Here is a striking sentence about Lewis’s lifelong pursuit: “Lewis’s perpetual task both as a defender of Christianity and as an advocate of medieval literature is to call people to delight” (p. 190).
One of his paths to this “perpetual task” was his analysis of the devil’s use of pleasure. Screwtape (speaking for the devil—“Our Father”—in The Screwtape Letters) says to one of his under-devils:
Never forget that when we are dealing with any pleasure in its healthy and satisfying form, we are, in a sense, on the Enemy's ground. I know we have won many a soul through pleasure. All the same, it is His invention, not ours. He made the pleasures: all our research so far has not enabled us to produce one. All we can do is encourage the humans to take the pleasures which our Enemy has produced, at times, or in ways, or in degrees, which he has forbidden.... An ever increasing craving for an ever diminishing pleasure is the formula.... To get a man's soul and give him nothing in return—that's what really gladdens Our Father's heart. (quoted in The Narnian, 189)
This is an astonishing view of pleasure. Hell has never been able to produce one! It can only misuse the ones that God created—in “times,” “ways,” and “degrees” that God forbids.
This means that all the debased enjoyments of the world are echoes of the joys of heaven. The analysis of this is worth a lifetime. And one effect of such an analysis would be to take the notion of “seeker-sensitive” ten miles deeper into Truth. How to penetrate the soul whose every desire is for Heaven while hating Heaven—that is the task.
"To get a man's soul and give him nothing in return." Wow...meditate on that for awhile.