‘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 … 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, 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 civilized 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 principles 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.’ (CS Lewis, Mere Christianity, Chapter 5)