In this oft discussed passage from Mere Christianity, C.S. Lewis spurns the supposed implications of a century’s worth of cultural anthropology, arguing that, in spite of surface differences, virtually all people possess an innate moral compass that is at bottom similar or the same. He begins by noting that human quarreling presupposes such a shared set of moral norms, that without a common set of “Rules of Human Nature”, quarreling would be, in effect, impossible. Lewis goes on to argue that this set of moral obligations we find in ourselves suggests a moral lawgiver. En route, he comments on the proper limits of science, on what we can infer on the basis of our own self-knowledge, and on the hypocrisy of those who claim no such common moral knowledge exists. Lewis’ essay is hardly the most rigorous moral argument for theism on offer, but it does display his knack for drawing on the everyday to illustrate his premises and his argument for a common ethic is especially worth considering in view of the conventional wisdom about the radical diversity of moral norms. The moral differences between persons and cultures is profound. Can Lewis’ argument for universal “Rules of Human Nature” be sustained? I’m particularly keen to reflect on the extent to which apparent moral differences should actually be attributed to different beliefs about reality. On this, see his thought provoking comments on the old practice of burning witches at the stake. Also note his observation that the materialistic and religious views of reality are not a bifurcation emerging out of the Enlightenment, but rather a fundamental divergence that turns up “wherever there having been thinking men”.

The Law of Human Nature

Every one has heard people quarrelling. Sometimes it sounds funny and sometimes it sounds merely unpleasant; but however it sounds, I believe we can learn something very important from listening to the kind of things they say. 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” — “Leave him alone, he isn’t doing you any harm” — “Why should you shove in first?” — “Give me a bit of your orange, I gave you a bit of mine” — “Come on, you promised.” People say things like that every day, educated people as well as uneducated and children as well as grown-ups.

Now what interests me about all these remarks is that the man who makes them is not merely saying that the other man’s behaviour does not happen to please him. He is appealing to some kind of standard of behaviour which he expects the other man to know about. And the other man very seldom replies: “To hell with your standard.” Nearly always he tries to make our that what he has been doing does not really go against the standard, or that if it does there is some special excuse. He pretends there is some special reason in this particular ease why the person who took the seat first should not keep it, or that things were quite different when he was given the bit of orange, or that something has turned up which lets him off keeping his promise. It looks, in fact, very much as if both parties had in mind some kind of Law or Rule of fair play or decent behaviour or morality or whatever you like to call it, about which they really agreed. And they have. If they had not, they might, of course, fight like animals, but they could not quarrel in the human sense of the word. Quarrelling means trying to show that the other man is in the wrong. And there would he no sense in trying to do that unless you and he had some sort of agreement as to what Right and Wrong are; just as there would be no sense in saying that a footballer had committed a foul unless there was some agreement about the rules of football.

Now this Law or Rule about Right and Wrong used to be called the Law of Nature. Nowadays, when we talk of the “laws of nature” we usually mean things like gravitation, or heredity, or the laws of chemistry. But when the older thinkers called the Law of Right and Wrong “the Law of Nature,” they really meant the Law of Human Nature. The idea was that, just as bodies are governed by the law of gravitation and organisms by biological laws, so the creature called man also had his law — with this great difference, that a body could not choose whether it obeyed the law of gravitation or not, but a man could choose either to obey the Law of Human Nature or to disobey it.

We may put this another way. Each man is at every moment subjected to several different sets of law but there is only one of these which he is free to disobey. As a body, he is subjected to gravitation and cannot disobey it; if you leave him unsupported in mid-air, he has no more choice about falling than a stone has. As an organism, he is subjected to various biological laws which he cannot disobey any more than an animal can. That is, he cannot disobey those laws which he shares with other things; but the law which is peculiar to his human nature, the law he does not share with animals or vegetables or inorganic things, is the one he can disobey if he chooses.

This law was called the Law of Nature because people thought that every one knew it by nature and did not need to be taught it. They did not mean, of course, that you might not find an odd individual here and there who did not know it, just as you find a few people who are colour-blind or have no ear for a tune. But taking the race as a whole, they thought that the human idea of decent behaviour was obvious to everyone. And I believe they were right. If they were not, then all things we said about the war were nonsense. What was the sense in saying the enemy were in the wrong unless Right is a real thing which the Nazis at bottom knew as well as we did and ought to have practiced? If they had had no notion of what we mean by right, then, though we might still have had to fight them, we could no more have blamed them for that than for the colour of their hair.

