Natural Law and Morality

"What is natural law and why does the Catholic Church appeal to it?"

3 Scripture passages2 objections answered2 Church Father quotes

The Short Answer

Natural law is the moral law written on every human heart by God, accessible through reason, and forming the basis of all human ethics. It reflects God's eternal law and guides us toward human flourishing.

Quick Overview

Have you ever felt that certain things are just wrong—like hurting innocent people or betraying a friend—even without being taught? That's natural law. God designed human beings with a built-in sense of right and wrong. Just as our eyes are made to see and our ears to hear, our conscience is made to recognize moral truth. This doesn't mean everyone always follows it, but deep down, we all have access to basic moral knowledge through our God-given reason.

Biblical Evidence

What the Scriptures say

Romans 2:14-15

"For when the Gentiles, who have not the law, do by nature those things that are of the law; these having not the law are a law to themselves: Who shew the work of the law written in their hearts, their conscience bearing witness to them."

Why This Matters

Paul teaches that even those without the written law of Moses have moral knowledge written on their hearts—the natural law accessible through conscience and reason.

Romans 1:19-20

"Because that which is known of God is manifest in them. For God hath manifested it unto them. For the invisible things of him, from the creation of the world, are clearly seen, being understood by the things that are made; his eternal power also, and divinity."

Why This Matters

God's truth is knowable through creation and reason. Moral truth is part of what can be known naturally about God's design.

Psalm 19:1-2

"The heavens shew forth the glory of God, and the firmament declareth the work of his hands. Day to day uttereth speech, and night to night sheweth knowledge."

Why This Matters

Creation itself communicates God's wisdom and order, including the moral order built into human nature.

What the Church Teaches

Official Catholic doctrine

The Catechism teaches that natural law 'expresses the original moral sense which enables man to discern by reason the good and the evil' (CCC 1954). It is universal, immutable, and participates in God's eternal law (CCC 1956-1958).

Common Objections

Questions answered

Early Church Fathers

What the first Christians believed

St. Justin Martyr

c. 150 AD

"Whatever things were rightly said among all men, are the property of us Christians. For next to God, we worship and love the Word who is from the unbegotten and ineffable God."

— Second Apology, 13

St. Thomas Aquinas

c. 1270 AD

"The natural law is nothing else than the rational creature's participation in the eternal law."

— Summa Theologica, I-II, Q.91, A.2

Divorce and Remarriage

Conscience

Earn Points

Ready to claim your points!

Share This Teaching

Help others discover the biblical basis for Catholic beliefs