The Law of Human Nature

Today's Scripture

Before Lewis says a word about God, the Bible has already made his opening argument.

Romans 2:14-15 — "For when Gentiles, who do not have the law, by nature do what the law requires, they are a law to themselves, even though they do not have the law. They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them."

Matthew 7:12 — "So whatever you wish that others would do to you, do also to them, for this is the Law and the Prophets."

James 4:17 — "So whoever knows the right thing to do and fails to do it, for him it is sin."

The Big Idea

Every human being, in every country and every century, carries a sense of right and wrong that they did not invent and cannot shake off. And no human being actually lives up to it. Lewis says those two facts — we know the rules, and we break them — are the foundation of all clear thinking about ourselves and the universe. That is where Mere Christianity begins, and where we begin today.

Reflection

Listen to people argue

C.S. Lewis was an Oxford professor and a former atheist, and Mere Christianity began as radio talks to a nation at war. You might expect him to open with God, or the Bible, or church. Instead he opens with eavesdropping.

"Every one has heard people quarrelling... They say things like this: 'How'd you like it if anyone did the same to you?' — 'That's my seat, I was there first' — 'Come on, you promised.' People say things like that every day." — C.S. Lewis, Mere Christianity

Think of the last argument you overheard in a school hallway or a kitchen. "You said you would." "I had it first." "That's not fair." Notice what those sentences are doing. Nobody is saying, "Your behavior is inconvenient to me." They are appealing to a rule — a standard of fair play — and expecting the other person to already know it.

"Quarrelling means trying to show that the other man is in the wrong. And there would be no sense in trying to do that unless you and he had some sort of agreement as to what Right and Wrong are." — C.S. Lewis, Mere Christianity

Jesus pointed to this same shared standard and made it a command. Matthew 7:12 — "So whatever you wish that others would do to you, do also to them, for this is the Law and the Prophets." We call it the Golden Rule, and here is the strange part: nobody needs it explained. Even people who have never opened a Bible use it constantly — usually against someone else.

Lewis adds that even people who claim morality is made up cannot live as if it were.

"Whenever you find a man who says he does not believe in a real Right and Wrong, you will find the same man going back on this a moment later. He may break his promise to you, but if you try breaking one to him he will be complaining 'It's not fair' before you can say Jack Robinson." — C.S. Lewis, Mere Christianity

You can deny the law of gravity all day, but you still take the stairs instead of stepping off the balcony. The same is true of the moral law. Our arguments give us away.

Remember when Lewis was saying all this. It was the early 1940s, and his listeners were sitting in blacked-out houses while German bombers crossed the Channel. Nobody in Britain was saying, "Well, invading Poland is right for the Nazis, even if it isn't right for us." They said the Nazis were wrong — really wrong, wrong in a way that was worth dying to resist. You cannot say that, Lewis observed, unless there is a real standard that stands over every nation, every army, and every heart. The whole war effort quietly assumed the very law his radio talks were pointing to.

A law you did not write

So where did this standard come from? You did not sit down one day and invent fairness. Neither did your parents, or your country. Paul gives the Bible's answer in Romans 2:14-15 — even people who never received the law of Moses "show that the work of the law is written on their hearts, while their conscience also bears witness." Conscience is like a courtroom inside you, where your own thoughts "accuse or even excuse" you.

John Calvin, writing four hundred years before Lewis, said something even stronger about what God has planted in us:

"There is within the human mind, and indeed by natural instinct, an awareness of divinity. This we take to be beyond controversy." — John Calvin, Institutes of the Christian Religion

In other words, God has not left himself without a signal inside us. Proverbs 20:27 paints the picture: "The spirit of man is the lamp of the LORD, searching all his innermost parts." Your conscience is a lamp God lit. It can flicker, and it can be ignored, but you did not light it and you cannot fully blow it out.

That is why Lewis insists the moral law is real knowledge, not personal taste:

"It seems, then, we are forced to believe in a real Right and Wrong. People may be sometimes mistaken about them, just as people sometimes get their sums wrong; but they are not a matter of mere taste and opinion any more than the multiplication table." — C.S. Lewis, Mere Christianity

A wrong answer in math is still about something real. So is a wrong answer in morality. Notice, too, that this law is different from every other law in nature. The law of gravity tells you what a falling stone does — the stone has no choice. The moral law tells you what a human being ought to do — and we can refuse. A law you can break, but cannot make go away, is a strange thing to find in a universe of mere atoms. It behaves less like a force and more like a voice.

