The Old Testament has no word for ‘conscience’, but it does speak of the true heart that interiorizes the divine law. Some Old Testament figures experience God calling them to live his will or Law; at other times they experience him probing or judging their hearts. Jesus taught his followers to have a pure heart:
God blesses those whose hearts are pure, for they will see God. Matthew 5:8
What goes into a man's mouth does not make him 'unclean', but what comes out of his mouth, that is what makes him 'unclean' ... the things that come out of the mouth come from the heart, and these make a man 'unclean'. Matthew 15:11,18
This then is how we know that we belong to the truth, and how we set our hearts at rest in his presence whenever our hearts condemn us. For God is greater than our hearts, and he knows everything. Dear friends, if our hearts do not condemn us, we have confidence before God. 1 John 3:19-21
Paul uses the term συνειδησις - often translated as 'conscience' and 'heart' - to describe the human ability to know and choose the good. He taught that all people, whether or not they are Christians, know what is right and wrong. He said it is written on our hearts:
When outsiders who have never heard of God's law follow it more or less by instinct, they confirm its truth by their obedience. They show that God's law is not something alien, imposed on us from without, but woven into the very fabric of our creation. There is something deep within them that echoes God's yes and no, right and wrong. (Romans 2:14,15, The Message). More Translations
For Paul, conscience is the universal knowledge of God's law, an inner guiding of our external behaviour. Our conscience can be corrupted, but through Christ's redeeming love, and the action of the Holy Spirit, we can 'put on the mind of Christ'.
Aquinas held reason in the highest esteem. He said "Reason in man is rather like God in the world." Most famously, Aquinas claimed:
To disparage the dictate of reason is equivalent to condemning the command of God.
Augustine had used the term 'synderesis' to mean an innate knowledge of right and wrong. He held that this was faulty, due to the fall, and that Christians should look to the authority of the Church and Scripture. Aquinas disagreed, holding that conscience has binding force.
Aquinas thought that practical reason, through reflection on human nature, can determine primary moral principles (which he called the 'Primary Precepts'). Our 'conscience' then derives secondary principles ('Secondary Precepts') which are applied. As we practice balancing our needs against the needs of others, we develop Prudence.
synderesis - an innate knowledge of human nature and primary precepts through practical reason
conscientia - deriving secondary precepts, and applying them
prudence - the virtue of right-reasoning in moral matters, balancing ours and others' needs
As with Paul, Aquinas said that a person's conscience could err (go wrong), either 'invincibly', through no fault of their own, or 'vincibly' - through our own fault. For example, if I give money to a man who is begging on the streets, I have good intentions, but my actions are actually unhelpful. If I had considered my actions carefully, I would have seen that I wasn't helping him to improve his situation - if anything, my actions would keep him on the streets longer. I erred 'vincibly', as I would have done differently if I'd thought about it.
Imagine if I'd given the money instead to a homeless charity, who would be able to help this man to find accommodation, help conquering his addictions etc. A much better thing to do. However, I did not know that workers at this charity were abusing the homeless people in their care. Supporting the charity was actually the wrong thing to do, but I couldn't have known this - I erred or got it wrong 'invincibly' - it wasn't my fault.
A different example - the bombing of Dresden. The British government terror bombed Dresden, killing up to 60,000 innocent people. This is a vincible error, as they should have known it was wrong - it was their fault, and they are responsible for what happened.
However, consider a bomb dropped on a weapons factory. Unknown to the British forces, a school was hidden under the factory. It was wrong to bomb the school, but this is invincible error, as it wasn't the fault of the British in this scenario - they couldn't have known about the school.
This example also illustrates what Aquinas thought about Conscience. It isn't a 'feeling' in your heart, like the guilt you feel when confronted with a homeless man. It is the process of reasoning, moving from the Primary Precepts (such as 'It is right to protect and preserve the innocent') to secondary precepts (such as 'It is wrong to give money to people who beg on the streets').
Butler was a Bishop in the Church of England. He believed, as Aquinas did, that we have a God-given ability to reason. Butler would say that we must listen to our conscience because it allows us to act as a moral judge. It is not an intuitive feeling about what is right - instead, it is an ability to use reason to weigh up factors in a moral decision.
