In this chapter, the narrator explains how to use the match-world function. He explains that deaf people can't see the world because they don't have sound, and that a simple smile can be interpreted as encouragement or sarcasm. A narrow-minded person can see a smile as ridicule, and a girl who's trying to lose weight can use the "weight loss mode" to observe the world. He also explains that if everyone in the world can see what's going on around them, they'll be able to see things that aren't there before. For example, if you're a teacher and you want to help your students lose weight, you can switch to the "observation mode" and let them do whatever they want with the world around them. This way, you'll have more control over what your students can see and hear. The narrator also says that if the world changes, it can also change someone else's life. In other words, if a person changes his or her life because of the world, then that person can also be changed by the world changing. This is the duty of the guardians, and the narrator hopes that the guardians will respond to this request and give them permission to change their lives.