Listers, the Catholic Church has long ruled in matters of sexuality. Issues of abortion, contraception, homosexuality and other sexual issues have been topics of discussion and legislation since our earliest Church Fathers. The following list is taken from the opening of Pope Paul VI’s largely ignored Humanae Vitae. The three points presuppose the ability of the Church and her magisterium rule authoritatively on subjects related to Divine law. The purpose of the list is to show why an authority over issues of revelation assumes the responsibility and the capability of ruling over issues of nature. In our modern world, the Church’s capacity to define and declare laws of nature deals heavily with issues of sexuality and politics.

1. Grace Perfects Nature

This kind of question [over birth control and the marital act] requires from the teaching authority of the Church a new and deeper reflection on the principles of the moral teaching on marriage — a teaching which is based on the natural law as illuminated and enriched by divine Revelation.

The following five questions focus on unpacking the phrase “natural law as illuminated and enriched by divine Revelation.”

What is nature’s relation to laws of the state? – Natural Law speaks in general principles by inclination to the human heart . All peoples of the earth have prohibitions against murder, stealing, rape and other repugnant acts. It is universal in humanity regardless of creed, area or race; and according to the greater Western political tradition, Natural law serves as the foundation of all human law. The general principles known in the hearts of men are discerned and specified into concrete laws of the state. The natural inclination to view murder as unlawful is then specified into various degrees of murder and corresponding punishments.

What of the fact different cultures have different laws? – There are many contributing factors to this variety, but at its core it must be acknowledged that nature’s general precepts have been articulated and demonstrated in multiple ways. Still, various specifications point back to a universal and general standard.

What of the cultures that do permit forms of murder or theft? – The genre of this question usually takes the from of such-and-such tribe has integrated cannibalism, adultery, murder, etc. into lawful culture, so what is to be made of natural law? It is important to note that using these people groups as anomalies presupposes that there is a greater standard. To wit, you cannot have an exception without a law; thus, these anomalies actually support the doctrine of natural law. Moreover, the conscience of men is formed by habit and principle. It is therefore possible that as a culture begins to adopt certain unnatural acts, it can overtime become immune to their natural repugnance, like tribal cannibalism.

Man is by nature a political animal.

What of Natural law and God’s self-revelation? – We have spoken in brief of Natural law’s relationship to Human law, but what of Natural law’s relation to Divine law? Here the principle that grace perfects nature must be clearly understood. Grace is erroneously understood to be an exemption from law, but in reality it enables one to more perfectly follow the law. Christ did not introduce the world to virtue. The Greeks – through observing nature – had deduced the concept of “right living” and articulated those acts with are good and natural for men: the virtues. Christ introduced the world to the Theological Virtues: faith, hope and charity. In these three virtues, the natural virtues of say prudence and justice are clarified and perfected in man. Grace perfects nature; thus, all men can live the natural virtues, but only Catholics receive the full grace of the Theological virtues and the full extent of the virtuous life.

What does nature and revelation’s relationship mean for marriage? – Holy Matrimony is unique among the sacraments, because it is the only one to also be a natural institution. All peoples of the earth have some type of marriage, but only the sacrament of Holy Matrimony is the visible sign of an invisible grace – a grace that perfects the natural institution of marriage. Consequently, since the Catholic Church is the Church of Christ and was given the keys of St. Peter, it and it alone is able to articulate in confidence not only the sacrament of Holy Matrimony but also the natural institution of marriage it perfects. Moreover, it is able to speak to the very nature of humanity; and, since humans are by national rational, political and sexual animals, the Church has the authority and obligation to speak to these matters.

2. Guardian of the Whole Moral Law

No member of the faithful could possibly deny that the Church is competent in her magisterium to interpret the natural moral law.

It is in fact indisputable, as Our predecessors have many times declared, that Jesus Christ, when He communicated His divine power to Peter and the other Apostles and sent them to teach all nations His commandments, constituted them as the authentic guardians and interpreters of the whole moral law, not only, that is, of the law of the Gospel but also of the natural law.

