Understanding Natural Law: Thomas Aquinas’s Guide to What’s Right and Wrong

How do we know what’s right and wrong? Is it just something we’re taught, or is there a deeper guide built into the world? Thomas Aquinas believed that the answer lies in something he called “Natural Law,” a way to understand morality using both reason and faith. Let’s break this idea down into simple terms with examples anyone can understand.

The Big Idea: A Moral Compass in Everyone

Imagine you have a compass. Just like a compass points north, Aquinas said we all have an inner compass pointing us toward what’s good. This compass isn’t random; it’s based on the way God designed the world and us. Natural Law is the idea that God’s design for humans includes moral truths we can discover using our reason.

Where Do We See Natural Law?

Think about some basic truths almost everyone agrees on:

• It’s wrong to steal.
• It’s wrong to hurt others without a good reason.
• It’s good to help people in need.

Even people who don’t believe in God often recognize these principles. Aquinas would say that’s because these laws aren’t just human inventions—they’re written into the fabric of human nature. God created us to live in harmony with these truths.

An Analogy: Traffic Laws and Roads

Imagine a city planner designs a road system. They include traffic laws to help people drive safely. The laws aren’t random; they’re based on the way the roads are built. For example, stop signs are placed where people need to pause to avoid crashes. Similarly, Natural Law is like God’s traffic laws for human life. It’s based on how we’re designed to live and thrive.

How Do We Discover Natural Law?

Aquinas said we use reason to figure out Natural Law. For example:

• If you think about what helps people live peacefully, you’ll see that fairness and honesty are important.
• If you reflect on what helps communities grow, you’ll notice the value of kindness and cooperation.

It’s like solving a puzzle. By observing human nature and the world around us, we can piece together what’s right and wrong.

Natural Law and the Catholic Church

The Catholic Church teaches that Natural Law is a gift from God. The Catechism of the Catholic Church says:

"The natural law is written and engraved in the soul of each and every man, because it is human reason ordaining him to do good and forbidding him to sin" (CCC 1954).

This means we don’t need special revelations to know some basic moral truths. God gave everyone the ability to recognize them through reason. However, faith can deepen our understanding and help us live out these truths more fully.

A Real-World Example: Helping a Friend

Imagine you see someone drop their books in the hallway. Even without being told, you probably feel it’s the right thing to help them. Why? Because your reason tells you it’s good to be kind and help others. That’s Natural Law in action.

What About When People Disagree?

Sometimes people break Natural Law or disagree about what’s right. Aquinas explained that this happens because of ignorance, bad habits, or selfishness. But the basic truths of Natural Law—like fairness and kindness—are still there, waiting to be rediscovered.

Conclusion

Thomas Aquinas’s idea of Natural Law is a way to understand right and wrong through reason and faith. It’s like a moral compass that points us toward what’s good, based on how God designed us to live. By observing the world and reflecting on human nature, we can discover these truths and live in harmony with them. For Catholics, Natural Law is part of God’s loving plan, helping us grow closer to Him and to each other.

So, the next time you wonder why certain things feel right or wrong, remember: you’re following a compass God built into all of us.

References

• Aquinas, Thomas. Summa Theologica. Translated by Fathers of the English Dominican Province. Benziger Bros., 1947. Available online at: New Advent.
• Catechism of the Catholic Church. Online at Vatican.va.
• Feser, Edward. Five Proofs of the Existence of God. Ignatius Press, 2017.
• Kreeft, Peter. A Shorter Summa: The Essential Philosophical Passages of St. Thomas Aquinas’s Summa Theologica. Ignatius Press, 2001.