Authors/Ockham/Summa Logicae/Book II/Chapter 34

Latin	English
[2.34. DE PROPOSITIONE CAUSALI]	On the causal proposition
Propositio causalis est illa quae componitur ex pluribus categoricis mediante hoc coniunctione 'quia' vel aequivalente ei. Unde ista est causalis 'quia Sortes est homo, Sortes est animal'. Similiter ista est causalis 'Sortes laborat, ut sanetur'; aequivalet enim isti 'Sortes laborat, quia vult sanari'. Similiter ista est causalis 'Sortes deambulat post cenam, ne infirmetur', quia aequivalet isti 'quia Sortes non uult infirmari, deambulat post cenam'. Similiter ista est causalis 'Sortes calefit in quantum movetur', quia aequivalet isti 'quia Sortes movetur, calefit'.	A causal proposition is one which is composed of several categoricals with the intermediary conjunction 'because' or something equivalent to it. Hence, this is a causal proposition: 'because Socrates is a man, Socrates is an animal'. Likewise, this is causal: 'Socrates works, in order to be healthy', for it is equivalent to 'Socrates works, because he wants to be healthy'. Likewise, this is a causal proposition: 'Socrates takes a walk after dinner, lest he become ill', because it is equivalent to 'because Socrates does not want to become ill, he takes a walk after dinner'. Likewise, this is a causal proposition: 'Socrates becomes warm insofar as he moves', for it is equivalent to: 'because Socrates moves, he becomes warm'.
Ad veritatem autem causalis requiritur quod quaelibet pars sit vera, et simul cum hoc quod antecedens sit causa consequentis. Et ideo ista non est vera 'Sortes est albus, quia Plato est albus'; quamvis enim utraque pars sit vera, quia tamen ista non est vera 'Sortes est albus propter hoc quod Plato est albus', ideo est falsa.	Now for the truth of a causal proposition it is required that each part is true and that together with this that the antecedent is the cause of the consequent. And therefore this proposition is not true: 'Socrates is white, because Plato is white'. For although each part is true, yet because 'Socrates is white on account of the fact that Plato is white' is not true, the [original] proposition is therefore false.
Et est sciendum quod hic accipitur causa large et non stricte. Non enim requiritur ad veritatem causalis quod una propositio sit causa quare alia ponitur in esse, sed sufficit quod exprimat causam requisitam ad hoc quod alia propositio sit vera. Sicut est hic 'lignum calefit, quia ignis est sibi praesens'; per illud enim antecedens 'ignis est praesens ligno' exprimitur causa sine qua haec non esset vera 'lignum calefit', ideo ista causalis est vera. Vel requiritur quod propositio illa sit prior alia, ita quod praedicatum antecedentis prius praedicetur de subiecto suo quam praedicatum consequentis praedicetur de subiecto suo -- Et secundum hoc potest haec esse vera 'isosceles habet tres, etc., quia triangulus habet tres etc.'.	And it should be known that 'cause' is used here in a broad sense and not in a strict sense. For it is not required for the truth of a causal proposition that one proposition be the cause whereby the other proposition is brought into being, rather, it suffices that it expresses a cause required for the other proposition to be true. For example 'the wood becomes hot, because fire is present to it', for by the antecedent, 'fire is present to it', there is expressed a cause without which 'The wood becomes hot' would not be true, therefore, the causal proposition is true. Or it is required that one proposition be prior to the other so that the predicate of the antecedent is predicated of its subject prior to the predicate of its subject. And accordingly, this can be true: 'An isosceles has three etc., because a triangle has three, etc.'.
Et est sciendum quod hic accipitur causa large, sive sit causa per se sive per accidens, sive voluntaria sive naturalis.	And it should be known that 'cause' is being used broadly here for a per se cause or a per accidens cause or for a voluntary cause or a natural cause.
Ex istis patet quod omnes tales sunt falsae 'asinus est risibilis, quia est homo', 'omnis homo peccat, quia est liberi arbitrii' et huiusmodi.	From these points it is clear that all propositions such as the following are false: 'a donkey is capable of laughter, because it is a man', 'every man sins, because he has a free will', etc.
Unde ad necessitatem causalis requiritur necessitas utriusque partis. Sed ad impossibilitatem causalis non requiritur impossibilitas nec falsitas alicuius partis, sed sufficit quod antecedens non possit esse causa consequentis, modo praedicto accipiendo causam.	Hence for the necessity of a causal proposition there is required the necessity of both parts. But for the impossibility of a causal proposition neither the impossibility nor the falsity of one of the parts is required, but rather it suffices that the antecedent cannot be the cause of the consequent, taking 'cause' in the way above.
Et est advertendum quod non dicitur hic antecedens illud quod secundum vocem praecedit, sed illa propositio quae immediate sequitur hanc coniunctionem 'quia', illa est antecedens.	And it should be noted that we do not call the 'antecedent' here what comes first in word order, but that proposition which immediately follows the conjunction 'because', that is the antecedent.
Similiter ad possibilitatem causalis requiritur quod quaelibet pars sit possibilis. Sed hoc non sufficit, sicut ad necessitatem non sufficit necessitas utriusque partis.	Likewise, for the possibility of a causal proposition it is required that each part is possible. But this does not suffice, just as for the necessity of a proposition the necessity of each part does not suffice.
Ex praedictis patet quod a causali ad alteram partem est consequentia bona sed non e converso. Similiter a causali ad copulativam est bona consequentia sed non e converso. Unde bene sequitur 'omnis homo peccat, quia est liberi arbitrii; igitur omnis homo peccat et omnis homo est liberi arbitrii'; sed e converso non sequitur.	From these points it is clear that there is a good consequence from a causal proposition to one or the other part of it, but not conversely. Likewise, there is a good consequence from a causal proposition to a copulative proposition, but not conversely. Hence, this follows: 'every man sins, because he has free will; therefore every man sins and every man has a free will', but the converse does not follow.