If there is a God, it is possible that he cannot be known by our reason. If reason could attain to religious truths, faith would be unnecessary. If faith is needed, reason is somehow inadequate. But why? Either because the human mind cannot comprehend the mysteries of God in whole or in part, so that (at least some) religious truths - such as the Resurrection or the Day of Judgment, according to Augustine (De vera relig. 8.14, cf. De Trin. 4.16.21) - are inaccessible to unaided reason; or because such truths cannot be demonstrated and can only be shown to be more or less plausible or possible; or because our minds are now damaged and need to be habituated - by faith, by the practice of the virtues or by both - to reason more effectively, and above all not merely to rationalize.