The Vatican Council
Third Session, Chapter 4
ON FAITH AND REASON
The perpetual agreement of the catholic church has maintained and maintains this too: that there is a twofold order of knowledge, distinct not only as regards its source, but also as regards its object. With regard to the source, we know at the one level by natural reason, at the other level by divine faith. With regard to the object, besides those things to which natural reason can attain, there are proposed for our belief mysteries hidden in God which, unless they are divinely revealed, are incapable of being known.
Wherefore, when the Apostle, who witnesses that God was known to the gentiles from created things  , comes to treat of the grace and truth which came by Jesus Christ  , he declares: We impart a secret and hidden wisdom of God, which God decreed before the ages for our glorification. None of the rulers of this age understood this. God has revealed it to us through the Spirit. For the Spirit searches everything, even the depths of God  . And the Only-begotten himself, in his confession to the Father, acknowledges that the Father has hidden these things from the wise and prudent and revealed them to the little ones  .
Now reason, does indeed when it seeks persistently, piously and soberly, achieve by God's gift some understanding, and that most profitable, of the mysteries, whether by analogy from what it knows naturally, or from the connexion of these mysteries with one another and with the final end of humanity; but reason is never rendered capable of penetrating these mysteries in the way in which it penetrates those truths which form its proper object. For the divine mysteries, by their very nature, so far surpass the created understanding that, even when a revelation has been given and accepted by faith, they remain covered by the veil of that same faith and wrapped, as it were, in a certain obscurity, as long as in this mortal life we are away from the Lord, for we walk by faith, and not by sight  .
Even though faith is above reason, there can never be any real disagreement between faith and reason, since it is the same God who reveals the mysteries and infuses faith, and who has endowed the human mind with the light of reason. God cannot deny himself, nor can truth ever be in opposition to truth. The appearance of this kind of specious contradiction is chiefly due to the fact that either the dogmas of faith are not understood and explained in accordance with the mind of the church, or unsound views are mistaken for the conclusions of reason. Therefore we define that every assertion contrary to the truth of enlightened faith is totally false  .
Furthermore the church which, together with its apostolic office of teaching, has received the charge of preserving the deposit of faith, has by divine appointment the right and duty of condemning what wrongly passes for knowledge, lest anyone be led astray by philosophy and empty deceit  .
Hence all faithful Christians are forbidden to defend as the legitimate conclusions of science those opinions which are known to be contrary to the doctrine of faith, particularly if they have been condemned by the church; and furthermore they are absolutely bound to hold them to be errors which wear the deceptive appearance of truth. Not only can faith and reason never be at odds with one another but they mutually support each other, for on the one hand right reason established the foundations of the faith and, illuminated by its light, develops the science of divine things; on the other hand, faith delivers reason from errors and protects it and furnishes it with knowledge of many kinds. Hence, so far is the church from hindering the development of human arts and studies, that in fact she assists and promotes them in many ways. For she is neither ignorant nor contemptuous of the advantages which derive from this source for human life, rather she acknowledges that those things flow from God, the lord of sciences, and, if they are properly used, lead to God by the help of his grace.
Nor does the church forbid these studies to employ, each within its own area, its own proper principles and method: but while she admits this just freedom, she takes particular care that they do not become infected with errors by conflicting with divine teaching, or, by going beyond their proper limits, intrude upon what belongs to faith and engender confusion. For the doctrine of the faith which God has revealed is put forward not as some philosophical discovery capable of being perfected by human intelligence, but as a divine deposit committed to the spouse of Christ to be faithfully protected and infallibly promulgated.
Hence, too,that meaning of the sacred dogmas is ever to be maintained which has once been declared by holy mother church, and there must never be any abandonment of this sense under the pretext or in the name of a more profound understanding.
May understanding, knowledge and wisdom increase as ages and centuries roll along, and greatly and vigorously flourish, in each and all, in the individual and the whole church: but this only in its own proper kind, that is to say, in the same doctrine, the same sense, and the same understanding  .
29. Rm 1, 20
30. Jn 1, 17
31. i Cor 2, 7-8, 10
32. Mt 11, 25
33. 2 Cor 5, 6-7
34. See Lateran council V, session 8 (see above p. 605).
35. See Col 2, 8
36. Vincent of Lerins, Commonitorium (Notebook), 28 (PL 50, 668).