I know that some people say the idea of a Law of Nature or decent behaviour known to all men is unsound, because different civilisations and different ages had quite different moralities.

But this is not true. There have been differences between their moralities, but these have never amounted to anything like a total difference. If anyone will take the trouble to compare the moral teaching of, say, the ancient Egyptians, Babylonians, Hindus, Chinese, Greeks, and Romans, what will really strike him will be how very like they are to each other and to our own. Some of the evidence for this I have a put together in the appendix of another book called The Abolition of Man; but for our present purpose I need only ask the reader to think what a totally different morality would mean. Think of a country where people were admired for running away in battle, or where a man felt proud of double-crossing all the people who had been kindest to him. You might just as well try to imagine a country where two and two made five. Men have differed as regards what people you ought to be unselfish to — whether it was only your own family, or your fellow countrymen, or everyone. But they have always agreed that you ought not to put yourself first. Selfishness has never been admired. Men have differed as to whether you should have one wife or four. But they have always agreed that you must not have any woman you liked.

But the most remarkable thing is this. 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. A nation may say treaties do not matter; but then next minute, they spoil their case by saying that the particular treaty they want to break was an unfair one. But if treaties do not matter, and if there is no such thing as Right and Wrong — in other words, if there is no Law of Nature — what is the difference between a fair treaty and an unfair one? Have they not let the cat out of the bag and shown that, whatever they say, they really know the Law of Nature just like anyone else?

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. Now if we are agreed about that, I go on to my next point, which is this. None of us are really keeping the Law of Nature. If there are any exceptions among you, I apologise to them. They had much better read some other work, for nothing I am going to say concerns them. And now, turning to the ordinary human beings who are left:

I hope you will not misunderstand what I am going to say. I am not preaching, and Heaven knows I do not pretend to better than anyone else. I am only trying to call attention to a fact; the fat that this year, or this month, or more likely, this very day, we have failed to practise ourselves the kind of behaviour we expect from other people. there may be all sorts of excuses for us. That time you were so unfair to the children was when you were very tired. That slightly shady business about the money — the one you have almost forgotten — came up when you were very hard up. And what you promised to do for old So-and-so and have never done — well, you never would have promised if you had known how frightfully busy you were going to be. And as for your behaviour to your wife (or husband) or sister (or brother) if I knew how irritating they could be, I would not wonder at it — and who the dickens am I, anyway? I am just the same. That is to say, I do not succeed in keeping the Law of Nature very well, and the moment anyone tells me I am not keeping it, there starts up in my mind a string of excuses as long as your arm. The question at the moment is not whether they are good excuses. The point is that they are one more proof of how deeply, whether we like it or not, we believe in the Law of Nature. If we do not believe in decent behaviour, why should we be so anxious to make excuses for not having behaved decently? The truth is, we believe in decency so much — we feel the Rule or Law pressing on us so — that we cannot bear to face the fact that we are breaking it, and consequently we try to shift the responsibility. For you notice that it is only for our bad behaviour that we find all these explanations. It is only our bad temper that we put down to being tired or worried or hungry; we put our good temper down to ourselves.

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.

Some Objections

Morality as Instinct

If they are the foundation, I had better stop to make that foundation firm before I go on. Some of the letters I have had show that a good many people find it difficult to understand just what this Law of Human Nature, or Moral Law, or Rule of Decent Behaviour is.

