8. We come across another class of objective data which philosophy knew well but which it approached with much hesitancy, and which, though not a part of revelation, was corroborated by revelation, In the noetic order, for instance, the Christian sees the validity of reason divinely confirmed -- recall St. Augustine's controversies with the Academicians -- by the fact that the act of faith, notwithstanding its supra-rational character, is eminently reasonable. In this confirmation of the validity of reason he sees by implication the validity of many certitudes of the rational sphere which relate to discerning the motives of credibility.