Conscience is our internal judgment tribunal by which we measure the worthiness of our own actions. It is the voice which tells us what we should do, and whether we have done things that should not have been done. It analyzes our thoughts and actions in the light of a moral code. The moral code however is external, coming from God, objective in its perception of truth. Below are excerpts from Church documents on the theme of “formation of conscience.”

In the depths of his conscience, man detects a law which he does not impose upon himself, but which holds him to obedience. Always summoning him to love good and avoid evil, the voice of conscience when necessary speaks to his heart: do this, shun that. For man has in his heart a law written by God; to obey it is the very dignity of man; according to it he will be judged. Conscience is the most secret core and sanctuary of a man. There he is alone with God, Whose voice echoes in his depths. In a wonderful manner conscience reveals that law which is fulfilled by love of God and neighbor. In fidelity to conscience, Christians are joined with the rest of men in the search for truth, and for the genuine solution to the numerous problems which arise in the life of individuals from social relationships. Hence the more right conscience holds sway, the more persons and groups turn aside from blind choice and strive to be guided by the objective norms of morality. Conscience frequently errs from invincible ignorance without losing its dignity. The same cannot be said for a man who cares but little for truth and goodness, or for a conscience which by degrees grows practically sightless as a result of habitual sin.
-Vatican II, Constitution on the Church in the Modern World Gaudium et Spes, n. 16

Many pressures are brought to bear upon the men of our day, to the point where the danger arises lest they lose the possibility of acting on their own judgment. On the other hand, not a few can be found who seem inclined to use the name of freedom as the pretext for refusing to submit to authority and for making light of the duty of obedience. Wherefore this Vatican Council urges everyone, especially those who are charged with the task of educating others, to do their utmost to form men who, on the one hand, will respect the moral order and be obedient to lawful authority, and on the other hand, will be lovers of true freedom-men, in other words, who will come to decisions on their own judgment and in the light of truth, govern their activities with a sense of responsibility, and strive after what is true and right, willing always to join with others in cooperative effort.
-Vatican II, Declaration Dignitatis Humanae, n. 8

Need we repeat that conscience on its own is not the arbiter of the moral worth of the actions which it inspires? It must take account of objective norms and, if necessary, reform and rectify itself.
-Pope Paul V,I Apostolic Exhortation Evangelica Testificatio, n. 28

Doing what is right means more than “judging what seems best” or knowing clearly what needs to be done, as important as this is. Often we prove inconsistent in our own convictions, however firm they may be; even when our conscience dictates a clear moral decision, other factors sometimes prove more attractive and powerful. We have to arrive at the point where the good that the intellect grasps can take root in us as a profound affective inclination, as a thirst for the good that outweighs other attractions and helps us to realize that what we consider objectively good is also good “for us” here and now. A good ethical education includes showing a person that it is in his own interest to do what is right. Today, it is less and less effective to demand something that calls for effort and sacrifice, without clearly pointing to the benefits which it can bring.
-Pope Francis, Apostolic Exhortation Amoris Laetitia, n. 265

If it is true that conscience is the place where the voice of the Lord resounds, the voice that indicates to us how to behave, it is also true that it is necessary to learn to listen to this voice very attentively in order to know how to recognize it and distinguish it from other voices. In fact, it is necessary not to confuse this voice with those which emerge from a subjectivism that ignores or disregards the sources and criteria that cannot be given up and are mandatory in the formation of judgments of conscience: “It is the ‘heart’ converted to the Lord and to the love of what is good which is really the source of true judgments of conscience,” and “freedom of conscience is never freedom ‘from’ the truth but always and only freedom ‘in’ the truth.”
-Congregation for Institutes of Consecrated Life and Societies of Apostolic Life, Instruction Faciem Tuam Domine Requiram, n. 27

From the Catechism of the Catholic Church:
Moral conscience, present at the heart of the person, enjoins him at the appropriate moment to do good and to avoid evil. It also judges particular choices, approving those that are good and denouncing those that are evil. It bears witness to the authority of truth in reference to the supreme Good to which the human person is drawn, and it welcomes the commandments. When he listens to his conscience, the prudent man can hear God speaking. (n. 1777)

Conscience is a judgment of reason whereby the human person recognizes the moral quality of a concrete act that he is going to perform, is in the process of performing, or has already completed. In all he says and does, man is obliged to follow faithfully what he knows to be just and right. It is by the judgment of his conscience that man perceives and recognizes the prescriptions of the divine law: ‘Conscience is a law of the mind; yet [Christians] would not grant that it is nothing more; I mean that it was not a dictate, nor conveyed the notion of responsibility, of duty, of a threat and a promise…. [Conscience] is a messenger of him, who, both in nature and in grace, speaks to us behind a veil, and teaches and rules us by his representatives. Conscience is the aboriginal Vicar of Christ.’ (John Henry Cardinal Newman) (n. 1778 )

Man has the right to act in conscience and in freedom so as personally to make moral decisions. He must not be forced to act contrary to his conscience. Nor must he be prevented from acting according to his conscience, especially in religious matters. Conscience must be informed and moral judgment enlightened. A well-formed conscience is upright and truthful. It formulates its judgments according to reason, in conformity with the true good willed by the wisdom of the Creator. the education of conscience is indispensable for human beings who are subjected to negative influences and tempted by sin to prefer their own judgment and to reject authoritative teachings. (nos. 1782-3)

1786 Faced with a moral choice, conscience can make either a right judgment in accordance with reason and the divine law or, on the contrary, an erroneous judgment that departs from them.

Man is sometimes confronted by situations that make moral judgments less assured and decision difficult. But he must always seriously seek what is right and good and discern the will of God expressed in divine law.

To this purpose, man strives to interpret the data of experience and the signs of the times assisted by the virtue of prudence, by the advice of competent people, and by the help of the Holy Spirit and his gifts. (nos. 1786-8)

Ignorance of Christ and his Gospel, bad example given by others, enslavement to one’s passions, assertion of a mistaken notion of autonomy of conscience, rejection of the Church’s authority and her teaching, lack of conversion and of charity: these can be at the source of errors of judgment in moral conduct. If – on the contrary – the ignorance is invincible, or the moral subject is not responsible for his erroneous judgment, the evil committed by the person cannot be imputed to him. It remains no less an evil, a privation, a disorder. One must therefore work to correct the errors of moral conscience. A good and pure conscience is enlightened by true faith, for charity proceeds at the same time “from a pure heart and a good conscience and sincere faith.” The more a correct conscience prevails, the more do persons and groups turn aside from blind choice and try to be guided by objective standards of moral conduct. (nos. 1792-4)

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