Abstract

The following paper proposes a critical reading of conventionalism in sacramental theology (“causalité-pacte”), to underline, by contrast, the theoretical merits of its main competitor, Aquinas’s instrumental causality. It shows that conventionalism, to make the sacrament truly efficient, assigns to the sacrament itself the power of convention, a power compared to the royal seal, which is naturally efficacious qua effect formally identical to its cause. This supports Aquinas’s conviction: rules are powerless, only things have powers.