Programme
Luca Gili
Université du Québec à Montréal
De Dicto and De Re Modalities in Averroes' and Aquinas’ Arguments for and against the Eternity of Time
In Phys. VIII, 1, Aristotle argues that if time is eternal, then necessarily motion is eternal. The necessity operator seems to capture a necessitas consequentiae, not a necessitas consequentis. Aristotle, however, seems also to maintain that it is necessary that time is eternal (the argument for the eternity of time rests on the definition of nunc). If Aristotle subscribed to the so-called K axiom (distribution of the necessity operator with respect to material implication), then it is necessary (de re) that motion is eternal. It is important to stress that motion is necessarily eternal de re, because in Phys. VIII 5 Aristotle argues that if every mover is accidentally moved, then it is impossible that there is motion (de re), which contradicts what had been stated in Phys. VIII 1. As is clear, Aristotle’s argument is sound but requires a particularly charitable reader, inasmuch as Phys. VIII 1 seems to conclude that motion is necessarily eternal de dicto. Averroes takes Aristotle’s argument as valid and argues along the above-mentioned lines. Aquinas, on the contrary, has many issues with this argument. The argument seems to rest on the acceptance of the principle of plenitude (that Aquinas had rejected in his commentary on Met. IX 4) and on the K-axiom (also rejected by Aquinas, see Demey-Gili 2017). However, Thomas does not deal with these logical issues because he rejects the validity of the argument on metaphysical grounds. In his opinion, the first premise of the whole argument (i.e. the definition of the nunc as a necessarily intermediate point) is mistaken. I suggest that for this reason Aquinas does not look into the logical minutiae of an argument that he would reject even if it were logically sound.