Faith: do you know this theological virtue in detail?

Faith is the first of the three theological virtues; the other two are hope and charity (or love). Unlike the cardinal virtues, which can be practiced by anyone, theological virtues are gifts of God through grace. Like all other virtues, theological virtues are habits; the practice of virtues strengthens them. Since they aim for a supernatural end, however - that is, they have God as "their immediate and proper object" (in the words of the Catholic Encyclopedia of 1913) - theological virtues must be supernaturally infused into the soul.

So faith is not something we can simply start practicing, but something beyond our nature. We can open ourselves to the gift of faith through right action - through, for example, the practice of cardinal virtues and the exercise of right reason - but without the action of God, faith can never reside in our soul.

What the theological virtue of faith is not
Most of the time when people use the word faith, they mean something other than theological virtue. The Oxford American Dictionary presents as its first definition "complete trust or trust in someone or something" and offers as an example "one's trust in politicians". Many people instinctively understand that trust in politicians is completely different from faith in God. But the use of the same word tends to confuse the waters and reduce the theological virtue of faith in the eyes of non-believers to nothing but a belief which is strong and in their mind irrationally supported. So faith opposes reason in popular understanding; the second, it is said, requires proof, while the first is characterized by the voluntary acceptance of things for which there is no rational proof.

Faith is the perfection of the intellect
In Christian understanding, however, faith and reason are not opposed but complementary. Faith, observes the Catholic Encyclopedia, is the virtue "with which the intellect is perfected by a supernatural light", allowing the intellect to assent "firmly to the supernatural truths of the Apocalypse". Faith is, as St. Paul says in the Letter to the Jews, "the substance of the things hoped for, the evidence of things not seen" (Hebrews 11: 1). In other words, it is a form of knowledge that extends beyond the natural limits of our intellect, to help us grasp the truths of divine revelation, truths that we cannot reach purely with the help of natural reason.

The whole truth is the truth of God
Although the truths of divine revelation cannot be inferred through natural reason, they are not, as modern empiricists often say, contrary to reason. As St Augustine said, the whole truth is the truth of God, whether revealed through the operation of reason or through divine revelation. The theological virtue of faith allows the person who has to see how the truths of reason and revelation flow from the same source.

What our senses fail to understand
This does not mean, however, that faith allows us to fully understand the truths of divine revelation. The intellect, even if illuminated by the theological virtue of faith, has its limitations: in this life, for example, man can never fully understand the nature of the Trinity, of how God can be both One and Three. As the Catholic Encyclopedia explains, “The light of faith, therefore, illuminates understanding, even if the truth still remains obscure, since it is beyond the understanding of the intellect; but supernatural grace moves the will, which now has a supernatural good, pushes the intellect to assent to what it does not understand. Or, as a popular translation of the Tantum Ergo Sacramentum says, "What our senses fail to understand / we try to understand through the consent of faith".

Losing faith
Since faith is a supernatural gift from God, and since man has free will, we can freely reject faith. When we openly rebel against God through our sin, God can withdraw the gift of faith. Of course it won't necessarily; but if he does, the loss of faith can be devastating, because the truths that had once been grasped thanks to the help of this theological virtue can now become unfathomable to the intellect without help. As the Catholic Encyclopedia observes, "This could perhaps explain why those who have had the misfortune to apostatize themselves by faith are often the most virulent in their attacks for reasons of faith", even more than those who have never been blessed by the gift of faith first.