The Church values God’s gift of conscience as the sacred place where God enlightens our path with the light of truth, the truth of the goodness and evil of our actions. When we seek to follow God’s will, the light of truth shines upon the conscience. This is why we are obliged to follow certain judgments, as the Catechism explains: “A human being must always obey the certain judgment of his conscience. If he were deliberately to act against it, he would condemn himself” (CCC 1790).

The judgment of the conscience is certain when a person places confidence in the moral judgment, which usually comes with knowledge and experience. This is also true with other types of mental judgments. For example, when a mother is reviewing the times tables with her child and asks the child: “What is 7 times 8?” The child may make the correct judgment, saying: “56…” and then look to his mother to make sure: “…that’s right, mom, is it not?” The child is uncertain about the answer, even though he has made the right judgment. This also happens with a child making simple judgments about right and wrong: the child lacks certainty because he can’t yet place confidence in the judgment.

We grow in certainty as we grow in confidence in the formation needed for true judgments. A well-formed intellect will make true and infallible judgments. Returning to our example: if a person has well-formed ideas of “seven,” “eight,” “fifty-six,” “times,” and “equal,” then his judgment, “7 times 8 equals 56” will be correct. When ideas are perfectly formed the mind’s judgment is infallible.

A child often lacks formation—is ignorant—and must learn words and concepts and thus receive formation until he can make true and certain judgments: good formation leads to true judgments; bad formation leads to erroneous judgments.

Yet it can happen that moral conscience remains in ignorance and makes erroneous judgments about acts to be performed or already committed (CCC 1791).

Suppose a child has a depraved mother who teaches the child erroneously. When the mother points to yellow objects, she tells her child it’s “red;” when she points out red objects, she says they are “blue;” and blue objects are “yellow.” If she does this in a consistent manner, the child will have erroneously formed ideas of color. Later, when the child goes to school, his teacher may hold up an apple and ask: “What color is this apple?” The boy answers as he has been formed: “It’s blue!” As the other children laugh, his teacher says, “No, Johnny, it’s red.” Johnny is confused and little by little discovers the error in his formation; eventually, he should even discover the source of his erroneous formation—his mother’s depravity.

This shows us how important formation is to the conscience. With good formation, our conscience makes judgments about what is right and wrong infallibly; to the extent we trust that formation, our conscience is certain. As St. Josemaría says: “With sincerity, a right intention, and a minimum of Christian formation, our conscience knows how to discover God’s will” (Conversations, 93). This means that we must always follow a certain conscience when it tells us that we must, or that must not, do something. To go against our conscience is to go against the voice of God speaking to us in the core of our being (see CCC 1790, 1800).

Man has a right to act in conscience and in freedom so as to personally make moral decisions. “He must not be found to act contrary to his conscience. Nor must he be prevented from acting according to his conscience, especially in religious matters” (CCC 1782).

So, we ought to respect the great dignity of the faculty by which man discovers the light of truth that leads to his true good and well-being: a well-formed conscience.