Over the centuries, Christian theology has exerted itself to keep the proper balance. Faith, besides being a gracious gift of God, is also a free and responsible decision on the part of the believer. God’s grace does not circumvent or suppress our native powers, but guides them so that they may act more perfectly. The believer has motives for believing that would not be present were it not for the light of grace. In his great encyclical Fides et Ratio, Pope John Paul II repeatedly declares that faith, by sharpening the inner eye of the mind, enables reason to rise above itself and in no sense diminishes it. Reinforcing reason, faith enables it to transcend its normal limits.
Faith, therefore, is not a simple achievement of reason. It is the work of reason submitting to the word of God, which comes by way of revelation. God, as the infinite source of all that is or can be, lies immeasurably beyond all that we can infer from the created order. His inner essence and intentions are known only to Himself unless He chooses to reveal them. For our sakes He has revealed something of Himself and His saving plans so that we may love and serve Him better. God’s great and unsurpassable revelation of Himself is His Son, His eternal Word, who has become flesh in Jesus Christ. The Christian clings to that living and incarnate Word, in whom salvation is to be found.
In this framework we may consider the task of apologetics, the rational defense of faith. Apologetics cannot and should not attempt to demonstrate the truth of the mysteries of faith, which, as I have said, lie beyond human investigation and are believed on the strength of God’s word, more certain than any logical deduction. But in order to believe we must find reasons for judging that what purports to be God’s word really is his word. To spell out these reasons in a systematic way is the task of apologetics. —from “The Rebirth of Apologetics” (2004)