And the Bible says God has given us two witnesses at once. Outside us: Psalm 19:1 — "The heavens declare the glory of God, and the sky above proclaims his handiwork." Inside us: Romans 1:19-20 — "what can be known about God is plain to them, because God has shown it to them," so plainly, Paul says, that people "are without excuse." The sky over your head and the law in your chest are saying the same name.

We know it — and we break it

If Lewis stopped there, this would just be an interesting philosophy lecture. He does not stop there. He adds a second fact, and it stings.

"These, then, are the two points I wanted to make. First, that human beings, all over the earth, have this curious idea that they ought to behave in a certain way, and cannot really get rid of it. Secondly, that they do not in fact behave in that way. They know the Law of Nature; they break it. These two facts are the foundation of all clear thinking about ourselves and the universe we live in." — C.S. Lewis, Mere Christianity

Test it on yourself. You believe in keeping promises — have you kept every one? You believe in honesty — including last Tuesday? You believe people deserve patience — did your little brother get any this morning? James 4:17 closes every loophole: "So whoever knows the right thing to do and fails to do it, for him it is sin." Sin, in the Bible, is not only doing monstrous things. It includes knowing the right thing and not doing it. By that measure, the most ordinary day convicts us.

Here is the uncomfortable experiment: hold yourself to the exact standard you hold everyone else to. The classmate who took credit for your work, the driver who cut you off, the friend who told your secret — you judged them instantly, by the law. Now run your own week through the same court. Lewis's point is not that we are all as bad as we could possibly be. It is that not one of us passes the test we confidently give to others.

Notice what we do next: we make excuses. "I was tired." "Everyone does it." "You don't know my week." Lewis loved to point out that excuses prove the law rather than erase it. You only explain away a debt you know you owe. Nobody apologizes for breaking a rule that does not exist.

So here we stand, every one of us: creatures who can recite the rules and cannot keep them. That is not a churchy accusation. It is simply the data of an honest life.

Where the clue points

What is the moral law for, then? Paul is blunt about what it cannot do. Romans 3:20 — "For by works of the law no human being will be justified in his sight, since through the law comes knowledge of sin." The law is a mirror, not a washcloth. It shows you the dirt on your face; it cannot scrub it off. People who treat morality as a ladder up to God end up either proud, because they grade themselves gently, or crushed, because they grade themselves honestly.

There are two popular escape routes, and both fail. The first is to lower the bar — decide the law is too strict and rewrite it until you pass. But we have already seen that we did not write this law, so we cannot edit it; the conscience keeps testifying no matter what the committee votes. The second is despair — conclude that you are simply a failure and stop hoping. The gospel rejects both, because it takes the law more seriously than the proud do and the lawbreaker more hopefully than the despairing do.

The gospel — an old word that simply means "good news" — says God did something the law never could. Romans 8:3-4 — "For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh, in order that the righteous requirement of the law might be fulfilled in us." The Lawgiver did not lower the standard. He came down and met it in person, in Jesus — and then took the penalty for everyone who had failed it.

Tim Keller compressed the whole thing into one sentence:

"The gospel is this: We are more sinful and flawed in ourselves than we ever dared believe, yet at the very same time we are more loved and accepted in Jesus Christ than we ever dared hope." — Tim Keller, The Meaning of Marriage

That is exactly the shape of Lewis's two facts, with the ending filled in. The law in your heart tells you the truth about yourself — worse news than you wanted. The gospel tells you the truth about God — better news than you dared guess. Over the next twenty-seven days, Lewis will follow the clue of the moral law step by step until it leads to a Person. Today, it is enough to admit the clue is real, and that it is pointing somewhere.

Going Deeper

Keep a "fairness log" today. Every time you hear someone — including yourself — appeal to the rules ("that's not fair," "you promised," "after all I did for her"), jot it down or note it on your phone. Tonight, read the list and ask two questions. Where did this standard we all keep quoting come from? And how did I do against it today? Then tell God your honest answers. He has known them all along, and he loves you anyway.