Ask a child the following questions:
What would happen if your mom tried to sew buttons onto your shirt using a fork instead of a needle? What if you tried to write a letter with a spaghetti noodle? How far would your dad’s car get if he filled the gas tank with water? Would eating sand keep your body healthy and well-nourished?
You and the child can have a lot of fun with those types of questions. Even a young kid can understand the silliness, the futility—and even the harm—of using something against its nature or purpose. And just as we humans create and design things with a certain purpose and end in mind, God did the same thing when he created and designed mankind.
“What is the nature of a thing?” and “What is the nature of a human being?”—these questions are the basis for understanding the natural law.
Natural law (not to be confused with the laws of nature) is simply another term for the universal moral law, which is inscribed on the heart of every human. Natural law applies to all people and in all eras without exception. In other words, the natural law is not merely “morality for Catholics” or a “religious thing”—it is universal. The Catechism puts it like this: “The natural law expresses the original moral sense which enables man to discern by reason the good and the evil, the truth and the lie” (1954).
Unlike truths we know through divine revelation (such as the nature of the Trinity or the sacraments), natural law can be accessed by the light of human reason alone. That is why atheists and believers alike can understand that things like murder, rape, stealing, lying, disrespecting one’s parents, and even cutting someone in line are unjust or immoral acts.
Now, that doesn’t ensure that individual humans will actually obey the moral law, nor that sin or bad formation will not obscure it, but natural law is knowable nonetheless. Pope Leo XIII describes the natural law:
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. . . . But this command of human reason would not have the force of law if it were not the voice and interpreter of a higher reason to which our spirit and our freedom must be submitted (Libertas Praestantissimum).
As anyone can see from the silly questions at the beginning of this article, if we use a thing against its nature or design, things don’t go so well. But if we use a thing according to its nature or design, there is flourishing. The same goes for human beings: when we act according to our nature and design, we see human flourishing, which means we see virtue, strong families, and thriving societies. When we act against our nature and design, we get confusion, disorder, and sin.
All around us today, we see that people are adrift and disoriented. “Progressivism,” specifically sexual progressivism, is redefining morality so rapidly that we can’t be sure that what is acceptable today will still be acceptable tomorrow. When we institute relativism as the norm for morality, nothing is fixed, everything is shifting beneath our feet. Because of that, we must bring back a way of teaching that will give people, especially our children, a sure footing.
To accomplish this as Catholics, we should look to our patrimony. St. Paul talks about the natural law explicitly (it’s not a new idea):
When Gentiles who have not the law do by nature what the law requires, they are a law to themselves, even though they do not have the law. They show that what the law requires is written on their hearts, while their conscience also bears witness and their conflicting thoughts accuse or perhaps excuse them (Rom. 2:14-15).
As Americans, we can look to our founding fathers, who based our nation’s laws on the natural law (the Declaration of Independence references the “Laws of Nature’s God”), and to the writings of Abraham Lincoln. And in 1963, Martin Luther King, Jr. said in his Letter from a Birmingham Jail:
How does one determine whether a law is just or unjust? A just law is a man-made code that squares with the moral law or the law of God. An unjust law is a code that is out of harmony with the moral law. To put it in the terms of St. Thomas Aquinas: an unjust law is a human law that is not rooted in eternal law and natural law.
In just a few decades, we have lost our immemorial acceptance of the natural law and replaced it with the idea that whatever feels right to the individual is morally correct. And because we now live in a culture that eschews reality and actual facts—denying even biology and basic science—the teaching of natural law will be more, not less, effective than in previous generations, in the same way that a light shines brighter in the darkness.
So let’s look at some other “silly” questions but with a focus on our human nature:
Is it good to purposely cause a healthy bodily system to malfunction? Can a man become a woman simply by having his private parts mutilated or destroyed? Is it the nature of the reproductive system to be used within another person’s digestive tract? Are we ever permitted to target and kill a defenseless and innocent human being?
These questions, like the silly questions at the beginning, are fundamentally understandable. We are hardwired to “get it,” since the soul was created to recognize truth.
Unfortunately, even some Catholics now argue that modern souls cannot possibly understand or accept natural law arguments and that they “won’t work” with this generation. I say baloney. If anything, this era of moral relativism and even complete detachment from material reality makes natural law more attractive than ever. The only thing keeping it from forming and enlightening our children is the fact that we no longer teach it. It’s up to all of us to change that.