Whether or not the conscience is the most reliable guide to ethical decision-making is, in my opinion, determined by one's own interpretation of what conscience actually is. There are two key approaches to defining conscience. The first, originally proposed by Freud and developed by Piaget and Fromm, argues that conscience is the result of environmental factors. Freud's definition of conscience is linked to an individual's feelings of guilt and fear of punishment. As such, it could be seen as an unreliable guide to ethical decision-making as it may inspire actions simply to gain approval. For example, the son of a thief may follow his father’s path simply to please him – an act that, to most, is considered wrong.
However, an entirely different approach to conscience, existing within the Christian tradition, is to define conscience as an innate or intuitive sense. This view has perpetuated from the early Christian writings of St Paul to Cardinal Newman's work at the end of the 19th Century. Another important proponent of an intuitive conscience was Joseph Butler, who identified conscience as the ultimate moral decision maker. Placed within us by God, it must be obeyed. Although directed towards increasing the happiness of others, it is conceivable that conscience could be misled or misinformed. Therefore, it is not necessarily a reliable guide. It was Aquinas who stated that there were two dimensions to moral decision making: synderesis, an awareness of the moral principle to do good and avoid evil, and conscientia, the power of reason to work out what is good and evil. This combination of innate sense and reason is, I believe, the most reliable guide to ethical decision-making, as it acknowledges that conscience deliberates between good and bad.
Freud (1856-1939) believed that the human psyche was inspired by powerful desires that begin at birth and need to be satisfied. These are