For example, some people wrote to me saying, “Isn’t what you call the Moral Law simply our herd instinct and hasn’t it been developed just like all our other instinct?” Now I do not deny that we may have a herd instinct: but that is not what I mean by the Moral Law. We all know what it feels like to be prompted by instinct — by mother love, or sexual instinct, or the instinct for food. It means that you feel a strong want or desire to act in a certain way. And, of course, we sometimes do feel just that sort of desire to help another person: and no doubt that desire is due to the herd instinct. But feeling a desire to help is quite different from feeling that you ought to help whether you want to or not. Supposing you hear a cry for help from a man in danger. You will probably feel two desires — one a desire to give help (due to your heard instinct), the other a desire to keep out of danger (due to the instinct for self-preservation). But you will find inside you, in addition to these two impulses, a third thing which tells you that you ought to follow the impulse to help, and suppress the impuse to run away. Now this thing that judges between two instincts, that decides which should be encourage, cannot itself be either of them. You might as well say that the sheet of music which tells you, at a given moment, to play one note on the piano and not another, is itself one of the notes on the keyboard. The Moral Law tells us the tune we have to play: our instincts are merely the keys.

Another way of seeing that the Moral Law is not simply one of our instincts is this. If two instincts are in conflict, and there is nothing in a creature’s mind except these two instincts, obviously the stronger of the two must win. But at those moments when we are most conscious of the Moral Law, it usually seems to be telling us to side with the weaker of the two impulses. Your probably want to be safe much more than you want to help the man who is drowning: but the Moral Law tells you to help him all the same. And surely it often tells us to try to make the right impulse stronger than it naturally is? I mean, we often feel it our duty to stimulate the herd instinct, by waking up our imaginations and arousing our pity and so on, so as to get up enough steam for doing the right thing. But clearly we are not acting from instinct when we set about making an instinct stronger than it is. The thing that says to you, “Your herd instinct is asleep. Wake it up,” cannot itslef be the herd instinct. The thing that tells you which note on the piano needs to be played louder cannot itself be that note.

Here is a third way of seeing it. If the Moral Law was one of our instincts, we ought to be able to point to some one impulse inside us which was always what we call “good,” always in agreement with the rule of right behaviour. But you cannot. There is non of our impluses which the Moral Law may not sometimes tell us to suppress, and none which it may not sometimes tell us to suppress, and none which it may not sometimes tell us to encourage. It is a mistake to think that some of our impulses — say mother lover or patriotism — are good, and others, like sex or the fighting instinct, are bad. All we mean is that the occasions on which the fighting instinct or the sexual desire need to be restrained are rather more frequent than those for restraining mother love or patriotism. But there are situation in which it is the duty of a married man to encourage his sexual impulse and of a soldier to encourage the fighting instinct. There are also occasion which a mother’s love for her own children or a man’s love for his own country have to be suppressed or they will lead to unfairness towards other people’s children or countries. Strictly speaking, there are no such things as good and bad impulses. Think once again of a piano. It has not got two kinds of notes on it, the ‘right’ notes and the ‘wrong’ ones. Every single note is right at one time and wrong at another. The Moral Law is not any one instinct or set of instincts: it is something which makes a kind of tune (the tune we call goodness or right conduct) by directing the instincts.

By the way, the point is of great practical consequence. The most dangerous thing you can do is to take any one impulse of your own nature and set it up as the thing you ought to follow at all costs. There is not one of them which will not make us into devils if we set it up as an absolute guide. You might think love of humanity in general was safe, but it is not. If you leave out justice you will find yourself breaking agreements and faking evidence in trials “for the sake of humanity”, and become in the end a crue and treacherous man.

Morality as Convention

Other people wrote to me saying, “Isn’t what you call the Moral Law just a social convention, something that is put into us by education?” I think there is a misunderstanding here. The people who ask that question are usually taking it for granted that if we have learned a thing from parents and teachers, then that thing must be merely a human invention. But, of course, that is not so. We all learned the multiplication table at school. A child who grew up alone on a desert island would not know it. But surely it does not follow that the multiplication table is simply a human convention, something human beings have made up for themselves and might have made different if they had like? I fully agree that we learn the Rule of Decent Behaviour from parents and teachers, and friends and books, as we learn everything else. But some the things we learn are mere convention which might have been different — we learn to keep to the left of the the road, but it might just as well have been the rule to keep to the right — and others of them, like mathematics, are real truths. The question is to which class the Law of Human Nature belongs.

