In his classic Mere Christianity, C.S. Lewis covers a myriad of topics related to the Christian faith. In his section on Christian morality, he deals with the subject of chastity. In this essay he responds to pervading cultural beliefs about sexuality, and finishes with a strong message to those who want to overcome temptation.

Lewis published Mere Christianity in 1952 and in this excerpt he refers to the lies about sex we’ve been fed “for the last twenty years.” Lewis has been dead for over 45 years, so we can only surmise what Lewis would say today about the cultural messages about sex:

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Chastity is the most unpopular of the Christian virtues. There is no getting away from it: the old Christian rule is, “Either marriage, with complete faithfulness to your partner, or else total abstinence.” Now this is so difficult and so contrary to our instincts, that obviously either Christianity is wrong or our sexual instinct, as it now is, has gone wrong. One or the other. Of course, being a Christian, I think it is the instinct which has gone wrong.

. . . You can get a large audience together for a strip-tease act—that is, to watch a girl undress on the stage. Now suppose you came to a country where you could fill a theatre by simply bringing a covered plate on to the stage and then slowly lifting the cover so as to let every one see, just before the lights went out, that it contained a mutton chop or a bit of bacon, would you not think that in that country something had gone wrong with the appetite for food? And would not anyone who had grown up in a different world think there was something equally queer about the state of the sex instinct among us?

. . . [Y]ou and I, for the last twenty years, have been fed all day long on good solid lies about sex. We have been told, till one is sick of hearing it, that sexual desire is in the same state as any of our other natural desires and that if only we abandon the silly old Victorian idea of hushing it up, everything in the garden will be lovely. It is not true. The moment you look at the facts, and away from the propaganda, you see that it is not.

They tell you sex has become a mess because it was hushed up. But for the last twenty years it has not been hushed up. It has been chattered about all day long. Yet it is still in a mess. If hushing up had been the cause of the trouble, ventilation would have set it right. But it has not. I think it is the other way round. I think the human race originally hushed it up because it had become such a mess. Modern people are always saying, “Sex is nothing to be ashamed of.” They may mean two things. They may mean “There is nothing to be ashamed of in the fact that the human race reproduces itself in a certain way, nor in the fact that it gives pleasure.” If they mean that, they are right. Christianity says the same. It is not the thing, nor the pleasure, that is the trouble. The old Christian teachers said that if man had never fallen, sexual pleasure, instead of being less than it is now, would actually have been greater. I know some muddle-headed Christians have talked as if Christianity thought that sex, or the body, or pleasure, were bad in themselves. But they were wrong. Christianity is almost the only one of the great religions which thoroughly approves of the body—which believes that matter is good, that God Himself once took on a human body, that some kind of body is going to be given to us even in Heaven and is going to be an essential part of our happiness, our beauty, and our energy. Christianity has glorified marriage more than any other religion: and nearly all the greatest love poetry in the world has been produced by Christians. If anyone says that sex, in itself, is bad, Christianity contradicts him at once. But, of course, when people say, “Sex is nothing to be ashamed of,” they may mean “the state into which the sexual instinct has now got is nothing to be ashamed of.”

If they mean that, I think they are wrong. I think it is everything to be ashamed of. There is nothing to be ashamed of in enjoying your food: there would be everything to be ashamed of if half the world made food the main interest of their lives and spent their time looking at pictures of food and dribbling and smacking their lips. I do not say you and I are individually responsible for the present situation. Our ancestors have handed over to us organisms which are warped in this respect: and we grow up surrounded by propaganda in favour of unchastity. There are people who want to keep our sex instinct inflamed in order to make money out of us. Because, of course, a man with an obsession is a man who has very little sales-resistance. God knows our situation; He will not judge us as if we had no difficulties to overcome. What matters is the sincerity and perseverance of our will to overcome them.

Before we can be cured we must want to be cured. Those who really wish for help will get it; but for many modern people even the wish is difficult. It is easy to think that we want something when we do not really want it. A famous Christian long ago told us that when he was a young man he prayed constantly for chastity; but years later he realised that while his lips had been saying, “Oh Lord, make me chaste,” his heart had been secretly adding, “But please don’t do it just yet.” This may happen in prayers for other virtues too; but there are three reasons why it is now specially difficult for us to desire—let alone to achieve—complete chastity.

