From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
As appears from this brief sketch of the history of the relationship between faith and philosophy, one can distinguish different stances of philosophy with regard to Christian faith. First, there is a philosophy completely independent of the Gospel’s Revelation: this is the stance adopted by philosophy as it took shape in history before the birth of the Redeemer and later in regions as yet untouched by the Gospel. We see here philosophy’s valid aspiration to be an autonomous enterprise, obeying its own rules and employing the powers of reason alone. Although seriously handicapped by the inherent weakness of human reason, this aspiration should be supported and strengthened. As a search for truth within the natural order, the enterprise of philosophy is always open—at least implicitly—to the supernatural.
Moreover, the demand for a valid autonomy of thought should be respected even when theological discourse makes use of philosophical concepts and arguments. Indeed, to argue according to rigorous rational criteria is to guarantee that the results attained are universally valid. This also confirms the principle that grace does not destroy nature but perfects it: the assent of faith, engaging the intellect and will, does not destroy but perfects the free will of each believer who deep within welcomes what has been revealed.
It is clear that this legitimate approach is rejected by the theory of so-called “separate” philosophy, pursued by some modern philosophers. This theory claims for philosophy not only a valid autonomy, but a self-sufficiency of thought which is patently invalid. In refusing the truth offered by divine Revelation, philosophy only does itself damage, since this is to preclude access to a deeper knowledge of truth.
— Fides et Ratio 75