There are two reasons for saying it belongs to the same class as mathematics. The first is, as I said in the first chapter, that though there are differences between the moral ideal of one time or country and those of another, the difference are not really very great — not nearly so great as most people imagine — and you can recognise the same law running through them all: whereas mere conventions, like the rule of the road or the kind of clothes people wear, may differ to any extent. The other reason is this. When you think about these differences between the morality of one people and another, do you think that the morality of one people is ever better or worse that that of another? Have any of the changes been improvements? If not, then of course there could never be any moral progress. Progress means not just changing, but changing for the better. If no set of moral ideas were truer or better than any other, there would be no sense in preferring civilised morality to savage morality, or Christian morality to Nazi morality. In fact, of course, we all do believe that some moralities are better than others. We do believe that some of the people who tried to change the moral ideas of their own age were what we call Reformers or Pioneers — people who understood morality better than their neighbours did. Very well then. The moment you say that one set of moral ideas can be better than another, you are, in fact, measuring them both by a standard, saying that one of them conforms to that standard more nearly than the other. But the standard that measures two things is something different from either. You are, in fact, comparing them both with some Real Morality, admitting that there is such a thing as a real Right, independent of what people think, and that some people’s ideas get nearer to that real Right than others. Or put it this way. If your moral ideas can be truer, and those of the Nazis less true, there must be something — some Real Morality — for them to be true about. The reason why your idea of New York can be truer or less true than mine is that New York is a real place, existing quite apart from what either of us thinks. If when each of us said “New York” each meant merely “The town I am imagining in my own head,” how could one of us have truer ideas than the other? There would be no question of truth or falsehood at all. In the same way, if the Rule of Decent Behaviour meant simply “whatever each nation happens to approve,” there would be no sense in saying that any one nation had ever been more correct in its approval than any other; no sense in saying that the world could ever grow morally better or morally worse.

Differences of Fact, not Morality

I conclude then, that though the differences between people’s ideas of Decent Behaviour make you suspect that there is no real natural Law of Behaviour at all, yet the things we are bound to think about these differences really prove just the opposite. But one word before I end. I have met people who exaggerate the difference, because they have not distinguished between differences of morality of differences of beliefs about facts. For example, on man said to me, “Three hundred years ago people in England were putting witches to death. Was that what you call the Rule of Human Nature or Right Conduct?” But surely the reason we do not execute witches is that we do not believe there are such things. If we did — if we really thought there were people going about who had sold themselves to the devil and received supernatural powers from him in return and were using the powers to kill their neighbours or drive them mad of bring bad weather, surely we would all agree that if anyone deserved the death penalty, then these filthy quislings did. There is no difference of moral principle here: the difference is imply about matter of fact. It may a great advance in knowledge not to believe in witches: there is no moral advance in not executing them when you do not think they are there. You would not call a man humane for ceasing to set mousetraps if he did so because he believed there were no mice in the house.

What Lies Behind the Law

Let us sum up what we have reached so far. In the case of stones and trees and things of that sort, what we call the Laws of Nature may not be anything except a way of speaking. When you say that nature is governed by certain laws, this may only mean that nature does, in fact, behave in a certain way. The so-called laws may not be anything real — anything above and beyond the actual facts which we observe. But in the case of Man, we saw that this will not do. The Law of Human  Nature, or of Right and Wrong, must be something above and beyond the actual facts of human behaviour. In this case, besides the actual facts, you have something else — a real law, which we did not invent and which we know we ought to obey.

