From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
In Scholastic theology, the role of philosophically trained reason becomes even more conspicuous under the impulse of Saint Anselm’s interpretation of the intellectus fidei. For the saintly Archbishop of Canterbury the priority of faith is not in competition with the search which is proper to reason. Reason in fact is not asked to pass judgement on the contents of faith, something of which it would be incapable, since this is not its function. Its function is rather to find meaning, to discover explanations which might allow everyone to come to a certain understanding of the contents of faith. Saint Anselm underscores the fact that the intellect must seek that which it loves: the more it loves, the more it desires to know. Whoever lives for the truth is reaching for a form of knowledge which is fired more and more with love for what it knows, while having to admit that it has not yet attained what it desires: “To see you was I conceived; and I have yet to conceive that for which I was conceived (Ad te videndum factus sum; et nondum feci propter quod factus sum)”.42 The desire for truth, therefore, spurs reason always to go further; indeed, it is as if reason were overwhelmed to see that it can always go beyond what it has already achieved. It is at this point, though, that reason can learn where its path will lead in the end: “I think that whoever investigates something incomprehensible should be satisfied if, by way of reasoning, he reaches a quite certain perception of its reality, even if his intellect cannot penetrate its mode of being . . . But is there anything so incomprehensible and ineffable as that which is above all things? Therefore, if that which until now has been a matter of debate concerning the highest essence has been established on the basis of due reasoning, then the foundation of one’s certainty is not shaken in the least if the intellect cannot penetrate it in a way that allows clear formulation. If prior thought has concluded rationally that one cannot comprehend (rationabiliter comprehendit incomprehensibile esse) how supernal wisdom knows its own accomplishments . . . , who then will explain how this same wisdom, of which the human being can know nothing or next to nothing, is to be known and expressed?”.43
The fundamental harmony between the knowledge of faith and the knowledge of philosophy is once again confirmed. Faith asks that its object be understood with the help of reason; and at the summit of its searching reason acknowledges that it cannot do without what faith presents.
42 Saint Anselm, Proslogion, 1: Patrologiæ Cursus completus, Series Latina [PL] 158, 226.
43 Idem, Monologion, 64: PL 158, 210.
— Fides et Ratio 42