Sometimes Luther is blamed for this since he said at the Diet of Worms:
Unless I am convinced by the testimony of the Scriptures or by clear reason (for I do not trust either in the pope or in councils alone, since it is well known that they have often erred and contradicted themselves), I am bound by the Scriptures I have quoted and my conscience is captive to the Word of God. I cannot and will not recant anything, since it is neither safe nor right to go against conscience. May God help me. AmenLuther had not read Shakespeare and was no Erasmus. He did not see the conscience as the ultimate guide and guardian but the conscience captive to the Word of God. Luther was not saying, as we do in modern terms, I must be true to myself. Luther was saying he had to be true to the Word of God. Whether or not you appreciate Luther's point, Luther cannot be credited or blamed for the idea that my conscience is my true me and this is the only voice to which I must listen and be true.
Maybe we need to begin with what conscience is not. Even Christians have come to think of conscience as the inner voice, the voice of the true self when in reality conscience was and has always been the voice of God. If God planted this conscience and informed it with His law, it remains His voice and His guiding. Apart from Scripture and the living tradition of the faith, conscience still informs this basic and natural law. But for the Christian, it is the voice of God that hears, recognizes, and heeds the Scriptures as the Word of God that endures forever and the living tradition of the faithful, the catholic faith of what has always been believed, confessed, and taught everywhere in Christendom. Conscience cannot simply be reduced to following your “inner voice.”
St. Thomas Aquinas defined conscience as “nothing else than the application of knowledge to some action,” and reminded us of how the conscience works:
- the conscience serves as a witness (to point us to the evil we have done and the good we have not done),
- the conscience works to incite to action or to bind (so that when we have judged an action evil or good, we are moved to act upon that judgment), and
- the conscience excuses, accuses, and/or torments us (when we have done the evil we should not and also then to assure us when we have done the good).
The voice of conscience can be manipulated. We can shut down this voice of God. When we have grown comfortable with the sins we commit, we effectively mute this voice of God. Even though our actions are violating what we know, the sting of conscience is removed. Even though this sin contradicts the law of God written in your heart, the sinner has learned a way to justify the sin in the mind and to feel comfortable with the sin in the heart so that the conscience is no longer pricked when that sin is committed. For this reason, the conscience must remain informed by the Word of the Lord which not only teaches but retains the boundaries for the conscience. Through the means of grace the Spirit is at work teaching and reinforcing the conscience -- not the inner voice but the voice of God's Word.
This is why the Church works in us through the agency of the means of grace to form our conscience according to the objective and unchanging truths of God. The more we know the good and the more we desire it, the more the conscience is able to inform and guide our feelings -- in effect working to make them honest.
So then to “follow your conscience” does not mean to do what feels right or what you think is right but to do that which is right -- the right of God's Word, the lamp to our feet that enlightens our path. Even in ordinary ways our laws on earth expect you to act not simply on the basis of what you know and believe to be right, good, and true BUT on the basis of what the law says. If you tell the cop you did not know the speed limit for that road was lower than the speed you were going, your ignorance does not excuse. You should have known.
This above all: to thine own self be true
And it must follow, as the night the day
Thou canst not then be false to any man...