One such misconception that seems to never go away is the idea that conscience is the final arbiter of what is morally right — a misconception often designated under the expression “primacy of conscience”.

But to put it bluntly, conscience is not the final arbiter of what is morally right, nor has the Church ever taught that it is.  In its truest sense, conscience is the intellectual apprehension of the Divine Law.  For this reason, Divine Law is primary.  

In his Letter to the Duke of Norfolk, Newman quotes Cardinal Gousset, who writes:  "The Divine Law is the supreme rule of actions; our thoughts, desires, words, acts, all that man is, is subject to the domain of the law of God; and this law is the rule of our conduct by means of our conscience. Hence it is never lawful to go against our conscience."  

Essentially, conscience is one's best judgment, in a given situation, on what here and now is to be done as good, or to be avoided as evil.  Because conscience is one's best judgment, hic et nunc, a person has a duty to obey it.  The Fourth Lateran Council says: "He who acts against his conscience loses his soul".  

Moreover, the duty to obey one's conscience includes an erroneous conscience.  For example, if, as a result of being brought up by neurotic parents, I judge that in this particular situation right now, drinking this cup of Tim Horton's coffee is contrary to God's will, then I have a duty not to drink the cup of coffee.  Should the Pope or a local Bishop try to persuade me that there is nothing sinful in drinking a cup of coffee, yet for some reason I continue to judge, erroneously, that drinking this cup of coffee would offend my Creator, I must nonetheless follow my conscience and not drink the coffee.  The reason is that if I were to drink it, I'd be doing what in my best judgment is morally wrong.  

This is what is meant by the “primacy of conscience”, that is, conscience having the final word on what I ought to do in the here and now situation.

”Primacy of conscience” does not mean that I can dissent from Church teaching on a particular issue because I don't agree with the teaching or see anything wrong with doing what the Church says I ought not to do.  That this is true is rather easy to demonstrate.  

  

Let us say that I regularly engage in a particular behavior that I think is perfectly innocent, such as telling certain off-color jokes to a classroom of teenagers, and my conscience does not bother me in the slightest when doing so.  Clearly, my conscience is deficiently formed.  But one day a colleague approaches and says:  "I think what you are doing is unprofessional, but I can't explain it now, I've got to run for an appointment.  We'll talk later."  At this point I am rather surprised, and I begin to consider my friend's character and past judgments.  I know he's not trying to manage my life and that he generally gives a great deal of thought to what he holds to be morally right or wrong.  

But conscience does not mean that Catholics are free to act on the basis of what they personally judge is morally right in spite of Church teaching.  Catholic conversion, as the etymology of “conversion” indicates, means a complete turn around (vertere), implying movement in a new direction in conjunction with (con) the community of Christ’s Mystical Body.

Already my conscience has been altered, even though my friend had no time to explain himself to me.  When I find myself in a situation in which I am about to tell these jokes, my judgment bearing upon the act is now different as a result of my colleague’s remarks.  Here and now I know that choosing to tell these off-color jokes might very well be morally wrong — although at this point I don't quite understand how — , because my friend whom I know to be reasonable told me that it is wrong.  My best judgment at this point is that "perhaps I should wait and think about this further".  For me to proceed with the jokes because I enjoy making people laugh and judge that doing so is morally noble is not good enough at this point; for I know that I have been wrong in the past, and so I know my judgment might now be mistaken.

If this is true for a colleague, how much more so for the Vicar of Christ himself, or the formulated teachings of the Church that was established not by man, but by the God-man, who sent the Holy Spirit to lead his Church to the complete truth (Jn 16, 13) and who said to the apostles: “He who hears you, hears me” (Lk 10, 16), and who said to Peter: “Whatever you bind on earth shall be considered bound in heaven; whatever you loose on earth shall be considered loosed in heaven” (Mt 16, 19)?

The only time I can reasonably act against my friend's counsel is if I judge, here and now, that were I not to tell those jokes to students, I would be doing what in my best judgment is sinful.  If, for example, a Catholic claims to be able to choose In Vitro Fertilization in good conscience while knowing that the Church teaches that such an option is morally wrong, it must mean that he or she is convinced that it would be sinful not to choose that option. That would certainly constitute an erroneous conscience; nevertheless, he or she would be obliged to obey it.

For the most part, however, this is not what people claim when they act contrary to Church teaching.  Rather, many simply choose to dissent, and they hide their dissent behind the catchphrase “primacy of conscience”.  But conscience does not mean that Catholics are free to act on the basis of what they personally judge is morally right in spite of Church teaching.  Catholic conversion, as the etymology of “conversion” indicates, means a complete turn around (vertere), implying movement in a new direction in conjunction with (con) the community of Christ’s Mystical Body.  As St. Paul says: “We all were among them too in the past, living sensual lives, ruled entirely by our own physical desires and our own ideas” (Eph 2, 3).  But, we have become a new creation (Gal 6, 13), and not everyone is an apostle who has been given the charism of office and commissioned to teach officially in Christ’s name (Eph 4, 11; Mt 28, 20).

Bishops and priests who have been exposed to the rich theological heritage that is ours in the Church have no excuse for employing a version of "conscience" which, in the final analysis, undercuts their very authority and renders it unnecessarily imposing and offensive.  If they don't begin to speak out soon and correct this and similar popular misunderstandings, their influence and authority in such a culture as ours can only dwindle so as to become virtually ineffective.