Cap. IX Arg. 6 Sol cont.: equivocation on 'cause' — true/direct vs abusive/indirect; sun illuminates truly, its setting is only abusively cause of darkness
Equivocation on the word cause has trapped our adversaries — or at least given them occasion to trap others. Something is called cause of an event or effect in two ways: truly, directly, and properly, as what flows in to produce the effect; abusively, indirectly, improperly, as what does not act to block the effect. So the sun at rising is truly and properly called cause why the air is lit; at setting it is only improperly and abusively called cause why it darkens — merely because its presence would have put darkness to flight.
Latin
Aequivocatio in hoc vocabulo causae imposuit adversariis nostris, aut saltem suppeditavit illis occasionem imponendi aliis. Nam dupliciter aliquid dici solet causa talis eventus aut effectus: Vere, directe, et proprie, per modum influentis ad producendum effectum; Abusive, indirecte, improprie, per modum non agentis ad prohibendum effectum: Sicuti sol ortu suo vere et proprie causa dicitur cur aer illuminetur; occasu improprie et abusive causa dicitur cur obtenebretur, hoc sensu solummodo, quia sua praesentia tenebras fugasset.