[Of argument in former times:] They still connected thinking with doing and were prepared to alter their way of life as the result of a chain of reasoning. But what with the weekly press and other such weapons we have largely altered that. Your man has been accustomed, ever since he was a boy, to have a dozen incompatible philosophies dancing together inside his head. his doesnt think of doctrines as primarily true, or false, but as academic or practical, outworn, contemporary, conventional., ruthless. Jargon not argument, is your best ally in keeping him from the Church. (Letter I; p.11.)
When two human beings have lived together for many years it usually happens that each has tones of voice and expressions of face which are almost unendurably irritating to the other. Work on that. Bring fully into the consciousness of your patient that particular lift of his mothers eyebrows which he learned to dislike in the nursery and let him know how much he dislikes it. (Letter III; p.22.)
the results of such fanciful hatred are often most disappointing, and of all human the English are in this respect the most deplorable milksops. They are creatures of that miserable sort who loudly proclaim that torture is too good for their enemies and then give tea and cigarettes to the first wounded German pilot who turns up at the back door. (Letter VI; p.36.)
Humans are amphibians - half spirit and half animal [...] As long as he lives on earth periods of emotional and bodily richness and liveliness will alternate with periods of numbness and poverty (Letter VIII; p.44-45; note that this is elaborated as a humane doctrine of the Incarnation, and a censure of extremes incl. celibacy.)
I gather that the middle-aged married couple who called at his office are just the sort of people we want him to know - rich, smart, superficially intellectual, and brightly sceptical about everything in the world. I gather they are even vaguely pacifist, not on moral grounds but from an ingrained habit of belittling anything that concerns the great mass of their fellow men and from a dash of purely fashionable and literary communism. (Letter X; p.53.)
How can you have failed to see that a real pleasure was the last thing you ought to have let him meet? [67 ...] The deepest likings and impulses of any man are the raw material, the starting-point, with which the enemy has furnished him [...] The man who truly and disinterestedly enjoys any one thing in the world, for its own sake, and without caring twopence what other peopel say about it, is by that very fact fore-armed against some of our subltest modes of attack. (Ibid., p.69.)
He would therefore have then continually concerned either with eternity (which means being concerned with Him) or with the Present - either meditating on their eternal union with, or separation from, Himself, or else obeying the present voice of conscience, bearing the present cross, receiving the present grace, giving thanks for the present pleasure. / Our business is to get them away from the eternal, and from the Present. With this in view, we sometimes tempt a human (say a widow or a scholar) to live in the Past. But this is of limited value, for they have some real knowledge of the past and it has a determinate nature and, to that extent, resembles Eternity. Biological necessity makes all their passions point in that direction already, so that thought about the Future inflames hope and fear. Also it is unknown to them, so that in making them think about it we make them think of unrealities. In a word, the Future is, of all things, the thing least like eternity. It is the most completely temporal part of time - for the Past is frozen and no longer flows, and the Present is all lit up with eternal rays. hence the encouragement we have given to all those schemes of thought such as Creative Evolution, Scientific Humanism, or Communism, which fix mens affections on the Future, on the very core of temporality. hence nearly all the vices are rooted in the future. (Letter XV, p.76-7.)
Critique of woman in the All-I-Want state of mind (p.87ff.)
The whole philosophy of Hell rests on the recognition of the axiom that one thing is not another thing, and specially, that one self is not another self. My good is my good and your good is your good. What one gains another loses. Even an inanimate object is what it is by excluding all other objects from the space it occupies; if it expands, it does so by thrusting other objects aside or by absorbing them. A self does the same. With beasts the absorption takes the form of eating; for us, it means the sucking of will and freedom out of a weaker self into a stronger. To be means to be in competition.
Now the Enemys [Gods] philosophy is nothing more nor less than one continued attempt to evade this very obvious truth. He aims at a contradiction. Things are to be many, yet somehow also one. The good of one self is to be the good of another. This impossibility he calls love, and this same monotonous panacea can be detected under all He does and even all He is - or claims to be. Thus He is not content, even Himself, to be a sheer arithmetical unity; [...] (Letter, XVIII, p.92.)
