Cap. IX Arg. 6 Sol cont.: special grace's gift is productive cause of salvation — its denial is not truly cause of perdition; Aristotle Metaph. 4.2
Much the same way: because the gift of special grace is the productive cause of human salvation, some are led to think its denial or defect is the cause of human perdition — as if its presence would have prevented that perdition. But the Philosopher speaks more carefully (Metaph. 4.2): what, when present, is cause of something, we sometimes say, when absent, is cause of the contrary. Note his words: sometimes and we say. He does not say absence itself is cause of the contrary, but that we allege or put it forward as a cause — and only sometimes. So the influx of special grace, denied by divine decree to some, can be held up by the unskilled as cause of their sin and perdition, because if given it would have saved them. That is false unless it can be proved either that God was bound to give such grace, or that the wicked's sins and perdition did not flow from their innate corruption and voluntary rebellion as true positive causes.
Latin
Ad hunc fere modum, quia gratiae specialis donatio est causa productiva salutis humanae, quidam inducuntur ut cogitent ejusdem gratiae negationem sive defectum esse causam perditionis humanae, utpote quae sua praesentia perditionem hanc impediret. At ipse Philosophus hac de re accuratius loquitur, Metaph. lib. 4. cap. 2. Quod, cum adsit, alicujus causa est, idem cum absit, aliquando dicimus esse causam contrarii. Observanda sunt illa verba Philosophi, aliquando et dicimus. Non dicit illud per absentiam esse causam contrarii, sed nos illud causari vel tanquam causam obtendere, idque aliquando. Hinc influxus gratiae specialis, Divino decreto quibusdam hominibus negatus, obtendi potest vel cogitari ab imperitis ut causa peccati et perditionis eorundem, quia concessus eosdem servasset; sed falso obtenditur, nisi probari possit, vel Deum obligatum fuisse ad talem gratiam praestandam, vel peccata ac perditionem improborum ex illorum innata corruptione, et voluntaria rebellione, tanquam veris ac positivis causis, non manasse.