Tractatio haec explicat, quomodo Thomas Aquinas argumentum Aristotelis contra determinismum et pro contingentia in rebus interpretatur. Radix huius sententiae determinismum respuentis in assertione, quae dicit dari aliquid in rebus per se incausatum (scil. effectus per accidens), consistit. Unde sequitur quod dato aliquo eventu per accidens, sit e, non datur continuus nexus causalis, qua e cum aliquo eventu praesenti vel praeteriti coniungeretur. Thomae autem, qui est Aristotelicus Christianus, alteram difficultatem oportet solvere – eam nempe, quae ex doctrina de divina providentia et praedeterminatione huiusmodi eventuum provenit. Solutio s. Thomae in hoc consistit, quod dicti actus divini transcendunt omnem determinationem modalem, i.e. sunt praeter necessitatem et contingentiam.

The paper deals with Aristotle’s argument against determinism and in favor of contingency in nature as interpreted by Thomas Aquinas. The case against determinism is based on the idea that there are properly uncaused accidental events in reality. This means that in case there is some coincidental future event e, one cannot trace an unbroken causal chain leading to e back to the present or the past. For a Christian Aristotelian, such as Aquinas, there arises a difficulty concerning divine foreknowledge and volitional determination of events of this sort. Thomas’s solution is based on the claim that the latter divine acts are not within the scope of modal determination (necessity/contingency).