1. Reasons on behalf of this Intention

259. As to the second principal point [n.231].

For this conclusion, which has been said to be the intention of both, namely of both Aristotle and Avicenna [nn.251-255], I argue as follows: in every difference of being necessity is a more perfect condition than contingency; the proof is that necessity is more perfect in being in itself, therefore in every difference too of being; therefore also in this difference of being, which is ‘cause’, necessity is more perfect than the most perfect contingency; therefore the cause necessarily causes.

260. The response is that necessity is a more perfect condition where it is possible; but necessity is incompossible with the idea of cause as cause, because thus are we speaking and not of the thing that is the cause. Against this: in many divisions of being one of the dividers is perfect, the other imperfect, and the extremes that are perfect in the diverse divisions are either necessary concomitants of each other or are compatible with each other. An example: if being is divided into finite and infinite, into necessary and possible, into potency and act, - act, necessity, and infinity are either necessary concomitants of each other or are compatible with each other. Therefore since, in the division of being into cause and caused, cause is the more perfect extreme, concomitant with it, or able to stand with it, will be any more perfect divider whatever of being, - and consequently necessity will be so.

261. Further, if the first causer were to cause naturally and were to cause necessarily, then it would give necessity to its caused; but no perfection is taken away from the caused because of an equally perfect mode of causing in the causer itself; but to cause voluntarily is not a mode of causing less perfect than to cause naturally, and thus no perfection is, because of there being this ‘to cause voluntarily’, necessarily taken away from the effect; therefore a cause, causing voluntarily, can give necessity to the effect. -A confirmation for the reason is that, if a cause were to cause naturally, it could produce several differences of being, to wit the possible and the necessary; therefore if a cause causing voluntarily can only cause contingent being, it would seem to be an imperfect cause, because then its causality would not extend itself to as many effects as it would extend itself to if it were to cause naturally.

262. Further, some cause necessarily causes its effect, therefore the first cause necessary causes its caused. - The antecedent seems manifest because of the many natural causes that necessarily cause their effects. I prove the consequence by the fact that in things essentially ordered the ‘posterior’ cannot have necessity unless the ‘prior’ has necessary being; the connections of caused things to their causes are essentially ordered;     therefore no such connection is necessary unless the connection of the first caused thing to its cause is necessary.