Faith here signifies supernatural faith; it includes the complexus of revealed truths and the subjective assent given these truths on the authority of God revealing them. Science is similarly taken to mean all natural truths and the intellectual assent given them. Science and faith cannot exist in the same intellect with regard to the same object, because the object of science must be luminously evident while that of faith is not intrinsically evident; hence these two from this point of view are mutually exclusive. A threefold relation between science and faith may be conceived:
- of act with act
- of habit with habit
- of habit with act
The act of science cannot exist with an act of faith in regard to the same object, because the objects of science and faith are essentially opposed, as the luminous to the obscure. The habit of science cannot coexist with the habit of faith, in regard to the same object, because philosophically they are contrary dispositions of the intellect and destroy each other. There are some theologians, however, who hold the opposite view. The habit of faith is not by its very nature (per se) incompatible with an act of knowledge, provided the act of knowledge does not generate the habit of science. Once the existence of God has been demonstrated by reason, faith, which led the intellect to believe in God antecedently to the demonstration, vanishes, but there remains a firm, supernatural adherence to the truth, which is not faith but an effect of it. The Christian who knows that God exists, knows also that this truth belongs to the deposit of faith and is bound up with the truths of faith.
Science and faith cannot contradict each other as Rationalists assert. Admitting, as one must, that the miracles, prophecies, and wonderful effects of the Christian religion prove sufficiently the truth of Christian Revelation, one is bound also to admit that faith and science cannot contradict each other. Only the false can be contrary to the true. Between a true faith and a true science, accord is necessarily established. When a teacher instructs a pupil, the knowledge of the teacher contains what he instils into the pupil’s mind. Now, the natural knowledge which we possess of principles comes to us from God, since God is the author of our nature. It follows that whatever is contrary to these principles is contrary to Divine Wisdom and consequently cannot come from God. Between science which comes from God, and Revelation which comes from God accord must, therefore, be of necessity; although at times, owing to the defects of our knowledge, there may appear to be discrepancy between them.