I now want to consider what this tells us about the universe we live in. Ever since men were able to think, they have been wondering what this universe really is and how it came to be there. And, very roughly, two views have been held. First, there is what is called the materialist view. People who take that view think that matter and space just happen to exist, and always have existed, nobody knows why; and that the matter, behaving in certain fixed ways, has just happened, by a sort of fluke, to produce creatures like ourselves who are able to think. By one chance in a thousand something hit our sun and made it produce the planets; and by another thousandth chance the chemicals necessary for life, and the right temperature, occurred on one of these planets, and so some of the matter on this earth came alive; and then, by a very long series of chances, the living creatures developed into things like us. The other view is the religious view. According to it, what is behind the universe is more like a mind than it is like anything else we know. That is to say, it is conscious, and has purposes, and prefers one thing to another. And on this view it made the universe, partly for purposes we do not know, but partly, at any rate, in order to produce creatures like itself — I mean, like itself to the extent of having minds. Please do not think that one of these views was held a long time ago and that the other has gradually taken its place. Wherever there have been thinking men both views turn up. And note this too. You cannot find out which view is the right one by science in the ordinary sense. Science works by experiments. It watches how things behave. Every scientific statement in the long run, however complicated it looks, really means something like, “I pointed the telescope to such and such a part of the sky at 2:20 A.M. on January 15th and saw so-and-so,” or “I put some of this stuff in a pot and heated it to such-and-such a temperature and it did so-and-so.” Do not think I am saying anything against science: I am only saying what its job is. And the more scientific a man is, the more (I believe) he would agree with me that this is the job of science — and a very useful and necessary job it is too. But why anything comes to be there at all, and whether there is anything behind the things science observes — something of a different kind — this is not a scientific question. If there is “Something Behind,” then either it will have to remain altogether unknown to men or make itself known in some different way. The statement that there is any such thing, and the statement that there is no such thing, are neither of them statements that science can make. And real scientists do not usually make them. It is usually the journalists and popular novelists who have picked up a few odds and ends of half-baked science from textbooks who go in for them. After all, it is really a matter of common sense. Supposing science ever became complete so that I knew every single thing in the whole universe. Is it not plain that the questions, “Why is there a universe?” “Why does it go on as it does?” “Has it any meaning?” would remain just as they were?

Now the position would be quite hopeless but for this. There is one thing, and only one, in the whole universe which we know more about than we can learn from external observation. That one thing is Man. We do not merely observe men, we are men. In this ease we have, so to speak, inside information; we are in the know. And because of that, we know that men find themselves under a moral law, which they do not make, and cannot quite forget even when they try, and which they know they ought to obey. Notice the following point. Anyone studying Man from the outside as we study electricity or cabbages, not knowing our language and consequently not able to get any inside knowledge from us, but merely observing what did, would never get the slightest evidence that we have this moral law. How could he? for his observation would only show what we did, and the moral law about what we ought to do. In the same way, if there were anything above or behind the observed facts in the case of stones or the weather, we, by studying them from outside, could never hope to discover it.

The position of the question, then, is like this. We want to know whether the universe simply happens be what it is for no reason or whether there is a power behind it that makes it what it is. Since that power, if it exists would be not one of the observed facts but a reality which makes them, no mere observation of the facts can find it. There is only one case in which we can know whether there is anything more, namely our own case. And in that one case we find there is. Or put it the other way round. If there was a controlling power outside the universe, it could not show itself to us as one of the facts inside the universe — no more than the architect of a house could actually be a wall or staircase or fireplace in that house. The only way in which we could expect it to show itself would be inside ourselves as an influence or a command trying to get us to behave in a certain way. And that is just what we do find inside ourselves. Surely this ought to arouse our suspicions? In the only case where you can expect to get answer, the answer turns out to be Yes; and in the other cases, where you do not get an answer, you see why you do not. Suppose someone asked me, when I see a man in a blue uniform going down the street leaving little paper packets at each house, why I suppose that they contain letters? I should reply, “Because whenever he leaves a similar little packet for me I find it does contain a letter.” And if he then objected, “But you’ve never seen all these letters which you think the other people are getting,” I should say, “Of course not, and I wouldn’t expect to, because they’re not addressed to me. I’m explaining the packets I’m not allowed to open by the ones I am allowed to open.” It is the same about this question. The only packet I am allowed to open is Man. When I do, especially when I open that particular man called Myself, I find that I do not exist on my own, that I am under a law; that somebody or something wants me to behave in a certain way. I do not, of course, think that if I could get inside a stone or a tree I should find exactly the same thing, just as I do not think all the other people in the street get the same letters as I do. I should expect, for instance, to find that the stone had to obey the law of gravity — that whereas the sender of the letters merely tells me to obey the law of my human nature, He compels the stone to obey the laws of its stony nature. But I should expect to find that there was, so to speak, a sender of letters in both cases, a Power behind the facts, a Director, a Guide…

[What] I have got to is a Something which is directing the universe, and which appears in me as a law urging me to do right and making me feel responsible and uncomfortable when I do wrong. I think we have to assume it is more like a mind than it is like anything else we know because after all the only other thing we know is matter and you can hardly imagine a bit of matter giving instructions.