For the natural law, too, declares the will of God, and its faithful observance is necessary for men’s eternal salvation.

How did Christ give power to the magisterium? – Again, this list presupposes the belief that the Church is founded upon the rock of St. Peter – the first Pope – and he was given the keys of the Kingdom. In brief, Jesus was the Son of David who would fulfill God’s promise to King David that a descendent of his would sit upon his throne and rule forever. Consequently, Christ’s kingdom is Davidic and the Old Testament goes into detail of the structure of this kingdom. The structure includes a vicar who watches over the kingdom when the king is gone, and yes, that vicar is given keys of kingdom as a symbol of this authority.

Christ and the Papacy: A Detailed and Biblical Account
1. St. Peter the Prince of the Apostles: Understanding His Uniqueness Amongst the Apostles
2. Jesus Christ Founded the Papacy: The Biblical Foundation of the Office of the Pope

Why can the Church rule on matters of nature? – It would be logically impossible for the Church to be able to rule on subjects of divine revelation – grace – without being able to articulate that which grace perfects: nature. Natural law is a lower science than Sacred Doctrine (The Queen of the Sciences), because revelation grants the principles that order our understanding of nature. If architecture orders the principle of the whole house then plumbing and carpentry must obey that principle if their crafts are to harmonize and fulfill their purpose. Divine revelation and nature work in a similar fashion; thus, though nature speaks in generalities and it available to all men, the Catholic Church – through the lens of grace – can determine the specifics of natural law in the confidence and security she has in God’s word.

3. The Obligation to Hold All Men to What is Natural

In carrying out this mandate, the Church has always issued appropriate documents on the nature of marriage, the correct use of conjugal rights, and the duties of spouses. These documents have been more copious in recent times.

How can the Church define sexuality? – If the Church can define marriage then it can define its acts, because to define something is speak of its nature, e.g., what is marriage? what is the goal of marriage? etc. It is the nature of marriage that characterizes all acts within marriage, because all acts must be harmonized and orientated toward their proper common marital end. Undoubtably the natural end of sex is procreation, but human societies have universally and naturally acknowledge that sex is more than simply procreation – the is a unitive and charitable significance to it. It is the natural unitive and procreative significance of sexuality that the Church can address by its authority over the whole of moral law – both revealed and natural. Acts that seek to rearrange  marriage – whether inside Catholicism or in the State – are not simply wrong by Catholic standards but are  wrong insofar as they are unnatural.

What does this have to do with politics? – The Catholic Church affirms that Natural law is the basis of all human societies. Moreover, humans are political animals by nature, and political organizations – there are a plurality of legitimate forms – exist by nature. Hierarchy is natural to man and as Aristotle taught, those who live outside of society must either be a beast or a god. Organized community is necessary for us as humans, as political animals. Similarly to if the human body eats or comes into contact with something that disturbs its nature, anything that is unnatural that is institutionalized by the natural state will in turn decay and corrupt the state. The Church has an obligation to speak to all men about Natural law (reason and nature) – the common ground between the State and the Church.

What of the Church in a liberal Democracy? – There is no utopian form of Catholic government. The Church does not nor can she seek a theocracy. However, her voice should be allowed to be heard in the greater society, even if it is simply one of many within a liberal democracy. What she cannot tolerate and what the state cannot do is regulate her voice to religion alone and categorize all her statements as relative religious beliefs. To censor her in this regard is to effectively deny there is any Natural law or any common standard of nature among all men that can be rightly and effectively discussed. The point is not to claim Catholic authority over non-Catholics, but for Catholics to recognize the obligation of the Church to speak to and be in dialogue with non-Catholics on matters of Nature. Natural law should be the context for political discussions among all people, because we all share in the same nature. Sexuality is simply one topic within man’s nature that must be discussed for the good of the state.

Understanding the State as a Natural Institution
The Catechism of the Catholic Church on Political Authority
The Best Regime: Understanding Ancient Political Philosophy
Political Animals: Book One of Aristotle’s Politics