Lex necessitatis vel contingentiae. Necessità, contingenza e provvidenza nell'universo di Tommaso d'Aquino

The article aims to reconsider, in a critical manner, two specific presuppositions of the Gilsonian interpretation of Thomas Aquinas: 1) the fact that in Aquinas’ metaphysics all beings different from God are marked by a «radical contingency»; 2) the idea that this contingency is based on the distinction between being and essence; and, more generally, 3) the conviction that Aquinas’ conception of providence represents a radical alternative to determinism and necessitarianism in the Graeco-Arabic tradition. To this end, we shall examine, in a sequence, the following points: the most common meanings that Aquinas confers upon the notions of necessity and contingency; the relationship between fortune, chance and providence; the conditioned rebuttal of astral determinism; the way in which Divine providence arranges necessary events as well as contingent ones; the contrasting reactions of Siger of Brabant and John Duns Scotus to the model with which Aquinas attempts to safeguard contingency in the providential order; Aquinas’ admission of the existence of formally necessary creatures. In conclusion, we suggest that Aquinas weakens certain fundamental presuppositions of the anti-deterministic strategy laid out by Aristotle in Book VI of Metaphysics, that the alternative between necessity and contingency does not represent for Aquinas the genuine point of discrimination between Creator and creature, and that, for this reason, the distinction between being and essence, according to Aquinas, does not, as its primary and principal objective, have to account for the contingency of all created beings.