, ‘every truth contingent on either side is possible to be false’, itself taken in the sense of composition. It is also clear that the conclusion does not follow in the sense of division. For these premises are true, ‘everything that can be white can be colored; it is possible for every created substance to be white’, and yet this conclusion is false, ‘everything that can be a [created] substance can be colored’, for an angel can be a [created] substance and yet cannot be colored.
Secundum, scilicet quod si minor sit singularis sequatur conclusio, patet, nam bene sequitur ‘omne verum contingens ad ƿ utrumlibet potest esse falsum; hoc verum esse verum contingens ad utrumlibet est possibile; igitur hoc verum potest esse falsum’. Sed non sequitur ista de possibili in sensu compositionis ‘hoc verum esse falsum est possibile’. Ratio autem quare plus sequitur conclusio talis de possibili quando minor est singularis quam quando minor est universalis, est quia semper singularis de possibili in sensu compositionis infert singularem de possibili in sensu divisionis, quamvis non e converso, nisi subiectum singularis sit praecise pronomen demonstrativum vel nomen proprium. Tunc enim sensus compositionis et divisionis convertuntur.	The second, namely that if the minor is singular the conclusion follows, is clear, for it follows well that ‘every true thing contingent on either can be false; it is possible for this true thing to be true contingent on either; therefore this true thing can be false’. But this proposition of the possible does not follow in the sense of composition ‘for this true thing to be false is possible’. But the reason why such a conclusion of the possible follows more when the minor is singular than when the minor is universal is that the singular possible in the sense of composition always infers the singular possible in the sense of division, although not vice versa, unless the subject of the singular is precisely a demonstrative pronoun or a proper noun. For then the senses of composition and division are converted.
Per idem patet quod si minor fuerit particularis, sequitur conclusio particularis in sensu divisionis, nam particularis in sensu compositionis semper infert particularem in sensu divisionis. Sequitur enim ‘haec est possibilis: homo est Deus; igitur quod potest esse homo, potest esse Deus’, quamvis non sequatur semper e converso. Non enim sequitur ‘quod potest esse album, potest esse nigrum, igitur haec est possibilis: album est nigrum’; nec sequitur ‘quod potest esse suppositum humanum, potest assumi a persona divina; igitur haec est possibilis: suppositum humanum est assumptum a persona divina’.	By the same token, it is clear that if the minor is particular, a particular conclusion follows in the sense of division, for a particular in the sense of composition always infers a particular in the sense of division. For it follows ‘this is possible: man is God; therefore what can be man can be God’, although it does not always follow conversely. For it does not follow ‘what can be white can be black, therefore this is possible: white is black’; nor does it follow ‘what can be a human suppositum can be assumed by a divine person; therefore this is possible: a human suppositum is assumed by a divine person’.
Circa istam generationem in prima figura sunt duo intelligenda. Primum, quod quamvis aliquando teneat uniformis de possibili, sicut in talibus casibus de quibus dictum est, non tamen semper in illis sequitur conclusio indirecta, quae scilicet praecise differat a conclusione directa per transpositionem terminorum. Quia non sequitur ‘omne quod potest esse falsum non-possibile, potest esse impossibile; aliquid, quod est verum, potest esse falsum non-possibile; igitur aliquid, quod est impossibile, potest esse verum’. Et tamen ista conclusio directa ‘aliquid, quod est verum, potest esse impossibile’ bene sequitur. Unde quando conclusio prima est directe convertibilis, tunc bene sequitur. Semper tamen sequitur illa in quam conclusio est convertibilis. Qualiter autem conclusio debeat converti, dictum est prius. ƿ	There are two things to be understood about this generation in the first figure. First, that although the uniform of possibility sometimes holds, as in such cases as were said , nevertheless in them an indirect conclusion does not always follow, which precisely differs from the direct conclusion by the transposition of the terms. For it does not follow that ‘everything that can be false and non-possible can be impossible; something that is true can be false and non-possible; therefore something that is impossible can be true’. And yet this direct conclusion ‘something that is true can be impossible’ follows well. Hence when the first conclusion is directly convertible, then it follows well. However, that into which the conclusion is convertible always follows. But how a conclusion should be convertible, has been said before . ƿ ​​
Aliud notandum est: quod sicut in illis de inesse non refert an maior sit universalis vel singularis, sic in illis de possibili non refert. Unde iste syllogismus est bonus ‘Sortes potest esse albus; omnis substantia potest esse Sortes; igitur omnis substantia potest esse alba’, Sed oportet quod subiectum minoris et conclusionis uniformiter accipiuntur, quia si in minore accipiatur pro his quae sunt et in conclusione pro his quae possunt esse, non valet. Sicut non sequitur ‘Sortes potest esse pater Platonis; omnis homo, qui est, potest esse Sortes; igitur omnis homo, qui est, potest esse pater Platonis’.	Another thing to note is that just as in those of inherence, it does not matter whether the major is universal or singular, so in those of possibility it does not matter. Hence this syllogism is good ‘Socrates can be white; every substance can be Socrates; therefore every substance can be white’. But it is necessary that the subject of the minor and the conclusion are taken uniformly, because if in the minor it is taken for things that are and in the conclusion for things that can be, it is not valid. Just as it does not follow ‘Socrates can be the father of Plato; every man who is can be Socrates; therefore every man who is can be the father of Plato’.