In the first place our warped natures, the devils who tempt us, and all the contemporary propaganda for lust, combine to make us feel that the desires we are resisting are so “natural,” so “healthy,” and so reasonable, that it is almost perverse and abnormal to resist them. Poster after poster, film after film, novel after novel, associate the idea of sexual indulgence with the ideas of health, normality, youth, frankness, and good humour. Now this association is a lie. Like all powerful lies, it is based on a truth—the truth, acknowledged above, that sex in itself (apart from the excesses and obsessions that have grown round it) is “normal” and “healthy,” and all the rest of it. The lie consists in the suggestion that any sexual act to which you are tempted at the moment is also healthy and normal. Now this, on any conceivable view, and quite apart from Christianity, must be nonsense. Surrender to all our desires obviously leads to impotence, disease, jealousies, lies, concealment, and everything that is the reverse of health, good humour, and frankness. For any happiness, even in this world, quite a lot of restraint is going to be necessary; so the claim made by every desire, when it is strong, to be healthy and reasonable, counts for nothing. Every sane and civilised man must have some set of principles by which he chooses to reject some of his desires and to permit others. One man does this on Christian principles, another on hygienic principles, another on sociological principles. The real conflict is not between Christianity and “nature,” but between Christian principle and other principles in the control of “nature.” For “nature” (in the sense of natural desire) will have to be controlled anyway, unless you are going to ruin your whole life. The Christian principles are, admittedly, stricter than the others; but then we think you will get help towards obeying them which you will not get towards obeying the others.

In the second place, many people are deterred from seriously attempting Christian chastity because they think (before trying) that it is impossible. But when a thing has to be attempted, one must never think about possibility or impossibility. Faced with an optional question in an examination paper, one considers whether one can do it or not: faced with a compulsory question, one must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. Not only in examinations but in war, in mountain climbing, in learning to skate, or swim, or ride a bicycle, even in fastening a stiff collar with cold fingers, people quite often do what seemed impossible before they did it. It is wonderful what you can do when you have to.

We may, indeed, be sure that perfect chastity—like perfect charity—will not be attained by any merely human efforts. You must ask for God’s help. Even when you have done so, it may seem to you for a long time that no help, or less help than you need, is being given. Never mind. After each failure, ask forgiveness, pick yourself up, and try again. Very often what God first helps us towards is not the virtue itself but just this power of always trying again. For however important chastity (or courage, or truthfulness, or any other virtue) may be, this process trains us in habits of the soul which are more important still. It cures our illusions about ourselves and teaches us to depend on God. We learn, on the one hand, that we cannot trust ourselves even in our best moments, and, on the other, that we need not despair even in our worst, for our failures are forgiven. The only fatal thing is to sit down content with anything less than perfection.

Thirdly, people often misunderstand what psychology teaches about “repressions.” It teaches us that “repressed” sex is dangerous. But “repressed” is here a technical term: it does not mean “suppressed” in the sense of “denied” or “resisted.” A repressed desire or thought is one which has been thrust into the subconscious (usually at a very early age) and can now come before the mind only in a disguised and unrecognisable form. Repressed sexuality does not appear to the patient to be sexuality at all. When an adolescent or an adult is engaged in resisting a conscious desire, he is not dealing with a repression nor is he in the least danger of creating a repression. On the contrary, those who are seriously attempting chastity are more conscious, and soon know a great deal more about their own sexuality than anyone else. They come to know their desires as Wellington knew Napoleon, or as Sherlock Holmes knew Moriarty; as a rat-catcher knows rats or a plumber knows about leaky pipes. Virtue—even attempted virtue—brings light; indulgence brings fog.

Finally, though I have had to speak at some length about sex, I want to make it as clear as I possibly can that the centre of Christian morality is not here. If anyone thinks that Christians regard unchastity as the supreme vice, he is quite wrong. The sins of the flesh are bad, but they are the least bad of all sins. All the worst pleasures are purely spiritual: the pleasure of putting other people in the wrong, of bossing and patronising and spoiling sport, and back-biting; the pleasures of power, of hatred. For there are two things inside me, competing with the human self which I must try to become. They are the Animal self, and the Diabolical self. The Diabolical self is the worse of the two. That is why a cold, self-righteous prig who goes regularly to church may be far nearer to hell than a prostitute. But, of course, it is better to be neither.