The travelers bound up the stairs, climbing so high that they push through the clouds. They reach the castle and meet the princesses of Sweet Rhyme and Pure Reason, who have apparently been expecting them. Milo stammers an apology about his trip taking so long because of all the mistakes he made, and the princesses assure him that there is nothing wrong with mistakes so long as he learned from them. Learning is important, they explain, but learning how to use the lessons is important too.

The talk of learning is interrupted by the demons below, who tear apart the staircase and send the Castle floating off into space. Since time flies, Tock volunteers to get everyone back to the ground safely. The group piles on his back, and Tock leaps out the window.

Analysis

In this section, the themes of education and everyday appreciation reach their climax as Milo does battle with the demons of ignorance and finally finds Rhyme and Reason. Throughout the preceding sections, Milo has been learning lessons that have contributed to his education and his wisdom. As symbols of his accepting of this knowledge, Milo has received a number of gifts that he will also use to defeat the various demons he encounters. Through a combination of his personal changes and the gifts he has received, Milo is able to find his way through a number of demon encounters.

First, we pick up with the faceless gentleman who predictably turns out to be a demon. After setting Milo, Tock, and the Humbug to work on pointless tasks that would take them nearly 1000 years, he thinks he has gotten the better of the trio. Milo, however, has learned about infinity and about boredom, and so he puts the magic staff he got from the Mathemagician to work to calculate how long his assigned task will take. Once he realizes that it is the worst sort of busywork, he unmasks the demon and beats a hasty retreat. The old would most probably have remained, busily moving the pile of sand forever.

Juster repeats this plot pattern with the Demon of Insincerity, who tricks Milo and his companions into cowering in a pit by convincing them that he is a horrible monster. Fortunately, Milo has learned how to see things because of his interactions in the Forest of Sight, and he has the telescope Alec Bings gave him. Once he looks upon the so-called monster with unclouded vision, Milo sees that there is nothing to be afraid of at all, and the demon is defeated. Remember that Alec Bings saw things from an adult's perspective; Milo's ability to use that perspective to his advantage suggests that he has grown up a little during his travels.

Similarly, Milo defeats the Gelatinous Giant with the words Azaz gave him, because there is nothing a conformist hates more than ideas. Even the seemingly mighty giant is no match for Milo's education and wisdom. Finally, at the base of the steps to the Castle in the Air, Milo escapes the Senses Taker by relying on his sense of humor. The laughter that saves him comes from his perspective, symbolically represented by the box of sounds that the Soundkeeper gave him.