Pope Benedict XVI's recent trip to Britain has placed Catholic teaching on conscience again in the public eye. On his pilgrimage in September 2010, Benedict beatified the English convert John Henry Newman, among whose most famous writings are those dealing with the dignity of conscience, and the Holy Father's address to the British Parliament in Westminster Hall repeatedly referred to another Englishman important to Catholic thinking on conscience, St. Thomas More. In his Westminster Hall address, the pope suggested that More's case is particularly relevant in the midst of modern secularism, where it is often advised that Christians serving in public roles "should be required at times to act against their conscience."1
Much of Catholic social thought on conscience, in fact, could have been written with More's case in mind. Leo XIII and Pius XI, the two popes who wrote most extensively on conscience between the First and Second Vatican Councils, beatified and canonized More in 1886 and 1935, respectively. Leo and Pius showed particular concern to defend the rights of Catholic consciences against interference from hostile civil governments, and their writings set the stage for the memorable passages in Gaudium et Spes and Dignitatis [End Page 13] Humanae in which Vatican II addressed the subject directly. The Council's treatment of conscience expands upon these popes' teaching but remains in essential continuity with the earlier tradition. Since the Council, the main focus of magisterial writings on conscience has been to defend this tradition's objective underpinnings. Magisterial teaching on the individual conscience has insisted upon its grounding in objective truth and the natural law. Neither the papal writings on conscience before or after the Council, nor the documents of Vatican II itself, can be adequately understood without grasping this connection to the natural law.
Conscience from Leo XIII to Vatican II
Leo XIII (1878-1903) is perhaps best known for his encyclical Rerum novarum (1891), which provided the foundation for much of later Catholic thought on issues relating to economics.2 Throughout the encyclical, Leo demonstrates evident concern with the living and working conditions of the laboring classes, the possibility of social unrest and violence as a result of class disparities, and the rise of socialist movements. The threat of violent revolution and the rise of governments hostile to the Church in some parts of Europe cast a shadow over many of Leo's writings. In a number of encyclicals, Leo seeks to define the relationship between Church, State, society, and the individual Catholic. He particularly wrestles with the concept of freedom, seeking always to preserve two important principles: the freedom of Catholics to fulfill their religious duties and the sense that freedom is not absolute and must be limited by the demands of truth and justice. In doing so, he upholds what will appear again and again as an important principle of Catholic social thought, the dependence of freedom upon truth.
These themes appear already in one of Leo's earlier encyclicals, Diuturnum (1881), written in response to the assassination of Emperor Alexander II of Russia earlier in the year.3 In the encyclical, Leo strongly defends the rights and prerogatives of legitimate civil [End Page 14] authority. Such authority is necessary to maintain order and is in conformity with the divine plan. Indeed, the authority of rulers derives ultimately from God (D, 5, 9). Nevertheless, precisely because the authority of civil rulers comes from God, it is also limited and subject to God. Leo reminds rulers that kings themselves will someday have to "render an account to the King of kings and Lord of lords" for their governance and actions (D, 16). While rulers have a right to demand obedience from their subjects, they also have a corresponding duty to rule in conformity with divine decrees. Understanding the centrality of such divine decrees—the divine law—is the key to Leo's thinking on the relationship between the Church and the State and between the individual Christian and the State. The idea of divine law appears in all his encyclicals on these subjects.
For Leo, law is understood in a straightforward way as "a fixed rule of...