What is natural law?

Natural law is the moral order God has written into human nature. Every person can know its basic principles through reason, even without reading Scripture or belonging to the Church.

Where it comes from. God created human beings with a definite nature and purpose. Natural law is the rational creature's participation in God's wise ordering of creation (CCC 1954). St. Paul teaches that Gentiles who did not possess the Mosaic Law could still do what the law required because its demands were “written in their hearts” (Rom 2:14-15). Natural law begins with the basic command to do good and avoid evil, then directs us toward goods such as life, truth, family, justice, friendship, and worship of God.

Why it applies to everyone. Natural law does not depend upon a government, culture, vote, or personal preference. It expresses the dignity and moral duties belonging to human nature itself. Its principal precepts are universal and remain valid in every age and society (CCC 1956-1958). Deliberately killing the innocent, lying under oath, and treating people as property remain wrong even if civil law permits them.

Why people disagree about it. Human reason is real but wounded by sin. Self-interest, habit, social pressure, passion, and bad education can obscure moral truth. For that reason, people do not always perceive or apply natural law clearly and immediately (CCC 1960). Conscience must be formed rather than treated as an automatic source of moral truth. Scripture, prayer, sound reasoning, and the Church's teaching help form a conscience that judges rightly (CCC 1776, 1783-1785).

How it relates to civil and revealed law. Just civil laws apply natural moral principles to particular circumstances. An unjust law, such as one authorizing direct attacks on innocent human life, lacks genuine moral authority. Divine revelation confirms and clarifies truths accessible to reason, especially where sin has darkened human understanding. Christ also gives grace and the new law of the Holy Spirit, enabling us to live the good that reason recognizes but human weakness struggles to fulfill (CCC 1965-1966).

In practice. Ask what kind of being the human person is, what goods allow that person to flourish, and whether an action respects those goods. Do not begin only with feelings or legality. Form your conscience through the Ten Commandments, Christ's teaching, the Catechism, and honest attention to the purposes God has placed within human nature.