The error is easy to produce because being in love does very often, in Western Europe, precede marriages which are made in obedience to the Enemys designs, that is, with the intention of fidelity, fertility, and good will; just as religious emotion very often, but not always, attends conversion. in other words, the humans are to be encouraged to regard as the basis for marriage a highly-coloured and distorted version of something the Enemy really promises as a result. Two advantages follow. In the first place, humans who have not the gift of continence can be deterred from seeking marriage as a solution because they do not find themselves in love, and, thanks to us, the idea of marrying with any other motive seems to them low and cynical. Yes, they think that. They regard the intention of loyalty to a partnership for mutual help, for the preservation of chastity, and for the transmission of life, as something lower than a storm of emotion [...] love will be held to excuse a man from all guilt, and to protect him from the consequences, of marrying a heathen, a fool, a wanton. (Letter XXVIII; pp.94-95.)
If he is an arrogant man with a contempt for the body really based on delicacy but mistaken by him for purity - and one who takes pleasure in flouting what most of his fellows approve - by all means let him decide against love. Instil into him an overweening asceticism and then, when you have separated his sexuality from all that might humanise it, weigh in on him with it in some much more brutal and cynical form. If, on the other hand, he is an emotion, gullible man, feed him on minor poets and fifth-rate novelists of the old school until you have made him believe that love is both irresistible and somehow intrinsically meritorious. This belief is not much help, I grant you, in producing casual unchastity; but it is an incomparable recipe for prolonged, noble, romantic tragic adulteries, ending, if all goes well, in murders and suicides. (Letter XIX, p.99).
It is the business of these great masters [viz., spirits of the Lowerarchy] to produce in every age a general misdirection of what may be called sexual taste. This they do by working through the small circle of popular artists, dressmakers, actresses and advertisers who determine the fashionable type. The aim is to guide each sex away from those members of the other with whom spiritually helpful, happy, and fertile marriages are most likely. Thus we have now for amny centuries triumped over nature to the extent of making certain secondary characteristics of the male (such as the beard) disagreeable to nearly all females - and there is more in that than you might suppose. Asregards the male taste we hve varied a good deal. At one time we have directed it to the statuesque and aristocratic type of beauty, mixking mens vanity with their desires and encouraging the race to breed chiefly from the most arrogant and prodigal women. At another, we have selected an exaggeratedly deminine type, faint and languishing, so that folly and cowardice, and all the general falseness and littleness of mind which to with them, shall be at a premium. At present we are on the opposite tack. The age of jazz has succeeded the age of the waltz, and we now teach me to like women whose bodies are scarcely distinguishable from those of boys. Since this is a kind of beauty even more transitory than most, we those aggrevate the females chronic horror of growing old (with many excellent results) and render her less willing and less able to bear children. [Further on nudes, deemed to be frank and healthy but in reality unnatural] [...] As a result we are more and more directing the desirtes of men to something which does not exist - making the role of the eye in sexuality more and more important and at the same time making its demands more and more impossible. What follows you can easily forecast! (Letter XX; p.103.)
Note that Screwtape changes into a centipede in the heat of the argument, and continues to dictate through Toadpipe when the patient gets to know a properly Christian girl (Letter XXII, ff.)
In Letter XXIII the devil notes the utility of the humanist reading of the Historical Jesus as a great man. Likewise, Unselfishness is the devils tool since it establishes a sense of self-importance and indebtedness.
Hatred has its pleasures. It is therefore often the compensation by which a frightened man reimburses himself for the miseries of Fear. The more he fears, the more he will hate. (Letter XXIX, p.147.)
[I]n fact, in the last war, thousands of human beings, by discovering their own cowardice, discovered the whole moral world for the first time. (p.148.)
Pilate was merciful until it became risky (p.149.)
The act of cowardice is all that matters; the emotion of fear is, in itself, no sin (p.150). Note that Lewis finds the use of the word chastity compatible with the idea of marriage and fidelity [vide Letter XXVIII, supra].