Conscience does not only offer itself to show us the way we should walk in, but it. likewise carries its own authority with it, that it is our natural guide, the guide assigned us by the Author of our nature: it therefore belongs to our condition of being: it is our duty to walk in that path, and follow this guide
Butler says we have a number of influences, but the conscience should not be seen as merely one among many drives or passions. The conscience should have ultimate authority over all of our instincts.
That principle by which we survey, and either approve or disapprove our own heart, temper, and actions, is not only to be considered as what is in its turn to have some influence; which may be said of every passion, of the lowest appetites: but likewise as being superior; as from its very nature manifestly claiming superiority over all others... Had it strength, as it has right; had it power, as it has manifest authority, it would absolutely govern the world.
Newman was an Anglican theologian who converted to Roman Catholicism and became a Cardinal. Newman's view on the conscience can be seen as intuitionist, which makes his approach quite different from Butler and Aquinas. He says that our conscience is "the voice of God" completely distinct from our will or desires. It is an innate principle planted in us before we had the ability to reason.
A law of the mind
Newman described conscience as a 'law of the mind', but he did not see it as giving us commandments to follow. The conscience is not a set of rules, a feeling of guilt or something that we obey in order to gain a reward from God. It is a clear indication of what is right:
It was not a dictate, nor conveyed the notion of responsibility, of duty, of a threat and a promise...
Newman is often quoted as saying he would drink a toast to the Pope, but to the conscience first. Seeing the full quote, this is an unfortunate epitaph, as Newman wasn't about to drink to either:
Certainly, if I am obliged to bring religion into after-dinner toasts, (which indeed does not seem quite the thing) I shall drink to the Pope, if you please, still, to Conscience first, and to the Pope afterwards.
Newman was merely saying, like Butler and Aquinas before him, that the conscience should have ultimate authority.
Freud was a psychiatrist most famous for founding the psychoanalytic school of psychology. Two key aspects of his approach are the assertion that sexual desire is the prime motivating drive in all humans, and the importance of the unconscious mind.
Freud's theory of the conscience is entirely at odds with all of the positions above. He saw the conscience as part of the unconscious mind, and believed that it arose as a result of bad experiences early in life, as well as disapproval from parents and society. This negative aspect of the human psyche, part of and sometimes equated with the 'superego', is not usually in control of our actions, or not in those with healthy minds. Freud taught that 'ego', our conscious personality, usually balanced the pull of the 'id' (our desires) and the 'superego' (our guilt).
To be ruled by your superego would make you overly judgmental, inflexible and irrational. Freud would argue against allowing the conscience tohave control over our decisions about how to act.
Many psychologists have come to question Freud's understanding of the conscience, and see a well-developed conscience as part of a healthy human mind. However, most continue to reject the notion of a God-given conscience. Piaget was a developmental psychologist. He believed that by studying human behaviour, you could see how conscience develops over time. It certainly isn't something that humans are born with. He highlighted four developmental stages:
0-2 years. During this stage, babies would learn about the world around them through their senses and by moving about. They become able to differentiate themselves from the worldaroundthem,and learn about the permanence of objects.
2-7 years. During this stage, children develop language, although they find it hard to see the world from a viewpoint other than their own. They classify things by single shared features.
8-11 years. They are able to think logically to develop explanations about the world around them.
11-15 year. They can reason using abstract concepts. They begin to think about the future, the hypothetical and ideological issues.
According to this model, a person doesn't have a fully functioning conscience before the age of 11.
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. VATICAN II, Gaudium et spes §16.
The individual conscience is accorded the status of a supreme tribunal of moral judgment which hands down categorical and infallible decisions about good and evil. To the affirmation that one has a duty to follow one’s conscience is unduly added the affirmation that one’s moral judgment is true merely by the fact that it has its origin in the conscience. But in this way the inescapable claims of truth disappear, yielding their place to a criterion of sincerity, authenticity and ‘being at peace with oneself,’ so much so that some have come to adopt a radically subjectivist conception of moral judgment. Pope John Paul II, Veritatis Splendor (1993) §32.