“Conscience itself is the ability of free will and reason to seek and to understand moral truth. The exercise of conscience is an act of will and intellect by which the human person seeks knowledge of moral truth. The fruit of conscience is the understanding of moral truth obtained by this search. Thus conscience is threefold: the ability to search for moral truth, the act of searching, and the knowledge obtained by the search.
“All human persons have a conscience because all human persons have free will (the ability to choose) and reason (the ability to understand). Conscience is not separate from, nor additional to, free will and reason. Conscience is inherent to the very nature of free will and reason. Whoever possesses and is able to exercise free will and reason, necessarily also possesses and is able to exercise conscience. For conscience itself is the ability of free will and reason to attain moral truth. And the entire moral law is accessible to reason. The use of conscience is the use of free will and reason to seek moral truth. And the fruit of conscience is the understanding of moral truth obtained by that use of free will and reason.
“The purpose of conscience is to obtain knowledge, so as to know wrong from right. A person who desires to do good and to avoid evil must first discern which acts are good and which acts are evil. This discernment of good and evil applies to general concepts, as well as to particular intentions, acts, and circumstances. The general search for moral truth seeks an understanding of the principles of morality. The particular search for moral truth applies those principles to particular intentions, acts, and circumstances. In both cases, the human person seeks knowledge of the eternal moral law. The substantial omission of either a general or a particular search for moral truth results in a bad conscience before the eyes of God.”
quoted from my book: The Catechism of Catholic Ethics
(now available in print and in Kindle format)
Ronald L. Conte Jr.
Roman Catholic theologian and Bible translator