The Catholic Church teaches that the existence of God can be known with complete certainty, from the natural light of human reason alone. In fact, all elements of the Catholic faith are reasonable and logical, because both faith and reason come from God. Since they have the same source, they do not and cannot contradict each other. [If it seems like science and religion are contradicting each other, then you either have bad science or bad religion.]
"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." (Vatican I)
The Church's teaching on faith and reason is contrary to at least two different groups.
- The Authoritarians, who teach that all elements of faith must be accepted, without any reasonable proof. An authoritarian would say something like, "God exists and you have to believe in him, because I said so."
- The Sentimentalists, who put all matters of faith into the realm of feelings. They say that internal experience or private inspiration is the only way to come to faith. A sentimentalist would say something like, "I know God exists, because I can feel it in my heart."