From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
Step by step, then, we are assembling the terms of the question. It is the nature of the human being to seek the truth. This search looks not only to the attainment of truths which are partial, empirical or scientific; nor is it only in individual acts of decision-making that people seek the true good. Their search looks towards an ulterior truth which would explain the meaning of life. And it is therefore a search which can reach its end only in reaching the absolute.28 Thanks to the inherent capacities of thought, man is able to encounter and recognize a truth of this kind. Such a truth—vital and necessary as it is for life—is attained not only by way of reason but also through trusting acquiescence to other persons who can guarantee the authenticity and certainty of the truth itself. There is no doubt that the capacity to entrust oneself and one’s life to another person and the decision to do so are among the most significant and expressive human acts.
It must not be forgotten that reason too needs to be sustained in all its searching by trusting dialogue and sincere friendship. A climate of suspicion and distrust, which can beset speculative research, ignores the teaching of the ancient philosophers who proposed friendship as one of the most appropriate contexts for sound philosophical enquiry.
From all that I have said to this point it emerges that men and women are on a journey of discovery which is humanly unstoppable—a search for the truth and a search for a person to whom they might entrust themselves. Christian faith comes to meet them, offering the concrete possibility of reaching the goal which they seek. Moving beyond the stage of simple believing, Christian faith immerses human beings in the order of grace, which enables them to share in the mystery of Christ, which in turn offers them a true and coherent knowledge of the Triune God. In Jesus Christ, who is the Truth, faith recognizes the ultimate appeal to humanity, an appeal made in order that what we experience as desire and nostalgia may come to its fulfilment.
28 This is a theme which I have long pursued and which I have addressed on a number of occasions. “’What is man and of what use is he? What is good in him and what is evil?’ (Sir 18:8) . . . These are questions in every human heart, as the poetic genius of every time and every people has shown, posing again and again—almost as the prophetic voice of humanity—the serious question which makes human beings truly what they are. They are questions which express the urgency of finding a reason for existence, in every moment, at life’s most important and decisive times as well as more ordinary times. These questions show the deep reasonableness of human existence, since they summon human intelligence and will to search freely for a solution which can reveal the full meaning of life. These enquiries, therefore, are the highest expression of human nature; which is why the answer to them is the gauge of the depth of his engagement with his own existence. In particular, when the why of things is explored in full harmony with the search for the ultimate answer, then human reason reaches its zenith and opens to the religious impulse. The religious impulse is the highest expression of the human person, because it is the highpoint of his rational nature. It springs from the profound human aspiration for the truth and it is the basis of the human being’s free and personal search for the divine”: General Audience (19 October 1983), 1-2: Insegnamenti VI, 2 (1983), 814-815.
— Fides et Ratio 33