Answer:
That there are no rules.
Step-by-step explanation:
This is the only rule that is present in John and Henry's class. We learn that in this class, the only rule is that there are no rules. This paradox is often used in order to talk about an environment where everything is allowed. Such freedom in a classroom can lead to many benefits for children, such as making them more inquisitive, more tolerant of other people's opinions and more confident.