The Silver Chair is one of my favorites among the Narnia series and the chapter titled "The Queen of Underland" is one of the reasons. That queen, using a familiar kind of argument and a dulling enchantment, is trying to convince Eustace Scrubb, Jill Pole, Prince Rilian, and one of my favorites among Lewis's creations, Puddleglum, that their memories of Narnia are all wish fulfillment:
The Witch shook her head. "I see," she said, "that we should do no better with your lion, as you call it, than we did with your sun. You have seen lamps, and so you imagined a bigger and better lamp and called it the sun. You've seen cats, and now you want a bigger and better cat, and it's to be called a lion. Well, 'tis a pretty make-believe, though, to say truth, it would suit you all better if you were younger. And look how you can put nothing into your make-believe without copying it from the real world, this world of mine, which is the only world. But even you children are too old for such play. As for you, my lord Prince, that art a man full grown, fie upon you! Are you not ashamed of such toys? Come, all of you. Put away these childish tricks. I have work for you all in the real world. There is no Narnia, no Overworld, no sky, no sun, no Aslan. And now, to bed all. And let us begin a wiser life tomorrow. But, first, to bed; to sleep; deep sleep, soft pillows, sleep without foolish dreams."
The Prince and the two children were standing with their heads hung down, their cheeks flushed, their eyes half closed; the strength all gone from them; the enchantment almost complete. But Puddleglum, desperately gathering all his strength, walked over to the fire. Then he did a very brave thing. He knew it wouldn't hurt him quite as much as it would hurt a human; for his feet (which were bare) were webbed and hard and cold-blooded like a duck's. But he knew it would hurt him badly enough; and so it did. With his bare foot he stamped on the fire, grinding a large part of it into ashes on the flat hearth. And three things happened at once.
Secondly, the Witch, in a loud, terrible voice, utterly different from all the sweet tones she had been using up till now, called out, "What are you doing? Dare to touch my fire again, mud-filth, and I'll turn the blood to fire inside your veins."
Thirdly, the pain itself made Puddleglum's head for a moment perfectly clear and he knew exactly what he really thought. There is nothing like a good shock of pain for dissolving certain kinds of magic.
"One word, Ma'am," he said, coming back from the fire; limping, because of the pain. "One word. All you've been saying is quite right, I shouldn't wonder. I'm a chap who always liked to know the worst and then put the best face I can on it. So I won't deny any of what you said. But there's one thing more to be said, even so. Suppose we have only dreamed, or made up, all those things—trees and grass and sun and moon and stars and Aslan himse1f. Suppose we have. Then all I can say is that, in that case, the made-up things seem a good deal more important than the real ones. Suppose this black pit of a kingdom of yours is the only world. Well, it strikes me as a pretty poor one. And that's a funny thing, when you come to think it. We're just babies making up a game, if you're right. But four babies playing a game can make a play-world which licks your real world hollow. That's why I'm going to stand by the play-world. I'm on Asian's side even if there isn't any Aslan to lead it. I'm going to live as like a Narnian as I can even if there isn't any Narnia. So, thanking you kindly for our supper, if these two gentlemen and the young lady are ready, we're leaving your court at once and setting out in the dark to spend our lives looking for Overland. Not that our lives will be very long, I should think; but that's small loss if the world's as dull a place as you say."
C.S. Lewis, The Silver Chair, 1953