 God would be subjected to mathematical truths just as human intellects are. He would know them as we know them. This would be the sign that the doctrine of univocity entered Mersenne’s thought, perhaps under the influence of Kepler, in an irretrievable fashion. This is also deemed to explain the striking disappearance of rational theology in Mersenne’s writings. Just as metaphysics had been entirely exhausted by natural theology in the first works, rational theology ended up being entirely exhausted by mathematics. The latter are not anymore an analogical resource for theology, but indeed they furnish the only possible non-analogical discourse on God, “the hidden object of all mathematical discourse” (Pessel 1987). As a consequence, Mersenne’s apologetics no longer needs to appeal to rational theology—the mere promotion of mathematical sciences has become the unique, or best, apology of Christian religion.