The Curious Assumption...

The Screwtape Letters is a Christian apologetics novel written in epistolary style by C.S. Lewis, first published in book form in 1942. The story takes the form of a series of letters from a senior demon, Screwtape, to his nephew, a junior tempter named Wormwood, so as to advise him on methods of securing the damnation of a British man, known only as "the Patient". Here is a helpful quotation from "Screwtape" to his bungling nephew:

"Now you will have noticed that nothing throws him into a passion so easily as to find a tract of time which he reckoned on having at his own disposal unexpectedly taken from him. It is the unexpected visitor (when he looked forward to a quiet evening), or the friend's talkative wife (turning up when he looked forward to a tête-à-tête with the friend), which throw him out of gear. Now he is not yet so uncharitable or slothful that these small demands on his courtesy are in themselves too much for it. They anger him because he regards his time as his own and feels that it is being stolen. You must therefore zealously guard in his own mind the curious assumption "My time is my own." Let him have the feeling that he starts each day as the lawful possessor of twenty-four hours. Let him feel as a grievous tax that portion of his property which he has to make over to his employers, and as a generous donation that further portion which he allows to religious duties. But what he must never be permitted to doubt is that the total from which these deductions have been made was, in some mysterious sense, his own personal birthright.

You have here a delicate task. The assumption which you want him to go on making is so absurd that, if once it is questioned, even we cannot find a shred of argument in its defense. The man can neither make, nor retain, one moment of time; it all comes to him by pure gift; he might as well regard the sun and moon as his chattels. He is also, in theory, committed to a total service of the Enemy [God]; and if the Enemy appeared to him in bodily form and demanded that total service for even one day, he would not refuse. He would be greatly relieved if that one day involved nothing harder than listening to the conversation of a foolish woman; and he would be relieved almost to the pitch of disappointment if for one half-hour in that day the Enemy said, "Now you may go and amuse yourself." Now, if he thinks about his assumption for a moment, even he is bound to realize that he is actually in this situation every day. When I speak of preserving this assumption in his mind, therefore, the last thing I mean you to do is to furnish him with arguments in its defense. There aren't any. Your task is purely negative. Don't let his thoughts come anywhere near it. Wrap a darkness about it, and in the centre of that darkenss let his sense of ownership-in-Time lie silent, uninspected, and operative."
- C.S. Lewis The Screwtape Letters: Letter XXI pg. 96-97